Bug 411718 - "Speed up JPEG decoding by 30% by skipping buffer" (try without the realloc optimization) [p=alfredkayser@gmail.com (Alfred Kayser) r=stuart sr=tor a=blocking1.9+]

modules/libpr0n/decoders/jpeg/nsJPEGDecoder.cpp

@@ -85,14 +85,15 @@ nsJPEGDecoder::nsJPEGDecoder()
 {
   mState = JPEG_HEADER;
   mReading = PR_TRUE;
+  mError = NS_OK;
 
   mBytesToSkip = 0;
   memset(&mInfo, 0, sizeof(jpeg_decompress_struct));
   memset(&mSourceMgr, 0, sizeof(mSourceMgr));
   mInfo.client_data = (void*)this;
 
-  mBuffer = nsnull;
+  mSegment = nsnull;
-  mBufferLen = mBufferSize = 0;
+  mSegmentLen = 0;
 
   mBackBuffer = nsnull;
   mBackBufferLen = mBackBufferSize = mBackBufferUnreadLen = 0;
@@ -107,7 +108,6 @@ nsJPEGDecoder::nsJPEGDecoder()
 
 nsJPEGDecoder::~nsJPEGDecoder()
 {
-  PR_FREEIF(mBuffer);
   PR_FREEIF(mBackBuffer);
   if (mTransform)
     cmsDeleteTransform(mTransform);
@@ -125,7 +125,6 @@ nsJPEGDecoder::~nsJPEGDecoder()
 /* void init (in imgILoad aLoad); */
 NS_IMETHODIMP nsJPEGDecoder::Init(imgILoad *aLoad)
 {
-  mImageLoad = aLoad;
   mObserver = do_QueryInterface(aLoad);
 
   /* We set up the normal JPEG error routines, then override error_exit. */
@@ -169,14 +168,14 @@ NS_IMETHODIMP nsJPEGDecoder::Init(imgILoad *aLoad)
    * If we have a mismatch in width/height for the container later on we will
    * generate an error.
    */
-  mImageLoad->GetImage(getter_AddRefs(mImage));
+  aLoad->GetImage(getter_AddRefs(mImage));
 
   if (!mImage) {
     mImage = do_CreateInstance("@mozilla.org/image/container;1");
     if (!mImage)
       return NS_ERROR_OUT_OF_MEMORY;
       
-    mImageLoad->SetImage(mImage);
+    aLoad->SetImage(mImage);
     nsresult result = mImage->SetDiscardable("image/jpeg");
     if (NS_FAILED(result)) {
       mState = JPEG_ERROR;
@@ -196,14 +195,17 @@ NS_IMETHODIMP nsJPEGDecoder::Close()
   PR_LOG(gJPEGlog, PR_LOG_DEBUG,
          ("[this=%p] nsJPEGDecoder::Close\n", this));
 
-  if (mState != JPEG_DONE && mState != JPEG_SINK_NON_JPEG_TRAILER)
-    NS_WARNING("Never finished decoding the JPEG.");
-
   /* Step 8: Release JPEG decompression object */
   mInfo.src = nsnull;
 
   jpeg_destroy_decompress(&mInfo);
 
+  if (mState != JPEG_DONE && mState != JPEG_SINK_NON_JPEG_TRAILER) {
+    NS_WARNING("Never finished decoding the JPEG.");
+    /* Tell imgLoader that image decoding has failed */
+    return NS_ERROR_FAILURE;
+  }
+
   return NS_OK;
 }
 
@@ -214,58 +216,57 @@ NS_IMETHODIMP nsJPEGDecoder::Flush()
 
   PRUint32 ret;
   if (mState != JPEG_DONE && mState != JPEG_SINK_NON_JPEG_TRAILER && mState != JPEG_ERROR)
-    return this->WriteFrom(nsnull, 0, &ret);
+    return this->ProcessData(nsnull, 0, &ret);
 
   return NS_OK;
 }
 
-/* unsigned long writeFrom (in nsIInputStream inStr, in unsigned long count); */
+static NS_METHOD ReadDataOut(nsIInputStream* in,
-NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PRUint32 *_retval)
+                             void* closure,
+                             const char* fromRawSegment,
+                             PRUint32 toOffset,
+                             PRUint32 count,
+                             PRUint32 *writeCount)
 {
-  LOG_SCOPE_WITH_PARAM(gJPEGlog, "nsJPEGDecoder::WriteFrom", "count", count);
+  nsJPEGDecoder *decoder = static_cast<nsJPEGDecoder*>(closure);
+  nsresult rv = decoder->ProcessData(fromRawSegment, count, writeCount);
+  if (NS_FAILED(rv)) {
+    /* Tell imgLoader that image decoding has failed */
+    decoder->mError = rv;
+    *writeCount = 0;
+  }
 
-  PR_LOG(gJPEGDecoderAccountingLog, PR_LOG_DEBUG,
+  return NS_OK;
-         ("nsJPEGDecoder::WriteFrom(decoder = %p) {\n"
+}
-          "        image container %s; %u bytes to be added",
-          this,
-          mImage ? "exists" : "does not exist",
-          count));
 
-  if (inStr) {
-    if (!mBuffer) {
-      mBuffer = (JOCTET *)PR_Malloc(count);
-      if (!mBuffer) {
-        mState = JPEG_ERROR;
-        PR_LOG(gJPEGDecoderAccountingLog, PR_LOG_DEBUG,
-               ("} (out of memory allocating buffer)"));
-        return NS_ERROR_OUT_OF_MEMORY;
-      }
-      mBufferSize = count;
-    } else if (count > mBufferSize) {
-      JOCTET *buf = (JOCTET *)PR_Realloc(mBuffer, count);
-      if (!buf) {
-        mState = JPEG_ERROR;
-        PR_LOG(gJPEGDecoderAccountingLog, PR_LOG_DEBUG,
-               ("} (out of memory resizing buffer)"));
-        return NS_ERROR_OUT_OF_MEMORY;
-      }
-      mBuffer = buf;
-      mBufferSize = count;
-    }
 
-    nsresult rv = inStr->Read((char*)mBuffer, count, &mBufferLen);
+/* unsigned long writeFrom (in nsIInputStream inStr, in unsigned long count); */
-    NS_ASSERTION(NS_SUCCEEDED(rv), "nsJPEGDecoder::WriteFrom -- inStr->Read failed");
+NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PRUint32 *writeCount)
+{
+  NS_ENSURE_ARG_POINTER(inStr);
+  NS_ENSURE_ARG_POINTER(writeCount);
 
-    PR_LOG(gJPEGDecoderAccountingLog, PR_LOG_DEBUG,
+  /* necko doesn't propagate the errors from ReadDataOut */
-           ("nsJPEGDecoder::WriteFrom(): decoder %p got %u bytes, read %u from the stream (buffer size %u)",
+  nsresult rv = inStr->ReadSegments(ReadDataOut, this, count, writeCount);
-            this,
+  if (NS_FAILED(mError)) {
-            count,
+    /* Tell imgLoader that image decoding has failed */
-            mBufferLen,
+    rv = NS_ERROR_FAILURE;
-            mBufferSize));
+  }
-    
-    *_retval = mBufferLen;
 
-    nsresult result = mImage->AddRestoreData((char *) mBuffer, count);
+  return rv;
+}
+
+//******************************************************************************
+nsresult nsJPEGDecoder::ProcessData(const char *data, PRUint32 count, PRUint32 *writeCount)
+{
+  LOG_SCOPE_WITH_PARAM(gJPEGlog, "nsJPEGDecoder::ProcessData", "count", count);
+
+  mSegment = (const JOCTET *)data;
+  mSegmentLen = count;
+  *writeCount = count;
+
+  if (data && count) {
+    nsresult result = mImage->AddRestoreData((char *) data, count);
 
     if (NS_FAILED(result)) {
       mState = JPEG_ERROR;
@@ -301,12 +302,12 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
   }
 
   PR_LOG(gJPEGlog, PR_LOG_DEBUG,
-         ("[this=%p] nsJPEGDecoder::WriteFrom -- processing JPEG data\n", this));
+         ("[this=%p] nsJPEGDecoder::ProcessData -- processing JPEG data\n", this));
 
   switch (mState) {
   case JPEG_HEADER:
   {
-    LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::WriteFrom -- entering JPEG_HEADER case");
+    LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::ProcessData -- entering JPEG_HEADER case");
 
     /* Step 3: read file parameters with jpeg_read_header() */
     if (jpeg_read_header(&mInfo, TRUE) == JPEG_SUSPENDED) {
@@ -494,7 +495,7 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
       mImage->AppendFrame(mFrame);
 
       PR_LOG(gJPEGDecoderAccountingLog, PR_LOG_DEBUG,
-             ("        JPEGDecoderAccounting: nsJPEGDecoder::WriteFrom -- created image frame with %ux%u pixels",
+             ("        JPEGDecoderAccounting: nsJPEGDecoder::ProcessData -- created image frame with %ux%u pixels",
               mInfo.image_width, mInfo.image_height));
     }
 
@@ -504,7 +505,7 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
 
   case JPEG_START_DECOMPRESS:
   {
-    LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::WriteFrom -- entering JPEG_START_DECOMPRESS case");
+    LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::ProcessData -- entering JPEG_START_DECOMPRESS case");
     /* Step 4: set parameters for decompression */
 
     /* FIXME -- Should reset dct_method and dither mode
@@ -535,7 +536,7 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
   {
     if (mState == JPEG_DECOMPRESS_SEQUENTIAL)
     {
-      LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::WriteFrom -- JPEG_DECOMPRESS_SEQUENTIAL case");
+      LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::ProcessData -- JPEG_DECOMPRESS_SEQUENTIAL case");
       
       if (!OutputScanlines()) {
         PR_LOG(gJPEGDecoderAccountingLog, PR_LOG_DEBUG,
@@ -553,7 +554,7 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
   {
     if (mState == JPEG_DECOMPRESS_PROGRESSIVE)
     {
-      LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::WriteFrom -- JPEG_DECOMPRESS_PROGRESSIVE case");
+      LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::ProcessData -- JPEG_DECOMPRESS_PROGRESSIVE case");
 
       int status;
       do {
@@ -618,7 +619,7 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
   {
     nsresult result;
 
-    LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::WriteFrom -- entering JPEG_DONE case");
+    LOG_SCOPE(gJPEGlog, "nsJPEGDecoder::ProcessData -- entering JPEG_DONE case");
 
     /* Step 7: Finish decompression */
 
@@ -643,13 +644,13 @@ NS_IMETHODIMP nsJPEGDecoder::WriteFrom(nsIInputStream *inStr, PRUint32 count, PR
   }
   case JPEG_SINK_NON_JPEG_TRAILER:
     PR_LOG(gJPEGlog, PR_LOG_DEBUG,
-           ("[this=%p] nsJPEGDecoder::WriteFrom -- entering JPEG_SINK_NON_JPEG_TRAILER case\n", this));
+           ("[this=%p] nsJPEGDecoder::ProcessData -- entering JPEG_SINK_NON_JPEG_TRAILER case\n", this));
 
     break;
 
   case JPEG_ERROR:
     PR_LOG(gJPEGlog, PR_LOG_DEBUG,
-           ("[this=%p] nsJPEGDecoder::WriteFrom -- entering JPEG_ERROR case\n", this));
+           ("[this=%p] nsJPEGDecoder::ProcessData -- entering JPEG_ERROR case\n", this));
 
     break;
   }
@@ -674,7 +675,6 @@ nsJPEGDecoder::OutputScanlines()
   mFrame->GetImageData(&imageData, &imageDataLength);
 
   while ((mInfo.output_scanline < mInfo.output_height)) {
-      /* Request one scanline.  Returns 0 or 1 scanlines. */    
       PRUint32 *imageRow = ((PRUint32*)imageData) +
                            (mInfo.output_scanline * mInfo.output_width);
 
@@ -686,6 +686,7 @@ nsJPEGDecoder::OutputScanlines()
         sampleRow += mInfo.output_width;
       }
 
+      /* Request one scanline.  Returns 0 or 1 scanlines. */    
       if (jpeg_read_scanlines(&mInfo, &sampleRow, 1) != 1) {
         rv = PR_FALSE; /* suspend */
         break;
@@ -878,13 +879,13 @@ fill_input_buffer (j_decompress_ptr jd)
   nsJPEGDecoder *decoder = (nsJPEGDecoder *)(jd->client_data);
 
   if (decoder->mReading) {
-    unsigned char *new_buffer = (unsigned char *)decoder->mBuffer;
+    const JOCTET *new_buffer = decoder->mSegment;
-    PRUint32 new_buflen = decoder->mBufferLen;
+    PRUint32 new_buflen = decoder->mSegmentLen;
   
     if (!new_buffer || new_buflen == 0)
       return PR_FALSE; /* suspend */
 
-    decoder->mBufferLen = 0;
+    decoder->mSegmentLen = 0;
 
     if (decoder->mBytesToSkip) {
       if (decoder->mBytesToSkip < new_buflen) {
@@ -908,7 +909,7 @@ fill_input_buffer (j_decompress_ptr jd)
     return PR_TRUE;
   }
 
-  if (src->next_input_byte != decoder->mBuffer) {
+  if (src->next_input_byte != decoder->mSegment) {
     /* Backtrack data has been permanently consumed. */
     decoder->mBackBufferUnreadLen = 0;
     decoder->mBackBufferLen = 0;
@@ -949,7 +950,7 @@ fill_input_buffer (j_decompress_ptr jd)
     }
   }
 
-  /* Copy remainder of netlib buffer into backtrack buffer. */
+  /* Copy remainder of netlib segment into backtrack buffer. */
   memmove(decoder->mBackBuffer + decoder->mBackBufferLen,
           src->next_input_byte,
           src->bytes_in_buffer);
@@ -980,9 +981,4 @@ term_source (j_decompress_ptr jd)
     decoder->mObserver->OnStopContainer(nsnull, decoder->mImage);
     decoder->mObserver->OnStopDecode(nsnull, NS_OK, nsnull);
   }
-
-  PRBool isMutable = PR_FALSE;
-  if (decoder->mImageLoad) 
-      decoder->mImageLoad->GetIsMultiPartChannel(&isMutable);
-  decoder->mFrame->SetMutable(isMutable);
 }

modules/libpr0n/decoders/jpeg/nsJPEGDecoder.h

@@ -91,12 +91,13 @@ public:
   nsJPEGDecoder();
   virtual ~nsJPEGDecoder();
 
+  nsresult  ProcessData(const char *data, PRUint32 count, PRUint32 *writeCount);
+
 protected:
   PRBool OutputScanlines();
 
 public:
   nsCOMPtr<imgIContainer> mImage;
-  nsCOMPtr<imgILoad> mImageLoad;
   nsCOMPtr<gfxIImageFrame> mFrame;
 
   nsCOMPtr<imgIDecoderObserver> mObserver;
@@ -105,12 +106,12 @@ public:
   struct jpeg_source_mgr mSourceMgr;
   decoder_error_mgr mErr;
   jstate mState;
+  nsresult mError;
 
   PRUint32 mBytesToSkip;
 
-  JOCTET *mBuffer;
+  const JOCTET *mSegment;   // The current segment we are decoding from
-  PRUint32 mBufferLen;  // amount of data currently in mBuffer
+  PRUint32 mSegmentLen;     // amount of data in mSegment
-  PRUint32 mBufferSize; // size in bytes what mBuffer was created with
 
   JOCTET *mBackBuffer;
   PRUint32 mBackBufferLen; // Offset of end of active backtrack data
@@ -124,10 +125,6 @@ public:
   cmsHTRANSFORM mTransform;
 
   PRPackedBool mReading;
-
-private:
-
-  nsresult AddToTmpAccumulateBuffer(JOCTET *src, PRUint32 len);
 };
 
 #endif // nsJPEGDecoder_h__