michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef vm_SharedArrayObject_h
michael@0: #define vm_SharedArrayObject_h
michael@0: 
michael@0: #include "mozilla/Atomics.h"
michael@0: 
michael@0: #include "jsapi.h"
michael@0: #include "jsobj.h"
michael@0: #include "jstypes.h"
michael@0: 
michael@0: #include "gc/Barrier.h"
michael@0: #include "vm/ArrayBufferObject.h"
michael@0: 
michael@0: typedef struct JSProperty JSProperty;
michael@0: 
michael@0: namespace js {
michael@0: 
michael@0: /*
michael@0:  * SharedArrayRawBuffer
michael@0:  *
michael@0:  * A bookkeeping object always stored immediately before the raw buffer.
michael@0:  * The buffer itself is mmap()'d and refcounted.
michael@0:  * SharedArrayBufferObjects and AsmJS code may hold references.
michael@0:  *
michael@0:  *           |<------ sizeof ------>|<- length ->|
michael@0:  *
michael@0:  *   | waste | SharedArrayRawBuffer | data array | waste |
michael@0:  */
michael@0: class SharedArrayRawBuffer
michael@0: {
michael@0:   private:
michael@0:     mozilla::Atomic<uint32_t, mozilla::ReleaseAcquire> refcount;
michael@0:     uint32_t length;
michael@0: 
michael@0:   protected:
michael@0:     SharedArrayRawBuffer(uint8_t *buffer, uint32_t length)
michael@0:       : refcount(1), length(length)
michael@0:     {
michael@0:         JS_ASSERT(buffer == dataPointer());
michael@0:     }
michael@0: 
michael@0:   public:
michael@0:     static SharedArrayRawBuffer *New(uint32_t length);
michael@0: 
michael@0:     inline uint8_t *dataPointer() const {
michael@0:         return ((uint8_t *)this) + sizeof(SharedArrayRawBuffer);
michael@0:     }
michael@0: 
michael@0:     inline uint32_t byteLength() const {
michael@0:         return length;
michael@0:     }
michael@0: 
michael@0:     void addReference();
michael@0:     void dropReference();
michael@0: };
michael@0: 
michael@0: /*
michael@0:  * SharedArrayBufferObject
michael@0:  *
michael@0:  * When transferred to a WebWorker, the buffer is not neutered on the parent side,
michael@0:  * and both child and parent reference the same buffer.
michael@0:  */
michael@0: class SharedArrayBufferObject : public ArrayBufferObject
michael@0: {
michael@0:     static bool byteLengthGetterImpl(JSContext *cx, CallArgs args);
michael@0: 
michael@0:   public:
michael@0:     static const Class class_;
michael@0:     static const Class protoClass;
michael@0: 
michael@0:     // Slot used for storing a pointer to the SharedArrayRawBuffer.
michael@0:     static const uint8_t RAWBUF_SLOT = ArrayBufferObject::RESERVED_SLOTS;
michael@0: 
michael@0:     static const uint8_t RESERVED_SLOTS = ArrayBufferObject::RESERVED_SLOTS + 1;
michael@0: 
michael@0:     static bool class_constructor(JSContext *cx, unsigned argc, Value *vp);
michael@0: 
michael@0:     // Create a SharedArrayBufferObject with a new SharedArrayRawBuffer.
michael@0:     static JSObject *New(JSContext *cx, uint32_t length);
michael@0: 
michael@0:     // Create a SharedArrayBufferObject using an existing SharedArrayRawBuffer.
michael@0:     static JSObject *New(JSContext *cx, SharedArrayRawBuffer *buffer);
michael@0: 
michael@0:     static bool byteLengthGetter(JSContext *cx, unsigned argc, Value *vp);
michael@0: 
michael@0:     static void Finalize(FreeOp *fop, JSObject *obj);
michael@0: 
michael@0:     void acceptRawBuffer(SharedArrayRawBuffer *buffer);
michael@0:     void dropRawBuffer();
michael@0: 
michael@0:     SharedArrayRawBuffer *rawBufferObject() const;
michael@0:     uint8_t *dataPointer() const;
michael@0:     uint32_t byteLength() const;
michael@0: };
michael@0: 
michael@0: bool
michael@0: IsSharedArrayBuffer(HandleValue v);
michael@0: 
michael@0: } // namespace js
michael@0: 
michael@0: #endif // vm_SharedArrayObject_h