Version 1.8 of gecko-sdk. Downloaded from here:...

gecko-sdk/idl/nsIMemory.idl

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsISupports.idl"
+
+/**
+ *
+ * nsIMemory: interface to allocate and deallocate memory. Also provides
+ * for notifications in low-memory situations.
+ *
+ * The frozen exported symbols NS_Alloc, NS_Realloc, and NS_Free
+ * provide a more efficient way to access XPCOM memory allocation. Using
+ * those symbols is preferred to using the methods on this interface.
+ *
+ * A client that wishes to be notified of low memory situations (for
+ * example, because the client maintains a large memory cache that
+ * could be released when memory is tight) should register with the
+ * observer service (see nsIObserverService) using the topic 
+ * "memory-pressure". There are three specific types of notications 
+ * that can occur.  These types will be passed as the |aData| 
+ * parameter of the of the "memory-pressure" notification: 
+ * 
+ * "low-memory"
+ * This will be passed as the extra data when the pressure 
+ * observer is being asked to flush for low-memory conditions.
+ *
+ * "heap-minimize"
+ * This will be passed as the extra data when the pressure 
+ * observer is being asked to flush because of a heap minimize 
+ * call.
+ *
+ * "alloc-failure"
+ * This will be passed as the extra data when the pressure 
+ * observer has been asked to flush because a malloc() or 
+ * realloc() has failed.
+ *
+ * @status FROZEN
+ */
+
+[scriptable, uuid(59e7e77a-38e4-11d4-8cf5-0060b0fc14a3)]
+interface nsIMemory : nsISupports
+{
+    /**
+     * Allocates a block of memory of a particular size. If the memory 
+     * cannot be allocated (because of an out-of-memory condition), null
+     * is returned.
+     *
+     * @param size - the size of the block to allocate
+     * @result the block of memory
+     */
+    [noscript, notxpcom] voidPtr alloc(in size_t size);
+
+    /**
+     * Reallocates a block of memory to a new size.
+     *
+     * @param ptr - the block of memory to reallocate
+     * @param size - the new size
+     * @result the reallocated block of memory
+     *
+     * If ptr is null, this function behaves like malloc.
+     * If s is the size of the block to which ptr points, the first
+     * min(s, size) bytes of ptr's block are copied to the new block.
+     * If the allocation succeeds, ptr is freed and a pointer to the 
+     * new block returned.  If the allocation fails, ptr is not freed
+     * and null is returned. The returned value may be the same as ptr.
+     */
+    [noscript, notxpcom] voidPtr realloc(in voidPtr ptr,
+                                         in size_t newSize);
+
+    /**
+     * Frees a block of memory. Null is a permissible value, in which case
+     * nothing happens. 
+     *
+     * @param ptr - the block of memory to free
+     */
+    [noscript, notxpcom] void free(in voidPtr ptr);
+
+    /**
+     * Attempts to shrink the heap.
+     * @param immediate - if true, heap minimization will occur
+     *   immediately if the call was made on the main thread. If
+     *   false, the flush will be scheduled to happen when the app is
+     *   idle.
+     * @return NS_ERROR_FAILURE if 'immediate' is set an the call
+     *   was not on the application's main thread.
+     */
+    void heapMinimize(in boolean immediate);
+
+    /**
+     * This predicate can be used to determine if we're in a low-memory
+     * situation (what constitutes low-memory is platform dependent). This
+     * can be used to trigger the memory pressure observers.
+     */
+    boolean isLowMemory();
+};
+