gecko-dev/content/base/src/nsContentUtils.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=2 sw=2 et tw=78:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Johnny Stenback <jst@netscape.com>
 *   Christopher A. Aillon <christopher@aillon.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/* A namespace class for static layout utilities. */

#include "nsJSUtils.h"
#include "nsCOMPtr.h"
#include "nsAString.h"
#include "nsPrintfCString.h"
#include "nsUnicharUtils.h"
#include "nsIPrefService.h"
#include "nsIPrefBranch.h"
#include "nsIPrefLocalizedString.h"
#include "nsServiceManagerUtils.h"
#include "nsIScriptGlobalObject.h"
#include "nsIScriptContext.h"
#include "nsIDOMScriptObjectFactory.h"
#include "nsDOMCID.h"
#include "nsContentUtils.h"
#include "nsIXPConnect.h"
#include "nsIContent.h"
#include "nsIDocument.h"
#include "nsINodeInfo.h"
#include "nsReadableUtils.h"
#include "nsIDOMDocument.h"
#include "nsIDOMNodeList.h"
#include "nsIDOMNode.h"
#include "nsIDOM3Node.h"
#include "nsIIOService.h"
#include "nsIURI.h"
#include "nsNetCID.h"
#include "nsNetUtil.h"
#include "nsIScriptSecurityManager.h"
#include "nsDOMError.h"
#include "nsPIDOMWindow.h"
#include "nsIJSContextStack.h"
#include "nsIDocShell.h"
#include "nsIDocShellTreeItem.h"
#include "nsParserCIID.h"
#include "nsIParser.h"
#include "nsIFragmentContentSink.h"
#include "nsIContentSink.h"
#include "nsHTMLParts.h"
#include "nsIParserService.h"
#include "nsIServiceManager.h"
#include "nsIAttribute.h"
#include "nsContentList.h"
#include "nsIHTMLDocument.h"
#include "nsIDOMHTMLDocument.h"
#include "nsIDOMHTMLCollection.h"
#include "nsIDOMHTMLFormElement.h"
#include "nsIForm.h"
#include "nsIFormControl.h"
#include "nsHTMLAtoms.h"
#include "nsISupportsPrimitives.h"
#include "nsLayoutAtoms.h"
#include "imgIDecoderObserver.h"
#include "imgIRequest.h"
#include "imgIContainer.h"
#include "imgILoader.h"
#include "nsIImage.h"
#include "gfxIImageFrame.h"
#include "nsIImageLoadingContent.h"
#include "nsIInterfaceRequestor.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsILink.h"
#include "nsILoadGroup.h"
#include "nsContentPolicyUtils.h"
#include "nsDOMString.h"
#include "nsNodeInfoManager.h"
#include "nsCRT.h"
#include "nsIDOMEvent.h"
#include "nsIDOMEventTarget.h"
#include "nsIDOMEventReceiver.h"
#include "nsIPrivateDOMEvent.h"
#include "nsIDOMDocumentEvent.h"
#ifdef MOZ_XTF
#include "nsIXTFService.h"
static NS_DEFINE_CID(kXTFServiceCID, NS_XTFSERVICE_CID);
#endif
#include "nsIMIMEService.h"
#include "nsLWBrkCIID.h"
#include "nsILineBreaker.h"
#include "nsIWordBreaker.h"
#include "jsdbgapi.h"
#include "nsIJSRuntimeService.h"
#include "nsIDOMDocumentXBL.h"
#include "nsIBindingManager.h"
#include "nsIURI.h"
#include "nsIURL.h"
#include "nsXBLBinding.h"
#include "nsXBLPrototypeBinding.h"
#include "nsEscape.h"
#include "nsICharsetConverterManager.h"
#include "nsXULAtoms.h"
#include "nsIEventListenerManager.h"
#include "nsAttrName.h"
#include "nsIDOMUserDataHandler.h"

// for ReportToConsole
#include "nsIStringBundle.h"
#include "nsIScriptError.h"
#include "nsIConsoleService.h"

static const char kJSStackContractID[] = "@mozilla.org/js/xpc/ContextStack;1";
static NS_DEFINE_CID(kParserServiceCID, NS_PARSERSERVICE_CID);
static NS_DEFINE_CID(kCParserCID, NS_PARSER_CID);

nsIDOMScriptObjectFactory *nsContentUtils::sDOMScriptObjectFactory = nsnull;
nsIXPConnect *nsContentUtils::sXPConnect;
nsIScriptSecurityManager *nsContentUtils::sSecurityManager;
nsIThreadJSContextStack *nsContentUtils::sThreadJSContextStack;
nsIParserService *nsContentUtils::sParserService = nsnull;
nsINameSpaceManager *nsContentUtils::sNameSpaceManager;
nsIIOService *nsContentUtils::sIOService;
#ifdef MOZ_XTF
nsIXTFService *nsContentUtils::sXTFService = nsnull;
#endif
nsIPrefBranch *nsContentUtils::sPrefBranch = nsnull;
nsIPref *nsContentUtils::sPref = nsnull;
imgILoader *nsContentUtils::sImgLoader;
nsIConsoleService *nsContentUtils::sConsoleService;
nsIStringBundleService *nsContentUtils::sStringBundleService;
nsIStringBundle *nsContentUtils::sStringBundles[PropertiesFile_COUNT];
nsIContentPolicy *nsContentUtils::sContentPolicyService;
PRBool nsContentUtils::sTriedToGetContentPolicy = PR_FALSE;
nsILineBreaker *nsContentUtils::sLineBreaker;
nsIWordBreaker *nsContentUtils::sWordBreaker;
nsVoidArray *nsContentUtils::sPtrsToPtrsToRelease;
nsIJSRuntimeService *nsContentUtils::sJSRuntimeService;
JSRuntime *nsContentUtils::sScriptRuntime;
PRInt32 nsContentUtils::sScriptRootCount = 0;


PRBool nsContentUtils::sInitialized = PR_FALSE;

static PLDHashTable sRangeListsHash;
static PLDHashTable sEventListenerManagersHash;

class RangeListMapEntry : public PLDHashEntryHdr
{
public:
  RangeListMapEntry(const void *aKey)
    : mKey(aKey), mRangeList(nsnull)
  {
  }

  ~RangeListMapEntry()
  {
    delete mRangeList;
  }

private:
  const void *mKey; // must be first to look like PLDHashEntryStub

public:
  // We want mRangeList to be an nsAutoVoidArray but we can't make an
  // nsAutoVoidArray a direct member of RangeListMapEntry since it
  // will be moved around in memory, and nsAutoVoidArray can't deal
  // with that.
  nsVoidArray *mRangeList;
};

class EventListenerManagerMapEntry : public PLDHashEntryHdr
{
public:
  EventListenerManagerMapEntry(const void *aKey)
    : mKey(aKey)
  {
  }

  ~EventListenerManagerMapEntry()
  {
    NS_ASSERTION(!mListenerManager, "caller must release and disconnect ELM");
  }

private:
  const void *mKey; // must be first, to look like PLDHashEntryStub

public:
  nsCOMPtr<nsIEventListenerManager> mListenerManager;
};

PR_STATIC_CALLBACK(PRBool)
RangeListHashInitEntry(PLDHashTable *table, PLDHashEntryHdr *entry,
                       const void *key)
{
  // Initialize the entry with placement new
  new (entry) RangeListMapEntry(key);
  return PR_TRUE;
}

PR_STATIC_CALLBACK(void)
RangeListHashClearEntry(PLDHashTable *table, PLDHashEntryHdr *entry)
{
  RangeListMapEntry *r = NS_STATIC_CAST(RangeListMapEntry *, entry);

  // Let the RangeListMapEntry clean itself up...
  r->~RangeListMapEntry();
}

PR_STATIC_CALLBACK(PRBool)
EventListenerManagerHashInitEntry(PLDHashTable *table, PLDHashEntryHdr *entry,
                                  const void *key)
{
  // Initialize the entry with placement new
  new (entry) EventListenerManagerMapEntry(key);
  return PR_TRUE;
}

PR_STATIC_CALLBACK(void)
EventListenerManagerHashClearEntry(PLDHashTable *table, PLDHashEntryHdr *entry)
{
  EventListenerManagerMapEntry *lm =
    NS_STATIC_CAST(EventListenerManagerMapEntry *, entry);

  // Let the EventListenerManagerMapEntry clean itself up...
  lm->~EventListenerManagerMapEntry();
}

PR_STATIC_CALLBACK(void)
NopClearEntry(PLDHashTable *table, PLDHashEntryHdr *entry)
{
  // Do nothing
}

// static
nsresult
nsContentUtils::Init()
{
  if (sInitialized) {
    NS_WARNING("Init() called twice");

    return NS_OK;
  }

  nsresult rv = CallGetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID,
                               &sSecurityManager);
  NS_ENSURE_SUCCESS(rv, rv);

  // It's ok to not have a pref service.
  CallGetService(NS_PREFSERVICE_CONTRACTID, &sPrefBranch);

  // It's ok to not have prefs too.
  CallGetService(NS_PREF_CONTRACTID, &sPref);

  rv = NS_GetNameSpaceManager(&sNameSpaceManager);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = CallGetService(nsIXPConnect::GetCID(), &sXPConnect);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = CallGetService(kJSStackContractID, &sThreadJSContextStack);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = CallGetService(NS_IOSERVICE_CONTRACTID, &sIOService);
  if (NS_FAILED(rv)) {
    // This makes life easier, but we can live without it.

    sIOService = nsnull;
  }

  rv = CallGetService(NS_LBRK_CONTRACTID, &sLineBreaker);
  NS_ENSURE_SUCCESS(rv, rv);
  
  rv = CallGetService(NS_WBRK_CONTRACTID, &sWordBreaker);
  NS_ENSURE_SUCCESS(rv, rv);

  // Ignore failure and just don't load images
  rv = CallGetService("@mozilla.org/image/loader;1", &sImgLoader);
  if (NS_FAILED(rv)) {
    // no image loading for us.  Oh, well.
    sImgLoader = nsnull;
  }

  sPtrsToPtrsToRelease = new nsVoidArray();
  if (!sPtrsToPtrsToRelease) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  if (!sRangeListsHash.ops) {
    static PLDHashTableOps hash_table_ops =
    {
      PL_DHashAllocTable,
      PL_DHashFreeTable,
      PL_DHashGetKeyStub,
      PL_DHashVoidPtrKeyStub,
      PL_DHashMatchEntryStub,
      PL_DHashMoveEntryStub,
      RangeListHashClearEntry,
      PL_DHashFinalizeStub,
      RangeListHashInitEntry
    };

    if (!PL_DHashTableInit(&sRangeListsHash, &hash_table_ops, nsnull,
                           sizeof(RangeListMapEntry), 16)) {
      sRangeListsHash.ops = nsnull;

      return NS_ERROR_OUT_OF_MEMORY;
    }
  }

  if (!sEventListenerManagersHash.ops) {
    static PLDHashTableOps hash_table_ops =
    {
      PL_DHashAllocTable,
      PL_DHashFreeTable,
      PL_DHashGetKeyStub,
      PL_DHashVoidPtrKeyStub,
      PL_DHashMatchEntryStub,
      PL_DHashMoveEntryStub,
      EventListenerManagerHashClearEntry,
      PL_DHashFinalizeStub,
      EventListenerManagerHashInitEntry
    };

    if (!PL_DHashTableInit(&sEventListenerManagersHash, &hash_table_ops,
                           nsnull, sizeof(EventListenerManagerMapEntry), 16)) {
      sEventListenerManagersHash.ops = nsnull;

      PL_DHashTableFinish(&sRangeListsHash);
      sRangeListsHash.ops = nsnull;

      return NS_ERROR_OUT_OF_MEMORY;
    }
  }

  sInitialized = PR_TRUE;

  return NS_OK;
}

/**
 * Access a cached parser service. Don't addref. We need only one
 * reference to it and this class has that one.
 */
/* static */
nsIParserService*
nsContentUtils::GetParserService()
{
  // XXX: This isn't accessed from several threads, is it?
  if (!sParserService) {
    // Lock, recheck sCachedParserService and aquire if this should be
    // safe for multiple threads.
    nsresult rv = CallGetService(kParserServiceCID, &sParserService);
    if (NS_FAILED(rv)) {
      sParserService = nsnull;
    }
  }

  return sParserService;
}

#ifdef MOZ_XTF
nsIXTFService*
nsContentUtils::GetXTFService()
{
  if (!sXTFService) {
    nsresult rv = CallGetService(kXTFServiceCID, &sXTFService);
    if (NS_FAILED(rv)) {
      sXTFService = nsnull;
    }
  }

  return sXTFService;
}
#endif

template <class OutputIterator>
struct NormalizeNewlinesCharTraits {
  public:
    typedef typename OutputIterator::value_type value_type;

  public:
    NormalizeNewlinesCharTraits(OutputIterator& aIterator) : mIterator(aIterator) { }
    void writechar(typename OutputIterator::value_type aChar) {
      *mIterator++ = aChar;
    }

  private:
    OutputIterator mIterator;
};

#ifdef HAVE_CPP_PARTIAL_SPECIALIZATION

template <class CharT>
struct NormalizeNewlinesCharTraits<CharT*> {
  public:
    typedef CharT value_type;

  public:
    NormalizeNewlinesCharTraits(CharT* aCharPtr) : mCharPtr(aCharPtr) { }
    void writechar(CharT aChar) {
      *mCharPtr++ = aChar;
    }

  private:
    CharT* mCharPtr;
};

#else

NS_SPECIALIZE_TEMPLATE
struct NormalizeNewlinesCharTraits<char*> {
  public:
    typedef char value_type;

  public:
    NormalizeNewlinesCharTraits(char* aCharPtr) : mCharPtr(aCharPtr) { }
    void writechar(char aChar) {
      *mCharPtr++ = aChar;
    }

  private:
    char* mCharPtr;
};

NS_SPECIALIZE_TEMPLATE
struct NormalizeNewlinesCharTraits<PRUnichar*> {
  public:
    typedef PRUnichar value_type;

  public:
    NormalizeNewlinesCharTraits(PRUnichar* aCharPtr) : mCharPtr(aCharPtr) { }
    void writechar(PRUnichar aChar) {
      *mCharPtr++ = aChar;
    }

  private:
    PRUnichar* mCharPtr;
};

#endif

template <class OutputIterator>
class CopyNormalizeNewlines
{
  public:
    typedef typename OutputIterator::value_type value_type;

  public:
    CopyNormalizeNewlines(OutputIterator* aDestination,
                          PRBool aLastCharCR=PR_FALSE) :
      mLastCharCR(aLastCharCR),
      mDestination(aDestination),
      mWritten(0)
    { }

    PRUint32 GetCharsWritten() {
      return mWritten;
    }

    PRBool IsLastCharCR() {
      return mLastCharCR;
    }

    PRUint32 write(const typename OutputIterator::value_type* aSource, PRUint32 aSourceLength) {

      const typename OutputIterator::value_type* done_writing = aSource + aSourceLength;

      // If the last source buffer ended with a CR...
      if (mLastCharCR) {
        // ..and if the next one is a LF, then skip it since
        // we've already written out a newline
        if (aSourceLength && (*aSource == value_type('\n'))) {
          ++aSource;
        }
        mLastCharCR = PR_FALSE;
      }

      PRUint32 num_written = 0;
      while ( aSource < done_writing ) {
        if (*aSource == value_type('\r')) {
          mDestination->writechar('\n');
          ++aSource;
          // If we've reached the end of the buffer, record
          // that we wrote out a CR
          if (aSource == done_writing) {
            mLastCharCR = PR_TRUE;
          }
          // If the next character is a LF, skip it
          else if (*aSource == value_type('\n')) {
            ++aSource;
          }
        }
        else {
          mDestination->writechar(*aSource++);
        }
        ++num_written;
      }

      mWritten += num_written;
      return aSourceLength;
    }

  private:
    PRBool mLastCharCR;
    OutputIterator* mDestination;
    PRUint32 mWritten;
};

// static
PRUint32
nsContentUtils::CopyNewlineNormalizedUnicodeTo(const nsAString& aSource,
                                               PRUint32 aSrcOffset,
                                               PRUnichar* aDest,
                                               PRUint32 aLength,
                                               PRBool& aLastCharCR)
{
  typedef NormalizeNewlinesCharTraits<PRUnichar*> sink_traits;

  sink_traits dest_traits(aDest);
  CopyNormalizeNewlines<sink_traits> normalizer(&dest_traits,aLastCharCR);
  nsReadingIterator<PRUnichar> fromBegin, fromEnd;
  copy_string(aSource.BeginReading(fromBegin).advance( PRInt32(aSrcOffset) ),
              aSource.BeginReading(fromEnd).advance( PRInt32(aSrcOffset+aLength) ),
              normalizer);
  aLastCharCR = normalizer.IsLastCharCR();
  return normalizer.GetCharsWritten();
}

// static
PRUint32
nsContentUtils::CopyNewlineNormalizedUnicodeTo(nsReadingIterator<PRUnichar>& aSrcStart, const nsReadingIterator<PRUnichar>& aSrcEnd, nsAString& aDest)
{
  typedef nsWritingIterator<PRUnichar> WritingIterator;
  typedef NormalizeNewlinesCharTraits<WritingIterator> sink_traits;

  WritingIterator iter;
  aDest.BeginWriting(iter);
  sink_traits dest_traits(iter);
  CopyNormalizeNewlines<sink_traits> normalizer(&dest_traits);
  copy_string(aSrcStart, aSrcEnd, normalizer);
  return normalizer.GetCharsWritten();
}

// static
void
nsContentUtils::Shutdown()
{
  sInitialized = PR_FALSE;

  NS_IF_RELEASE(sContentPolicyService);
  sTriedToGetContentPolicy = PR_FALSE;
  PRInt32 i;
  for (i = 0; i < PRInt32(PropertiesFile_COUNT); ++i)
    NS_IF_RELEASE(sStringBundles[i]);
  NS_IF_RELEASE(sStringBundleService);
  NS_IF_RELEASE(sConsoleService);
  NS_IF_RELEASE(sDOMScriptObjectFactory);
  NS_IF_RELEASE(sXPConnect);
  NS_IF_RELEASE(sSecurityManager);
  NS_IF_RELEASE(sThreadJSContextStack);
  NS_IF_RELEASE(sNameSpaceManager);
  NS_IF_RELEASE(sParserService);
  NS_IF_RELEASE(sIOService);
  NS_IF_RELEASE(sLineBreaker);
  NS_IF_RELEASE(sWordBreaker);
#ifdef MOZ_XTF
  NS_IF_RELEASE(sXTFService);
#endif
  NS_IF_RELEASE(sImgLoader);
  NS_IF_RELEASE(sPrefBranch);
  NS_IF_RELEASE(sPref);
  if (sPtrsToPtrsToRelease) {
    for (i = 0; i < sPtrsToPtrsToRelease->Count(); ++i) {
      nsISupports** ptrToPtr =
        NS_STATIC_CAST(nsISupports**, sPtrsToPtrsToRelease->ElementAt(i));
      NS_RELEASE(*ptrToPtr);
    }
    delete sPtrsToPtrsToRelease;
    sPtrsToPtrsToRelease = nsnull;
  }

  if (sRangeListsHash.ops) {
    NS_ASSERTION(sRangeListsHash.entryCount == 0,
                 "Range list hash not empty at shutdown!");

    // We're already being shut down and if there are entries left in
    // this hash at this point it means we leaked nsGenericElements or
    // nsGenericDOMDataNodes. Since we're already partly through the
    // shutdown process it's too late to release what's held on to by
    // this hash (since the teardown code relies on some things being
    // around that aren't around any more) so we rather leak what's
    // already leaked in stead of crashing trying to release what
    // should've been released much earlier on.

    // Copy the ops out of the hash table
    PLDHashTableOps hash_table_ops = *sRangeListsHash.ops;

    // Set the clearEntry hook to be a nop
    hash_table_ops.clearEntry = NopClearEntry;

    // Set the ops in the hash table to be the new ops
    sRangeListsHash.ops = &hash_table_ops;

    PL_DHashTableFinish(&sRangeListsHash);

    sRangeListsHash.ops = nsnull;
  }

  if (sEventListenerManagersHash.ops) {
    NS_ASSERTION(sEventListenerManagersHash.entryCount == 0,
                 "Event listener manager hash not empty at shutdown!");

    // See comment above.

    // However, we have to handle this table differently.  If it still
    // has entries, we want to leak it too, so that we can keep it alive
    // in case any elements are destroyed.  Because if they are, we need
    // their event listener managers to be destroyed too, or otherwise
    // it could leave dangling references in DOMClassInfo's preserved
    // wrapper table.

    if (sEventListenerManagersHash.entryCount == 0) {
      PL_DHashTableFinish(&sEventListenerManagersHash);
    }
  }
}

// static
nsISupports *
nsContentUtils::GetClassInfoInstance(nsDOMClassInfoID aID)
{
  if (!sDOMScriptObjectFactory) {
    static NS_DEFINE_CID(kDOMScriptObjectFactoryCID,
                         NS_DOM_SCRIPT_OBJECT_FACTORY_CID);

    CallGetService(kDOMScriptObjectFactoryCID, &sDOMScriptObjectFactory);

    if (!sDOMScriptObjectFactory) {
      return nsnull;
    }
  }

  return sDOMScriptObjectFactory->GetClassInfoInstance(aID);
}

/**
 * Checks whether two nodes come from the same origin. aTrustedNode is
 * considered 'safe' in that a user can operate on it and that it isn't
 * a js-object that implements nsIDOMNode.
 * Never call this function with the first node provided by script, it
 * must always be known to be a 'real' node!
 */
// static
nsresult
nsContentUtils::CheckSameOrigin(nsIDOMNode *aTrustedNode,
                                nsIDOMNode *aUnTrustedNode)
{
  NS_PRECONDITION(aTrustedNode, "There must be a trusted node");

  PRBool isSystem = PR_FALSE;
  sSecurityManager->SubjectPrincipalIsSystem(&isSystem);
  if (isSystem) {
    // we're running as system, grant access to the node.

    return NS_OK;
  }

  /*
   * Get hold of each node's principal
   */
  nsCOMPtr<nsINode> trustedNode = do_QueryInterface(aTrustedNode);
  nsCOMPtr<nsINode> unTrustedNode = do_QueryInterface(aUnTrustedNode);

  // Make sure these are both real nodes
  NS_ENSURE_TRUE(trustedNode && unTrustedNode, NS_ERROR_UNEXPECTED);

  nsIPrincipal* trustedPrincipal = trustedNode->NodePrincipal();
  nsIPrincipal* unTrustedPrincipal = unTrustedNode->NodePrincipal();

  if (trustedPrincipal == unTrustedPrincipal) {
    return NS_OK;
  }

  return sSecurityManager->CheckSameOriginPrincipal(trustedPrincipal,
                                                    unTrustedPrincipal);
}

// static
PRBool
nsContentUtils::CanCallerAccess(nsIDOMNode *aNode)
{
  // XXXbz why not check the IsCapabilityEnabled thing up front, and not bother
  // with the system principal games?  But really, there should be a simpler
  // API here, dammit.
  nsCOMPtr<nsIPrincipal> subjectPrincipal;
  sSecurityManager->GetSubjectPrincipal(getter_AddRefs(subjectPrincipal));

  if (!subjectPrincipal) {
    // we're running as system, grant access to the node.

    return PR_TRUE;
  }

  nsCOMPtr<nsIPrincipal> systemPrincipal;
  sSecurityManager->GetSystemPrincipal(getter_AddRefs(systemPrincipal));

  if (subjectPrincipal == systemPrincipal) {
    // we're running as system, grant access to the node.

    return PR_TRUE;
  }

  nsCOMPtr<nsINode> node = do_QueryInterface(aNode);
  NS_ENSURE_TRUE(node, PR_FALSE);

  nsresult rv = sSecurityManager->
    CheckSameOriginPrincipal(subjectPrincipal, node->NodePrincipal());
  if (NS_SUCCEEDED(rv)) {
    return PR_TRUE;
  }

  // see if the caller has otherwise been given the ability to touch
  // input args to DOM methods

  PRBool enabled = PR_FALSE;
  rv = sSecurityManager->IsCapabilityEnabled("UniversalBrowserRead",
                                             &enabled);
  NS_ENSURE_SUCCESS(rv, PR_FALSE);
  return enabled;
}

//static
PRBool
nsContentUtils::InProlog(nsINode *aNode)
{
  NS_PRECONDITION(aNode, "missing node to nsContentUtils::InProlog");

  nsINode* parent = aNode->GetNodeParent();
  if (!parent || !parent->IsNodeOfType(nsINode::eDOCUMENT)) {
    return PR_FALSE;
  }

  nsIDocument* doc = NS_STATIC_CAST(nsIDocument*, parent);
  nsIContent* root = doc->GetRootContent();

  return !root || doc->IndexOf(aNode) < doc->IndexOf(root);
}

// static
nsresult
nsContentUtils::doReparentContentWrapper(nsIContent *aNode,
                                         JSContext *cx,
                                         JSObject *aOldGlobal,
                                         JSObject *aNewGlobal)
{
  nsCOMPtr<nsIXPConnectJSObjectHolder> old_wrapper;

  nsresult rv;

  rv = sXPConnect->ReparentWrappedNativeIfFound(cx, aOldGlobal, aNewGlobal,
                                                aNode,
                                                getter_AddRefs(old_wrapper));
  NS_ENSURE_SUCCESS(rv, rv);

  // Whether or not aChild is already wrapped we must iterate through
  // its descendants since there's no guarantee that a descendant isn't
  // wrapped even if this child is not wrapped. That used to be true
  // when every DOM node's JSObject was parented at the DOM node's
  // parent's JSObject, but that's no longer the case.

  PRUint32 i, count = aNode->GetChildCount();

  for (i = 0; i < count; i++) {
    nsIContent *child = aNode->GetChildAt(i);
    NS_ENSURE_TRUE(child, NS_ERROR_UNEXPECTED);

    rv = doReparentContentWrapper(child, cx, aOldGlobal, aNewGlobal);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return rv;
}

static JSContext *
GetContextFromDocument(nsIDocument *aDocument, JSObject** aGlobalObject)
{
  nsIScriptGlobalObject *sgo = aDocument->GetScopeObject();
  if (!sgo) {
    // No script global, no context.

    *aGlobalObject = nsnull;

    return nsnull;
  }

  *aGlobalObject = sgo->GetGlobalJSObject();

  nsIScriptContext *scx = sgo->GetContext();
  if (!scx) {
    // No context left in the old scope...

    return nsnull;
  }

  return (JSContext *)scx->GetNativeContext();
}

// static
nsresult
nsContentUtils::ReparentContentWrapper(nsIContent *aContent,
                                       nsIContent *aNewParent,
                                       nsIDocument *aNewDocument,
                                       nsIDocument *aOldDocument)
{
  if (!aNewDocument || aNewDocument == aOldDocument) {
    return NS_OK;
  }

  nsIScriptGlobalObject *newSGO = aNewDocument->GetScopeObject();
  JSObject *newScope;

  // If we can't find our old document we don't know what our old
  // scope was so there's no way to find the old wrapper, and if there
  // is no new scope there's no reason to reparent.
  if (!aOldDocument || !newSGO || !(newScope = newSGO->GetGlobalJSObject())) {
    return NS_OK;
  }

  NS_ENSURE_TRUE(sXPConnect, NS_ERROR_NOT_INITIALIZED);

  // Make sure to get our hands on the right scope object, since
  // GetWrappedNativeOfNativeObject doesn't call PreCreate and hence won't get
  // the right scope if we pass in something bogus.  The right scope lives on
  // the script global of the old document.
  // XXXbz note that if GetWrappedNativeOfNativeObject did call PreCreate it
  // would get the wrong scope (that of the _new_ document), so we should be
  // glad it doesn't!
  JSObject *globalObj;
  JSContext *cx = GetContextFromDocument(aOldDocument, &globalObj);

  if (!globalObj) {
    // No global object around; can't find the old wrapper w/o the old
    // global object

    return NS_OK;
  }

  if (!cx) {
    JSObject *dummy;
    cx = GetContextFromDocument(aNewDocument, &dummy);

    if (!cx) {
      // No context reachable from the old or new document, use the
      // calling context, or the safe context if no caller can be
      // found.

      sThreadJSContextStack->Peek(&cx);

      if (!cx) {
        sThreadJSContextStack->GetSafeJSContext(&cx);

        if (!cx) {
          // No safe context reachable, bail.
          NS_WARNING("No context reachable in ReparentContentWrapper()!");

          return NS_ERROR_NOT_AVAILABLE;
        }
      }
    }
  }

  return doReparentContentWrapper(aContent, cx, globalObj, newScope);
}

nsresult
nsContentUtils::ReparentContentWrappersInScope(nsIScriptGlobalObject *aOldScope,
                                               nsIScriptGlobalObject *aNewScope)
{
  JSContext *cx = nsnull;

  // Try really hard to find a context to work on.
  nsIScriptContext *context = aOldScope->GetContext();
  if (context) {
    cx = NS_STATIC_CAST(JSContext *, context->GetNativeContext());
  }

  if (!cx) {
    context = aNewScope->GetContext();
    if (context) {
      cx = NS_STATIC_CAST(JSContext *, context->GetNativeContext());
    }

    if (!cx) {
      sThreadJSContextStack->Peek(&cx);

      if (!cx) {
        sThreadJSContextStack->GetSafeJSContext(&cx);

        if (!cx) {
          // Wow, this is really bad!
          NS_WARNING("No context reachable in ReparentContentWrappers()!");

          return NS_ERROR_NOT_AVAILABLE;
        }
      }
    }
  }

  // Now that we have a context, let's get the global objects from the two
  // scopes and ask XPConnect to do the rest of the work.

  JSObject *oldScopeObj = aOldScope->GetGlobalJSObject();
  JSObject *newScopeObj = aNewScope->GetGlobalJSObject();

  if (!newScopeObj || !oldScopeObj) {
    // We can't really do anything without the JSObjects.

    return NS_ERROR_NOT_AVAILABLE;
  }

  return sXPConnect->ReparentScopeAwareWrappers(cx, oldScopeObj, newScopeObj);
}

nsIDocShell *
nsContentUtils::GetDocShellFromCaller()
{
  JSContext *cx = nsnull;
  sThreadJSContextStack->Peek(&cx);

  if (cx) {
    nsIScriptGlobalObject *sgo = nsJSUtils::GetDynamicScriptGlobal(cx);
    nsCOMPtr<nsPIDOMWindow> win(do_QueryInterface(sgo));

    if (win) {
      return win->GetDocShell();
    }
  }

  return nsnull;
}

nsIDOMDocument *
nsContentUtils::GetDocumentFromCaller()
{
  JSContext *cx = nsnull;
  sThreadJSContextStack->Peek(&cx);

  nsIDOMDocument *doc = nsnull;

  if (cx) {
    JSObject *callee = nsnull;
    JSStackFrame *fp = nsnull;
    while (!callee && (fp = ::JS_FrameIterator(cx, &fp))) {
      callee = ::JS_GetFrameCalleeObject(cx, fp);
    }

    nsCOMPtr<nsPIDOMWindow> win =
      do_QueryInterface(nsJSUtils::GetStaticScriptGlobal(cx, callee));
    if (win) {
      doc = win->GetExtantDocument();
    }
  }

  return doc;
}

nsIDOMDocument *
nsContentUtils::GetDocumentFromContext()
{
  JSContext *cx = nsnull;
  sThreadJSContextStack->Peek(&cx);

  if (cx) {
    nsIScriptGlobalObject *sgo = nsJSUtils::GetDynamicScriptGlobal(cx);

    if (sgo) {
      nsCOMPtr<nsPIDOMWindow> pwin = do_QueryInterface(sgo);
      if (pwin) {
        return pwin->GetExtantDocument();
      }
    }
  }

  return nsnull;
}

PRBool
nsContentUtils::IsCallerChrome()
{
  PRBool is_caller_chrome = PR_FALSE;
  nsresult rv = sSecurityManager->SubjectPrincipalIsSystem(&is_caller_chrome);
  if (NS_FAILED(rv)) {
    return PR_FALSE;
  }

  return is_caller_chrome;
}

static PRBool IsCallerTrustedForCapability(const char* aCapability)
{
  // The secman really should handle UniversalXPConnect case, since that
  // should include UniversalBrowserRead... doesn't right now, though.
  PRBool hasCap;
  nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
  if (NS_FAILED(ssm->IsCapabilityEnabled(aCapability, &hasCap)))
    return PR_FALSE;
  if (hasCap)
    return PR_TRUE;
    
  if (NS_FAILED(ssm->IsCapabilityEnabled("UniversalXPConnect", &hasCap)))
    return PR_FALSE;
  return hasCap;
}

PRBool
nsContentUtils::IsCallerTrustedForRead()
{
  return IsCallerTrustedForCapability("UniversalBrowserRead");
}

PRBool
nsContentUtils::IsCallerTrustedForWrite()
{
  return IsCallerTrustedForCapability("UniversalBrowserWrite");
}

// static
PRBool
nsContentUtils::InSameDoc(nsIDOMNode* aNode, nsIDOMNode* aOther)
{
  if (!aNode || !aOther) {
    return PR_FALSE;
  }

  nsCOMPtr<nsIContent> content(do_QueryInterface(aNode));
  nsCOMPtr<nsIContent> other(do_QueryInterface(aOther));

  if (content && other) {
    // XXXcaa Don't bother to check that either node is in a
    // document.  Editor relies on us returning true if neither
    // node is in a document.  See bug 154401.
    return content->GetDocument() == other->GetDocument();
  }

  return PR_FALSE;
}

// static
PRBool
nsContentUtils::ContentIsDescendantOf(nsINode* aPossibleDescendant,
                                      nsINode* aPossibleAncestor)
{
  NS_PRECONDITION(aPossibleDescendant, "The possible descendant is null!");
  NS_PRECONDITION(aPossibleAncestor, "The possible ancestor is null!");

  do {
    if (aPossibleDescendant == aPossibleAncestor)
      return PR_TRUE;
    aPossibleDescendant = aPossibleDescendant->GetNodeParent();
  } while (aPossibleDescendant);

  return PR_FALSE;
}


// static
nsresult
nsContentUtils::GetAncestors(nsIDOMNode* aNode,
                             nsVoidArray* aArray)
{
  NS_ENSURE_ARG_POINTER(aNode);

  nsCOMPtr<nsIDOMNode> node(aNode);
  nsCOMPtr<nsIDOMNode> ancestor;

  do {
    aArray->AppendElement(node.get());
    node->GetParentNode(getter_AddRefs(ancestor));
    node.swap(ancestor);
  } while (node);

  return NS_OK;
}

// static
nsresult
nsContentUtils::GetAncestorsAndOffsets(nsIDOMNode* aNode,
                                       PRInt32 aOffset,
                                       nsVoidArray* aAncestorNodes,
                                       nsVoidArray* aAncestorOffsets)
{
  NS_ENSURE_ARG_POINTER(aNode);

  nsCOMPtr<nsIContent> content(do_QueryInterface(aNode));

  if (!content) {
    return NS_ERROR_FAILURE;
  }

  if (aAncestorNodes->Count() != 0) {
    NS_WARNING("aAncestorNodes is not empty");
    aAncestorNodes->Clear();
  }

  if (aAncestorOffsets->Count() != 0) {
    NS_WARNING("aAncestorOffsets is not empty");
    aAncestorOffsets->Clear();
  }

  // insert the node itself
  aAncestorNodes->AppendElement(content.get());
  aAncestorOffsets->AppendElement(NS_INT32_TO_PTR(aOffset));

  // insert all the ancestors
  nsIContent* child = content;
  nsIContent* parent = child->GetParent();
  while (parent) {
    aAncestorNodes->AppendElement(parent);
    aAncestorOffsets->AppendElement(NS_INT32_TO_PTR(parent->IndexOf(child)));
    child = parent;
    parent = parent->GetParent();
  }

  return NS_OK;
}

// static
nsresult
nsContentUtils::GetCommonAncestor(nsIDOMNode *aNode,
                                  nsIDOMNode *aOther,
                                  nsIDOMNode** aCommonAncestor)
{
  *aCommonAncestor = nsnull;

  nsCOMPtr<nsINode> node1 = do_QueryInterface(aNode);
  nsCOMPtr<nsINode> node2 = do_QueryInterface(aOther);

  NS_ENSURE_TRUE(node1 && node2, NS_ERROR_UNEXPECTED);

  nsINode* common = GetCommonAncestor(node1, node2);
  NS_ENSURE_TRUE(common, NS_ERROR_NOT_AVAILABLE);

  return CallQueryInterface(common, aCommonAncestor);
}

// static
nsINode*
nsContentUtils::GetCommonAncestor(nsINode* aNode1,
                                  nsINode* aNode2)
{
  if (aNode1 == aNode2) {
    return aNode1;
  }

  // Build the chain of parents
  nsAutoVoidArray parents1, parents2;
  do {
    parents1.AppendElement(aNode1);
    aNode1 = aNode1->GetNodeParent();
  } while (aNode1);
  do {
    parents2.AppendElement(aNode2);
    aNode2 = aNode2->GetNodeParent();
  } while (aNode2);

  // Find where the parent chain differs
  PRUint32 pos1 = parents1.Count();
  PRUint32 pos2 = parents2.Count();
  nsINode* parent = nsnull;
  PRUint32 len;
  for (len = PR_MIN(pos1, pos2); len > 0; --len) {
    nsINode* child1 = NS_STATIC_CAST(nsINode*, parents1.FastElementAt(--pos1));
    nsINode* child2 = NS_STATIC_CAST(nsINode*, parents2.FastElementAt(--pos2));
    if (child1 != child2) {
      break;
    }
    parent = child1;
  }

  return parent;
}

PRUint16
nsContentUtils::ComparePosition(nsINode* aNode1,
                                nsINode* aNode2)
{
  NS_PRECONDITION(aNode1 && aNode2, "don't pass null");

  if (aNode1 == aNode2) {
    return 0;
  }

  nsAutoVoidArray parents1, parents2;

  // Check if either node is an attribute
  nsIAttribute* attr1 = nsnull;
  if (aNode1->IsNodeOfType(nsINode::eATTRIBUTE)) {
    attr1 = NS_STATIC_CAST(nsIAttribute*, aNode1);
    nsIContent* elem = attr1->GetContent();
    // If there is an owner element add the attribute
    // to the chain and walk up to the element
    if (elem) {
      aNode1 = elem;
      parents1.AppendElement(attr1);
    }
  }
  if (aNode2->IsNodeOfType(nsINode::eATTRIBUTE)) {
    nsIAttribute* attr2 = NS_STATIC_CAST(nsIAttribute*, aNode2);
    nsIContent* elem = attr2->GetContent();
    if (elem == aNode1 && attr1) {
      // Both nodes are attributes on the same element.
      // Compare position between the attributes.

      PRUint32 i;
      const nsAttrName* attrName;
      for (i = 0; (attrName = elem->GetAttrNameAt(i)); ++i) {
        if (attrName->Equals(attr1->NodeInfo())) {
          NS_ASSERTION(!attrName->Equals(attr2->NodeInfo()),
                       "Different attrs at same position");
          return nsIDOM3Node::DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC |
            nsIDOM3Node::DOCUMENT_POSITION_PRECEDING;
        }
        if (attrName->Equals(attr2->NodeInfo())) {
          return nsIDOM3Node::DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC |
            nsIDOM3Node::DOCUMENT_POSITION_FOLLOWING;
        }
      }
      NS_NOTREACHED("neither attribute in the element");
      return nsIDOM3Node::DOCUMENT_POSITION_DISCONNECTED;
    }

    if (elem) {
      aNode2 = elem;
      parents2.AppendElement(attr2);
    }
  }

  // We now know that both nodes are either nsIContents or nsIDocuments.
  // If either node started out as an attribute, that attribute will have
  // the same relative position as its ownerElement, except if the
  // ownerElement ends up being the container for the other node

  // Build the chain of parents
  do {
    parents1.AppendElement(aNode1);
    aNode1 = aNode1->GetNodeParent();
  } while (aNode1);
  do {
    parents2.AppendElement(aNode2);
    aNode2 = aNode2->GetNodeParent();
  } while (aNode2);

  // Check if the nodes are disconnected.
  PRUint32 pos1 = parents1.Count();
  PRUint32 pos2 = parents2.Count();
  nsINode* top1 = NS_STATIC_CAST(nsINode*, parents1.FastElementAt(--pos1));
  nsINode* top2 = NS_STATIC_CAST(nsINode*, parents2.FastElementAt(--pos2));
  if (top1 != top2) {
    return top1 < top2 ?
      (nsIDOM3Node::DOCUMENT_POSITION_PRECEDING |
       nsIDOM3Node::DOCUMENT_POSITION_DISCONNECTED |
       nsIDOM3Node::DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC) :
      (nsIDOM3Node::DOCUMENT_POSITION_FOLLOWING |
       nsIDOM3Node::DOCUMENT_POSITION_DISCONNECTED |
       nsIDOM3Node::DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC);
  }

  // Find where the parent chain differs and check indices in the parent.
  nsINode* parent = top1;
  PRUint32 len;
  for (len = PR_MIN(pos1, pos2); len > 0; --len) {
    nsINode* child1 = NS_STATIC_CAST(nsINode*, parents1.FastElementAt(--pos1));
    nsINode* child2 = NS_STATIC_CAST(nsINode*, parents2.FastElementAt(--pos2));
    if (child1 != child2) {
      // child1 or child2 can be an attribute here. This will work fine since
      // IndexOf will return -1 for the attribute making the attribute be
      // considered before any child.
      return parent->IndexOf(child1) < parent->IndexOf(child2) ?
        NS_STATIC_CAST(PRUint16, nsIDOM3Node::DOCUMENT_POSITION_PRECEDING) :
        NS_STATIC_CAST(PRUint16, nsIDOM3Node::DOCUMENT_POSITION_FOLLOWING);
    }
    parent = child1;
  }

  // We hit the end of one of the parent chains without finding a difference
  // between the chains. That must mean that one node is an ancestor of the
  // other. The one with the shortest chain must be the ancestor.
  return pos1 < pos2 ?
    (nsIDOM3Node::DOCUMENT_POSITION_PRECEDING |
     nsIDOM3Node::DOCUMENT_POSITION_CONTAINS) :
    (nsIDOM3Node::DOCUMENT_POSITION_FOLLOWING |
     nsIDOM3Node::DOCUMENT_POSITION_CONTAINED_BY);    
}

inline PRBool
IsCharInSet(const char* aSet,
            const PRUnichar aChar)
{
  PRUnichar ch;
  while ((ch = *aSet)) {
    if (aChar == PRUnichar(ch)) {
      return PR_TRUE;
    }
    ++aSet;
  }
  return PR_FALSE;
}

/**
 * This method strips leading/trailing chars, in given set, from string.
 */

// static
const nsDependentSubstring
nsContentUtils::TrimCharsInSet(const char* aSet,
                               const nsAString& aValue)
{
  nsAString::const_iterator valueCurrent, valueEnd;

  aValue.BeginReading(valueCurrent);
  aValue.EndReading(valueEnd);

  // Skip charaters in the beginning
  while (valueCurrent != valueEnd) {
    if (!IsCharInSet(aSet, *valueCurrent)) {
      break;
    }
    ++valueCurrent;
  }

  if (valueCurrent != valueEnd) {
    for (;;) {
      --valueEnd;
      if (!IsCharInSet(aSet, *valueEnd)) {
        break;
      }
    }
    ++valueEnd; // Step beyond the last character we want in the value.
  }

  // valueEnd should point to the char after the last to copy
  return Substring(valueCurrent, valueEnd);
}

/**
 * This method strips leading and trailing whitespace from a string.
 */

// static
const nsDependentSubstring
nsContentUtils::TrimWhitespace(const nsAString& aStr, PRBool aTrimTrailing)
{
  nsAString::const_iterator start, end;

  aStr.BeginReading(start);
  aStr.EndReading(end);

  // Skip whitespace charaters in the beginning
  while (start != end && nsCRT::IsAsciiSpace(*start)) {
    ++start;
  }

  if (aTrimTrailing) {
    // Skip whitespace characters in the end.
    while (end != start) {
      --end;

      if (!nsCRT::IsAsciiSpace(*end)) {
        // Step back to the last non-whitespace character.
        ++end;

        break;
      }
    }
  }

  // Return a substring for the string w/o leading and/or trailing
  // whitespace

  return Substring(start, end);
}

static inline void KeyAppendSep(nsACString& aKey)
{
  if (!aKey.IsEmpty()) {
    aKey.Append('>');
  }
}

static inline void KeyAppendString(const nsAString& aString, nsACString& aKey)
{
  KeyAppendSep(aKey);

  // Could escape separator here if collisions happen.  > is not a legal char
  // for a name or type attribute, so we should be safe avoiding that extra work.

  AppendUTF16toUTF8(aString, aKey);
}

static inline void KeyAppendString(const nsACString& aString, nsACString& aKey)
{
  KeyAppendSep(aKey);

  // Could escape separator here if collisions happen.  > is not a legal char
  // for a name or type attribute, so we should be safe avoiding that extra work.

  aKey.Append(aString);
}

static inline void KeyAppendInt(PRInt32 aInt, nsACString& aKey)
{
  KeyAppendSep(aKey);

  aKey.Append(nsPrintfCString("%d", aInt));
}

static inline void KeyAppendAtom(nsIAtom* aAtom, nsACString& aKey)
{
  NS_PRECONDITION(aAtom, "KeyAppendAtom: aAtom can not be null!\n");

  const char* atomString = nsnull;
  aAtom->GetUTF8String(&atomString);

  KeyAppendString(nsDependentCString(atomString), aKey);
}

static inline PRBool IsAutocompleteOff(nsIDOMElement* aElement)
{
  nsAutoString autocomplete;
  aElement->GetAttribute(NS_LITERAL_STRING("autocomplete"), autocomplete);
  return autocomplete.LowerCaseEqualsLiteral("off");
}

/*static*/ nsresult
nsContentUtils::GenerateStateKey(nsIContent* aContent,
                                 nsIDocument* aDocument,
                                 nsIStatefulFrame::SpecialStateID aID,
                                 nsACString& aKey)
{
  aKey.Truncate();

  PRUint32 partID = aDocument ? aDocument->GetPartID() : 0;

  // SpecialStateID case - e.g. scrollbars around the content window
  // The key in this case is a special state id
  if (nsIStatefulFrame::eNoID != aID) {
    KeyAppendInt(partID, aKey);  // first append a partID
    KeyAppendInt(aID, aKey);
    return NS_OK;
  }

  // We must have content if we're not using a special state id
  NS_ENSURE_TRUE(aContent, NS_ERROR_FAILURE);

  // Don't capture state for anonymous content
  if (aContent->IsNativeAnonymous() || aContent->GetBindingParent()) {
    return NS_OK;
  }

  nsCOMPtr<nsIDOMElement> element(do_QueryInterface(aContent));
  if (element && IsAutocompleteOff(element)) {
    return NS_OK;
  }

  nsCOMPtr<nsIHTMLDocument> htmlDocument(do_QueryInterface(aContent->GetCurrentDoc()));

  KeyAppendInt(partID, aKey);  // first append a partID
  // Make sure we can't possibly collide with an nsIStatefulFrame
  // special id of some sort
  KeyAppendInt(nsIStatefulFrame::eNoID, aKey);
  PRBool generatedUniqueKey = PR_FALSE;

  if (htmlDocument) {
    // Flush our content model so it'll be up to date
    aContent->GetCurrentDoc()->FlushPendingNotifications(Flush_Content);

    nsContentList *htmlForms = htmlDocument->GetForms();
    nsRefPtr<nsContentList> htmlFormControls =
      GetFormControlElements(aDocument);

    NS_ENSURE_TRUE(htmlForms && htmlFormControls, NS_ERROR_OUT_OF_MEMORY);

    // If we have a form control and can calculate form information, use that
    // as the key - it is more reliable than just recording position in the
    // DOM.
    // XXXbz Is it, really?  We have bugs on this, I think...
    // Important to have a unique key, and tag/type/name may not be.
    //
    // If the control has a form, the format of the key is:
    // f>type>IndOfFormInDoc>IndOfControlInForm>FormName>name
    // else:
    // d>type>IndOfControlInDoc>name
    //
    // XXX We don't need to use index if name is there
    // XXXbz We don't?  Why not?  I don't follow.
    //
    nsCOMPtr<nsIFormControl> control(do_QueryInterface(aContent));
    if (control && htmlFormControls && htmlForms) {

      // Append the control type
      KeyAppendInt(control->GetType(), aKey);

      // If in a form, add form name / index of form / index in form
      PRInt32 index = -1;
      nsCOMPtr<nsIDOMHTMLFormElement> formElement;
      control->GetForm(getter_AddRefs(formElement));
      if (formElement) {

        if (IsAutocompleteOff(formElement)) {
          aKey.Truncate();
          return NS_OK;
        }

        KeyAppendString(NS_LITERAL_CSTRING("f"), aKey);

        // Append the index of the form in the document
        nsCOMPtr<nsIContent> formContent(do_QueryInterface(formElement));
        index = htmlForms->IndexOf(formContent, PR_FALSE);
        if (index <= -1) {
          //
          // XXX HACK this uses some state that was dumped into the document
          // specifically to fix bug 138892.  What we are trying to do is *guess*
          // which form this control's state is found in, with the highly likely
          // guess that the highest form parsed so far is the one.
          // This code should not be on trunk, only branch.
          //
          index = htmlDocument->GetNumFormsSynchronous() - 1;
        }
        if (index > -1) {
          KeyAppendInt(index, aKey);

          // Append the index of the control in the form
          nsCOMPtr<nsIForm> form(do_QueryInterface(formElement));
          form->IndexOfControl(control, &index);

          if (index > -1) {
            KeyAppendInt(index, aKey);
            generatedUniqueKey = PR_TRUE;
          }
        }

        // Append the form name
        nsAutoString formName;
        formElement->GetName(formName);
        KeyAppendString(formName, aKey);

      } else {

        KeyAppendString(NS_LITERAL_CSTRING("d"), aKey);

        // If not in a form, add index of control in document
        // Less desirable than indexing by form info.

        // Hash by index of control in doc (we are not in a form)
        // These are important as they are unique, and type/name may not be.

        // Note that we've already flushed content, so there's no
        // reason to flush it again.
        index = htmlFormControls->IndexOf(aContent, PR_FALSE);
        if (index > -1) {
          KeyAppendInt(index, aKey);
          generatedUniqueKey = PR_TRUE;
        }
      }

      // Append the control name
      nsAutoString name;
      aContent->GetAttr(kNameSpaceID_None, nsHTMLAtoms::name, name);
      KeyAppendString(name, aKey);
    }
  }

  if (!generatedUniqueKey) {
    // Either we didn't have a form control or we aren't in an HTML document so
    // we can't figure out form info.  First append a character that is not "d"
    // or "f" to disambiguate from the case when we were a form control in an
    // HTML document.
    KeyAppendString(NS_LITERAL_CSTRING("o"), aKey);
    
    // Now start at aContent and append the indices of it and all its ancestors
    // in their containers.  That should at least pin down its position in the
    // DOM...
    nsINode* parent = aContent->GetNodeParent();
    nsINode* content = aContent;
    while (parent) {
      KeyAppendInt(parent->IndexOf(content), aKey);
      content = parent;
      parent = content->GetNodeParent();
    }
  }

  return NS_OK;
}

// static
nsresult
nsContentUtils::NewURIWithDocumentCharset(nsIURI** aResult,
                                          const nsAString& aSpec,
                                          nsIDocument* aDocument,
                                          nsIURI* aBaseURI)
{
  return NS_NewURI(aResult, aSpec,
                   aDocument ? aDocument->GetDocumentCharacterSet().get() : nsnull,
                   aBaseURI, sIOService);
}

// static
PRBool
nsContentUtils::BelongsInForm(nsIDOMHTMLFormElement *aForm,
                              nsIContent *aContent)
{
  NS_PRECONDITION(aForm, "Must have a form");
  NS_PRECONDITION(aContent, "Must have a content node");

  nsCOMPtr<nsIContent> form(do_QueryInterface(aForm));

  if (!form) {
    NS_ERROR("This should not happen, form is not an nsIContent!");

    return PR_TRUE;
  }

  if (form == aContent) {
    // A form does not belong inside itself, so we return false here

    return PR_FALSE;
  }

  nsIContent* content = aContent->GetParent();

  while (content) {
    if (content == form) {
      // aContent is contained within the form so we return true.

      return PR_TRUE;
    }

    if (content->Tag() == nsHTMLAtoms::form &&
        content->IsNodeOfType(nsINode::eHTML)) {
      // The child is contained within a form, but not the right form
      // so we ignore it.

      return PR_FALSE;
    }

    content = content->GetParent();
  }

  if (form->GetChildCount() > 0) {
    // The form is a container but aContent wasn't inside the form,
    // return false

    return PR_FALSE;
  }

  // The form is a leaf and aContent wasn't inside any other form so
  // we check whether the content comes after the form.  If it does,
  // return true.  If it does not, then it couldn't have been inside
  // the form in the HTML.
  if (PositionIsBefore(form, aContent)) {
    // We could be in this form!
    // In the future, we may want to get document.forms, look at the
    // form after aForm, and if aContent is after that form after
    // aForm return false here....
    return PR_TRUE;
  }

  return PR_FALSE;
}

// static
nsresult
nsContentUtils::CheckQName(const nsAString& aQualifiedName,
                           PRBool aNamespaceAware)
{
  nsIParserService *parserService = GetParserService();
  NS_ENSURE_TRUE(parserService, NS_ERROR_FAILURE);

  const PRUnichar *colon;
  return parserService->CheckQName(PromiseFlatString(aQualifiedName),
                                   aNamespaceAware, &colon);
}

//static
nsresult
nsContentUtils::SplitQName(nsIContent* aNamespaceResolver,
                           const nsAFlatString& aQName,
                           PRInt32 *aNamespace, nsIAtom **aLocalName)
{
  nsIParserService* parserService = GetParserService();
  NS_ENSURE_TRUE(parserService, NS_ERROR_FAILURE);

  const PRUnichar* colon;
  nsresult rv = parserService->CheckQName(aQName, PR_TRUE, &colon);
  NS_ENSURE_SUCCESS(rv, rv);

  if (colon) {
    const PRUnichar* end;
    aQName.EndReading(end);
    nsAutoString nameSpace;
    rv = LookupNamespaceURI(aNamespaceResolver, Substring(aQName.get(), colon),
                            nameSpace);
    NS_ENSURE_SUCCESS(rv, rv);

    *aNamespace = NameSpaceManager()->GetNameSpaceID(nameSpace);
    if (*aNamespace == kNameSpaceID_Unknown)
      return NS_ERROR_FAILURE;

    *aLocalName = NS_NewAtom(Substring(colon + 1, end));
  }
  else {
    *aNamespace = kNameSpaceID_None;
    *aLocalName = NS_NewAtom(aQName);
  }
  NS_ENSURE_TRUE(aLocalName, NS_ERROR_OUT_OF_MEMORY);
  return NS_OK;
}

// static
nsresult
nsContentUtils::LookupNamespaceURI(nsIContent* aNamespaceResolver,
                                   const nsAString& aNamespacePrefix,
                                   nsAString& aNamespaceURI)
{
  if (aNamespacePrefix.EqualsLiteral("xml")) {
    // Special-case for xml prefix
    aNamespaceURI.AssignLiteral("http://www.w3.org/XML/1998/namespace");
    return NS_OK;
  }

  if (aNamespacePrefix.EqualsLiteral("xmlns")) {
    // Special-case for xmlns prefix
    aNamespaceURI.AssignLiteral("http://www.w3.org/2000/xmlns/");
    return NS_OK;
  }

  nsCOMPtr<nsIAtom> name;
  if (!aNamespacePrefix.IsEmpty()) {
    name = do_GetAtom(aNamespacePrefix);
    NS_ENSURE_TRUE(name, NS_ERROR_OUT_OF_MEMORY);
  }
  else {
    name = nsLayoutAtoms::xmlns;
  }
  // Trace up the content parent chain looking for the namespace
  // declaration that declares aNamespacePrefix.
  for (nsIContent* content = aNamespaceResolver; content;
       content = content->GetParent()) {
    if (content->GetAttr(kNameSpaceID_XMLNS, name, aNamespaceURI))
      return NS_OK;
  }
  return NS_ERROR_FAILURE;
}

// static
nsresult
nsContentUtils::GetNodeInfoFromQName(const nsAString& aNamespaceURI,
                                     const nsAString& aQualifiedName,
                                     nsNodeInfoManager* aNodeInfoManager,
                                     nsINodeInfo** aNodeInfo)
{
  nsIParserService* parserService = GetParserService();
  NS_ENSURE_TRUE(parserService, NS_ERROR_FAILURE);

  const nsAFlatString& qName = PromiseFlatString(aQualifiedName);
  const PRUnichar* colon;
  nsresult rv = parserService->CheckQName(qName, PR_TRUE, &colon);
  NS_ENSURE_SUCCESS(rv, rv);

  PRInt32 nsID;
  sNameSpaceManager->RegisterNameSpace(aNamespaceURI, nsID);
  if (colon) {
    const PRUnichar* end;
    qName.EndReading(end);

    nsCOMPtr<nsIAtom> prefix = do_GetAtom(Substring(qName.get(), colon));

    rv = aNodeInfoManager->GetNodeInfo(Substring(colon + 1, end), prefix,
                                       nsID, aNodeInfo);
  }
  else {
    rv = aNodeInfoManager->GetNodeInfo(aQualifiedName, nsnull, nsID,
                                       aNodeInfo);
  }
  NS_ENSURE_SUCCESS(rv, rv);

  return nsContentUtils::IsValidNodeName((*aNodeInfo)->NameAtom(),
                                         (*aNodeInfo)->GetPrefixAtom(),
                                         (*aNodeInfo)->NamespaceID()) ?
         NS_OK : NS_ERROR_DOM_NAMESPACE_ERR;
}

// static
void
nsContentUtils::SplitExpatName(const PRUnichar *aExpatName, nsIAtom **aPrefix,
                               nsIAtom **aLocalName, PRInt32* aNameSpaceID)
{
  /**
   *  Expat can send the following:
   *    localName
   *    namespaceURI<separator>localName
   *    namespaceURI<separator>localName<separator>prefix
   *
   *  and we use 0xFFFF for the <separator>.
   *
   */

  const PRUnichar *uriEnd = nsnull;
  const PRUnichar *nameEnd = nsnull;
  const PRUnichar *pos;
  for (pos = aExpatName; *pos; ++pos) {
    if (*pos == 0xFFFF) {
      if (uriEnd) {
        nameEnd = pos;
      }
      else {
        uriEnd = pos;
      }
    }
  }

  const PRUnichar *nameStart;
  if (uriEnd) {
    if (sNameSpaceManager) {
      sNameSpaceManager->RegisterNameSpace(nsDependentSubstring(aExpatName,
                                                                uriEnd),
                                           *aNameSpaceID);
    }
    else {
      *aNameSpaceID = kNameSpaceID_Unknown;
    }

    nameStart = (uriEnd + 1);
    if (nameEnd)  {
      const PRUnichar *prefixStart = nameEnd + 1;
      *aPrefix = NS_NewAtom(NS_ConvertUTF16toUTF8(prefixStart,
                                                  pos - prefixStart));
    }
    else {
      nameEnd = pos;
      *aPrefix = nsnull;
    }
  }
  else {
    *aNameSpaceID = kNameSpaceID_None;
    nameStart = aExpatName;
    nameEnd = pos;
    *aPrefix = nsnull;
  }
  *aLocalName = NS_NewAtom(NS_ConvertUTF16toUTF8(nameStart,
                                                 nameEnd - nameStart));
}

// static
PRBool
nsContentUtils::CanLoadImage(nsIURI* aURI, nsISupports* aContext,
                             nsIDocument* aLoadingDocument,
                             PRInt16* aImageBlockingStatus)
{
  NS_PRECONDITION(aURI, "Must have a URI");
  NS_PRECONDITION(aLoadingDocument, "Must have a document");

  nsresult rv;

  PRUint32 appType = nsIDocShell::APP_TYPE_UNKNOWN;

  {
    nsCOMPtr<nsISupports> container = aLoadingDocument->GetContainer();
    nsCOMPtr<nsIDocShellTreeItem> docShellTreeItem =
      do_QueryInterface(container);

    if (docShellTreeItem) {
      nsCOMPtr<nsIDocShellTreeItem> root;
      docShellTreeItem->GetRootTreeItem(getter_AddRefs(root));

      nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(root));

      if (!docShell || NS_FAILED(docShell->GetAppType(&appType))) {
        appType = nsIDocShell::APP_TYPE_UNKNOWN;
      }
    }
  }

  if (appType != nsIDocShell::APP_TYPE_EDITOR) {
    // Editor apps get special treatment here, editors can load images
    // from anywhere.
    rv = sSecurityManager->
      CheckLoadURIWithPrincipal(aLoadingDocument->NodePrincipal(), aURI,
                                nsIScriptSecurityManager::ALLOW_CHROME);
    if (NS_FAILED(rv)) {
      if (aImageBlockingStatus) {
        // Reject the request itself, not all requests to the relevant
        // server...
        *aImageBlockingStatus = nsIContentPolicy::REJECT_REQUEST;
      }
      return PR_FALSE;
    }
  }

  PRInt16 decision = nsIContentPolicy::ACCEPT;

  rv = NS_CheckContentLoadPolicy(nsIContentPolicy::TYPE_IMAGE,
                                 aURI,
                                 aLoadingDocument->GetDocumentURI(),
                                 aContext,
                                 EmptyCString(), //mime guess
                                 nsnull,         //extra
                                 &decision,
                                 GetContentPolicy());

  if (aImageBlockingStatus) {
    *aImageBlockingStatus =
      NS_FAILED(rv) ? nsIContentPolicy::REJECT_REQUEST : decision;
  }
  return NS_FAILED(rv) ? PR_FALSE : NS_CP_ACCEPTED(decision);
}

// static
nsresult
nsContentUtils::LoadImage(nsIURI* aURI, nsIDocument* aLoadingDocument,
                          nsIURI* aReferrer, imgIDecoderObserver* aObserver,
                          PRInt32 aLoadFlags, imgIRequest** aRequest)
{
  NS_PRECONDITION(aURI, "Must have a URI");
  NS_PRECONDITION(aLoadingDocument, "Must have a document");
  NS_PRECONDITION(aRequest, "Null out param");

  if (!sImgLoader) {
    // nothing we can do here
    return NS_OK;
  }

  nsCOMPtr<nsILoadGroup> loadGroup = aLoadingDocument->GetDocumentLoadGroup();
  NS_ASSERTION(loadGroup, "Could not get loadgroup; onload may fire too early");

  nsIURI *documentURI = aLoadingDocument->GetDocumentURI();

  // XXXbz using "documentURI" for the initialDocumentURI is not quite
  // right, but the best we can do here...
  return sImgLoader->LoadImage(aURI,                 /* uri to load */
                               documentURI,          /* initialDocumentURI */
                               aReferrer,            /* referrer */
                               loadGroup,            /* loadgroup */
                               aObserver,            /* imgIDecoderObserver */
                               aLoadingDocument,     /* uniquification key */
                               aLoadFlags,           /* load flags */
                               nsnull,               /* cache key */
                               nsnull,               /* existing request*/
                               aRequest);
}

// static
already_AddRefed<nsIImage>
nsContentUtils::GetImageFromContent(nsIImageLoadingContent* aContent,
                                    imgIRequest **aRequest)
{
  if (aRequest) {
    *aRequest = nsnull;
  }

  NS_ENSURE_TRUE(aContent, nsnull);

  nsCOMPtr<imgIRequest> imgRequest;
  aContent->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
                      getter_AddRefs(imgRequest));
  if (!imgRequest) {
    return nsnull;
  }

  nsCOMPtr<imgIContainer> imgContainer;
  imgRequest->GetImage(getter_AddRefs(imgContainer));

  if (!imgContainer) {
    return nsnull;
  }

  nsCOMPtr<gfxIImageFrame> imgFrame;
  imgContainer->GetFrameAt(0, getter_AddRefs(imgFrame));

  if (!imgFrame) {
    return nsnull;
  }

  nsCOMPtr<nsIInterfaceRequestor> ir = do_QueryInterface(imgFrame);

  if (!ir) {
    return nsnull;
  }

  if (aRequest) {
    imgRequest.swap(*aRequest);
  }

  nsIImage* image = nsnull;
  CallGetInterface(ir.get(), &image);
  return image;
}

// static
PRBool
nsContentUtils::IsDraggableImage(nsIContent* aContent)
{
  NS_PRECONDITION(aContent, "Must have content node to test");

  nsCOMPtr<nsIImageLoadingContent> imageContent(do_QueryInterface(aContent));
  if (!imageContent) {
    return PR_FALSE;
  }

  nsCOMPtr<imgIRequest> imgRequest;
  imageContent->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
                           getter_AddRefs(imgRequest));

  // XXXbz It may be draggable even if the request resulted in an error.  Why?
  // Not sure; that's what the old nsContentAreaDragDrop/nsFrame code did.
  return imgRequest != nsnull;
}

// static
PRBool
nsContentUtils::IsDraggableLink(nsIContent* aContent) {
  nsCOMPtr<nsIURI> linkURI = GetLinkURI(aContent);

  // Does it have a URI?  If not, it's not draggable
  return linkURI != nsnull;
}

// static
already_AddRefed<nsIURI>
nsContentUtils::GetLinkURI(nsIContent* aContent)
{
  NS_PRECONDITION(aContent, "Must have content node to work with");

  nsCOMPtr<nsILink> link(do_QueryInterface(aContent));
  if (link) {
    nsIURI* uri = nsnull;
    link->GetHrefURI(&uri);
    if (uri) {
      return uri;
    }
  }

  // It could still be an XLink
  return GetXLinkURI(aContent);
}

// static
already_AddRefed<nsIURI>
nsContentUtils::GetXLinkURI(nsIContent* aContent)
{
  NS_PRECONDITION(aContent, "Must have content node to work with");

  if (aContent->AttrValueIs(kNameSpaceID_XLink, nsGkAtoms::type,
                            nsGkAtoms::simple, eCaseMatters)) {
    nsAutoString value;
    // Check that we have a URI
    if (aContent->GetAttr(kNameSpaceID_XLink, nsHTMLAtoms::href, value)) {
      //  Resolve it relative to aContent's base URI.
      nsCOMPtr<nsIURI> baseURI = aContent->GetBaseURI();

      nsIURI* uri = nsnull;
      nsContentUtils::NewURIWithDocumentCharset(&uri, value,
                                                aContent->GetDocument(),
                                                baseURI);
      return uri;
    }
  }

  return nsnull;
}

// static
nsAdoptingCString
nsContentUtils::GetCharPref(const char *aPref)
{
  nsAdoptingCString result;

  if (sPrefBranch) {
    sPrefBranch->GetCharPref(aPref, getter_Copies(result));
  }

  return result;
}

// static
PRPackedBool
nsContentUtils::GetBoolPref(const char *aPref, PRBool aDefault)
{
  PRBool result;

  if (!sPrefBranch ||
      NS_FAILED(sPrefBranch->GetBoolPref(aPref, &result))) {
    result = aDefault;
  }

  return (PRPackedBool)result;
}

// static
PRInt32
nsContentUtils::GetIntPref(const char *aPref, PRInt32 aDefault)
{
  PRInt32 result;

  if (!sPrefBranch ||
      NS_FAILED(sPrefBranch->GetIntPref(aPref, &result))) {
    result = aDefault;
  }

  return result;
}

// static
nsAdoptingString
nsContentUtils::GetLocalizedStringPref(const char *aPref)
{
  nsAdoptingString result;

  if (sPrefBranch) {
    nsCOMPtr<nsIPrefLocalizedString> prefLocalString;
    sPrefBranch->GetComplexValue(aPref, NS_GET_IID(nsIPrefLocalizedString),
                                 getter_AddRefs(prefLocalString));
    if (prefLocalString) {
      prefLocalString->GetData(getter_Copies(result));
    }
  }

  return result;
}

// static
nsAdoptingString
nsContentUtils::GetStringPref(const char *aPref)
{
  nsAdoptingString result;

  if (sPrefBranch) {
    nsCOMPtr<nsISupportsString> theString;
    sPrefBranch->GetComplexValue(aPref, NS_GET_IID(nsISupportsString),
                                 getter_AddRefs(theString));
    if (theString) {
      theString->ToString(getter_Copies(result));
    }
  }

  return result;
}

// static
void
nsContentUtils::RegisterPrefCallback(const char *aPref,
                                     PrefChangedFunc aCallback,
                                     void * aClosure)
{
  if (sPref)
    sPref->RegisterCallback(aPref, aCallback, aClosure);
}

// static
void
nsContentUtils::UnregisterPrefCallback(const char *aPref,
                                       PrefChangedFunc aCallback,
                                       void * aClosure)
{
  if (sPref)
    sPref->UnregisterCallback(aPref, aCallback, aClosure);
}


static const char gEventName[] = "event";
static const char gSVGEventName[] = "evt";

// static
const char *
nsContentUtils::GetEventArgName(PRInt32 aNameSpaceID)
{
  if (aNameSpaceID == kNameSpaceID_SVG)
    return gSVGEventName;

  return gEventName;
}

nsCxPusher::nsCxPusher(nsISupports *aCurrentTarget)
    : mScriptIsRunning(PR_FALSE)
{
  if (aCurrentTarget) {
    Push(aCurrentTarget);
  }
}

nsCxPusher::~nsCxPusher()
{
  Pop();
}

static PRBool
IsContextOnStack(nsIJSContextStack *aStack, JSContext *aContext)
{
  JSContext *ctx = nsnull;
  aStack->Peek(&ctx);
  if (!ctx)
    return PR_FALSE;
  if (ctx == aContext)
    return PR_TRUE;
  
  nsCOMPtr<nsIJSContextStackIterator>
    iterator(do_CreateInstance("@mozilla.org/js/xpc/ContextStackIterator;1"));
  NS_ENSURE_TRUE(iterator, PR_FALSE);

  nsresult rv = iterator->Reset(aStack);
  NS_ENSURE_SUCCESS(rv, PR_FALSE);
  
  PRBool done;
  while (NS_SUCCEEDED(iterator->Done(&done)) && !done) {
    rv = iterator->Prev(&ctx);
    NS_ASSERTION(NS_SUCCEEDED(rv), "Broken iterator implementation");

    if (nsJSUtils::GetDynamicScriptContext(ctx) && ctx == aContext)
      return PR_TRUE;
  }

  return PR_FALSE;
}

void
nsCxPusher::Push(nsISupports *aCurrentTarget)
{
  if (mScx) {
    NS_ERROR("Whaaa! No double pushing with nsCxPusher::Push()!");

    return;
  }

  nsCOMPtr<nsIScriptGlobalObject> sgo;
  nsCOMPtr<nsIContent> content(do_QueryInterface(aCurrentTarget));
  nsCOMPtr<nsIDocument> document;

  if (content) {
    document = content->GetDocument();
  }

  if (!document) {
    document = do_QueryInterface(aCurrentTarget);
  }

  if (document) {
    sgo = document->GetScriptGlobalObject();
  }

  if (!document && !sgo) {
    sgo = do_QueryInterface(aCurrentTarget);
  }

  JSContext *cx = nsnull;

  if (sgo) {
    mScx = sgo->GetContext();

    if (mScx) {
      cx = (JSContext *)mScx->GetNativeContext();
    }
  }

  if (cx) {
    if (!mStack) {
      mStack = do_GetService(kJSStackContractID);
    }

    if (mStack) {
      if (IsContextOnStack(mStack, cx)) {
        // If the context is on the stack, that means that a script
        // is running at the moment in the context.
        mScriptIsRunning = PR_TRUE;
      }

      mStack->Push(cx);
    }
  } else {
    // If there's no native context in the script context it must be
    // in the process or being torn down. We don't want to notify the
    // script context about scripts having been evaluated in such a
    // case, so null out mScx.

    mScx = nsnull;
  }
}

void
nsCxPusher::Pop()
{
  if (!mScx || !mStack) {
    mScx = nsnull;

    NS_ASSERTION(!mScriptIsRunning, "Huh, this can't be happening, "
                 "mScriptIsRunning can't be set here!");

    return;
  }

  JSContext *unused;
  mStack->Pop(&unused);

  if (!mScriptIsRunning) {
    // No JS is running in the context, but executing the event handler might have
    // caused some JS to run. Tell the script context that it's done.

    mScx->ScriptEvaluated(PR_TRUE);
  }

  mScx = nsnull;
  mScriptIsRunning = PR_FALSE;
}

static const char gPropertiesFiles[nsContentUtils::PropertiesFile_COUNT][56] = {
  // Must line up with the enum values in |PropertiesFile| enum.
  "chrome://global/locale/css.properties",
  "chrome://global/locale/xbl.properties",
  "chrome://global/locale/xul.properties",
  "chrome://global/locale/layout_errors.properties",
  "chrome://global/locale/layout/HtmlForm.properties",
  "chrome://global/locale/printing.properties",
  "chrome://global/locale/dom/dom.properties",
  "chrome://branding/locale/brand.properties",
  "chrome://global/locale/commonDialogs.properties"
};

/* static */ nsresult
nsContentUtils::EnsureStringBundle(PropertiesFile aFile)
{
  if (!sStringBundles[aFile]) {
    if (!sStringBundleService) {
      nsresult rv =
        CallGetService(NS_STRINGBUNDLE_CONTRACTID, &sStringBundleService);
      NS_ENSURE_SUCCESS(rv, rv);
    }
    nsIStringBundle *bundle;
    nsresult rv =
      sStringBundleService->CreateBundle(gPropertiesFiles[aFile], &bundle);
    NS_ENSURE_SUCCESS(rv, rv);
    sStringBundles[aFile] = bundle; // transfer ownership
  }
  return NS_OK;
}

/* static */
nsresult nsContentUtils::GetLocalizedString(PropertiesFile aFile,
                                            const char* aKey,
                                            nsXPIDLString& aResult)
{
  nsresult rv = EnsureStringBundle(aFile);
  NS_ENSURE_SUCCESS(rv, rv);
  nsIStringBundle *bundle = sStringBundles[aFile];

  return bundle->GetStringFromName(NS_ConvertASCIItoUTF16(aKey).get(),
                                   getter_Copies(aResult));
}

/* static */
nsresult nsContentUtils::FormatLocalizedString(PropertiesFile aFile,
                                               const char* aKey,
                                               const PRUnichar **aParams,
                                               PRUint32 aParamsLength,
                                               nsXPIDLString& aResult)
{
  nsresult rv = EnsureStringBundle(aFile);
  NS_ENSURE_SUCCESS(rv, rv);
  nsIStringBundle *bundle = sStringBundles[aFile];

  return bundle->FormatStringFromName(NS_ConvertASCIItoUTF16(aKey).get(),
                                      aParams, aParamsLength,
                                      getter_Copies(aResult));
}

/* static */ nsresult
nsContentUtils::ReportToConsole(PropertiesFile aFile,
                                const char *aMessageName,
                                const PRUnichar **aParams,
                                PRUint32 aParamsLength,
                                nsIURI* aURI,
                                const nsAFlatString& aSourceLine,
                                PRUint32 aLineNumber,
                                PRUint32 aColumnNumber,
                                PRUint32 aErrorFlags,
                                const char *aCategory)
{
  NS_ASSERTION((aParams && aParamsLength) || (!aParams && !aParamsLength),
               "Supply either both parameters and their number or no"
               "parameters and 0.");

  nsresult rv;
  if (!sConsoleService) { // only need to bother null-checking here
    rv = CallGetService(NS_CONSOLESERVICE_CONTRACTID, &sConsoleService);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  nsXPIDLString errorText;
  if (aParams) {
    rv = FormatLocalizedString(aFile, aMessageName, aParams, aParamsLength,
                               errorText);
  }
  else {
    rv = GetLocalizedString(aFile, aMessageName, errorText);
  }
  NS_ENSURE_SUCCESS(rv, rv);

  nsCAutoString spec;
  if (aURI)
    aURI->GetSpec(spec);

  nsCOMPtr<nsIScriptError> errorObject =
      do_CreateInstance(NS_SCRIPTERROR_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);
  rv = errorObject->Init(errorText.get(),
                         NS_ConvertUTF8toUTF16(spec).get(), // file name
                         aSourceLine.get(),
                         aLineNumber, aColumnNumber,
                         aErrorFlags, aCategory);
  NS_ENSURE_SUCCESS(rv, rv);

  return sConsoleService->LogMessage(errorObject);
}

static PRBool MatchFormControls(nsIContent* aContent, PRInt32 aNamespaceID,
                                nsIAtom* aAtom, const nsAString& aData)
{
  return aContent->IsNodeOfType(nsINode::eHTML_FORM_CONTROL);
}

/* static */ already_AddRefed<nsContentList>
nsContentUtils::GetFormControlElements(nsIDocument *aDocument)
{
  nsContentList *list = new nsContentList(aDocument,
                                          MatchFormControls, EmptyString());
  NS_IF_ADDREF(list);
  return list;
}

PRBool
nsContentUtils::IsChromeDoc(nsIDocument *aDocument)
{
  if (!aDocument) {
    return PR_FALSE;
  }
  
  nsCOMPtr<nsIPrincipal> systemPrincipal;
  sSecurityManager->GetSystemPrincipal(getter_AddRefs(systemPrincipal));

  return aDocument->NodePrincipal() == systemPrincipal;
}

void
nsContentUtils::NotifyXPCIfExceptionPending(JSContext* aCx)
{
  if (!::JS_IsExceptionPending(aCx)) {
    return;
  }

  nsCOMPtr<nsIXPCNativeCallContext> nccx;
  XPConnect()->GetCurrentNativeCallContext(getter_AddRefs(nccx));
  if (nccx) {
    // Check to make sure that the JSContext that nccx will mess with is the
    // same as the JSContext we've set an exception on.  If they're not the
    // same, don't mess with nccx.
    JSContext* cx;
    nccx->GetJSContext(&cx);
    if (cx == aCx) {
      nccx->SetExceptionWasThrown(PR_TRUE);
    }
  }
}

// static
nsIContentPolicy*
nsContentUtils::GetContentPolicy()
{
  if (!sTriedToGetContentPolicy) {
    CallGetService(NS_CONTENTPOLICY_CONTRACTID, &sContentPolicyService);
    // It's OK to not have a content policy service
    sTriedToGetContentPolicy = PR_TRUE;
  }

  return sContentPolicyService;
}

// static
nsresult
nsContentUtils::AddJSGCRoot(void* aPtr, const char* aName)
{
  if (!sScriptRuntime) {
    nsresult rv = CallGetService("@mozilla.org/js/xpc/RuntimeService;1",
                                 &sJSRuntimeService);
    NS_ENSURE_TRUE(sJSRuntimeService, rv);

    sJSRuntimeService->GetRuntime(&sScriptRuntime);
    if (!sScriptRuntime) {
      NS_RELEASE(sJSRuntimeService);
      NS_WARNING("Unable to get JS runtime from JS runtime service");
      return NS_ERROR_FAILURE;
    }
  }

  PRBool ok;
  ok = ::JS_AddNamedRootRT(sScriptRuntime, aPtr, aName);
  if (!ok) {
    if (sScriptRootCount == 0) {
      // We just got the runtime... Just null things out, since no
      // one's expecting us to have a runtime yet
      NS_RELEASE(sJSRuntimeService);
      sScriptRuntime = nsnull;
    }
    NS_WARNING("JS_AddNamedRootRT failed");
    return NS_ERROR_OUT_OF_MEMORY;
  }

  // We now have one more root we added to the runtime
  ++sScriptRootCount;

  return NS_OK;
}

/* static */
nsresult
nsContentUtils::RemoveJSGCRoot(void* aPtr)
{
  if (!sScriptRuntime) {
    NS_NOTREACHED("Trying to remove a JS GC root when none were added");
    return NS_ERROR_UNEXPECTED;
  }

  ::JS_RemoveRootRT(sScriptRuntime, aPtr);

  if (--sScriptRootCount == 0) {
    NS_RELEASE(sJSRuntimeService);
    sScriptRuntime = nsnull;
  }

  return NS_OK;
}

// static
nsresult
nsContentUtils::DispatchTrustedEvent(nsIDocument* aDoc, nsISupports* aTarget,
                                     const nsAString& aEventName,
                                     PRBool aCanBubble, PRBool aCancelable,
                                     PRBool *aDefaultAction)
{
  nsCOMPtr<nsIDOMDocumentEvent> docEvent(do_QueryInterface(aDoc));
  nsCOMPtr<nsIDOMEventTarget> target(do_QueryInterface(aTarget));
  NS_ENSURE_TRUE(docEvent && target, NS_ERROR_INVALID_ARG);

  nsCOMPtr<nsIDOMEvent> event;
  nsresult rv =
    docEvent->CreateEvent(NS_LITERAL_STRING("Events"), getter_AddRefs(event));
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIPrivateDOMEvent> privateEvent(do_QueryInterface(event));
  NS_ENSURE_TRUE(privateEvent, NS_ERROR_FAILURE);

  rv = event->InitEvent(aEventName, aCanBubble, aCancelable);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = privateEvent->SetTrusted(PR_TRUE);
  NS_ENSURE_SUCCESS(rv, rv);

  PRBool dummy;
  return target->DispatchEvent(event, aDefaultAction ? aDefaultAction : &dummy);
}

/* static */
nsIContent*
nsContentUtils::MatchElementId(nsIContent *aContent, nsIAtom* aId)
{
  if (aId == aContent->GetID()) {
    return aContent;
  }
  
  nsIContent *result = nsnull;
  PRUint32 i, count = aContent->GetChildCount();

  for (i = 0; i < count && result == nsnull; i++) {
    result = MatchElementId(aContent->GetChildAt(i), aId);
  }

  return result;
}

// Id attribute matching function used by nsXMLDocument and
// nsHTMLDocument and others.
/* static */
nsIContent *
nsContentUtils::MatchElementId(nsIContent *aContent, const nsAString& aId)
{
  NS_PRECONDITION(!aId.IsEmpty(), "Will match random elements");
  
  // ID attrs are generally stored as atoms, so just atomize this up front
  nsCOMPtr<nsIAtom> id(do_GetAtom(aId));
  if (!id) {
    // OOM, so just bail
    return nsnull;
  }

  return MatchElementId(aContent, id);
}

// Convert the string from the given charset to Unicode.
/* static */
nsresult
nsContentUtils::ConvertStringFromCharset(const nsACString& aCharset,
                                         const nsACString& aInput,
                                         nsAString& aOutput)
{
  if (aCharset.IsEmpty()) {
    // Treat the string as UTF8
    CopyUTF8toUTF16(aInput, aOutput);
    return NS_OK;
  }

  nsresult rv;
  nsCOMPtr<nsICharsetConverterManager> ccm =
    do_GetService(NS_CHARSETCONVERTERMANAGER_CONTRACTID, &rv);
  if (NS_FAILED(rv))
    return rv;

  nsCOMPtr<nsIUnicodeDecoder> decoder;
  rv = ccm->GetUnicodeDecoder(PromiseFlatCString(aCharset).get(),
                              getter_AddRefs(decoder));
  if (NS_FAILED(rv))
    return rv;

  nsPromiseFlatCString flatInput(aInput);
  PRInt32 srcLen = flatInput.Length();
  PRInt32 dstLen;
  rv = decoder->GetMaxLength(flatInput.get(), srcLen, &dstLen);
  if (NS_FAILED(rv))
    return rv;

  PRUnichar *ustr = (PRUnichar *)nsMemory::Alloc((dstLen + 1) *
                                                 sizeof(PRUnichar));
  if (!ustr)
    return NS_ERROR_OUT_OF_MEMORY;

  rv = decoder->Convert(flatInput.get(), &srcLen, ustr, &dstLen);
  if (NS_SUCCEEDED(rv)) {
    ustr[dstLen] = 0;
    aOutput.Assign(ustr, dstLen);
  }

  nsMemory::Free(ustr);
  return rv;
}

static PRBool EqualExceptRef(nsIURL* aURL1, nsIURL* aURL2)
{
  nsCOMPtr<nsIURI> u1;
  nsCOMPtr<nsIURI> u2;

  nsresult rv = aURL1->Clone(getter_AddRefs(u1));
  if (NS_SUCCEEDED(rv)) {
    rv = aURL2->Clone(getter_AddRefs(u2));
  }
  if (NS_FAILED(rv))
    return PR_FALSE;

  nsCOMPtr<nsIURL> url1 = do_QueryInterface(u1);
  nsCOMPtr<nsIURL> url2 = do_QueryInterface(u2);
  if (!url1 || !url2) {
    NS_WARNING("Cloning a URL produced a non-URL");
    return PR_FALSE;
  }
  url1->SetRef(EmptyCString());
  url2->SetRef(EmptyCString());

  PRBool equal;
  rv = url1->Equals(url2, &equal);
  return NS_SUCCEEDED(rv) && equal;
}

/* static */
nsIContent*
nsContentUtils::GetReferencedElement(nsIURI* aURI, nsIContent *aFromContent)
{
  nsCOMPtr<nsIURL> url = do_QueryInterface(aURI);
  if (!url)
    return nsnull;

  nsCAutoString refPart;
  url->GetRef(refPart);
  // Unescape %-escapes in the reference. The result will be in the
  // origin charset of the URL, hopefully...
  NS_UnescapeURL(refPart);

  nsCAutoString charset;
  url->GetOriginCharset(charset);
  nsAutoString ref;
  nsresult rv = ConvertStringFromCharset(charset, refPart, ref);
  if (NS_FAILED(rv)) {
    CopyUTF8toUTF16(refPart, ref);
  }
  if (ref.IsEmpty())
    return nsnull;

  // Get the current document
  nsIDocument *doc = aFromContent->GetCurrentDoc();
  if (!doc)
    return nsnull;

  // This will be the URI of the document the content belongs to
  // (the URI of the XBL document if the content is anonymous
  // XBL content)
  nsCOMPtr<nsIURL> documentURL = do_QueryInterface(doc->GetDocumentURI());
  nsIContent* bindingParent = aFromContent->GetBindingParent();
  PRBool isXBL = PR_FALSE;
  if (bindingParent) {
    nsXBLBinding* binding = doc->BindingManager()->GetBinding(bindingParent);
    if (binding) {
      // XXX sXBL/XBL2 issue
      // If this is an anonymous XBL element then the URI is
      // relative to the binding document. A full fix requires a
      // proper XBL2 implementation but for now URIs that are
      // relative to the binding document should be resolve to the
      // copy of the target element that has been inserted into the
      // bound document.
      documentURL = do_QueryInterface(binding->PrototypeBinding()->DocURI());
      isXBL = PR_TRUE;
    }
  }
  if (!documentURL)
    return nsnull;

  if (!EqualExceptRef(url, documentURL)) {
    // Oops -- we don't support off-document references
    return nsnull;
  }

  // Get the element
  nsCOMPtr<nsIContent> content;
  if (isXBL) {
    nsCOMPtr<nsIDOMNodeList> anonymousChildren;
    doc->BindingManager()->
      GetAnonymousNodesFor(bindingParent, getter_AddRefs(anonymousChildren));

    if (anonymousChildren) {
      PRUint32 length;
      anonymousChildren->GetLength(&length);
      for (PRUint32 i = 0; i < length && !content; ++i) {
        nsCOMPtr<nsIDOMNode> node;
        anonymousChildren->Item(i, getter_AddRefs(node));
        nsCOMPtr<nsIContent> c = do_QueryInterface(node);
        if (c) {
          content = MatchElementId(c, ref);
        }
      }
    }
  } else {
    nsCOMPtr<nsIDOMDocument> domDoc = do_QueryInterface(doc);
    NS_ASSERTION(domDoc, "Content doesn't reference a dom Document");

    nsCOMPtr<nsIDOMElement> element;
    rv = domDoc->GetElementById(ref, getter_AddRefs(element));
    if (element) {
      content = do_QueryInterface(element);
    }
  }

  return content;
}

/* static */
PRBool
nsContentUtils::HasNonEmptyAttr(nsIContent* aContent, PRInt32 aNameSpaceID,
                                nsIAtom* aName)
{
  static nsIContent::AttrValuesArray strings[] = {&nsXULAtoms::_empty, nsnull};
  return aContent->FindAttrValueIn(aNameSpaceID, aName, strings, eCaseMatters)
    == nsIContent::ATTR_VALUE_NO_MATCH;
}

/* static */
PRBool
nsContentUtils::HasMutationListeners(nsINode* aNode,
                                     PRUint32 aType)
{
  nsIDocument* doc = aNode->GetOwnerDoc();
  if (!doc) {
    return PR_FALSE;
  }

  // global object will be null for documents that don't have windows.
  nsCOMPtr<nsPIDOMWindow> window;
  window = do_QueryInterface(doc->GetScriptGlobalObject());
  if (window && !window->HasMutationListeners(aType)) {
    return PR_FALSE;
  }

  // If we have a window, we can check it for mutation listeners now.
  nsCOMPtr<nsIDOMEventReceiver> rec(do_QueryInterface(window));
  if (rec) {
    nsCOMPtr<nsIEventListenerManager> manager;
    rec->GetListenerManager(PR_FALSE, getter_AddRefs(manager));
    if (manager) {
      PRBool hasListeners = PR_FALSE;
      manager->HasMutationListeners(&hasListeners);
      if (hasListeners) {
        return PR_TRUE;
      }
    }
  }

  // If we have a window, we know a mutation listener is registered, but it
  // might not be in our chain.  If we don't have a window, we might have a
  // mutation listener.  Check quickly to see.
  while (aNode) {
    nsCOMPtr<nsIEventListenerManager> manager;
    aNode->GetListenerManager(PR_FALSE, getter_AddRefs(manager));
    if (manager) {
      PRBool hasListeners = PR_FALSE;
      manager->HasMutationListeners(&hasListeners);
      if (hasListeners) {
        return PR_TRUE;
      }
    }
    aNode = aNode->GetNodeParent();
  }

  return PR_FALSE;
}

/* static */
nsresult
nsContentUtils::GetListenerManager(nsINode *aNode,
                                   PRBool aCreateIfNotFound,
                                   nsIEventListenerManager **aResult,
                                   PRBool *aCreated)
{
  *aResult = nsnull;
  *aCreated = PR_FALSE;

  if (!sEventListenerManagersHash.ops) {
    // We're already shut down, don't bother creating an event listener
    // manager.

    return NS_ERROR_NOT_AVAILABLE;
  }

  if (!aCreateIfNotFound) {
    EventListenerManagerMapEntry *entry =
      NS_STATIC_CAST(EventListenerManagerMapEntry *,
                     PL_DHashTableOperate(&sEventListenerManagersHash, aNode,
                                          PL_DHASH_LOOKUP));
    if (PL_DHASH_ENTRY_IS_BUSY(entry)) {
      *aResult = entry->mListenerManager;
      NS_ADDREF(*aResult);
    }
    return NS_OK;
  }

  EventListenerManagerMapEntry *entry =
    NS_STATIC_CAST(EventListenerManagerMapEntry *,
                   PL_DHashTableOperate(&sEventListenerManagersHash, aNode,
                                        PL_DHASH_ADD));

  if (!entry) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  if (!entry->mListenerManager) {
    nsresult rv =
      NS_NewEventListenerManager(getter_AddRefs(entry->mListenerManager));

    if (NS_FAILED(rv)) {
      PL_DHashTableRawRemove(&sEventListenerManagersHash, entry);

      return rv;
    }

    entry->mListenerManager->SetListenerTarget(aNode);

    *aCreated = PR_TRUE;
  }

  NS_ADDREF(*aResult = entry->mListenerManager);

  return NS_OK;
}

/* static */
void
nsContentUtils::RemoveListenerManager(nsINode *aNode)
{
  if (sEventListenerManagersHash.ops) {
    EventListenerManagerMapEntry *entry =
      NS_STATIC_CAST(EventListenerManagerMapEntry *,
                     PL_DHashTableOperate(&sEventListenerManagersHash, aNode,
                                          PL_DHASH_LOOKUP));
    if (PL_DHASH_ENTRY_IS_BUSY(entry)) {
      nsCOMPtr<nsIEventListenerManager> listenerManager;
      listenerManager.swap(entry->mListenerManager);
      // Remove the entry and *then* do operations that could cause further
      // modification of sEventListenerManagersHash.  See bug 334177.
      PL_DHashTableRawRemove(&sEventListenerManagersHash, entry);
      if (listenerManager) {
        listenerManager->Disconnect();
      }
    }
  }
}

/* static */
nsresult
nsContentUtils::AddToRangeList(nsINode *aNode, nsIDOMRange *aRange,
                               PRBool *aCreated)
{
  *aCreated = PR_FALSE;

  if (!sRangeListsHash.ops) {
    // We've already been shut down, don't bother adding a range...

    return NS_OK;
  }

  RangeListMapEntry *entry =
    NS_STATIC_CAST(RangeListMapEntry *,
                   PL_DHashTableOperate(&sRangeListsHash, aNode,
                                        PL_DHASH_ADD));

  if (!entry) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  // lazy allocation of range list
  if (!entry->mRangeList) {
    entry->mRangeList = new nsAutoVoidArray();

    if (!entry->mRangeList) {
      PL_DHashTableRawRemove(&sRangeListsHash, entry);

      return NS_ERROR_OUT_OF_MEMORY;
    }

    *aCreated = PR_TRUE;
  }
  else {
    // Make sure we don't add a range that is already in the list!
    PRInt32 i = entry->mRangeList->IndexOf(aRange);

    if (i >= 0) {
      // Range is already in the list, so there is nothing to do!

      return NS_OK;
    }
  }

  // dont need to addref - this call is made by the range object
  // itself
  PRBool rv = entry->mRangeList->AppendElement(aRange);
  if (!rv) {
    if (entry->mRangeList->Count() == 0) {
      // Fresh entry, remove it from the hash...

      PL_DHashTableRawRemove(&sRangeListsHash, entry);
    }

    return NS_ERROR_OUT_OF_MEMORY;
  }

  return NS_OK;
}

/* static */
PRBool
nsContentUtils::RemoveFromRangeList(nsINode *aNode, nsIDOMRange *aRange)
{
  if (!sRangeListsHash.ops) {
    // We've already been shut down, don't bother removing a range...

    return PR_FALSE;
  }

  RangeListMapEntry *entry =
    NS_STATIC_CAST(RangeListMapEntry *,
                   PL_DHashTableOperate(&sRangeListsHash, aNode,
                                        PL_DHASH_LOOKUP));

  if (PL_DHASH_ENTRY_IS_FREE(entry)) {
    return PR_FALSE;
  }

  NS_ASSERTION(entry->mRangeList, "In the hash but without an object?");

  // dont need to release - this call is made by the range object itself
  entry->mRangeList->RemoveElement(aRange);

  if (entry->mRangeList->Count() != 0) {
    return PR_FALSE;
  }

  PL_DHashTableRawRemove(&sRangeListsHash, entry);

  return PR_TRUE;
}

/* static */
const nsVoidArray*
nsContentUtils::LookupRangeList(const nsINode *aNode)
{
  if (!sRangeListsHash.ops) {
    // We've already been shut down, don't bother getting a range list...

    return nsnull;
  }

  RangeListMapEntry *entry =
    NS_STATIC_CAST(RangeListMapEntry *,
                   PL_DHashTableOperate(&sRangeListsHash, aNode,
                                        PL_DHASH_LOOKUP));

  return PL_DHASH_ENTRY_IS_BUSY(entry) ? entry->mRangeList : nsnull;
}

/* static */
void
nsContentUtils::RemoveRangeList(nsINode *aNode)
{
  if (sRangeListsHash.ops) {
    PL_DHashTableOperate(&sRangeListsHash, aNode, PL_DHASH_REMOVE);
  }
}

/* static */
PRBool
nsContentUtils::IsValidNodeName(nsIAtom *aLocalName, nsIAtom *aPrefix,
                                PRInt32 aNamespaceID)
{
  if (!aPrefix) {
    // If the prefix is null, then either the QName must be xmlns or the
    // namespace must not be XMLNS.
    return (aLocalName == nsGkAtoms::xmlns) ==
           (aNamespaceID == kNameSpaceID_XMLNS);
  }

  // If the prefix is non-null then the namespace must not be null.
  if (aNamespaceID == kNameSpaceID_None) {
    return PR_FALSE;
  }

  // If the namespace is the XMLNS namespace then the prefix must be xmlns,
  // but the localname must not be xmlns.
  if (aNamespaceID == kNameSpaceID_XMLNS) {
    return aPrefix == nsGkAtoms::xmlns && aLocalName != nsGkAtoms::xmlns;
  }

  // If the namespace is not the XMLNS namespace then the prefix must not be
  // xmlns.
  // If the namespace is the XML namespace then the prefix can be anything.
  // If the namespace is not the XML namespace then the prefix must not be xml.
  return aPrefix != nsGkAtoms::xmlns &&
         (aNamespaceID == kNameSpaceID_XML || aPrefix != nsGkAtoms::xml);
}

/* static */
nsresult
nsContentUtils::SetUserData(nsINode *aNode, nsIAtom *aKey,
                            nsIVariant *aData, nsIDOMUserDataHandler *aHandler,
                            nsIVariant **aResult)
{
  *aResult = nsnull;

  nsresult rv;
  void *data;
  if (aData) {
    rv = aNode->SetProperty(DOM_USER_DATA, aKey, aData,
                            nsPropertyTable::SupportsDtorFunc,
                            &data);
    NS_ENSURE_SUCCESS(rv, rv);

    NS_ADDREF(aData);
  }
  else {
    data = aNode->UnsetProperty(DOM_USER_DATA, aKey);
  }

  // Take over ownership of the old data from the property table.
  nsCOMPtr<nsIVariant> oldData = dont_AddRef(NS_STATIC_CAST(nsIVariant*, data));

  if (aData && aHandler) {
    rv = aNode->SetProperty(DOM_USER_DATA_HANDLER, aKey, aHandler,
                            nsPropertyTable::SupportsDtorFunc);
    if (NS_FAILED(rv)) {
      // We failed to set the handler, remove the data.
      aNode->DeleteProperty(DOM_USER_DATA, aKey);

      return rv;
    }

    NS_ADDREF(aHandler);
  }
  else {
    aNode->DeleteProperty(DOM_USER_DATA_HANDLER, aKey);
  }

  oldData.swap(*aResult);

  return NS_OK;
}

struct nsHandlerData
{
  PRUint16 mOperation;
  nsIDOMNode *mSource;
  nsIDOMNode *mDest;
};

static void
CallHandler(void *aObject, nsIAtom *aKey, void *aHandler, void *aData)
{
  nsHandlerData *handlerData = NS_STATIC_CAST(nsHandlerData*, aData);
  nsCOMPtr<nsIDOMUserDataHandler> handler =
    NS_STATIC_CAST(nsIDOMUserDataHandler*, aHandler);

  nsINode *node = NS_STATIC_CAST(nsINode*, aObject);
  nsCOMPtr<nsIVariant> data =
    NS_STATIC_CAST(nsIVariant*, node->GetProperty(DOM_USER_DATA, aKey));
  NS_ASSERTION(data, "Handler without data?");

  nsAutoString key;
  aKey->ToString(key);
  handler->Handle(handlerData->mOperation, key, data, handlerData->mSource,
                  handlerData->mDest);
}

/* static */
void
nsContentUtils::CallUserDataHandler(nsIDocument *aDocument, PRUint16 aOperation,
                                    const nsINode *aNode, nsIDOMNode *aSource,
                                    nsIDOMNode *aDest)
{
#ifdef DEBUG
  // XXX Should we guard from QI'ing nodes that are being destroyed?
  nsCOMPtr<nsINode> node = do_QueryInterface(NS_CONST_CAST(nsINode*, aNode));
  NS_ASSERTION(node == aNode, "Use canonical nsINode pointer!");
#endif

  nsHandlerData handlerData = { aOperation, aSource, aDest };
  aDocument->PropertyTable()->Enumerate(aNode, DOM_USER_DATA_HANDLER,
                                        CallHandler, &handlerData);
}

static void
CopyData(void *aObject, nsIAtom *aKey, void *aUserData, void *aData)
{
  nsPropertyTable *propertyTable = NS_STATIC_CAST(nsPropertyTable*, aData);
  nsINode *node = NS_STATIC_CAST(nsINode*, aObject);
  nsIDOMUserDataHandler *handler =
    NS_STATIC_CAST(nsIDOMUserDataHandler*,
                   propertyTable->GetProperty(node, DOM_USER_DATA_HANDLER,
                                              aKey));

  nsCOMPtr<nsIVariant> result;
  nsContentUtils::SetUserData(node, aKey,
                              NS_STATIC_CAST(nsIVariant*, aUserData), handler,
                              getter_AddRefs(result));
}

/* static */
void
nsContentUtils::CopyUserData(nsIDocument *aOldDocument, const nsINode *aNode)
{
#ifdef DEBUG
  nsCOMPtr<nsINode> node = do_QueryInterface(NS_CONST_CAST(nsINode*, aNode));
  NS_ASSERTION(node == aNode, "Use canonical nsINode pointer!");
#endif

  nsPropertyTable *table = aOldDocument->PropertyTable();
  table->Enumerate(aNode, DOM_USER_DATA, CopyData, table);
}

/* static */
nsresult
nsContentUtils::CreateContextualFragment(nsIDOMNode* aContextNode,
                                         const nsAString& aFragment,
                                         nsIDOMDocumentFragment** aReturn)
{
  NS_ENSURE_ARG(aContextNode);
  *aReturn = nsnull;

  // Create a new parser for this entire operation
  nsresult rv;
  nsCOMPtr<nsIParser> parser = do_CreateInstance(kCParserCID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIDocument> document;
  nsCOMPtr<nsIDOMDocument> domDocument;

  aContextNode->GetOwnerDocument(getter_AddRefs(domDocument));
  document = do_QueryInterface(domDocument);

  // If we don't have a document here, we can't get the right security context
  // for compiling event handlers... so just bail out.
  NS_ENSURE_TRUE(document, NS_ERROR_NOT_AVAILABLE);

  nsVoidArray tagStack;
  nsCOMPtr<nsIDOMNode> parent = aContextNode;
  while (parent && (parent != domDocument)) {
    PRUint16 nodeType;
    parent->GetNodeType(&nodeType);
    if (nsIDOMNode::ELEMENT_NODE == nodeType) {
      nsAutoString tagName, uriStr;
      parent->GetNodeName(tagName);

      // see if we need to add xmlns declarations
      nsCOMPtr<nsIContent> content = do_QueryInterface(parent);
      if (!content) {
        rv = NS_ERROR_FAILURE;
        break;
      }

      PRUint32 count = content->GetAttrCount();
      PRBool setDefaultNamespace = PR_FALSE;
      if (count > 0) {
        PRUint32 index;
        nsAutoString nameStr, prefixStr, valueStr;

        for (index = 0; index < count; index++) {
          const nsAttrName* name = content->GetAttrNameAt(index);
          if (name->NamespaceEquals(kNameSpaceID_XMLNS)) {
            content->GetAttr(kNameSpaceID_XMLNS, name->LocalName(), uriStr);

            // really want something like nsXMLContentSerializer::SerializeAttr
            tagName.Append(NS_LITERAL_STRING(" xmlns")); // space important
            if (name->GetPrefix()) {
              tagName.Append(PRUnichar(':'));
              name->LocalName()->ToString(nameStr);
              tagName.Append(nameStr);
            } else {
              setDefaultNamespace = PR_TRUE;
            }
            tagName.Append(NS_LITERAL_STRING("=\"") + uriStr +
              NS_LITERAL_STRING("\""));
          }
        }
      }

      if (!setDefaultNamespace) {
        nsINodeInfo* info = content->NodeInfo();
        if (!info->GetPrefixAtom() &&
            info->NamespaceID() != kNameSpaceID_None) {
          // We have no namespace prefix, but have a namespace ID.  Push
          // default namespace attr in, so that our kids will be in our
          // namespace.
          nsAutoString uri;
          info->GetNamespaceURI(uri);
          tagName.Append(NS_LITERAL_STRING(" xmlns=\"") + uri +
                         NS_LITERAL_STRING("\""));
        }
      }

      // XXX Wish we didn't have to allocate here
      PRUnichar* name = ToNewUnicode(tagName);
      if (name) {
        tagStack.AppendElement(name);
        nsCOMPtr<nsIDOMNode> temp = parent;
        rv = temp->GetParentNode(getter_AddRefs(parent));
        if (NS_FAILED(rv)) {
          break;
        }
      } else {
        rv = NS_ERROR_OUT_OF_MEMORY;
        break;
      }
    } else {
      nsCOMPtr<nsIDOMNode> temp = parent;
      rv = temp->GetParentNode(getter_AddRefs(parent));
      if (NS_FAILED(rv)) {
        break;
      }
    }
  }

  if (NS_SUCCEEDED(rv)) {
    nsCAutoString contentType;
    PRBool bCaseSensitive = PR_TRUE;
    nsAutoString buf;
    document->GetContentType(buf);
    LossyCopyUTF16toASCII(buf, contentType);
    bCaseSensitive = document->IsCaseSensitive();

    nsCOMPtr<nsIHTMLDocument> htmlDoc(do_QueryInterface(domDocument));
    PRBool bHTML = htmlDoc && !bCaseSensitive;
    nsCOMPtr<nsIFragmentContentSink> sink;
    if (bHTML) {
      rv = NS_NewHTMLFragmentContentSink(getter_AddRefs(sink));
    } else {
      rv = NS_NewXMLFragmentContentSink(getter_AddRefs(sink));
    }
    if (NS_SUCCEEDED(rv)) {
      sink->SetTargetDocument(document);
      nsCOMPtr<nsIContentSink> contentsink(do_QueryInterface(sink));
      parser->SetContentSink(contentsink);

      nsDTDMode mode = eDTDMode_autodetect;
      if (bHTML) {
        switch (htmlDoc->GetCompatibilityMode()) {
          case eCompatibility_NavQuirks:
            mode = eDTDMode_quirks;
            break;
          case eCompatibility_AlmostStandards:
            mode = eDTDMode_almost_standards;
            break;
          case eCompatibility_FullStandards:
            mode = eDTDMode_full_standards;
            break;
          default:
            NS_NOTREACHED("unknown mode");
            break;
        }
      } else {
        mode = eDTDMode_full_standards;
      }
      rv = parser->ParseFragment(aFragment, nsnull, tagStack,
                                 !bHTML, contentType, mode);

      if (NS_SUCCEEDED(rv)) {
        rv = sink->GetFragment(aReturn);
      }
    }
  }

  // XXX Ick! Delete strings we allocated above.
  PRInt32 count = tagStack.Count();
  for (PRInt32 i = 0; i < count; i++) {
    PRUnichar* str = (PRUnichar*)tagStack.ElementAt(i);
    if (str) {
      nsCRT::free(str);
    }
  }

  return NS_OK;
}