1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/vm/SharedArrayObject.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,106 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef vm_SharedArrayObject_h
1.11 +#define vm_SharedArrayObject_h
1.12 +
1.13 +#include "mozilla/Atomics.h"
1.14 +
1.15 +#include "jsapi.h"
1.16 +#include "jsobj.h"
1.17 +#include "jstypes.h"
1.18 +
1.19 +#include "gc/Barrier.h"
1.20 +#include "vm/ArrayBufferObject.h"
1.21 +
1.22 +typedef struct JSProperty JSProperty;
1.23 +
1.24 +namespace js {
1.25 +
1.26 +/*
1.27 + * SharedArrayRawBuffer
1.28 + *
1.29 + * A bookkeeping object always stored immediately before the raw buffer.
1.30 + * The buffer itself is mmap()'d and refcounted.
1.31 + * SharedArrayBufferObjects and AsmJS code may hold references.
1.32 + *
1.33 + * |<------ sizeof ------>|<- length ->|
1.34 + *
1.35 + * | waste | SharedArrayRawBuffer | data array | waste |
1.36 + */
1.37 +class SharedArrayRawBuffer
1.38 +{
1.39 + private:
1.40 + mozilla::Atomic<uint32_t, mozilla::ReleaseAcquire> refcount;
1.41 + uint32_t length;
1.42 +
1.43 + protected:
1.44 + SharedArrayRawBuffer(uint8_t *buffer, uint32_t length)
1.45 + : refcount(1), length(length)
1.46 + {
1.47 + JS_ASSERT(buffer == dataPointer());
1.48 + }
1.49 +
1.50 + public:
1.51 + static SharedArrayRawBuffer *New(uint32_t length);
1.52 +
1.53 + inline uint8_t *dataPointer() const {
1.54 + return ((uint8_t *)this) + sizeof(SharedArrayRawBuffer);
1.55 + }
1.56 +
1.57 + inline uint32_t byteLength() const {
1.58 + return length;
1.59 + }
1.60 +
1.61 + void addReference();
1.62 + void dropReference();
1.63 +};
1.64 +
1.65 +/*
1.66 + * SharedArrayBufferObject
1.67 + *
1.68 + * When transferred to a WebWorker, the buffer is not neutered on the parent side,
1.69 + * and both child and parent reference the same buffer.
1.70 + */
1.71 +class SharedArrayBufferObject : public ArrayBufferObject
1.72 +{
1.73 + static bool byteLengthGetterImpl(JSContext *cx, CallArgs args);
1.74 +
1.75 + public:
1.76 + static const Class class_;
1.77 + static const Class protoClass;
1.78 +
1.79 + // Slot used for storing a pointer to the SharedArrayRawBuffer.
1.80 + static const uint8_t RAWBUF_SLOT = ArrayBufferObject::RESERVED_SLOTS;
1.81 +
1.82 + static const uint8_t RESERVED_SLOTS = ArrayBufferObject::RESERVED_SLOTS + 1;
1.83 +
1.84 + static bool class_constructor(JSContext *cx, unsigned argc, Value *vp);
1.85 +
1.86 + // Create a SharedArrayBufferObject with a new SharedArrayRawBuffer.
1.87 + static JSObject *New(JSContext *cx, uint32_t length);
1.88 +
1.89 + // Create a SharedArrayBufferObject using an existing SharedArrayRawBuffer.
1.90 + static JSObject *New(JSContext *cx, SharedArrayRawBuffer *buffer);
1.91 +
1.92 + static bool byteLengthGetter(JSContext *cx, unsigned argc, Value *vp);
1.93 +
1.94 + static void Finalize(FreeOp *fop, JSObject *obj);
1.95 +
1.96 + void acceptRawBuffer(SharedArrayRawBuffer *buffer);
1.97 + void dropRawBuffer();
1.98 +
1.99 + SharedArrayRawBuffer *rawBufferObject() const;
1.100 + uint8_t *dataPointer() const;
1.101 + uint32_t byteLength() const;
1.102 +};
1.103 +
1.104 +bool
1.105 +IsSharedArrayBuffer(HandleValue v);
1.106 +
1.107 +} // namespace js
1.108 +
1.109 +#endif // vm_SharedArrayObject_h
