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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */
#ifndef nsMemory_h__
#define nsMemory_h__
#include "nsXPCOM.h"
class nsIMemory;
#define NS_MEMORY_CONTRACTID "@mozilla.org/xpcom/memory-service;1"
#define NS_MEMORY_CID \
{ /* 30a04e40-38e7-11d4-8cf5-0060b0fc14a3 */ \
0x30a04e40, \
0x38e7, \
0x11d4, \
{0x8c, 0xf5, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
}
/**
* Static helper routines to manage memory. These routines allow easy access
* to xpcom's built-in (global) nsIMemory implementation, without needing
* to go through the service manager to get it. However this requires clients
* to link with the xpcom DLL.
*
* This class is not threadsafe and is intented for use only on the main
* thread.
*/
class nsMemory
{
public:
static NS_HIDDEN_(void*) Alloc(size_t size)
{ return NS_Alloc(size); }
static NS_HIDDEN_(void*) Realloc(void* ptr, size_t size)
{ return NS_Realloc(ptr, size); }
static NS_HIDDEN_(void) Free(void* ptr)
{ NS_Free(ptr); }
static NS_COM_GLUE nsresult HeapMinimize(bool aImmediate);
static NS_COM_GLUE void* Clone(const void* ptr, size_t size);
static NS_COM_GLUE nsIMemory* GetGlobalMemoryService(); // AddRefs
};
/**
* Macro to free all elements of an XPCOM array of a given size using
* freeFunc, then frees the array itself using nsMemory::Free().
*
* Note that this macro (and its wrappers) can be used to deallocate a
* partially- or completely-built array while unwinding an error
* condition inside the XPCOM routine that was going to return the
* array. For this to work on a partially-built array, your code
* needs to be building the array from index 0 upwards, and simply
* pass the number of elements that have already been built (and thus
* need to be freed) as |size|.
*
* Thanks to <alecf@netscape.com> for suggesting this form, which
* allows the macro to be used with NS_RELEASE / NS_RELEASE_IF in
* addition to nsMemory::Free.
*
* @param size Number of elements in the array. If not a constant, this
* should be a int32_t. Note that this means this macro
* will not work if size >= 2^31.
* @param array The array to be freed.
* @param freeFunc The function or macro to be used to free it.
* For arrays of nsISupports (or any class derived
* from it), NS_IF_RELEASE (or NS_RELEASE) should be
* passed as freeFunc. For most (all?) other pointer
* types (including XPCOM strings and wstrings),
* nsMemory::Free should be used, since the
* shared-allocator (nsMemory) is what will have been
* used to allocate the memory.
*/
#define NS_FREE_XPCOM_POINTER_ARRAY(size, array, freeFunc) \
PR_BEGIN_MACRO \
int32_t iter_ = int32_t(size); \
while (--iter_ >= 0) \
freeFunc((array)[iter_]); \
NS_Free((array)); \
PR_END_MACRO
// convenience macros for commonly used calls. mmmmm. syntactic sugar.
/**
* Macro to free arrays of non-refcounted objects allocated by the
* shared allocator (nsMemory) such as strings and wstrings. A
* convenience wrapper around NS_FREE_XPCOM_POINTER_ARRAY.
*
* @param size Number of elements in the array. If not a constant, this
* should be a int32_t. Note that this means this macro
* will not work if size >= 2^31.
* @param array The array to be freed.
*/
#define NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(size, array) \
NS_FREE_XPCOM_POINTER_ARRAY((size), (array), NS_Free)
/**
* Macro to free an array of pointers to nsISupports (or classes
* derived from it). A convenience wrapper around
* NS_FREE_XPCOM_POINTER_ARRAY.
*
* Note that if you know that none of your nsISupports pointers are
* going to be 0, you can gain a bit of speed by calling
* NS_FREE_XPCOM_POINTER_ARRAY directly and using NS_RELEASE as your
* free function.
*
* @param size Number of elements in the array. If not a constant, this
* should be a int32_t. Note that this means this macro
* will not work if size >= 2^31.
* @param array The array to be freed.
*/
#define NS_FREE_XPCOM_ISUPPORTS_POINTER_ARRAY(size, array) \
NS_FREE_XPCOM_POINTER_ARRAY((size), (array), NS_IF_RELEASE)
/**
* Helpful array length function for calculating the length of a
* statically declared array.
*/
#define NS_ARRAY_LENGTH(array_) \
(sizeof(array_)/sizeof(array_[0]))
/**
* A macro, NS_ALIGNMENT_OF(t_) that determines the alignment
* requirements of a type.
*/
namespace mozilla {
template <class T>
struct AlignmentTestStruct
{
char c;
T t;
};
}
#define NS_ALIGNMENT_OF(t_) \
(sizeof(mozilla::AlignmentTestStruct<t_>) - sizeof(t_))
/**
* An enumeration type used to represent a method of assignment.
*/
enum nsAssignmentType {
NS_ASSIGNMENT_COPY, // copy by value
NS_ASSIGNMENT_DEPEND, // copy by reference
NS_ASSIGNMENT_ADOPT // copy by reference (take ownership of resource)
};
#endif // nsMemory_h__
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