dom/streams/UnderlyingSourceCallbackHelpers.cpp

   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 #include "mozilla/dom/ReadableStreamDefaultController.h"
   8 #include "mozilla/dom/UnderlyingSourceCallbackHelpers.h"
   9 #include "mozilla/dom/UnderlyingSourceBinding.h"
  10
  11 namespace mozilla::dom {
  12
  13 // UnderlyingSourceAlgorithmsBase
  14 NS_IMPL_CYCLE_COLLECTION(UnderlyingSourceAlgorithmsBase)
  15 NS_IMPL_CYCLE_COLLECTING_ADDREF(UnderlyingSourceAlgorithmsBase)
  16 NS_IMPL_CYCLE_COLLECTING_RELEASE(UnderlyingSourceAlgorithmsBase)
  17 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(UnderlyingSourceAlgorithmsBase)
  18   NS_INTERFACE_MAP_ENTRY(nsISupports)
  19 NS_INTERFACE_MAP_END
  20 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(UnderlyingSourceAlgorithmsBase)
  21 NS_IMPL_CYCLE_COLLECTION_TRACE_END
  22
  23 NS_IMPL_CYCLE_COLLECTION_INHERITED_WITH_JS_MEMBERS(
  24     UnderlyingSourceAlgorithms, UnderlyingSourceAlgorithmsBase,
  25     (mGlobal, mStartCallback, mPullCallback, mCancelCallback),
  26     (mUnderlyingSource))
  27 NS_IMPL_ADDREF_INHERITED(UnderlyingSourceAlgorithms,
  28                          UnderlyingSourceAlgorithmsBase)
  29 NS_IMPL_RELEASE_INHERITED(UnderlyingSourceAlgorithms,
  30                           UnderlyingSourceAlgorithmsBase)
  31 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(UnderlyingSourceAlgorithms)
  32 NS_INTERFACE_MAP_END_INHERITING(UnderlyingSourceAlgorithmsBase)
  33
  34 // https://streams.spec.whatwg.org/#set-up-readable-stream-default-controller-from-underlying-source
  35 void UnderlyingSourceAlgorithms::StartCallback(
  36     JSContext* aCx, ReadableStreamController& aController,
  37     JS::MutableHandle<JS::Value> aRetVal, ErrorResult& aRv) {
  38   if (!mStartCallback) {
  39     // Step 2: Let startAlgorithm be an algorithm that returns undefined.
  40     aRetVal.setUndefined();
  41     return;
  42   }
  43
  44   // Step 5: If underlyingSourceDict["start"] exists, then set startAlgorithm to
  45   // an algorithm which returns the result of invoking
  46   // underlyingSourceDict["start"] with argument list « controller » and
  47   // callback this value underlyingSource.
  48   JS::RootedObject thisObj(aCx, mUnderlyingSource);
  49   ReadableStreamDefaultControllerOrReadableByteStreamController controller;
  50   if (aController.IsDefault()) {
  51     controller.SetAsReadableStreamDefaultController() = aController.AsDefault();
  52   } else {
  53     controller.SetAsReadableByteStreamController() = aController.AsByte();
  54   }
  55
  56   return mStartCallback->Call(thisObj, controller, aRetVal, aRv,
  57                               "UnderlyingSource.start",
  58                               CallbackFunction::eRethrowExceptions);
  59 }
  60
  61 // https://streams.spec.whatwg.org/#set-up-readable-stream-default-controller-from-underlying-source
  62 already_AddRefed<Promise> UnderlyingSourceAlgorithms::PullCallback(
  63     JSContext* aCx, ReadableStreamController& aController, ErrorResult& aRv) {
  64   JS::RootedObject thisObj(aCx, mUnderlyingSource);
  65   if (!mPullCallback) {
  66     // Step 3: Let pullAlgorithm be an algorithm that returns a promise resolved
  67     // with undefined.
  68     return Promise::CreateResolvedWithUndefined(mGlobal, aRv);
  69   }
  70
  71   // Step 6: If underlyingSourceDict["pull"] exists, then set pullAlgorithm to
  72   // an algorithm which returns the result of invoking
  73   // underlyingSourceDict["pull"] with argument list « controller » and callback
  74   // this value underlyingSource.
  75   ReadableStreamDefaultControllerOrReadableByteStreamController controller;
  76   if (aController.IsDefault()) {
  77     controller.SetAsReadableStreamDefaultController() = aController.AsDefault();
  78   } else {
  79     controller.SetAsReadableByteStreamController() = aController.AsByte();
  80   }
  81
  82   RefPtr<Promise> promise =
  83       mPullCallback->Call(thisObj, controller, aRv, "UnderlyingSource.pull",
  84                           CallbackFunction::eRethrowExceptions);
  85
  86   return promise.forget();
  87 }
  88
  89 // https://streams.spec.whatwg.org/#set-up-readable-stream-default-controller-from-underlying-source
  90 already_AddRefed<Promise> UnderlyingSourceAlgorithms::CancelCallback(
  91     JSContext* aCx, const Optional<JS::Handle<JS::Value>>& aReason,
  92     ErrorResult& aRv) {
  93   if (!mCancelCallback) {
  94     // Step 4: Let cancelAlgorithm be an algorithm that returns a promise
  95     // resolved with undefined.
  96     return Promise::CreateResolvedWithUndefined(mGlobal, aRv);
  97   }
  98
  99   // Step 7: If underlyingSourceDict["cancel"] exists, then set cancelAlgorithm
 100   // to an algorithm which takes an argument reason and returns the result of
 101   // invoking underlyingSourceDict["cancel"] with argument list « reason » and
 102   // callback this value underlyingSource.
 103   JS::RootedObject thisObj(aCx, mUnderlyingSource);
 104   RefPtr<Promise> promise =
 105       mCancelCallback->Call(thisObj, aReason, aRv, "UnderlyingSource.cancel",
 106                             CallbackFunction::eRethrowExceptions);
 107
 108   return promise.forget();
 109 }
 110
 111 }  // namespace mozilla::dom