DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (d38398e5144e)

VCS Links

AllocFunction

SystemAllocPolicy

TempAllocPolicy

Macros

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * JS allocation policies.
 *
 * The allocators here are for system memory with lifetimes which are not
 * managed by the GC. See the comment at the top of vm/MallocProvider.h.
 */

#ifndef jsalloc_h
#define jsalloc_h

#include "js/TypeDecls.h"
#include "js/Utility.h"

namespace js {

enum class AllocFunction {
    Malloc,
    Calloc,
    Realloc
};

/* Policy for using system memory functions and doing no error reporting. */
class SystemAllocPolicy
{
  public:
    template <typename T> T* maybe_pod_malloc(size_t numElems) { return js_pod_malloc<T>(numElems); }
    template <typename T> T* maybe_pod_calloc(size_t numElems) { return js_pod_calloc<T>(numElems); }
    template <typename T> T* maybe_pod_realloc(T* p, size_t oldSize, size_t newSize) {
        return js_pod_realloc<T>(p, oldSize, newSize);
    }
    template <typename T> T* pod_malloc(size_t numElems) { return maybe_pod_malloc<T>(numElems); }
    template <typename T> T* pod_calloc(size_t numElems) { return maybe_pod_calloc<T>(numElems); }
    template <typename T> T* pod_realloc(T* p, size_t oldSize, size_t newSize) {
        return maybe_pod_realloc<T>(p, oldSize, newSize);
    }
    void free_(void* p) { js_free(p); }
    void reportAllocOverflow() const {}
    bool checkSimulatedOOM() const {
        return !js::oom::ShouldFailWithOOM();
    }
};

void ReportOutOfMemory(JSContext* cx);

/*
 * Allocation policy that calls the system memory functions and reports errors
 * to the context. Since the JSContext given on construction is stored for
 * the lifetime of the container, this policy may only be used for containers
 * whose lifetime is a shorter than the given JSContext.
 *
 * FIXME bug 647103 - rewrite this in terms of temporary allocation functions,
 * not the system ones.
 */
class TempAllocPolicy
{
    JSContext* const cx_;

    /*
     * Non-inline helper to call JSRuntime::onOutOfMemory with minimal
     * code bloat.
     */
    JS_FRIEND_API(void*) onOutOfMemory(AllocFunction allocFunc, size_t nbytes,
                                       void* reallocPtr = nullptr);

    template <typename T>
    T* onOutOfMemoryTyped(AllocFunction allocFunc, size_t numElems, void* reallocPtr = nullptr) {
        size_t bytes;
        if (MOZ_UNLIKELY(!CalculateAllocSize<T>(numElems, &bytes)))
            return nullptr;
        return static_cast<T*>(onOutOfMemory(allocFunc, bytes, reallocPtr));
    }

  public:
    MOZ_IMPLICIT TempAllocPolicy(JSContext* cx) : cx_(cx) {}

    template <typename T>
    T* maybe_pod_malloc(size_t numElems) {
        return js_pod_malloc<T>(numElems);
    }

    template <typename T>
    T* maybe_pod_calloc(size_t numElems) {
        return js_pod_calloc<T>(numElems);
    }

    template <typename T>
    T* maybe_pod_realloc(T* prior, size_t oldSize, size_t newSize) {
        return js_pod_realloc<T>(prior, oldSize, newSize);
    }

    template <typename T>
    T* pod_malloc(size_t numElems) {
        T* p = maybe_pod_malloc<T>(numElems);
        if (MOZ_UNLIKELY(!p))
            p = onOutOfMemoryTyped<T>(AllocFunction::Malloc, numElems);
        return p;
    }

    template <typename T>
    T* pod_calloc(size_t numElems) {
        T* p = maybe_pod_calloc<T>(numElems);
        if (MOZ_UNLIKELY(!p))
            p = onOutOfMemoryTyped<T>(AllocFunction::Calloc, numElems);
        return p;
    }

    template <typename T>
    T* pod_realloc(T* prior, size_t oldSize, size_t newSize) {
        T* p2 = maybe_pod_realloc<T>(prior, oldSize, newSize);
        if (MOZ_UNLIKELY(!p2))
            p2 = onOutOfMemoryTyped<T>(AllocFunction::Realloc, newSize, prior);
        return p2;
    }

    void free_(void* p) {
        js_free(p);
    }

    JS_FRIEND_API(void) reportAllocOverflow() const;

    bool checkSimulatedOOM() const {
        if (js::oom::ShouldFailWithOOM()) {
            ReportOutOfMemory(cx_);
            return false;
        }

        return true;
    }
};

} /* namespace js */

#endif /* jsalloc_h */