tor-browser

The Tor Browser
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MemoryFunctions.h (3148B)

      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 /* Low-level memory-allocation functions. */
      7 
      8 #ifndef js_MemoryFunctions_h
      9 #define js_MemoryFunctions_h
     10 
     11 #include "mozilla/Assertions.h"  // MOZ_ASSERT
     12 
     13 #include <stddef.h>  // size_t
     14 
     15 #include "jstypes.h"  // JS_PUBLIC_API
     16 
     17 struct JS_PUBLIC_API JSContext;
     18 class JS_PUBLIC_API JSObject;
     19 struct JS_PUBLIC_API JSRuntime;
     20 
     21 extern JS_PUBLIC_API void* JS_malloc(JSContext* cx, size_t nbytes);
     22 
     23 extern JS_PUBLIC_API void* JS_realloc(JSContext* cx, void* p, size_t oldBytes,
     24                                      size_t newBytes);
     25 
     26 /**
     27 * A wrapper for |js_free(p)| that may delay |js_free(p)| invocation as a
     28 * performance optimization.  |cx| may be nullptr.
     29 */
     30 extern JS_PUBLIC_API void JS_free(JSContext* cx, void* p);
     31 
     32 /**
     33 * Same as above, but for buffers that will be used with the BYOB
     34 * (Bring Your Own Buffer) JSString creation functions, such as
     35 * JS_NewLatin1String and JS_NewUCString
     36 */
     37 extern JS_PUBLIC_API void* JS_string_malloc(JSContext* cx, size_t nbytes);
     38 
     39 extern JS_PUBLIC_API void* JS_string_realloc(JSContext* cx, void* p,
     40                                             size_t oldBytes, size_t newBytes);
     41 
     42 extern JS_PUBLIC_API void JS_string_free(JSContext* cx, void* p);
     43 
     44 namespace JS {
     45 
     46 /**
     47 * The different possible memory uses to pass to Add/RemoveAssociatedMemory.
     48 */
     49 #define JS_FOR_EACH_PUBLIC_MEMORY_USE(_) \
     50  _(XPCWrappedNative)                    \
     51  _(DOMBinding)                          \
     52  _(CTypeFFIType)                        \
     53  _(CTypeFFITypeElements)                \
     54  _(CTypeFunctionInfo)                   \
     55  _(CTypeFieldInfo)                      \
     56  _(CDataBufferPtr)                      \
     57  _(CDataBuffer)                         \
     58  _(CClosureInfo)                        \
     59  _(CTypesInt64)                         \
     60  _(Embedding1)                          \
     61  _(Embedding2)                          \
     62  _(Embedding3)                          \
     63  _(Embedding4)                          \
     64  _(Embedding5)
     65 
     66 enum class MemoryUse : uint8_t {
     67 #define DEFINE_MEMORY_USE(Name) Name,
     68  JS_FOR_EACH_PUBLIC_MEMORY_USE(DEFINE_MEMORY_USE)
     69 #undef DEFINE_MEMORY_USE
     70 };
     71 
     72 /**
     73 * Advise the GC of external memory owned by a JSObject. This is used to
     74 * determine when to collect zones. Calls must be matched by calls to
     75 * RemoveAssociatedMemory() when the memory is deallocated or no longer owned by
     76 * the object.
     77 */
     78 extern JS_PUBLIC_API void AddAssociatedMemory(JSObject* obj, size_t nbytes,
     79                                              MemoryUse use);
     80 
     81 /**
     82 * Advise the GC that external memory reported by JS::AddAssociatedMemory() is
     83 * no longer owned by a JSObject. Calls must match those to
     84 * AddAssociatedMemory().
     85 */
     86 extern JS_PUBLIC_API void RemoveAssociatedMemory(JSObject* obj, size_t nbytes,
     87                                                 MemoryUse use);
     88 
     89 }  // namespace JS
     90 
     91 #endif /* js_MemoryFunctions_h */