dom/streams/ReadableStreamTee.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 mozilla_dom_ReadableStreamTee_h
   8 #define mozilla_dom_ReadableStreamTee_h
   9
  10 #include "mozilla/dom/ReadRequest.h"
  11 #include "mozilla/dom/ReadableStreamController.h"
  12 #include "mozilla/dom/UnderlyingSourceCallbackHelpers.h"
  13 #include "nsCycleCollectionParticipant.h"
  14 #include "nsISupportsImpl.h"
  15
  16 namespace mozilla::dom {
  17 struct TeeState;
  18 enum class TeeBranch : bool;
  19 class ReadableStream;
  20
  21 // Implementation of the Pull algorithm steps for ReadableStreamDefaultTee,
  22 // from
  23 // https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaulttee
  24 // Step 12.
  25 class ReadableStreamDefaultTeeSourceAlgorithms final
  26     : public UnderlyingSourceAlgorithmsBase {
  27  public:
  28   NS_DECL_ISUPPORTS_INHERITED
  29   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(
  30       ReadableStreamDefaultTeeSourceAlgorithms, UnderlyingSourceAlgorithmsBase)
  31
  32   ReadableStreamDefaultTeeSourceAlgorithms(TeeState* aTeeState,
  33                                            TeeBranch aBranch)
  34       : mTeeState(aTeeState), mBranch(aBranch) {}
  35
  36   MOZ_CAN_RUN_SCRIPT void StartCallback(JSContext* aCx,
  37                                         ReadableStreamController& aController,
  38                                         JS::MutableHandle<JS::Value> aRetVal,
  39                                         ErrorResult& aRv) override {
  40     aRetVal.setUndefined();
  41   }
  42
  43   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> PullCallback(
  44       JSContext* aCx, ReadableStreamController& aController,
  45       ErrorResult& aRv) override;
  46
  47   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CancelCallback(
  48       JSContext* aCx, const Optional<JS::Handle<JS::Value>>& aReason,
  49       ErrorResult& aRv) override;
  50
  51  protected:
  52   ~ReadableStreamDefaultTeeSourceAlgorithms() override = default;
  53
  54  private:
  55   // Virtually const, but is cycle collected
  56   MOZ_KNOWN_LIVE RefPtr<TeeState> mTeeState;
  57   TeeBranch mBranch;
  58 };
  59
  60 // https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaulttee
  61 // Step 12.3
  62 struct ReadableStreamDefaultTeeReadRequest final : public ReadRequest {
  63   NS_DECL_ISUPPORTS_INHERITED
  64   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ReadableStreamDefaultTeeReadRequest,
  65                                            ReadRequest)
  66
  67   RefPtr<TeeState> mTeeState;
  68
  69   explicit ReadableStreamDefaultTeeReadRequest(TeeState* aTeeState)
  70       : mTeeState(aTeeState) {}
  71
  72   void ChunkSteps(JSContext* aCx, JS::Handle<JS::Value> aChunk,
  73                   ErrorResult& aRv) override;
  74
  75   MOZ_CAN_RUN_SCRIPT void CloseSteps(JSContext* aCx, ErrorResult& aRv) override;
  76
  77   void ErrorSteps(JSContext* aCx, JS::Handle<JS::Value> aError,
  78                   ErrorResult& aRv) override;
  79
  80  protected:
  81   ~ReadableStreamDefaultTeeReadRequest() override = default;
  82 };
  83
  84 namespace streams_abstract {
  85 MOZ_CAN_RUN_SCRIPT void ReadableByteStreamTee(
  86     JSContext* aCx, ReadableStream* aStream,
  87     nsTArray<RefPtr<ReadableStream>>& aResult, ErrorResult& aRv);
  88 }
  89
  90 }  // namespace mozilla::dom
  91 #endif