dom/streams/TeeState.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_TeeState_h
   8 #define mozilla_dom_TeeState_h
   9
  10 #include "mozilla/HoldDropJSObjects.h"
  11 #include "nsISupports.h"
  12 #include "mozilla/dom/ReadableStream.h"
  13 #include "mozilla/dom/ReadableStreamDefaultReader.h"
  14 #include "mozilla/dom/Promise.h"
  15
  16 namespace mozilla::dom {
  17
  18 class ReadableStreamDefaultTeeSourceAlgorithms;
  19
  20 enum class TeeBranch : bool {
  21   Branch1,
  22   Branch2,
  23 };
  24
  25 inline TeeBranch OtherTeeBranch(TeeBranch aBranch) {
  26   if (aBranch == TeeBranch::Branch1) {
  27     return TeeBranch::Branch2;
  28   }
  29   return TeeBranch::Branch1;
  30 }
  31
  32 // A closure capturing the free variables in the ReadableStreamTee family of
  33 // algorithms.
  34 // https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaulttee
  35 // https://streams.spec.whatwg.org/#abstract-opdef-readablebytestreamtee
  36 struct TeeState : public nsISupports {
  37   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  38   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(TeeState)
  39
  40   static already_AddRefed<TeeState> Create(ReadableStream* aStream,
  41                                            bool aCloneForBranch2,
  42                                            ErrorResult& aRv);
  43
  44   ReadableStream* GetStream() const { return mStream; }
  45   void SetStream(ReadableStream* aStream) { mStream = aStream; }
  46
  47   ReadableStreamGenericReader* GetReader() const { return mReader; }
  48   void SetReader(ReadableStreamGenericReader* aReader) { mReader = aReader; }
  49
  50   ReadableStreamDefaultReader* GetDefaultReader() const {
  51     return mReader->AsDefault();
  52   }
  53
  54   bool ReadAgain() const { return mReadAgain; }
  55   void SetReadAgain(bool aReadAgain) { mReadAgain = aReadAgain; }
  56
  57   // ReadableByteStreamTee uses ReadAgainForBranch{1,2};
  58   bool ReadAgainForBranch1() const { return ReadAgain(); }
  59   void SetReadAgainForBranch1(bool aReadAgainForBranch1) {
  60     SetReadAgain(aReadAgainForBranch1);
  61   }
  62
  63   bool ReadAgainForBranch2() const { return mReadAgainForBranch2; }
  64   void SetReadAgainForBranch2(bool aReadAgainForBranch2) {
  65     mReadAgainForBranch2 = aReadAgainForBranch2;
  66   }
  67
  68   bool Reading() const { return mReading; }
  69   void SetReading(bool aReading) { mReading = aReading; }
  70
  71   bool Canceled1() const { return mCanceled1; }
  72   void SetCanceled1(bool aCanceled1) { mCanceled1 = aCanceled1; }
  73
  74   bool Canceled2() const { return mCanceled2; }
  75   void SetCanceled2(bool aCanceled2) { mCanceled2 = aCanceled2; }
  76
  77   void SetCanceled(TeeBranch aBranch, bool aCanceled) {
  78     aBranch == TeeBranch::Branch1 ? SetCanceled1(aCanceled)
  79                                   : SetCanceled2(aCanceled);
  80   }
  81   bool Canceled(TeeBranch aBranch) {
  82     return aBranch == TeeBranch::Branch1 ? Canceled1() : Canceled2();
  83   }
  84
  85   JS::Value Reason1() const { return mReason1; }
  86   void SetReason1(JS::Handle<JS::Value> aReason1) { mReason1 = aReason1; }
  87
  88   JS::Value Reason2() const { return mReason2; }
  89   void SetReason2(JS::Handle<JS::Value> aReason2) { mReason2 = aReason2; }
  90
  91   void SetReason(TeeBranch aBranch, JS::Handle<JS::Value> aReason) {
  92     aBranch == TeeBranch::Branch1 ? SetReason1(aReason) : SetReason2(aReason);
  93   }
  94
  95   ReadableStream* Branch1() const { return mBranch1; }
  96   void SetBranch1(already_AddRefed<ReadableStream> aBranch1) {
  97     mBranch1 = aBranch1;
  98   }
  99
 100   ReadableStream* Branch2() const { return mBranch2; }
 101   void SetBranch2(already_AddRefed<ReadableStream> aBranch2) {
 102     mBranch2 = aBranch2;
 103   }
 104
 105   Promise* CancelPromise() const { return mCancelPromise; }
 106   void SetCancelPromise(Promise* aCancelPromise) {
 107     mCancelPromise = aCancelPromise;
 108   }
 109
 110   bool CloneForBranch2() const { return mCloneForBranch2; }
 111   void setCloneForBranch2(bool aCloneForBranch2) {
 112     mCloneForBranch2 = aCloneForBranch2;
 113   }
 114
 115   // Some code is better served by using an enum into various internal slots to
 116   // avoid duplication: Here we provide alternative accessors for that case.
 117   ReadableStream* Branch(TeeBranch aBranch) const {
 118     return aBranch == TeeBranch::Branch1 ? Branch1() : Branch2();
 119   }
 120
 121   void SetReadAgainForBranch(TeeBranch aBranch, bool aValue) {
 122     if (aBranch == TeeBranch::Branch1) {
 123       SetReadAgainForBranch1(aValue);
 124       return;
 125     }
 126     SetReadAgainForBranch2(aValue);
 127   }
 128
 129   MOZ_CAN_RUN_SCRIPT void PullCallback(JSContext* aCx, nsIGlobalObject* aGlobal,
 130                                        ErrorResult& aRv);
 131
 132  private:
 133   TeeState(ReadableStream* aStream, bool aCloneForBranch2);
 134
 135   // Implicit:
 136   RefPtr<ReadableStream> mStream;
 137
 138   // Step 3. (Step Numbering is based on ReadableStreamDefaultTee)
 139   RefPtr<ReadableStreamGenericReader> mReader;
 140
 141   // Step 4.
 142   bool mReading = false;
 143
 144   // Step 5.
 145   // (Aliased to readAgainForBranch1, for the purpose of ReadableByteStreamTee)
 146   bool mReadAgain = false;
 147
 148   // ReadableByteStreamTee
 149   bool mReadAgainForBranch2 = false;
 150
 151   // Step 6.
 152   bool mCanceled1 = false;
 153
 154   // Step 7.
 155   bool mCanceled2 = false;
 156
 157   // Step 8.
 158   JS::Heap<JS::Value> mReason1;
 159
 160   // Step 9.
 161   JS::Heap<JS::Value> mReason2;
 162
 163   // Step 10.
 164   RefPtr<ReadableStream> mBranch1;
 165
 166   // Step 11.
 167   RefPtr<ReadableStream> mBranch2;
 168
 169   // Step 12.
 170   RefPtr<Promise> mCancelPromise;
 171
 172   // Implicit:
 173   bool mCloneForBranch2 = false;
 174
 175   virtual ~TeeState() { mozilla::DropJSObjects(this); }
 176 };
 177
 178 }  // namespace mozilla::dom
 179 #endif