зеркало из https://github.com/mozilla/pjs.git
393 строки
14 KiB
C++
393 строки
14 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla.org code.
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*
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* The Initial Developer of the Original Code is Mozilla Foundation.
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* Portions created by the Initial Developer are Copyright (C) 2006
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Jonas Sicking <jonas@sicking.cc> (Original Author)
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* Daniel Witte <dwitte@stanford.edu>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsTObserverArray_h___
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#define nsTObserverArray_h___
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#include "nsTArray.h"
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class NS_COM_GLUE nsTObserverArray_base {
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public:
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typedef PRUint32 index_type;
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typedef PRUint32 size_type;
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typedef PRInt32 diff_type;
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protected:
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class Iterator_base {
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protected:
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friend class nsTObserverArray_base;
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Iterator_base(index_type aPosition, Iterator_base* aNext)
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: mPosition(aPosition),
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mNext(aNext) {
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}
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// The current position of the iterator. Its exact meaning differs
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// depending on iterator. See nsTObserverArray<T>::ForwardIterator.
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index_type mPosition;
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// The next iterator currently iterating the same array
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Iterator_base* mNext;
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};
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nsTObserverArray_base()
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: mIterators(nsnull) {
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}
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~nsTObserverArray_base() {
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NS_ASSERTION(mIterators == nsnull, "iterators outlasting array");
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}
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/**
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* Adjusts iterators after an element has been inserted or removed
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* from the array.
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* @param modPos Position where elements were added or removed.
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* @param adjustment -1 if an element was removed, 1 if an element was
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* added.
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*/
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void AdjustIterators(index_type aModPos, diff_type aAdjustment);
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/**
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* Clears iterators when the array is destroyed.
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*/
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void ClearIterators();
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mutable Iterator_base* mIterators;
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};
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/**
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* An array of observers. Like a normal array, but supports iterators that are
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* stable even if the array is modified during iteration.
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* The template parameter T is the observer type the array will hold;
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* N is the number of built-in storage slots that come with the array.
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* NOTE: You probably want to use nsTObserverArray, unless you specifically
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* want built-in storage. See below.
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* @see nsTObserverArray, nsTArray
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*/
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template<class T, PRUint32 N>
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class nsAutoTObserverArray : protected nsTObserverArray_base {
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public:
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typedef T elem_type;
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typedef nsTArray<T> array_type;
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nsAutoTObserverArray() {
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}
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//
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// Accessor methods
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//
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// @return The number of elements in the array.
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size_type Length() const {
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return mArray.Length();
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}
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// @return True if the array is empty or false otherwise.
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PRBool IsEmpty() const {
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return mArray.IsEmpty();
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}
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// This method provides direct access to the i'th element of the array.
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// The given index must be within the array bounds.
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// @param i The index of an element in the array.
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// @return A reference to the i'th element of the array.
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elem_type& ElementAt(index_type i) {
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return mArray.ElementAt(i);
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}
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// Same as above, but readonly.
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const elem_type& ElementAt(index_type i) const {
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return mArray.ElementAt(i);
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}
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// This method provides direct access to the i'th element of the array in
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// a bounds safe manner. If the requested index is out of bounds the
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// provided default value is returned.
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// @param i The index of an element in the array.
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// @param def The value to return if the index is out of bounds.
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elem_type& SafeElementAt(index_type i, elem_type& def) {
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return mArray.SafeElementAt(i, def);
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}
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// Same as above, but readonly.
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const elem_type& SafeElementAt(index_type i, const elem_type& def) const {
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return mArray.SafeElementAt(i, def);
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}
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//
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// Search methods
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//
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// This method searches, starting from the beginning of the array,
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// for the first element in this array that is equal to the given element.
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// 'operator==' must be defined for elem_type.
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// @param item The item to search for.
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// @return PR_TRUE if the element was found.
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template<class Item>
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PRBool Contains(const Item& item) const {
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return IndexOf(item) != array_type::NoIndex;
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}
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// This method searches for the offset of the first element in this
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// array that is equal to the given element.
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// 'operator==' must be defined for elem_type.
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// @param item The item to search for.
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// @param start The index to start from.
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// @return The index of the found element or NoIndex if not found.
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template<class Item>
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index_type IndexOf(const Item& item, index_type start = 0) const {
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return mArray.IndexOf(item, start);
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}
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//
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// Mutation methods
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//
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// Prepend an element to the array unless it already exists in the array.
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// 'operator==' must be defined for elem_type.
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// @param item The item to prepend.
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// @return PR_TRUE if the element was found, or inserted successfully.
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template<class Item>
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PRBool PrependElementUnlessExists(const Item& item) {
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return Contains(item) || mArray.InsertElementAt(0, item) != nsnull;
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}
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// Append an element to the array.
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// @param item The item to append.
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// @return A pointer to the newly appended element, or null on OOM.
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template<class Item>
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elem_type* AppendElement(const Item& item) {
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return mArray.AppendElement(item);
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}
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// Same as above, but without copy-constructing. This is useful to avoid
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// temporaries.
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elem_type* AppendElement() {
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return mArray.AppendElement();
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}
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// Append an element to the array unless it already exists in the array.
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// 'operator==' must be defined for elem_type.
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// @param item The item to append.
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// @return PR_TRUE if the element was found, or inserted successfully.
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template<class Item>
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PRBool AppendElementUnlessExists(const Item& item) {
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return Contains(item) || AppendElement(item) != nsnull;
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}
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// Remove an element from the array.
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// @param index The index of the item to remove.
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void RemoveElementAt(index_type index) {
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NS_ASSERTION(index < mArray.Length(), "invalid index");
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mArray.RemoveElementAt(index);
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AdjustIterators(index, -1);
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}
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// This helper function combines IndexOf with RemoveElementAt to "search
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// and destroy" the first element that is equal to the given element.
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// 'operator==' must be defined for elem_type.
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// @param item The item to search for.
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// @return PR_TRUE if the element was found and removed.
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template<class Item>
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PRBool RemoveElement(const Item& item) {
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index_type index = mArray.IndexOf(item, 0);
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if (index == array_type::NoIndex)
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return PR_FALSE;
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mArray.RemoveElementAt(index);
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AdjustIterators(index, -1);
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return PR_TRUE;
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}
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// Removes all observers and collapses all iterators to the beginning of
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// the array. The result is that forward iterators will see all elements
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// in the array.
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void Clear() {
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mArray.Clear();
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ClearIterators();
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}
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//
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// Iterators
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//
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// Base class for iterators. Do not use this directly.
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class Iterator : public Iterator_base {
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protected:
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friend class nsAutoTObserverArray;
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typedef nsAutoTObserverArray<T, N> array_type;
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Iterator(index_type aPosition, const array_type& aArray)
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: Iterator_base(aPosition, aArray.mIterators),
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mArray(const_cast<array_type&>(aArray)) {
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aArray.mIterators = this;
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}
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~Iterator() {
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NS_ASSERTION(mArray.mIterators == this,
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"Iterators must currently be destroyed in opposite order "
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"from the construction order. It is suggested that you "
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"simply put them on the stack");
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mArray.mIterators = mNext;
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}
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// The array we're iterating
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array_type& mArray;
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};
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// Iterates the array forward from beginning to end. mPosition points
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// to the element that will be returned on next call to GetNext.
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// Elements:
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// - prepended to the array during iteration *will not* be traversed
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// - appended during iteration *will* be traversed
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// - removed during iteration *will not* be traversed.
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// @see EndLimitedIterator
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class ForwardIterator : protected Iterator {
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public:
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typedef nsAutoTObserverArray<T, N> array_type;
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typedef Iterator base_type;
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ForwardIterator(const array_type& aArray)
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: Iterator(0, aArray) {
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}
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ForwardIterator(const array_type& aArray, index_type aPos)
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: Iterator(aPos, aArray) {
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}
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PRBool operator <(const ForwardIterator& aOther) const {
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NS_ASSERTION(&this->mArray == &aOther.mArray,
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"not iterating the same array");
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return base_type::mPosition < aOther.mPosition;
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}
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// Returns PR_TRUE if there are more elements to iterate.
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// This must precede a call to GetNext(). If PR_FALSE is
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// returned, GetNext() must not be called.
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PRBool HasMore() const {
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return base_type::mPosition < base_type::mArray.Length();
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}
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// Returns the next element and steps one step. This must
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// be preceded by a call to HasMore().
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// @return The next observer.
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elem_type& GetNext() {
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NS_ASSERTION(HasMore(), "iterating beyond end of array");
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return base_type::mArray.ElementAt(base_type::mPosition++);
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}
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};
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// EndLimitedIterator works like ForwardIterator, but will not iterate new
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// observers appended to the array after the iterator was created.
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class EndLimitedIterator : protected ForwardIterator {
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public:
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typedef nsAutoTObserverArray<T, N> array_type;
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typedef Iterator base_type;
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EndLimitedIterator(const array_type& aArray)
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: ForwardIterator(aArray),
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mEnd(aArray, aArray.Length()) {
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}
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// Returns PR_TRUE if there are more elements to iterate.
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// This must precede a call to GetNext(). If PR_FALSE is
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// returned, GetNext() must not be called.
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PRBool HasMore() const {
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return *this < mEnd;
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}
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// Returns the next element and steps one step. This must
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// be preceded by a call to HasMore().
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// @return The next observer.
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elem_type& GetNext() {
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NS_ASSERTION(HasMore(), "iterating beyond end of array");
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return base_type::mArray.ElementAt(base_type::mPosition++);
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}
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private:
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ForwardIterator mEnd;
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};
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protected:
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nsAutoTArray<T, N> mArray;
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};
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template<class T>
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class nsTObserverArray : public nsAutoTObserverArray<T, 0> {
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public:
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typedef nsAutoTObserverArray<T, 0> base_type;
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typedef nsTObserverArray_base::size_type size_type;
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//
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// Initialization methods
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//
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nsTObserverArray() {}
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// Initialize this array and pre-allocate some number of elements.
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explicit nsTObserverArray(size_type capacity) {
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base_type::mArray.SetCapacity(capacity);
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}
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};
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// XXXbz I wish I didn't have to pass in the observer type, but I
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// don't see a way to get it out of array_.
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// Note that this macro only works if the array holds pointers to XPCOM objects.
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#define NS_OBSERVER_ARRAY_NOTIFY_XPCOM_OBSERVERS(array_, obstype_, func_, params_) \
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PR_BEGIN_MACRO \
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nsTObserverArray<obstype_ *>::ForwardIterator iter_(array_); \
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nsCOMPtr<obstype_> obs_; \
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while (iter_.HasMore()) { \
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obs_ = iter_.GetNext(); \
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obs_ -> func_ params_ ; \
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} \
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PR_END_MACRO
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// Note that this macro only works if the array holds pointers to XPCOM objects.
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#define NS_OBSERVER_ARRAY_NOTIFY_OBSERVERS(array_, obstype_, func_, params_) \
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PR_BEGIN_MACRO \
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nsTObserverArray<obstype_ *>::ForwardIterator iter_(array_); \
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obstype_* obs_; \
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while (iter_.HasMore()) { \
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obs_ = iter_.GetNext(); \
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obs_ -> func_ params_ ; \
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} \
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PR_END_MACRO
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#endif // nsTObserverArray_h___
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