gecko-dev/layout/base/nsPresContext.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 *
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */
#include "nsPresContext.h"
#include "nsIPresShell.h"
#include "nsILinkHandler.h"
#include "nsIStyleContext.h"
#include "nsIStyleSet.h"
#include "nsIFontMetrics.h"
#include "nsIImageManager.h"
#include "nsIImageGroup.h"
#include "nsIImageRequest.h"
#include "nsIImageObserver.h"
#include "nsIView.h"
#include "nsIViewManager.h"
#include "nsIFrame.h"
#include "nsIRenderingContext.h"
#include "nsTransform2D.h"
#include "nsIDocument.h"
#include "nsIURL.h"
#include "nsString.h"

static NS_DEFINE_IID(kIPresContextIID, NS_IPRESCONTEXT_IID);

#if 0
// XXX this code needs to move far away from here
static nsIImageManager* gImageManager = nsnull;
static void InitImageLibrary()
{
  // Initialize image library
  if (NS_OK == NS_NewImageManager(&gImageManager)) {
    if (NS_OK == gImageManager->Init()) {
      gImageManager->SetCacheSize(1024*1024);
      return;
    }
  }
  printf("can't initialize image library\n");
}
// XXX end code with no home...
#endif

class ImageLoader :  public nsIImageRequestObserver {
public:
  ImageLoader(nsPresContext* aCX, nsIImageGroup* aGroup, nsIFrame* aFrame);
  ~ImageLoader();

  NS_DECL_ISUPPORTS

  void LoadImage(const nsString& aURL);

  const nsString& GetURL() const {
    return mURL;
  }

  nsIImage* GetImage() {
    return mImage;
  }

  PRInt32 FrameCount();

  PRBool RemoveFrame(nsIFrame* aFrame);

  void AddFrame(nsIFrame* aFrame);

  void UpdateFrames();

  virtual void Notify(nsIImageRequest *aImageRequest,
                      nsIImage *aImage,
                      nsImageNotification aNotificationType,
                      PRInt32 aParam1, PRInt32 aParam2,
                      void *aParam3);

  virtual void NotifyError(nsIImageRequest *aImageRequest,
                           nsImageError aErrorType);

  nsVoidArray mFrames;
  nsString mURL;
  nsPresContext* mCX;
  nsIImage* mImage;
  nsIImageRequest* mImageRequest;
  nsIImageGroup* mImageGroup;

  PRInt32 mWidth, mHeight;              // in pixels
};

ImageLoader::ImageLoader(nsPresContext* aCX, nsIImageGroup* aGroup,
                         nsIFrame* aFrame)
{
  mCX = aCX;
  AddFrame(aFrame);
  mImage = nsnull;
  mImageRequest = nsnull;
  mImageGroup = aGroup; NS_ADDREF(aGroup);
  mWidth = -1;
  mHeight = -1;
}

ImageLoader::~ImageLoader()
{
  if (nsnull != mImageRequest) {
    mImageRequest->Interrupt();
    mImageRequest->RemoveObserver(this);
  }
}

void ImageLoader::LoadImage(const nsString& aURL)
{
  if (nsnull == mImage) {
    // Save url
    mURL.SetLength(0);
    mURL.Append(aURL);

    // Start image load
    char* cp = aURL.ToNewCString();
    mImageRequest = mImageGroup->GetImage(cp, this, NS_RGB(255,255,255),
                                          0, 0, 0);
    delete cp;
  }
}

static NS_DEFINE_IID(kIImageRequestObserver, NS_IIMAGEREQUESTOBSERVER_IID);

NS_IMPL_ISUPPORTS(ImageLoader, kIImageRequestObserver);

static PRBool gXXXInstalledColorMap;
void ImageLoader::Notify(nsIImageRequest *aImageRequest,
                         nsIImage *aImage,
                         nsImageNotification aNotificationType,
                         PRInt32 aParam1, PRInt32 aParam2,
                         void *aParam3)
{
  switch (aNotificationType) {
  case nsImageNotification_kDimensions:
#ifdef NOISY
    printf("Image:%d x %d\n", aParam1, aParam2);
#endif
    mWidth = aParam1;
    mHeight = aParam2;
    break;

  case nsImageNotification_kPixmapUpdate:
  case nsImageNotification_kImageComplete:
  case nsImageNotification_kFrameComplete:
    if ((mImage == nsnull) && (nsnull != aImage)) {
      mImage = aImage;
      NS_ADDREF(aImage);
    }
    UpdateFrames();
  }
}

PRInt32 ImageLoader::FrameCount()
{
  return mFrames.Count();
}

PRBool ImageLoader::RemoveFrame(nsIFrame* aFrame)
{
  return mFrames.RemoveElement(aFrame);
}

void ImageLoader::AddFrame(nsIFrame* aFrame)
{
  PRInt32 i, n = mFrames.Count();
  for (i = 0; i < n; i++) {
    nsIFrame* frame = (nsIFrame*) mFrames.ElementAt(i);
    if (frame == aFrame) {
      return;
    }
  }
  mFrames.AppendElement(aFrame);
}

void ImageLoader::UpdateFrames()
{
  PRInt32 i, n = mFrames.Count();
  for (i = 0; i < n; i++) {
    nsIFrame* frame = (nsIFrame*) mFrames.ElementAt(i);

    // XXX installed colormap should be presentation-context/window state
    nsIWidget* window;
     
    frame->GetWindow(window);
    if (!gXXXInstalledColorMap && mImage) {
      nsColorMap* cmap = mImage->GetColorMap();
      if ((nsnull != cmap) && (cmap->NumColors > 0)) {
        window->SetColorMap(cmap);
      }
      gXXXInstalledColorMap = PR_TRUE;
    }

    // Determine damaged area and tell view manager to redraw it
    nsPoint offset;
    nsRect bounds;
    frame->GetRect(bounds);
    nsIView* view;
     
    frame->GetOffsetFromView(offset, view);
    nsIViewManager* vm = view->GetViewManager();
    bounds.x = offset.x;
    bounds.y = offset.y;
    vm->UpdateView(view, &bounds, 0);
    NS_RELEASE(vm);
    NS_RELEASE(view);
  }
}

void ImageLoader::NotifyError(nsIImageRequest *aImageRequest,
                              nsImageError aErrorType)
{
  printf("XXX image error: %d\n", aErrorType);
}

//----------------------------------------------------------------------

nsPresContext::nsPresContext()
  : mVisibleArea(0, 0, 0, 0),
    mDefaultFont("Times", NS_FONT_STYLE_NORMAL,
                 NS_FONT_VARIANT_NORMAL,
                 NS_FONT_WEIGHT_NORMAL,
                 0,
                 NS_POINTS_TO_TWIPS_INT(12))
{
  NS_INIT_REFCNT();
  mShell = nsnull;
  mDeviceContext = nsnull;
  mImageGroup = nsnull;
  mLinkHandler = nsnull;
  mContainer = nsnull;
}

nsPresContext::~nsPresContext()
{
  mShell = nsnull;

  // XXX there is a race between an async notify and this code because
  // the presentation shell code deletes the frame tree first and then
  // deletes us. We need an "Deactivation" hook for this code too

  // Release all the image loaders
  PRInt32 n = mImageLoaders.Count();
  for (PRInt32 i = 0; i < n; i++) {
    ImageLoader* loader = (ImageLoader*) mImageLoaders.ElementAt(i);
    delete loader;
  }

  // XXX Release all the cached images

  if (nsnull != mImageGroup) {
    mImageGroup->Interrupt();
    NS_RELEASE(mImageGroup);
  }

  NS_IF_RELEASE(mLinkHandler);
  NS_IF_RELEASE(mContainer);
}

nsrefcnt nsPresContext::AddRef(void)
{
  return ++mRefCnt;
}

nsrefcnt nsPresContext::Release(void)
{
  NS_PRECONDITION(0 != mRefCnt, "bad refcnt");
  if (--mRefCnt == 0) {
    delete this;
    return 0;
  }
  return mRefCnt;
}

NS_IMPL_QUERY_INTERFACE(nsPresContext, kIPresContextIID);

// Note: We don't hold a reference on the shell; it has a reference to
// us
void nsPresContext::SetShell(nsIPresShell* aShell)
{
  mShell = aShell;
}

nsIPresShell* nsPresContext::GetShell()
{
  if (nsnull != mShell) {
    NS_ADDREF(mShell);
  }
  return mShell;
}

nsIStyleContext*
nsPresContext::ResolveStyleContextFor(nsIContent* aContent,
                                      nsIFrame* aParentFrame)
{
  nsIStyleContext* result = nsnull;

  nsIStyleSet* set = mShell->GetStyleSet();
  if (nsnull != set) {
    result = set->ResolveStyleFor(this, aContent, aParentFrame);
    NS_RELEASE(set);
  }

  return result;
}

nsIFontMetrics* nsPresContext::GetMetricsFor(const nsFont& aFont)
{
  if (nsnull != mDeviceContext)
    return mDeviceContext->GetMetricsFor(aFont);

  return nsnull;
}

const nsFont& nsPresContext::GetDefaultFont(void)
{
  return mDefaultFont;
}

nsRect nsPresContext::GetVisibleArea()
{
  return mVisibleArea;
}

void nsPresContext::SetVisibleArea(const nsRect& r)
{
  mVisibleArea = r;
}

float nsPresContext::GetPixelsToTwips() const
{
  if (nsnull != mDeviceContext)
    return mDeviceContext->GetDevUnitsToAppUnits();

  return 1.0f;
}

float nsPresContext::GetTwipsToPixels() const
{
  if (nsnull != mDeviceContext)
    return mDeviceContext->GetAppUnitsToDevUnits();

  return 1.0f;
}

nsIDeviceContext * nsPresContext::GetDeviceContext() const
{
  NS_IF_ADDREF(mDeviceContext);
  return mDeviceContext;
}

nsIImage* nsPresContext::LoadImage(const nsString& aURL, nsIFrame* aForFrame)
{
  if (nsnull == mImageGroup) {
    // XXX this is bad; if we allow for subwindows that have different
    // rendering context's this won't work
    nsIWidget* window;
     
    aForFrame->GetWindow(window);
    nsIRenderingContext* drawCtx = window->GetRenderingContext();
    drawCtx->Scale(mDeviceContext->GetAppUnitsToDevUnits(),
                   mDeviceContext->GetAppUnitsToDevUnits());
    if ((NS_OK != NS_NewImageGroup(&mImageGroup)) ||
        (NS_OK != mImageGroup->Init(drawCtx))) {
      // XXX what to do?
      printf("XXX: can't get image group created\n");
      NS_RELEASE(drawCtx);
      return nsnull;
    }
    NS_RELEASE(drawCtx);
  }

  // Get absolute version of the url
  nsIDocument* doc = mShell->GetDocument();
  nsIURL* docURL = doc->GetDocumentURL();
  char* spec = aURL.ToNewCString();
  nsIURL* url;
  nsresult rv = NS_NewURL(&url, docURL, spec);
  delete spec;
  NS_RELEASE(docURL);
  NS_RELEASE(doc);
  if (NS_OK != rv) {
    // XXX lost error
    return nsnull;
  }
  nsAutoString absURL;
  url->ToString(absURL);
  NS_RELEASE(url);

  PRInt32 n = mImageLoaders.Count();
  for (PRInt32 i = 0; i < n; i++) {
    ImageLoader* loader = (ImageLoader*) mImageLoaders.ElementAt(i);
    if (absURL.Equals(loader->GetURL())) {
      loader->AddFrame(aForFrame);
      return loader->GetImage();
    }
  }

  ImageLoader* loader = new ImageLoader(this, mImageGroup, aForFrame);
  mImageLoaders.AppendElement(loader);

  loader->LoadImage(absURL);
  return loader->GetImage();
}

void nsPresContext::StopLoadImage(nsIFrame* aForFrame)
{
  PRInt32 n = mImageLoaders.Count();
  for (PRInt32 i = 0; i < n;) {
    ImageLoader* loader = (ImageLoader*) mImageLoaders.ElementAt(i);
    if (loader->RemoveFrame(aForFrame)) {
      if (0 == loader->FrameCount()) {
        delete loader;
        mImageLoaders.RemoveElementAt(i);
        n--;
        continue;
      }
    }
    i++;
  }
}

NS_IMETHODIMP nsPresContext::SetLinkHandler(nsILinkHandler* aHandler)
{ // XXX should probably be a WEAK reference
  NS_IF_RELEASE(mLinkHandler);
  mLinkHandler = aHandler;
  NS_IF_ADDREF(aHandler);
  return NS_OK;
}

NS_IMETHODIMP nsPresContext::GetLinkHandler(nsILinkHandler** aResult)
{
  NS_PRECONDITION(nsnull != aResult, "null ptr");
  if (nsnull == aResult) {
    return NS_ERROR_NULL_POINTER;
  }
  *aResult = mLinkHandler;
  NS_IF_ADDREF(mLinkHandler);
  return NS_OK;
}

NS_IMETHODIMP nsPresContext::SetContainer(nsISupports* aHandler)
{ // XXX should most likely be a WEAK reference
  NS_IF_RELEASE(mContainer);
  mContainer = aHandler;
  NS_IF_ADDREF(aHandler);
  return NS_OK;
}

NS_IMETHODIMP nsPresContext::GetContainer(nsISupports** aResult)
{
  NS_PRECONDITION(nsnull != aResult, "null ptr");
  if (nsnull == aResult) {
    return NS_ERROR_NULL_POINTER;
  }
  *aResult = mContainer;
  NS_IF_ADDREF(mContainer);
  return NS_OK;
}