The Tor Browser: js/src/vm/MallocProvider.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: set ts=8 sts=4 et sw=4 tw=99:

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 /*

     8  * Hierarchy of SpiderMonkey system memory allocators:

     9  *

    10  *   - System {m,c,re}alloc/new/free: Overridden by jemalloc in most

    11  *     environments. Do not use these functions directly.

    12  *

    13  *   - js_{m,c,re}alloc/new/free: Wraps the system allocators and adds a

    14  *     failure injection framework for use by the fuzzers as well as templated,

    15  *     typesafe variants. See js/public/Utility.h.

    16  *

    17  *   - AllocPolicy: An interface for the js allocators, for use with templates.

    18  *     These allocators are for system memory whose lifetime is not associated

    19  *     with a GC thing. See js/src/jsalloc.h.

    20  *

    21  *       - SystemAllocPolicy: No extra functionality over bare allocators.

    22  *

    23  *       - TempAllocPolicy: Adds automatic error reporting to the provided

    24  *         Context when allocations fail.

    25  *

    26  *   - MallocProvider. A mixin base class that handles automatically updating

    27  *     the GC's state in response to allocations that are tied to a GC lifetime

    28  *     or are for a particular GC purpose. These allocators must only be used

    29  *     for memory that will be freed when a GC thing is swept.

    30  *

    31  *       - gc::Zone:  Automatically triggers zone GC.

    32  *       - JSRuntime: Automatically triggers full GC.

    33  *       - ThreadsafeContext > ExclusiveContext > JSContext:

    34  *                    Dispatches directly to the runtime.

    35  */

    37 #ifndef vm_MallocProvider_h

    38 #define vm_MallocProvider_h

    40 #include "mozilla/Attributes.h"

    41 #include "mozilla/Likely.h"

    43 #include "js/Utility.h"

    45 namespace js {

    47 template<class Client>

    48 struct MallocProvider

    49 {

    50     void *malloc_(size_t bytes) {

    51         Client *client = static_cast<Client *>(this);

    52         client->updateMallocCounter(bytes);

    53         void *p = js_malloc(bytes);

    54         return MOZ_LIKELY(!!p) ? p : client->onOutOfMemory(nullptr, bytes);

    55     }

    57     void *calloc_(size_t bytes) {

    58         Client *client = static_cast<Client *>(this);

    59         client->updateMallocCounter(bytes);

    60         void *p = js_calloc(bytes);

    61         return MOZ_LIKELY(!!p) ? p : client->onOutOfMemory(reinterpret_cast<void *>(1), bytes);

    62     }

    64     void *realloc_(void *p, size_t oldBytes, size_t newBytes) {

    65         Client *client = static_cast<Client *>(this);

    66         /*

    67          * For compatibility we do not account for realloc that decreases

    68          * previously allocated memory.

    69          */

    70         if (newBytes > oldBytes)

    71             client->updateMallocCounter(newBytes - oldBytes);

    72         void *p2 = js_realloc(p, newBytes);

    73         return MOZ_LIKELY(!!p2) ? p2 : client->onOutOfMemory(p, newBytes);

    74     }

    76     void *realloc_(void *p, size_t bytes) {

    77         Client *client = static_cast<Client *>(this);

    78         /*

    79          * For compatibility we do not account for realloc that increases

    80          * previously allocated memory.

    81          */

    82         if (!p)

    83             client->updateMallocCounter(bytes);

    84         void *p2 = js_realloc(p, bytes);

    85         return MOZ_LIKELY(!!p2) ? p2 : client->onOutOfMemory(p, bytes);

    86     }

    88     template <class T>

    89     T *pod_malloc() {

    90         return (T *)malloc_(sizeof(T));

    91     }

    93     template <class T>

    94     T *pod_calloc() {

    95         return (T *)calloc_(sizeof(T));

    96     }

    98     template <class T>

    99     T *pod_malloc(size_t numElems) {

   100         if (numElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {

   101             Client *client = static_cast<Client *>(this);

   102             client->reportAllocationOverflow();

   103             return nullptr;

   104         }

   105         return (T *)malloc_(numElems * sizeof(T));

   106     }

   108     template <class T>

   109     T *pod_calloc(size_t numElems, JSCompartment *comp = nullptr, JSContext *cx = nullptr) {

   110         if (numElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {

   111             Client *client = static_cast<Client *>(this);

   112             client->reportAllocationOverflow();

   113             return nullptr;

   114         }

   115         return (T *)calloc_(numElems * sizeof(T));

   116     }

   118     JS_DECLARE_NEW_METHODS(new_, malloc_, MOZ_ALWAYS_INLINE)

   119 };

   121 } /* namespace js */

   123 #endif /* vm_MallocProvider_h */

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