js/public/SharedArrayBuffer.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /* ArrayBuffer functionality. */
   7
   8 #ifndef js_SharedArrayBuffer_h
   9 #define js_SharedArrayBuffer_h
  10
  11 #include <stddef.h>  // size_t
  12 #include <stdint.h>  // uint8_t
  13
  14 #include "jstypes.h"  // JS_PUBLIC_API
  15
  16 struct JS_PUBLIC_API JSContext;
  17 class JS_PUBLIC_API JSObject;
  18
  19 namespace JS {
  20 class JS_PUBLIC_API AutoRequireNoGC;
  21
  22 // CREATION
  23
  24 /**
  25  * Create a new SharedArrayBuffer with the given byte length.  This
  26  * may only be called if
  27  * JS::RealmCreationOptionsRef(cx).getSharedMemoryAndAtomicsEnabled() is
  28  * true.
  29  */
  30 extern JS_PUBLIC_API JSObject* NewSharedArrayBuffer(JSContext* cx,
  31                                                     size_t nbytes);
  32
  33 // TYPE TESTING
  34
  35 /**
  36  * Check whether obj supports the JS::GetSharedArrayBuffer* APIs.  Note that
  37  * this may return false if a security wrapper is encountered that denies the
  38  * unwrapping. If this test succeeds, then it is safe to call the various
  39  * accessor JSAPI calls defined below.
  40  */
  41 extern JS_PUBLIC_API bool IsSharedArrayBufferObject(JSObject* obj);
  42
  43 // ACCESSORS
  44
  45 extern JS_PUBLIC_API JSObject* UnwrapSharedArrayBuffer(JSObject* obj);
  46
  47 extern JS_PUBLIC_API size_t GetSharedArrayBufferByteLength(JSObject* obj);
  48
  49 extern JS_PUBLIC_API uint8_t* GetSharedArrayBufferData(JSObject* obj,
  50                                                        bool* isSharedMemory,
  51                                                        const AutoRequireNoGC&);
  52
  53 // Ditto for SharedArrayBuffer.
  54 //
  55 // There is an isShared out argument for API consistency (eases use from DOM).
  56 // It will always be set to true.
  57 extern JS_PUBLIC_API void GetSharedArrayBufferLengthAndData(
  58     JSObject* obj, size_t* length, bool* isSharedMemory, uint8_t** data);
  59
  60 /**
  61  * Returns true if there are any live SharedArrayBuffer objects, including those
  62  * for wasm memories, associated with the context.  This is conservative,
  63  * because it does not run GC.  Some dead objects may not have been collected
  64  * yet and thus will be thought live.
  65  */
  66 extern JS_PUBLIC_API bool ContainsSharedArrayBuffer(JSContext* cx);
  67
  68 /**
  69  * Return the isShared flag of a ArrayBufferView subtypes, which denotes whether
  70  * the underlying buffer is a SharedArrayBuffer.
  71  *
  72  * |obj| must have passed a JS_IsArrayBufferViewObject test, or somehow
  73  * be known that it would pass such a test: it is a ArrayBufferView subtypes or
  74  * a wrapper of a ArrayBufferView subtypes, and the unwrapping will succeed.
  75  */
  76 extern JS_PUBLIC_API bool IsArrayBufferViewShared(JSObject* obj);
  77
  78 }  // namespace JS
  79
  80 #endif /* js_SharedArrayBuffer_h */