#501: functional decoder wrapper

image/decoders/nsWEBPDecoder.cpp

@@ -0,0 +1,195 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/* Contributor(s):
+ *   Vikas Arora <vikasa@google.com> */
+
+#include "nsWEBPDecoder.h"
+
+#include "ImageLogging.h"
+#include "gfxColor.h"
+#include "gfxPlatform.h"
+
+namespace mozilla {
+namespace image {
+
+#if defined(PR_LOGGING)
+static PRLogModuleInfo* gWEBPDecoderAccountingLog =
+  PR_NewLogModule("WEBPDecoderAccounting");
+#else
+#define gWEBPDecoderAccountingLog
+#endif
+
+nsWEBPDecoder::nsWEBPDecoder(RasterImage* aImage)
+  : Decoder(aImage)
+  , mDecoder(nullptr)
+  , mLastLine(0)
+  , mWidth(0)
+  , mHeight(0)
+  , haveSize(false)
+{
+  MOZ_LOG(gWEBPDecoderAccountingLog, LogLevel::Debug,
+         ("nsWEBPDecoder::nsWEBPDecoder: Creating WEBP decoder %p",
+          this));
+}
+
+nsWEBPDecoder::~nsWEBPDecoder()
+{
+  MOZ_LOG(gWEBPDecoderAccountingLog, LogLevel::Debug,
+         ("nsWEBPDecoder::~nsWEBPDecoder: Destroying WEBP decoder %p",
+          this));
+}
+
+void
+nsWEBPDecoder::InitInternal()
+{
+  if (!WebPInitDecBuffer(&mDecBuf)) {
+    PostDecoderError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  if (IsMetadataDecode()) {
+    return; // don't need a decoder yet
+  }
+
+  MOZ_ASSERT(!mImageData, "Shouldn't have a buffer yet");
+
+  mDecBuf.colorspace = MODE_bgrA;
+  mDecBuf.is_external_memory = 1;
+  mDecBuf.u.RGBA.rgba = mImageData; // nullptr right now
+  mDecoder = WebPINewDecoder(&mDecBuf);
+  if (!mDecoder) {
+    PostDecoderError(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+void
+nsWEBPDecoder::WriteInternal(const char* aBuffer, uint32_t aCount)
+{
+  const uint8_t* buf = (const uint8_t*)aBuffer;
+
+  if (IsMetadataDecode() || !haveSize) {
+    WebPBitstreamFeatures features;
+    const VP8StatusCode rv = WebPGetFeatures(buf, aCount, &features);
+
+    if (rv == VP8_STATUS_OK) {
+      if (features.has_animation) {
+        PostDecoderError(NS_ERROR_FAILURE);
+        return;
+      }
+      if (features.has_alpha) {
+        PostHasTransparency();
+      }
+      // Post our size to the superclass
+      if (IsMetadataDecode()) {
+        PostSize(features.width, features.height);
+      }
+      mWidth = features.width;
+      mHeight = features.height;
+      mDecBuf.width = mWidth;
+      mDecBuf.height = mHeight;
+      mDecBuf.u.RGBA.stride = mWidth * sizeof(uint32_t);
+      mDecBuf.u.RGBA.size = mDecBuf.u.RGBA.stride * mHeight;
+      haveSize = true;
+    } else if (rv != VP8_STATUS_NOT_ENOUGH_DATA) {
+      PostDecoderError(NS_ERROR_FAILURE);
+      return;
+    } else {
+#if DEBUG
+      fprintf(stderr, "WebP had unexpected return code: %d\n", rv);
+#endif
+      return;
+    }
+
+    // If we're doing a size decode, we're done.
+    if (IsMetadataDecode()) return;
+  }
+
+  MOZ_ASSERT(!mImageData, "Already have a buffer allocated?");
+  MOZ_ASSERT(haveSize, "Didn't fetch metadata?");
+  PostSize(mWidth, mHeight);
+  nsresult rv_ = AllocateBasicFrame();
+  if (NS_FAILED(rv_)) {
+      return;
+  }
+
+  MOZ_ASSERT(mImageData, "Should have a buffer now");
+  MOZ_ASSERT(mDecoder, "Should have a decoder now");
+  mDecBuf.u.RGBA.rgba = mImageData; // no longer null
+  const VP8StatusCode rv = WebPIAppend(mDecoder, buf, aCount);
+
+  if (rv == VP8_STATUS_OUT_OF_MEMORY) {
+    PostDecoderError(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  } else if (rv == VP8_STATUS_INVALID_PARAM ||
+             rv == VP8_STATUS_BITSTREAM_ERROR) {
+    PostDataError();
+    return;
+  } else if (rv == VP8_STATUS_UNSUPPORTED_FEATURE ||
+             rv == VP8_STATUS_USER_ABORT) {
+    PostDecoderError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  // Catch any remaining erroneous return value.
+  if (rv != VP8_STATUS_OK && rv != VP8_STATUS_SUSPENDED) {
+    PostDecoderError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  int lastLineRead = -1;
+  int width = 0;
+  int height = 0;
+  int stride = 0;
+
+  const uint8_t* data =
+    WebPIDecGetRGB(mDecoder, &lastLineRead, &width, &height, &stride);
+
+  // WebP encoded image data hasn't been read yet, return.
+  if (lastLineRead == -1 || !data) {
+    return;
+  }
+
+  // Ensure valid image height & width.
+  if (width <= 0 || height <= 0) {
+    PostDataError();
+    return;
+  }
+
+  if (!mImageData) {
+    PostDecoderError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  if (lastLineRead > mLastLine) {
+    // Invalidate
+    nsIntRect r(0, mLastLine, width, lastLineRead - mLastLine);
+    PostInvalidation(r);
+    mLastLine = lastLineRead;
+  }
+}
+
+void
+nsWEBPDecoder::FinishInternal()
+{
+  // We should never make multiple frames
+  MOZ_ASSERT(GetFrameCount() <= 1, "Multiple WebP frames?");
+
+  // Send notifications if appropriate
+  if (!IsMetadataDecode() && (GetFrameCount() == 1)) {
+    // Flush the decoder
+    WebPIDelete(mDecoder);
+    WebPFreeDecBuffer(&mDecBuf);
+
+    PostFrameStop();
+    PostDecodeDone();
+
+    mDecoder = nullptr;
+  }
+}
+
+} // namespace image
+} // namespace mozilla

image/decoders/nsWEBPDecoder.h

@@ -0,0 +1,78 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * ***** 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.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 2001
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Vikas Arora <vikasa@google.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either 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 ***** */
+
+#ifndef nsWEBPDecoder_h
+#define nsWEBPDecoder_h
+
+#include "Decoder.h"
+
+extern "C" {
+#include "webp/decode.h"
+}
+
+namespace mozilla {
+namespace image {
+class RasterImage;
+
+//////////////////////////////////////////////////////////////////////
+// nsWEBPDecoder Definition
+
+class nsWEBPDecoder : public Decoder
+{
+public:
+  explicit nsWEBPDecoder(RasterImage* aImage);
+  virtual ~nsWEBPDecoder();
+
+  virtual void InitInternal() override;
+  virtual void WriteInternal(const char* aBuffer, uint32_t aCount) override;
+  virtual void FinishInternal() override;
+
+private:
+  WebPIDecoder* mDecoder;  // Pointer to Incremental WebP Decoder.
+  WebPDecBuffer mDecBuf;   // Decoder buffer for output RGBA data.
+  int mLastLine;           // Last image scan-line read so far.
+  int mWidth;              // Image Width
+  int mHeight;             // Image Height
+  bool haveSize;           // True if mDecBuf contains image dimension
+};
+
+} // namespace image
+} // namespace mozilla
+
+#endif // nsWEBPDecoder_h