The Tor Browser: memory/mozalloc/mozalloc

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: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: sw=4 ts=4 et :

     3  */

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

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

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

     8 #if defined(XP_WIN)

     9 #  define MOZALLOC_EXPORT __declspec(dllexport)

    10 #endif

    12 #include "mozilla/mozalloc_abort.h"

    13 #include "mozilla/mozalloc_oom.h"

    14 #include "mozilla/Assertions.h"

    16 static mozalloc_oom_abort_handler gAbortHandler;

    18 #define OOM_MSG_LEADER "out of memory: 0x"

    19 #define OOM_MSG_DIGITS "0000000000000000" // large enough for 2^64

    20 #define OOM_MSG_TRAILER " bytes requested"

    21 #define OOM_MSG_FIRST_DIGIT_OFFSET sizeof(OOM_MSG_LEADER) - 1

    22 #define OOM_MSG_LAST_DIGIT_OFFSET sizeof(OOM_MSG_LEADER) + \

    23                                   sizeof(OOM_MSG_DIGITS) - 3

    25 static const char *hex = "0123456789ABCDEF";

    27 void

    28 mozalloc_handle_oom(size_t size)

    29 {

    30     char oomMsg[] = OOM_MSG_LEADER OOM_MSG_DIGITS OOM_MSG_TRAILER;

    31     size_t i;

    33     // NB: this is handle_oom() stage 1, which simply aborts on OOM.

    34     // we might proceed to a stage 2 in which an attempt is made to

    35     // reclaim memory

    37     if (gAbortHandler)

    38         gAbortHandler(size);

    40     static_assert(OOM_MSG_FIRST_DIGIT_OFFSET > 0,

    41                   "Loop below will never terminate (i can't go below 0)");

    43     // Insert size into the diagnostic message using only primitive operations

    44     for (i = OOM_MSG_LAST_DIGIT_OFFSET;

    45          size && i >= OOM_MSG_FIRST_DIGIT_OFFSET; i--) {

    46       oomMsg[i] = hex[size % 16];

    47       size /= 16;

    48     }

    50     mozalloc_abort(oomMsg);

    51 }

    53 void

    54 mozalloc_set_oom_abort_handler(mozalloc_oom_abort_handler handler)

    55 {

    56     gAbortHandler = handler;

    57 }

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