1 files changed, 260 insertions, 0 deletions
diff --git a/dom/media/webcodecs/DecoderTemplate.h b/dom/media/webcodecs/DecoderTemplate.h
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+++ b/dom/media/webcodecs/DecoderTemplate.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 mozilla_dom_DecoderTemplate_h
+#define mozilla_dom_DecoderTemplate_h
+
+#include <queue>
+
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/DecoderAgent.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Result.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/media/MediaUtils.h"
+#include "nsStringFwd.h"
+#include "WebCodecsUtils.h"
+
+namespace mozilla {
+
+class TrackInfo;
+
+namespace dom {
+
+class WebCodecsErrorCallback;
+class Promise;
+enum class CodecState : uint8_t;
+
+template <typename DecoderType>
+class DecoderTemplate : public DOMEventTargetHelper {
+  using Self = DecoderTemplate<DecoderType>;
+  using ConfigType = typename DecoderType::ConfigType;
+  using ConfigTypeInternal = typename DecoderType::ConfigTypeInternal;
+  using InputType = typename DecoderType::InputType;
+  using InputTypeInternal = typename DecoderType::InputTypeInternal;
+  using OutputType = typename DecoderType::OutputType;
+  using OutputCallbackType = typename DecoderType::OutputCallbackType;
+
+  /* ControlMessage classes */
+ protected:
+  class ConfigureMessage;
+  class DecodeMessage;
+  class FlushMessage;
+
+  class ControlMessage {
+   public:
+    explicit ControlMessage(const nsACString& aTitle);
+    virtual ~ControlMessage() = default;
+    virtual void Cancel() = 0;
+    virtual bool IsProcessing() = 0;
+
+    virtual const nsCString& ToString() const { return mTitle; }
+    virtual ConfigureMessage* AsConfigureMessage() { return nullptr; }
+    virtual DecodeMessage* AsDecodeMessage() { return nullptr; }
+    virtual FlushMessage* AsFlushMessage() { return nullptr; }
+
+    const nsCString mTitle;  // Used to identify the message in the logs.
+  };
+
+  class ConfigureMessage final
+      : public ControlMessage,
+        public MessageRequestHolder<DecoderAgent::ConfigurePromise> {
+   public:
+    using Id = DecoderAgent::Id;
+    static constexpr Id NoId = 0;
+    static ConfigureMessage* Create(UniquePtr<ConfigTypeInternal>&& aConfig);
+
+    ~ConfigureMessage() = default;
+    virtual void Cancel() override { Disconnect(); }
+    virtual bool IsProcessing() override { return Exists(); };
+    virtual ConfigureMessage* AsConfigureMessage() override { return this; }
+    const ConfigTypeInternal& Config() { return *mConfig; }
+    UniquePtr<ConfigTypeInternal> TakeConfig() { return std::move(mConfig); }
+
+    const Id mId;  // A unique id shown in log.
+
+   private:
+    ConfigureMessage(Id aId, UniquePtr<ConfigTypeInternal>&& aConfig);
+
+    UniquePtr<ConfigTypeInternal> mConfig;
+  };
+
+  class DecodeMessage final
+      : public ControlMessage,
+        public MessageRequestHolder<DecoderAgent::DecodePromise> {
+   public:
+    using Id = size_t;
+    using ConfigId = typename Self::ConfigureMessage::Id;
+    DecodeMessage(Id aId, ConfigId aConfigId,
+                  UniquePtr<InputTypeInternal>&& aData);
+    ~DecodeMessage() = default;
+    virtual void Cancel() override { Disconnect(); }
+    virtual bool IsProcessing() override { return Exists(); };
+    virtual DecodeMessage* AsDecodeMessage() override { return this; }
+    const Id mId;  // A unique id shown in log.
+
+    UniquePtr<InputTypeInternal> mData;
+  };
+
+  class FlushMessage final
+      : public ControlMessage,
+        public MessageRequestHolder<DecoderAgent::DecodePromise> {
+   public:
+    using Id = size_t;
+    using ConfigId = typename Self::ConfigureMessage::Id;
+    FlushMessage(Id aId, ConfigId aConfigId, Promise* aPromise);
+    ~FlushMessage() = default;
+    virtual void Cancel() override { Disconnect(); }
+    virtual bool IsProcessing() override { return Exists(); };
+    virtual FlushMessage* AsFlushMessage() override { return this; }
+    already_AddRefed<Promise> TakePromise() { return mPromise.forget(); }
+    void RejectPromiseIfAny(const nsresult& aReason);
+
+    const Id mId;  // A unique id shown in log.
+
+   private:
+    RefPtr<Promise> mPromise;
+  };
+
+ protected:
+  DecoderTemplate(nsIGlobalObject* aGlobalObject,
+                  RefPtr<WebCodecsErrorCallback>&& aErrorCallback,
+                  RefPtr<OutputCallbackType>&& aOutputCallback);
+
+  virtual ~DecoderTemplate() = default;
+
+  /* WebCodecs interfaces */
+ public:
+  IMPL_EVENT_HANDLER(dequeue)
+
+  CodecState State() const { return mState; };
+
+  uint32_t DecodeQueueSize() const { return mDecodeQueueSize; };
+
+  void Configure(const ConfigType& aConfig, ErrorResult& aRv);
+
+  void Decode(InputType& aInput, ErrorResult& aRv);
+
+  already_AddRefed<Promise> Flush(ErrorResult& aRv);
+
+  void Reset(ErrorResult& aRv);
+
+  void Close(ErrorResult& aRv);
+
+  /* Type conversion functions for the Decoder implementation */
+ protected:
+  virtual already_AddRefed<MediaRawData> InputDataToMediaRawData(
+      UniquePtr<InputTypeInternal>&& aData, TrackInfo& aInfo,
+      const ConfigTypeInternal& aConfig) = 0;
+  virtual nsTArray<RefPtr<OutputType>> DecodedDataToOutputType(
+      nsIGlobalObject* aGlobalObject, const nsTArray<RefPtr<MediaData>>&& aData,
+      ConfigTypeInternal& aConfig) = 0;
+
+ protected:
+  // DecoderTemplate can run on either main thread or worker thread.
+  void AssertIsOnOwningThread() const {
+    NS_ASSERT_OWNINGTHREAD(DecoderTemplate);
+  }
+
+  Result<Ok, nsresult> ResetInternal(const nsresult& aResult);
+  // Calling this method calls the error callback synchronously.
+  MOZ_CAN_RUN_SCRIPT
+  void CloseInternal(const nsresult& aResult);
+  // Calling this method doesn't call the error calback.
+  Result<Ok, nsresult> CloseInternalWithAbort();
+
+  MOZ_CAN_RUN_SCRIPT void ReportError(const nsresult& aResult);
+  MOZ_CAN_RUN_SCRIPT void OutputDecodedData(
+      const nsTArray<RefPtr<MediaData>>&& aData);
+
+  void ScheduleDequeueEventIfNeeded();
+  nsresult FireEvent(nsAtom* aTypeWithOn, const nsAString& aEventType);
+
+  void ProcessControlMessageQueue();
+  void CancelPendingControlMessages(const nsresult& aResult);
+
+  // Queue a task to the control thread. This is to be used when a task needs to
+  // perform multiple steps.
+  template <typename Func>
+  void QueueATask(const char* aName, Func&& aSteps);
+
+  MessageProcessedResult ProcessConfigureMessage(
+      UniquePtr<ControlMessage>& aMessage);
+
+  MessageProcessedResult ProcessDecodeMessage(
+      UniquePtr<ControlMessage>& aMessage);
+
+  MessageProcessedResult ProcessFlushMessage(
+      UniquePtr<ControlMessage>& aMessage);
+
+  // Returns true when mAgent can be created.
+  bool CreateDecoderAgent(DecoderAgent::Id aId,
+                          UniquePtr<ConfigTypeInternal>&& aConfig,
+                          UniquePtr<TrackInfo>&& aInfo);
+  void DestroyDecoderAgentIfAny();
+
+  // Constant in practice, only set in ctor.
+  RefPtr<WebCodecsErrorCallback> mErrorCallback;
+  RefPtr<OutputCallbackType> mOutputCallback;
+
+  CodecState mState;
+  bool mKeyChunkRequired;
+
+  bool mMessageQueueBlocked;
+  std::queue<UniquePtr<ControlMessage>> mControlMessageQueue;
+  UniquePtr<ControlMessage> mProcessingMessage;
+
+  uint32_t mDecodeQueueSize;
+  bool mDequeueEventScheduled;
+
+  // A unique id tracking the ConfigureMessage and will be used as the
+  // DecoderAgent's Id.
+  uint32_t mLatestConfigureId;
+  // Tracking how many decode data has been enqueued and this number will be
+  // used as the DecodeMessage's Id.
+  size_t mDecodeCounter;
+  // Tracking how many flush request has been enqueued and this number will be
+  // used as the FlushMessage's Id.
+  size_t mFlushCounter;
+
+  // DecoderAgent will be created every time "configure" is being processed, and
+  // will be destroyed when "reset" or another "configure" is called (spec
+  // allows calling two "configure" without a "reset" in between).
+  RefPtr<DecoderAgent> mAgent;
+  UniquePtr<ConfigTypeInternal> mActiveConfig;
+
+  // Used to add a nsIAsyncShutdownBlocker on main thread to block
+  // xpcom-shutdown before the underlying MediaDataDecoder is created. The
+  // blocker will be held until the underlying MediaDataDecoder has been shut
+  // down. This blocker guarantees RemoteDecoderManagerChild's thread, where the
+  // underlying RemoteMediaDataDecoder is on, outlives the
+  // RemoteMediaDataDecoder, since the thread releasing, which happens on main
+  // thread when getting a xpcom-shutdown signal, is blocked by the added
+  // blocker. As a result, RemoteMediaDataDecoder can safely work on worker
+  // thread with a holding blocker (otherwise, if RemoteDecoderManagerChild
+  // releases its thread on main thread before RemoteMediaDataDecoder's
+  // Shutdown() task run on worker thread, RemoteMediaDataDecoder has no thread
+  // to run).
+  UniquePtr<media::ShutdownBlockingTicket> mShutdownBlocker;
+
+  // Held to make sure the dispatched tasks can be done before worker is going
+  // away. As long as this worker-ref is held somewhere, the tasks dispatched to
+  // the worker can be executed (otherwise the tasks would be canceled). This
+  // ref should be activated as long as the underlying MediaDataDecoder is
+  // alive, and should keep alive until mShutdownBlocker is dropped, so all
+  // MediaDataDecoder's tasks and mShutdownBlocker-releasing task can be
+  // executed.
+  // TODO: Use StrongWorkerRef instead if this is always used in the same
+  // thread?
+  RefPtr<ThreadSafeWorkerRef> mWorkerRef;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_DecoderTemplate_h