diff options
Diffstat (limited to 'xpcom/glue/nsMemory.h')
| -rw-r--r-- | xpcom/glue/nsMemory.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/xpcom/glue/nsMemory.h b/xpcom/glue/nsMemory.h new file mode 100644 index 0000000000..6f19b81171 --- /dev/null +++ b/xpcom/glue/nsMemory.h @@ -0,0 +1,136 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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 nsresult HeapMinimize(bool aImmediate); + static void* Clone(const void* aPtr, size_t aSize); + static nsIMemory* GetGlobalMemoryService(); // AddRefs +}; + +/** + * Macro to free all elements of an XPCOM array of a given size using + * freeFunc, then frees the array itself using 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 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), + * free should be used. + */ +#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) + +/** + * 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; +}; +} // namespace mozilla + +#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__ + |