1 files changed, 126 insertions, 0 deletions
diff --git a/dom/base/ImageEncoder.h b/dom/base/ImageEncoder.h
new file mode 100644
index 0000000000..005628739f
--- /dev/null
+++ b/dom/base/ImageEncoder.h
@@ -0,0 +1,126 @@
+/* -*- 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/. */
+
+#ifndef ImageEncoder_h
+#define ImageEncoder_h
+
+#include "imgIEncoder.h"
+#include "nsError.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/dom/HTMLCanvasElementBinding.h"
+#include "mozilla/UniquePtr.h"
+#include "nsSize.h"
+
+class nsICanvasRenderingContextInternal;
+
+namespace mozilla {
+
+namespace layers {
+class Image;
+}  // namespace layers
+
+namespace dom {
+
+class EncodeCompleteCallback;
+class EncodingRunnable;
+class OffscreenCanvasDisplayHelper;
+
+class ImageEncoder {
+ public:
+  // Extracts data synchronously and gives you a stream containing the image
+  // represented by aContext. aType may change to "image/png" if we had to fall
+  // back to a PNG encoder. A return value of NS_OK implies successful data
+  // extraction. If there are any unrecognized custom parse options in
+  // aOptions, NS_ERROR_INVALID_ARG will be returned. When encountering this
+  // error it is usual to call this function again without any options at all.
+  static nsresult ExtractData(nsAString& aType, const nsAString& aOptions,
+                              const nsIntSize aSize, bool aUsePlaceholder,
+                              nsICanvasRenderingContextInternal* aContext,
+                              OffscreenCanvasDisplayHelper* aOffscreenDisplay,
+                              nsIInputStream** aStream);
+
+  // Extracts data asynchronously. aType may change to "image/png" if we had to
+  // fall back to a PNG encoder. aOptions are the options to be passed to the
+  // encoder and aUsingCustomOptions specifies whether custom parse options were
+  // used (i.e. by using -moz-parse-options). If there are any unrecognized
+  // custom parse options, we fall back to the default values for the encoder
+  // without any options at all. A return value of NS_OK only implies
+  // successful dispatching of the extraction step to the encoding thread.
+  // aEncodeCallback will be called on main thread when encoding process is
+  // success.
+  // Note: The callback has to set a valid parent for content for the generated
+  // Blob object.
+  static nsresult ExtractDataAsync(nsAString& aType, const nsAString& aOptions,
+                                   bool aUsingCustomOptions,
+                                   UniquePtr<uint8_t[]> aImageBuffer,
+                                   int32_t aFormat, const nsIntSize aSize,
+                                   bool aUsePlaceholder,
+                                   EncodeCompleteCallback* aEncodeCallback);
+
+  // Extract an Image asynchronously. Its function is same as ExtractDataAsync
+  // except for the parameters. aImage is the uncompressed data. aEncodeCallback
+  // will be called on main thread when encoding process is success.
+  // Note: The callback has to set a valid parent for content for the generated
+  // Blob object.
+  static nsresult ExtractDataFromLayersImageAsync(
+      nsAString& aType, const nsAString& aOptions, bool aUsingCustomOptions,
+      layers::Image* aImage, bool aUsePlaceholder,
+      EncodeCompleteCallback* aEncodeCallback);
+
+  // Gives you a stream containing the image represented by aImageBuffer.
+  // The format is given in aFormat, for example
+  // imgIEncoder::INPUT_FORMAT_HOSTARGB.
+  static nsresult GetInputStream(int32_t aWidth, int32_t aHeight,
+                                 uint8_t* aImageBuffer, int32_t aFormat,
+                                 imgIEncoder* aEncoder,
+                                 const nsAString& aEncoderOptions,
+                                 nsIInputStream** aStream);
+
+ private:
+  // When called asynchronously, aContext and aRenderer are null.
+  static nsresult ExtractDataInternal(
+      const nsAString& aType, const nsAString& aOptions, uint8_t* aImageBuffer,
+      int32_t aFormat, const nsIntSize aSize, bool aUsePlaceholder,
+      layers::Image* aImage, nsICanvasRenderingContextInternal* aContext,
+      OffscreenCanvasDisplayHelper* aOffscreenDisplay, nsIInputStream** aStream,
+      imgIEncoder* aEncoder);
+
+  // Creates and returns an encoder instance of the type specified in aType.
+  // aType may change to "image/png" if no instance of the original type could
+  // be created and we had to fall back to a PNG encoder. A null return value
+  // should be interpreted as NS_IMAGELIB_ERROR_NO_ENCODER and aType is
+  // undefined in this case.
+  static already_AddRefed<imgIEncoder> GetImageEncoder(nsAString& aType);
+
+  friend class EncodingRunnable;
+  friend class EncoderThreadPoolTerminator;
+};
+
+/**
+ *  The callback interface of ExtractDataAsync and
+ * ExtractDataFromLayersImageAsync. ReceiveBlobImpl() is called on main thread
+ * when encoding is complete.
+ */
+class EncodeCompleteCallback {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(EncodeCompleteCallback)
+
+  MOZ_CAN_RUN_SCRIPT
+  virtual nsresult ReceiveBlobImpl(already_AddRefed<BlobImpl> aBlobImpl) = 0;
+
+  // CanBeDeletedOnAnyThread is pure virtual, so that whoever extends this class
+  // needs to think how to handle cases like the owning DOM worker thread
+  // shutting down.
+  virtual bool CanBeDeletedOnAnyThread() = 0;
+
+ protected:
+  virtual ~EncodeCompleteCallback() = default;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // ImageEncoder_h