gecko/modules/libpr0n/decoders/icon/nsIconDecoder.cpp

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 * 1.1 (the "License"); you may not use this file except in compliance with
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 * The Original Code is mozilla.org code.
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 * The Initial Developer of the Original Code is
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 * Contributor(s):
 *   Scott MacGregor <mscott@netscape.com>
 *   Bobby Holley <bobbyholley@gmail.com>
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#include "nsIconDecoder.h"
#include "nsIInputStream.h"
#include "imgIContainer.h"
#include "imgIContainerObserver.h"
#include "nspr.h"
#include "nsIComponentManager.h"
#include "nsRect.h"
#include "nsComponentManagerUtils.h"

#include "nsIInterfaceRequestorUtils.h"
#include "ImageErrors.h"

NS_IMPL_THREADSAFE_ADDREF(nsIconDecoder)
NS_IMPL_THREADSAFE_RELEASE(nsIconDecoder)

NS_INTERFACE_MAP_BEGIN(nsIconDecoder)
   NS_INTERFACE_MAP_ENTRY(imgIDecoder)
NS_INTERFACE_MAP_END_THREADSAFE


nsIconDecoder::nsIconDecoder() :
  mImage(nsnull),
  mObserver(nsnull),
  mFlags(imgIDecoder::DECODER_FLAG_NONE),
  mWidth(-1),
  mHeight(-1),
  mPixBytesRead(0),
  mPixBytesTotal(0),
  mImageData(nsnull),
  mState(iconStateStart),
  mNotifiedDone(PR_FALSE)
{
  // Nothing to do
}

nsIconDecoder::~nsIconDecoder()
{ }


/** imgIDecoder methods **/

NS_IMETHODIMP nsIconDecoder::Init(imgIContainer *aImage,
                                  imgIDecoderObserver *aObserver,
                                  PRUint32 aFlags)
{

  // Grab parameters
  mImage = aImage;
  mObserver = aObserver;
  mFlags = aFlags;

  // Fire OnStartDecode at init time to support bug 512435
  if (!(mFlags & imgIDecoder::DECODER_FLAG_HEADERONLY) && mObserver)
    mObserver->OnStartDecode(nsnull);

  return NS_OK;
}

NS_IMETHODIMP nsIconDecoder::Close(PRUint32 aFlags)
{
  // If we haven't notified of completion yet for a full/success decode, we
  // didn't finish. Notify in error mode
  if (!(aFlags & CLOSE_FLAG_DONTNOTIFY) &&
      !(mFlags & imgIDecoder::DECODER_FLAG_HEADERONLY) &&
      !mNotifiedDone)
    NotifyDone(/* aSuccess = */ PR_FALSE);

  mImage = nsnull;
  return NS_OK;
}

NS_IMETHODIMP nsIconDecoder::Flush()
{
  return NS_OK;
}

NS_IMETHODIMP
nsIconDecoder::Write(const char *aBuffer, PRUint32 aCount)
{
  nsresult rv;

  // We put this here to avoid errors about crossing initialization with case
  // jumps on linux.
  PRUint32 bytesToRead = 0;

  // Performance isn't critical here, so our update rectangle is 
  // always the full icon
  nsIntRect r(0, 0, mWidth, mHeight);

  // Loop until the input data is gone
  while (aCount > 0) {
    switch (mState) {
      case iconStateStart:

        // Grab the width
        mWidth = (PRUint8)*aBuffer;

        // Book Keeping
        aBuffer++;
        aCount--;
        mState = iconStateHaveHeight;
        break;

      case iconStateHaveHeight:

        // Grab the Height
        mHeight = (PRUint8)*aBuffer;

        // Set up the container and signal
        mImage->SetSize(mWidth, mHeight);
        if (mObserver)
          mObserver->OnStartContainer(nsnull, mImage);

        // If We're doing a header-only decode, we're done
        if (mFlags & imgIDecoder::DECODER_FLAG_HEADERONLY) {
          mState = iconStateFinished;
          break;
        }

        // Add the frame and signal
        rv = mImage->AppendFrame(0, 0, mWidth, mHeight,
                                 gfxASurface::ImageFormatARGB32,
                                 &mImageData, &mPixBytesTotal);
        if (NS_FAILED(rv)) {
          mState = iconStateError;
          return rv;
        }
        if (mObserver)
         mObserver->OnStartFrame(nsnull, 0);

        // Book Keeping
        aBuffer++;
        aCount--;
        mState = iconStateReadPixels;
        break;

      case iconStateReadPixels:

        // How many bytes are we reading?
        bytesToRead = PR_MIN(aCount, mPixBytesTotal - mPixBytesRead);

        // Copy the bytes
        memcpy(mImageData + mPixBytesRead, aBuffer, bytesToRead);

        // Notify
        rv = mImage->FrameUpdated(0, r);
        if (NS_FAILED(rv)) {
          mState = iconStateError;
          return rv;
        }
        if (mObserver)
          mObserver->OnDataAvailable(nsnull, PR_TRUE, &r);

        // Book Keeping
        aBuffer += bytesToRead;
        aCount -= bytesToRead;
        mPixBytesRead += bytesToRead;

        // If we've got all the pixel bytes, we're finished
        if (mPixBytesRead == mPixBytesTotal) {
          NotifyDone(/* aSuccess = */ PR_TRUE);
          mState = iconStateFinished;
        }
        break;

      case iconStateFinished:

        // Consume all excess data silently
        aCount = 0;

        break;

      case iconStateError:
        return NS_IMAGELIB_ERROR_FAILURE;
        break;
    }
  }

  return NS_OK;
}

void
nsIconDecoder::NotifyDone(PRBool aSuccess)
{
  // We should only call this once
  NS_ABORT_IF_FALSE(!mNotifiedDone, "Calling NotifyDone twice");

  // Notify
  if (mObserver)
    mObserver->OnStopFrame(nsnull, 0);
  if (aSuccess)
    mImage->DecodingComplete();
  if (mObserver) {
    mObserver->OnStopContainer(nsnull, mImage);
    mObserver->OnStopDecode(nsnull, aSuccess ? NS_OK : NS_ERROR_FAILURE,
                            nsnull);
  }

  // Flag that we've notified
  mNotifiedDone = PR_TRUE;
}