gecko-dev/js/src/jsalloc.h

89 lines
2.5 KiB
C++

/* -*- 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 {
class ContextFriendFields;
/* Policy for using system memory functions and doing no error reporting. */
class SystemAllocPolicy
{
public:
void *malloc_(size_t bytes) { return js_malloc(bytes); }
void *calloc_(size_t bytes) { return js_calloc(bytes); }
void *realloc_(void *p, size_t oldBytes, size_t bytes) { return js_realloc(p, bytes); }
void free_(void *p) { js_free(p); }
void reportAllocOverflow() const {}
};
/*
* 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
{
ContextFriendFields *const cx_;
/*
* Non-inline helper to call JSRuntime::onOutOfMemory with minimal
* code bloat.
*/
JS_FRIEND_API(void *) onOutOfMemory(void *p, size_t nbytes);
public:
TempAllocPolicy(JSContext *cx) : cx_((ContextFriendFields *) cx) {} // :(
TempAllocPolicy(ContextFriendFields *cx) : cx_(cx) {}
void *malloc_(size_t bytes) {
void *p = js_malloc(bytes);
if (MOZ_UNLIKELY(!p))
p = onOutOfMemory(nullptr, bytes);
return p;
}
void *calloc_(size_t bytes) {
void *p = js_calloc(bytes);
if (MOZ_UNLIKELY(!p))
p = onOutOfMemory(nullptr, bytes);
return p;
}
void *realloc_(void *p, size_t oldBytes, size_t bytes) {
void *p2 = js_realloc(p, bytes);
if (MOZ_UNLIKELY(!p2))
p2 = onOutOfMemory(p2, bytes);
return p2;
}
void free_(void *p) {
js_free(p);
}
JS_FRIEND_API(void) reportAllocOverflow() const;
};
} /* namespace js */
#endif /* jsalloc_h */