dom/streams/TransformerCallbackHelpers.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_STREAMS_TRANSFORMERCALLBACKHELPERS_H_
   8 #define DOM_STREAMS_TRANSFORMERCALLBACKHELPERS_H_
   9
  10 #include "mozilla/HoldDropJSObjects.h"
  11 #include "mozilla/dom/TransformerBinding.h"
  12 #include "nsCycleCollectionParticipant.h"
  13
  14 namespace mozilla::dom {
  15
  16 class Promise;
  17
  18 class TransformerAlgorithmsBase : public nsISupports {
  19  public:
  20   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  21   NS_DECL_CYCLE_COLLECTION_CLASS(TransformerAlgorithmsBase)
  22
  23   MOZ_CAN_RUN_SCRIPT virtual already_AddRefed<Promise> TransformCallback(
  24       JSContext* aCx, JS::Handle<JS::Value> aChunk,
  25       TransformStreamDefaultController& aController, ErrorResult& aRv) = 0;
  26
  27   MOZ_CAN_RUN_SCRIPT virtual already_AddRefed<Promise> FlushCallback(
  28       JSContext* aCx, TransformStreamDefaultController& aController,
  29       ErrorResult& aRv) = 0;
  30
  31  protected:
  32   virtual ~TransformerAlgorithmsBase() = default;
  33 };
  34
  35 // https://streams.spec.whatwg.org/#set-up-transform-stream-default-controller-from-transformer
  36 class TransformerAlgorithms final : public TransformerAlgorithmsBase {
  37  public:
  38   NS_DECL_ISUPPORTS_INHERITED
  39   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(
  40       TransformerAlgorithms, TransformerAlgorithmsBase)
  41
  42   TransformerAlgorithms(nsIGlobalObject* aGlobal,
  43                         JS::Handle<JSObject*> aTransformer,
  44                         Transformer& aTransformerDict)
  45       : mGlobal(aGlobal), mTransformer(aTransformer) {
  46     // Step 4. (Step 2 is implicitly done through the initialization of
  47     // mTransformCallback to null)
  48     if (aTransformerDict.mTransform.WasPassed()) {
  49       mTransformCallback = aTransformerDict.mTransform.Value();
  50     }
  51
  52     // Step 5. (Step 3 is implicitly done through the initialization of
  53     // mTransformCallback to null)
  54     if (aTransformerDict.mFlush.WasPassed()) {
  55       mFlushCallback = aTransformerDict.mFlush.Value();
  56     }
  57
  58     mozilla::HoldJSObjects(this);
  59   };
  60
  61   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> TransformCallback(
  62       JSContext* aCx, JS::Handle<JS::Value> aChunk,
  63       TransformStreamDefaultController& aController, ErrorResult& aRv) override;
  64
  65   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> FlushCallback(
  66       JSContext* aCx, TransformStreamDefaultController& aController,
  67       ErrorResult& aRv) override;
  68
  69  protected:
  70   ~TransformerAlgorithms() { mozilla::DropJSObjects(this); }
  71
  72  private:
  73   // Virtually const, but are cycle collected
  74   nsCOMPtr<nsIGlobalObject> mGlobal;
  75   JS::Heap<JSObject*> mTransformer;
  76   MOZ_KNOWN_LIVE RefPtr<TransformerTransformCallback> mTransformCallback;
  77   MOZ_KNOWN_LIVE RefPtr<TransformerFlushCallback> mFlushCallback;
  78 };
  79
  80 // https://streams.spec.whatwg.org/#transformstream-set-up
  81 class TransformerAlgorithmsWrapper : public TransformerAlgorithmsBase {
  82   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> TransformCallback(
  83       JSContext*, JS::Handle<JS::Value> aChunk,
  84       TransformStreamDefaultController& aController, ErrorResult& aRv) final;
  85
  86   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> FlushCallback(
  87       JSContext*, TransformStreamDefaultController& aController,
  88       ErrorResult& aRv) final;
  89
  90   MOZ_CAN_RUN_SCRIPT virtual void TransformCallbackImpl(
  91       JS::Handle<JS::Value> aChunk,
  92       TransformStreamDefaultController& aController, ErrorResult& aRv) = 0;
  93
  94   MOZ_CAN_RUN_SCRIPT virtual void FlushCallbackImpl(
  95       TransformStreamDefaultController& aController, ErrorResult& aRv) = 0;
  96 };
  97
  98 }  // namespace mozilla::dom
  99
 100 #endif  // DOM_STREAMS_TRANSFORMERCALLBACKHELPERS_H_