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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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/. */
/* Class ReadableStream. */
#ifndef builtin_streams_ReadableStream_h
#define builtin_streams_ReadableStream_h
#include "mozilla/Assertions.h" // MOZ_ASSERT{,_IF}
#include <stdint.h> // uint32_t
#include "jstypes.h" // JS_PUBLIC_API
#include "js/Class.h" // JSClass, js::ClassSpec
#include "js/RootingAPI.h" // JS::Handle
#include "js/Stream.h" // JS::ReadableStream{Mode,UnderlyingSource}
#include "js/Value.h" // JS::Int32Value, JS::ObjectValue, JS::UndefinedValue
#include "vm/NativeObject.h" // js::NativeObject
class JS_PUBLIC_API JSObject;
namespace js {
class ReadableStreamController;
class ReadableStream : public NativeObject {
public:
/**
* Memory layout of Stream instances.
*
* the stored state. [[state]] and [[disturbed]] are stored in
* StreamSlot_State as ReadableStream::State enum values.
*
* Of the stored values, Reader and StoredError might be cross-compartment
* wrappers. This can happen if the Reader was created by applying a
* different compartment's ReadableStream.prototype.getReader method.
*
* A stream's associated controller is always created from under the
* stream's constructor and thus cannot be in a different compartment.
*/
enum Slots {
/**
* Optional pointer to make the stream participate in Gecko's cycle
* collection. See also JSCLASS_SLOT0_IS_NSISUPPORTS.
*/
Slot_ISupports,
Slot_Controller,
Slot_Reader,
Slot_State,
Slot_StoredError,
SlotCount
};
private:
enum StateBits {
Readable = 0,
Closed = 1,
Errored = 2,
StateMask = 0x000000ff,
Disturbed = 0x00000100
};
uint32_t stateBits() const { return getFixedSlot(Slot_State).toInt32(); }
void initStateBits(uint32_t stateBits) {
MOZ_ASSERT((stateBits & ~Disturbed) <= Errored);
setFixedSlot(Slot_State, JS::Int32Value(stateBits));
}
void setStateBits(uint32_t stateBits) {
#ifdef DEBUG
bool wasDisturbed = disturbed();
bool wasClosedOrErrored = closed() || errored();
#endif
initStateBits(stateBits);
MOZ_ASSERT_IF(wasDisturbed, disturbed());
MOZ_ASSERT_IF(wasClosedOrErrored, !readable());
}
StateBits state() const { return StateBits(stateBits() & StateMask); }
void setState(StateBits state) {
MOZ_ASSERT(state <= Errored);
uint32_t current = stateBits() & ~StateMask;
setStateBits(current | state);
}
public:
bool readable() const { return state() == Readable; }
bool closed() const { return state() == Closed; }
void setClosed() { setState(Closed); }
bool errored() const { return state() == Errored; }
void setErrored() { setState(Errored); }
bool disturbed() const { return stateBits() & Disturbed; }
void setDisturbed() { setStateBits(stateBits() | Disturbed); }
bool hasController() const {
return !getFixedSlot(Slot_Controller).isUndefined();
}
inline ReadableStreamController* controller() const;
inline void setController(ReadableStreamController* controller);
void clearController() {
setFixedSlot(Slot_Controller, JS::UndefinedValue());
}
bool hasReader() const { return !getFixedSlot(Slot_Reader).isUndefined(); }
void setReader(JSObject* reader) {
setFixedSlot(Slot_Reader, JS::ObjectValue(*reader));
}
void clearReader() { setFixedSlot(Slot_Reader, JS::UndefinedValue()); }
JS::Value storedError() const { return getFixedSlot(Slot_StoredError); }
void setStoredError(JS::Handle<JS::Value> value) {
setFixedSlot(Slot_StoredError, value);
}
JS::ReadableStreamMode mode() const;
bool locked() const;
[[nodiscard]] static ReadableStream* create(
JSContext* cx, void* nsISupportsObject_alreadyAddreffed = nullptr,
JS::Handle<JSObject*> proto = nullptr);
static ReadableStream* createExternalSourceStream(
JSContext* cx, JS::ReadableStreamUnderlyingSource* source,
void* nsISupportsObject_alreadyAddreffed = nullptr,
JS::Handle<JSObject*> proto = nullptr);
static bool constructor(JSContext* cx, unsigned argc, Value* vp);
static const ClassSpec classSpec_;
static const JSClass class_;
static const ClassSpec protoClassSpec_;
static const JSClass protoClass_;
};
[[nodiscard]] extern bool SetUpExternalReadableByteStreamController(
JSContext* cx, JS::Handle<ReadableStream*> stream,
JS::ReadableStreamUnderlyingSource* source);
} // namespace js
#endif // builtin_streams_ReadableStream_h