gecko-dev/layout/generic/nsAreaFrame.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 *
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#include "nsAreaFrame.h"
#include "nsBlockBandData.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsIPresContext.h"
#include "nsIViewManager.h"
#include "nsHTMLAtoms.h"
#include "nsIView.h"
#include "nsHTMLValue.h"
#include "nsHTMLParts.h"
#include "nsLayoutAtoms.h"

#ifdef INCLUDE_XUL
#include "nsINameSpaceManager.h"
#include "nsXULAtoms.h"
#include "nsIEventStateManager.h"
#endif

#undef NOISY_MAX_ELEMENT_SIZE
#undef NOISY_FINAL_SIZE

nsresult
NS_NewAreaFrame(nsIPresShell* aPresShell, nsIFrame** aNewFrame, PRUint32 aFlags)
{
  NS_PRECONDITION(aNewFrame, "null OUT ptr");
  if (nsnull == aNewFrame) {
    return NS_ERROR_NULL_POINTER;
  }
  nsAreaFrame* it = new (aPresShell) nsAreaFrame;
  if (nsnull == it) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  it->SetFlags(aFlags);
  *aNewFrame = it;
  return NS_OK;
}

nsAreaFrame::nsAreaFrame()
{
}

#ifdef INCLUDE_XUL

// If you make changes to this function, check its counterparts 
// in nsBoxFrame and nsTextBoxFrame
nsresult
nsAreaFrame::RegUnregAccessKey(nsIPresContext* aPresContext,
                               PRBool aDoReg)
{
  // if we have no content, we can't do anything
  if (!mContent)
    return NS_ERROR_FAILURE;

  PRBool isXUL = mContent->IsContentOfType(nsIContent::eXUL);
  if (!isXUL)
    return NS_OK;

  // find out what type of element this is
  nsCOMPtr<nsIAtom> atom;
  nsresult rv = mContent->GetTag(*getter_AddRefs(atom));
  if (NS_FAILED(rv))
    return rv;

  // only support accesskeys for the following elements
  if (atom != nsXULAtoms::label)
    return NS_OK;

  // To filter out <label>s without a control attribute.
  // XXXjag a side-effect is that we filter out anonymous <label>s
  // in e.g. <menu>, <menuitem>, <button>. These <label>s inherit
  // |accesskey| and would otherwise register themselves, overwriting
  // the content we really meant to be registered.
  if (!mContent->HasAttr(kNameSpaceID_None, nsXULAtoms::control))
    return NS_OK;

  nsAutoString accessKey;
  mContent->GetAttr(kNameSpaceID_None, nsXULAtoms::accesskey, accessKey);

  if (accessKey.IsEmpty())
    return NS_OK;

  // With a valid PresContext we can get the ESM 
  // and register the access key
  nsCOMPtr<nsIEventStateManager> esm;
  aPresContext->GetEventStateManager(getter_AddRefs(esm));

  rv = NS_OK;

  if (esm) {
    PRUint32 key = accessKey.First();
    if (aDoReg)
      rv = esm->RegisterAccessKey(mContent, key);
    else
      rv = esm->UnregisterAccessKey(mContent, key);
  }

  return rv;
}
#endif

/////////////////////////////////////////////////////////////////////////////
// nsIFrame

#ifdef INCLUDE_XUL
NS_IMETHODIMP
nsAreaFrame::Init(nsIPresContext*  aPresContext,
                  nsIContent*      aContent,
                  nsIFrame*        aParent,
                  nsStyleContext*  aContext,
                  nsIFrame*        aPrevInFlow)
{
  nsresult rv = nsBlockFrame::Init(aPresContext,
                                   aContent,
                                   aParent,
                                   aContext,
                                   aPrevInFlow);
  if (NS_FAILED(rv))
    return rv;

  // register access key
  return RegUnregAccessKey(aPresContext, PR_TRUE);
}

NS_IMETHODIMP
nsAreaFrame::Destroy(nsIPresContext* aPresContext)
{
  // unregister access key
  RegUnregAccessKey(aPresContext, PR_FALSE);

  return nsBlockFrame::Destroy(aPresContext);
} 

NS_IMETHODIMP
nsAreaFrame::AttributeChanged(nsIPresContext* aPresContext,
                              nsIContent* aChild,
                              PRInt32 aNameSpaceID,
                              nsIAtom* aAttribute,
                              PRInt32 aModType,
                              PRInt32 aHint)
{
  nsresult rv = nsBlockFrame::AttributeChanged(aPresContext, aChild,
                                               aNameSpaceID, aAttribute,
                                               aModType, aHint);

  // If the accesskey changed, register for the new value
  // The old value has been unregistered in nsXULElement::SetAttr
  if (aAttribute == nsXULAtoms::accesskey || aAttribute == nsXULAtoms::control)
    RegUnregAccessKey(aPresContext, PR_TRUE);

  return rv;
}
#endif

NS_IMETHODIMP
nsAreaFrame::GetFrameType(nsIAtom** aType) const
{
  NS_PRECONDITION(nsnull != aType, "null OUT parameter pointer");
  *aType = nsLayoutAtoms::areaFrame; 
  NS_ADDREF(*aType);
  return NS_OK;
}

/////////////////////////////////////////////////////////////////////////////
// Diagnostics

#ifdef NS_DEBUG
NS_IMETHODIMP
nsAreaFrame::GetFrameName(nsAString& aResult) const
{
  return MakeFrameName(NS_LITERAL_STRING("Area"), aResult);
}
#endif