Update PPB_VideoDecoder documentation.

The Decode function should not require the plugin to
maintain its buffer when it completes asynchronously.

BUG=281689
R=dmichael@chromium.org

Review URL: https://codereview.chromium.org/291083003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271917 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 83 insertions, 47 deletions

diff --git a/ppapi/api/ppb_video_decoder.idl b/ppapi/api/ppb_video_decoder.idl
index 90a3520..ab38e9f 100644
--- a/ppapi/api/ppb_video_decoder.idl
+++ b/ppapi/api/ppb_video_decoder.idl
@@ -91,9 +91,8 @@ interface PPB_VideoDecoder {
 
   /**
    * Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
-   * |buffer|. The plugin should maintain the buffer and not call Decode() again
-   * until the decoder signals completion by returning PP_OK or by running
-   * |callback|.
+   * |buffer|. The plugin should wait until the decoder signals completion by
+   * returning PP_OK or by running |callback| before calling Decode() again.
    *
    * In general, each bitstream buffer should contain a demuxed bitstream frame
    * for the selected video codec. For example, H264 decoders expect to receive
@@ -117,6 +116,11 @@ interface PPB_VideoDecoder {
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Flush()
+   * or Reset() call is pending.
+   * Returns PP_ERROR_INPROGRESS if there is another Decode() call pending.
+   * Returns PP_ERROR_NOMEMORY if a bitstream buffer can't be created.
+   * Returns PP_ERROR_ABORTED when Reset() is called while Decode() is pending.
    */
   int32_t Decode(
       [in] PP_Resource video_decoder,
@@ -140,7 +144,9 @@ interface PPB_VideoDecoder {
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
-   * Returns PP_OK if a picture is available.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Reset()
+   * call is pending.
+   * Returns PP_ERROR_INPROGRESS if there is another GetPicture() call pending.
    * Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
    * completes while GetPicture() is pending.
    */
@@ -164,13 +170,15 @@ interface PPB_VideoDecoder {
       [in] PP_VideoPicture picture);
 
   /**
-   * Flushes the decoder. The plugin should call this when it reaches the end of
-   * its video stream in order to stop cleanly. The decoder will run all pending
-   * calls to completion. The plugin should make no further calls to the decoder
-   * other than GetPicture() and RecyclePicture() until the decoder signals
-   * completion by running the callback. Just before completion, any pending
-   * GetPicture() call will complete by running the callback with result
-   * PP_ERROR_ABORTED to signal that no more pictures are available.
+   * Flushes the decoder. The plugin should call Flush() when it reaches the
+   * end of its video stream in order to stop cleanly. The decoder will run any
+   * pending Decode() call to completion. The plugin should make no further
+   * calls to the decoder other than GetPicture() and RecyclePicture() until
+   * the decoder signals completion by running |callback|. Just before
+   * completion, any pending GetPicture() call will complete by running its
+   * callback with result PP_ERROR_ABORTED to signal that no more pictures are
+   * available. The plugin should recycle any pictures it is using before
+   * resuming decoding.
    *
    * @param[in] video_decoder A <code>PP_Resource</code> identifying the video
    * decoder.
@@ -178,6 +186,7 @@ interface PPB_VideoDecoder {
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized.
    */
   int32_t Flush(
       [in] PP_Resource video_decoder,
@@ -185,10 +194,12 @@ interface PPB_VideoDecoder {
 
   /**
    * Resets the decoder as quickly as possible. The plugin can call Reset() to
-   * skip to another position in the video stream. Pending calls to Decode() and
-   * GetPicture()) are immediately aborted, causing their callbacks to run with
-   * PP_ERROR_ABORTED. The plugin should not make any further calls to the
-   * decoder until the decoder signals completion by running |callback|.
+   * skip to another position in the video stream. After Reset() returns, any
+   * pending calls to Decode() and GetPicture()) abort, causing their callbacks
+   * to run with PP_ERROR_ABORTED. The plugin should not make further calls to
+   * the decoder until the decoder signals completion by running |callback|.
+   * The pictures in use by the plugin remain valid until decoding is resumed,
+   * but need not be recycled.
    *
    * @param[in] video_decoder A <code>PP_Resource</code> identifying the video
    * decoder.
@@ -196,6 +207,7 @@ interface PPB_VideoDecoder {
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized.
    */
   int32_t Reset(
       [in] PP_Resource video_decoder,
diff --git a/ppapi/c/ppb_video_decoder.h b/ppapi/c/ppb_video_decoder.h
index f09908c..721e238 100644
--- a/ppapi/c/ppb_video_decoder.h
+++ b/ppapi/c/ppb_video_decoder.h
@@ -3,7 +3,7 @@
  * found in the LICENSE file.
  */
 
-/* From ppb_video_decoder.idl modified Tue May  6 05:19:45 2014. */
+/* From ppb_video_decoder.idl modified Wed May 21 09:50:52 2014. */
 
 #ifndef PPAPI_C_PPB_VIDEO_DECODER_H_
 #define PPAPI_C_PPB_VIDEO_DECODER_H_
@@ -100,9 +100,8 @@ struct PPB_VideoDecoder_0_1 { /* dev */
                         struct PP_CompletionCallback callback);
   /**
    * Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
-   * |buffer|. The plugin should maintain the buffer and not call Decode() again
-   * until the decoder signals completion by returning PP_OK or by running
-   * |callback|.
+   * |buffer|. The plugin should wait until the decoder signals completion by
+   * returning PP_OK or by running |callback| before calling Decode() again.
    *
    * In general, each bitstream buffer should contain a demuxed bitstream frame
    * for the selected video codec. For example, H264 decoders expect to receive
@@ -126,6 +125,11 @@ struct PPB_VideoDecoder_0_1 { /* dev */
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Flush()
+   * or Reset() call is pending.
+   * Returns PP_ERROR_INPROGRESS if there is another Decode() call pending.
+   * Returns PP_ERROR_NOMEMORY if a bitstream buffer can't be created.
+   * Returns PP_ERROR_ABORTED when Reset() is called while Decode() is pending.
    */
   int32_t (*Decode)(PP_Resource video_decoder,
                     uint32_t decode_id,
@@ -147,7 +151,9 @@ struct PPB_VideoDecoder_0_1 { /* dev */
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
-   * Returns PP_OK if a picture is available.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Reset()
+   * call is pending.
+   * Returns PP_ERROR_INPROGRESS if there is another GetPicture() call pending.
    * Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
    * completes while GetPicture() is pending.
    */
@@ -167,13 +173,15 @@ struct PPB_VideoDecoder_0_1 { /* dev */
   void (*RecyclePicture)(PP_Resource video_decoder,
                          const struct PP_VideoPicture* picture);
   /**
-   * Flushes the decoder. The plugin should call this when it reaches the end of
-   * its video stream in order to stop cleanly. The decoder will run all pending
-   * calls to completion. The plugin should make no further calls to the decoder
-   * other than GetPicture() and RecyclePicture() until the decoder signals
-   * completion by running the callback. Just before completion, any pending
-   * GetPicture() call will complete by running the callback with result
-   * PP_ERROR_ABORTED to signal that no more pictures are available.
+   * Flushes the decoder. The plugin should call Flush() when it reaches the
+   * end of its video stream in order to stop cleanly. The decoder will run any
+   * pending Decode() call to completion. The plugin should make no further
+   * calls to the decoder other than GetPicture() and RecyclePicture() until
+   * the decoder signals completion by running |callback|. Just before
+   * completion, any pending GetPicture() call will complete by running its
+   * callback with result PP_ERROR_ABORTED to signal that no more pictures are
+   * available. The plugin should recycle any pictures it is using before
+   * resuming decoding.
    *
    * @param[in] video_decoder A <code>PP_Resource</code> identifying the video
    * decoder.
@@ -181,15 +189,18 @@ struct PPB_VideoDecoder_0_1 { /* dev */
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized.
    */
   int32_t (*Flush)(PP_Resource video_decoder,
                    struct PP_CompletionCallback callback);
   /**
    * Resets the decoder as quickly as possible. The plugin can call Reset() to
-   * skip to another position in the video stream. Pending calls to Decode() and
-   * GetPicture()) are immediately aborted, causing their callbacks to run with
-   * PP_ERROR_ABORTED. The plugin should not make any further calls to the
-   * decoder until the decoder signals completion by running |callback|.
+   * skip to another position in the video stream. After Reset() returns, any
+   * pending calls to Decode() and GetPicture()) abort, causing their callbacks
+   * to run with PP_ERROR_ABORTED. The plugin should not make further calls to
+   * the decoder until the decoder signals completion by running |callback|.
+   * The pictures in use by the plugin remain valid until decoding is resumed,
+   * but need not be recycled.
    *
    * @param[in] video_decoder A <code>PP_Resource</code> identifying the video
    * decoder.
@@ -197,6 +208,7 @@ struct PPB_VideoDecoder_0_1 { /* dev */
    * completion.
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if the decoder isn't initialized.
    */
   int32_t (*Reset)(PP_Resource video_decoder,
                    struct PP_CompletionCallback callback);
diff --git a/ppapi/cpp/video_decoder.h b/ppapi/cpp/video_decoder.h
index f1f2d91..d1eded3 100644
--- a/ppapi/cpp/video_decoder.h
+++ b/ppapi/cpp/video_decoder.h
@@ -81,9 +81,8 @@ class VideoDecoder : public Resource {
                      const CompletionCallback& callback);
 
   /// Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
-  /// |buffer|. The plugin should maintain the buffer and not call Decode()
-  /// again until the decoder signals completion by returning PP_OK or by
-  /// running |callback|.
+  /// |buffer|. The plugin should wait until the decoder signals completion by
+  /// returning PP_OK or by running |callback| before calling Decode() again.
   ///
   /// In general, each bitstream buffer should contain a demuxed bitstream frame
   /// for the selected video codec. For example, H264 decoders expect to receive
@@ -105,6 +104,11 @@ class VideoDecoder : public Resource {
   /// completion.
   ///
   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  /// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Flush()
+  /// or Reset() call is pending.
+  /// Returns PP_ERROR_INPROGRESS if there is another Decode() call pending.
+  /// Returns PP_ERROR_NOMEMORY if a bitstream buffer can't be created.
+  /// Returns PP_ERROR_ABORTED when Reset() is called while Decode() is pending.
   int32_t Decode(uint32_t decode_id,
                  uint32_t size,
                  const void* buffer,
@@ -122,7 +126,9 @@ class VideoDecoder : public Resource {
   /// called on completion, and on success, to hold the picture descriptor.
   ///
   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
-  /// Returns PP_OK if a picture is available.
+  /// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Reset()
+  /// call is pending.
+  /// Returns PP_ERROR_INPROGRESS if there is another GetPicture() call pending.
   /// Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
   /// completes while GetPicture() is pending.
   int32_t GetPicture(
@@ -136,31 +142,37 @@ class VideoDecoder : public Resource {
   /// decoder.
   void RecyclePicture(const PP_VideoPicture& picture);
 
-  /// Flushes the decoder. The plugin should call this when it reaches the end
-  /// of its video stream in order to stop cleanly. The decoder will run all
-  /// pending calls to completion. The plugin should make no further calls to
-  /// the decoder other than GetPicture() and RecyclePicture() until the decoder
-  /// signals completion by running the callback. Just before completion, any
-  /// pending GetPicture() call will complete by running the callback with
-  /// result PP_ERROR_ABORTED to signal that no more pictures are available.
+  /// Flushes the decoder. The plugin should call Flush() when it reaches the
+  /// end of its video stream in order to stop cleanly. The decoder will run any
+  /// pending Decode() call to completion. The plugin should make no further
+  /// calls to the decoder other than GetPicture() and RecyclePicture() until
+  /// the decoder signals completion by running |callback|. Just before
+  /// completion, any pending GetPicture() call will complete by running its
+  /// callback with result PP_ERROR_ABORTED to signal that no more pictures are
+  /// available. The plugin should recycle any pictures it is using before
+  /// resuming decoding.
   ///
   /// @param[in] callback A <code>CompletionCallback</code> to be called on
   /// completion.
   ///
   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  /// Returns PP_ERROR_FAILED if the decoder isn't initialized.
   int32_t Flush(const CompletionCallback& callback);
 
   /// Resets the decoder as quickly as possible. The plugin can call Reset() to
-  /// skip to another position in the video stream. Pending calls to Decode()
-  /// and GetPicture()) are immediately aborted, causing their callbacks to run
-  /// with PP_ERROR_ABORTED. The plugin should not make any further calls to the
-  /// decoder until the decoder signals completion by running |callback|.
+  /// skip to another position in the video stream. After Reset() returns, any
+  /// pending calls to Decode() and GetPicture()) abort, causing their callbacks
+  /// to run with PP_ERROR_ABORTED. The plugin should not make further calls to
+  /// the decoder until the decoder signals completion by running |callback|.
+  /// The pictures in use by the plugin remain valid until decoding is resumed,
+  /// but need not be recycled.
   ///
   /// @param[in] callback A <code>CompletionCallback</code> to be called on
   /// completion.
   ///
   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
-  int32_t Reset(const CompletionCallback& callback);
+    /// Returns PP_ERROR_FAILED if the decoder isn't initialized.
+int32_t Reset(const CompletionCallback& callback);
 };
 
 }  // namespace pp