LCOV - app.info - objdir/dist/include/nsTObserverArray.h

LCOV - code coverage report
| Current view: | directory - objdir/dist/include - nsTObserverArray.h (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 86 | 80 | 93.0 %
| Date: | 2012-06-02 | Functions: | 207 | 134 | 64.7 %

           1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
           2                 : /* ***** BEGIN LICENSE BLOCK *****
           3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
           4                 :  *
           5                 :  * The contents of this file are subject to the Mozilla Public License Version
           6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
           7                 :  * the License. You may obtain a copy of the License at
           8                 :  * http://www.mozilla.org/MPL/
           9                 :  *
          10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
          11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
          12                 :  * for the specific language governing rights and limitations under the
          13                 :  * License.
          14                 :  *
          15                 :  * The Original Code is Mozilla.org code.
          16                 :  *
          17                 :  * The Initial Developer of the Original Code is Mozilla Foundation.
          18                 :  * Portions created by the Initial Developer are Copyright (C) 2006
          19                 :  * the Initial Developer. All Rights Reserved.
          20                 :  *
          21                 :  * Contributor(s):
          22                 :  *   Jonas Sicking <jonas@sicking.cc> (Original Author)
          23                 :  *   Daniel Witte <dwitte@stanford.edu>
          24                 :  *
          25                 :  * Alternatively, the contents of this file may be used under the terms of
          26                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
          27                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
          28                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
          29                 :  * of those above. If you wish to allow use of your version of this file only
          30                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
          31                 :  * use your version of this file under the terms of the MPL, indicate your
          32                 :  * decision by deleting the provisions above and replace them with the notice
          33                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
          34                 :  * the provisions above, a recipient may use your version of this file under
          35                 :  * the terms of any one of the MPL, the GPL or the LGPL.
          36                 :  *
          37                 :  * ***** END LICENSE BLOCK ***** */
          38                 :
          39                 : #ifndef nsTObserverArray_h___
          40                 : #define nsTObserverArray_h___
          41                 :
          42                 : #include "nsTArray.h"
          43                 :
          44                 : /**
          45                 :  * An array of observers. Like a normal array, but supports iterators that are
          46                 :  * stable even if the array is modified during iteration.
          47                 :  * The template parameter T is the observer type the array will hold;
          48                 :  * N is the number of built-in storage slots that come with the array.
          49                 :  * NOTE: You probably want to use nsTObserverArray, unless you specifically
          50                 :  * want built-in storage. See below.
          51                 :  * @see nsTObserverArray, nsTArray
          52                 :  */
          53                 :
          54                 : class NS_COM_GLUE nsTObserverArray_base {
          55                 :   public:
          56                 :     typedef PRUint32 index_type;
          57                 :     typedef PRUint32 size_type;
          58                 :     typedef PRInt32  diff_type;
          59                 :
          60                 :   protected:
          61                 :     class Iterator_base {
          62                 :       protected:
          63                 :         friend class nsTObserverArray_base;
          64                 :
          65          385871 :         Iterator_base(index_type aPosition, Iterator_base* aNext)
          66                 :           : mPosition(aPosition),
          67          385871 :             mNext(aNext) {
          68          385871 :         }
          69                 :
          70                 :         // The current position of the iterator. Its exact meaning differs
          71                 :         // depending on iterator. See nsTObserverArray<T>::ForwardIterator.
          72                 :         index_type mPosition;
          73                 :
          74                 :         // The next iterator currently iterating the same array
          75                 :         Iterator_base* mNext;
          76                 :     };
          77                 :
          78           17871 :     nsTObserverArray_base()
          79           17871 :       : mIterators(nsnull) {
          80           17871 :     }
          81                 :
          82           17852 :     ~nsTObserverArray_base() {
          83           17852 :       NS_ASSERTION(mIterators == nsnull, "iterators outlasting array");
          84           17852 :     }
          85                 :
          86                 :     /**
          87                 :      * Adjusts iterators after an element has been inserted or removed
          88                 :      * from the array.
          89                 :      * @param modPos     Position where elements were added or removed.
          90                 :      * @param adjustment -1 if an element was removed, 1 if an element was
          91                 :      *                   added.
          92                 :      */
          93                 :     void AdjustIterators(index_type aModPos, diff_type aAdjustment);
          94                 :
          95                 :     /**
          96                 :      * Clears iterators when the array is destroyed.
          97                 :      */
          98                 :     void ClearIterators();
          99                 :
         100                 :     mutable Iterator_base* mIterators;
         101                 : };
         102                 :
         103                 : template<class T, PRUint32 N>
         104           17852 : class nsAutoTObserverArray : protected nsTObserverArray_base {
         105                 :   public:
         106                 :     typedef T           elem_type;
         107                 :     typedef nsTArray<T> array_type;
         108                 :
         109           17871 :     nsAutoTObserverArray() {
         110           17871 :     }
         111                 :
         112                 :     //
         113                 :     // Accessor methods
         114                 :     //
         115                 :
         116                 :     // @return The number of elements in the array.
         117         1120645 :     size_type Length() const {
         118         1120645 :       return mArray.Length();
         119                 :     }
         120                 :
         121                 :     // @return True if the array is empty or false otherwise.
         122          639331 :     bool IsEmpty() const {
         123          639331 :       return mArray.IsEmpty();
         124                 :     }
         125                 :
         126                 :     // This method provides direct access to the i'th element of the array.
         127                 :     // The given index must be within the array bounds.
         128                 :     // @param i  The index of an element in the array.
         129                 :     // @return   A reference to the i'th element of the array.
         130          387681 :     elem_type& ElementAt(index_type i) {
         131          387681 :       return mArray.ElementAt(i);
         132                 :     }
         133                 :
         134                 :     // Same as above, but readonly.
         135               0 :     const elem_type& ElementAt(index_type i) const {
         136               0 :       return mArray.ElementAt(i);
         137                 :     }
         138                 :
         139                 :     // This method provides direct access to the i'th element of the array in
         140                 :     // a bounds safe manner. If the requested index is out of bounds the
         141                 :     // provided default value is returned.
         142                 :     // @param i  The index of an element in the array.
         143                 :     // @param def The value to return if the index is out of bounds.
         144                 :     elem_type& SafeElementAt(index_type i, elem_type& def) {
         145                 :       return mArray.SafeElementAt(i, def);
         146                 :     }
         147                 :
         148                 :     // Same as above, but readonly.
         149               0 :     const elem_type& SafeElementAt(index_type i, const elem_type& def) const {
         150               0 :       return mArray.SafeElementAt(i, def);
         151                 :     }
         152                 :
         153                 :     //
         154                 :     // Search methods
         155                 :     //
         156                 :
         157                 :     // This method searches, starting from the beginning of the array,
         158                 :     // for the first element in this array that is equal to the given element.
         159                 :     // 'operator==' must be defined for elem_type.
         160                 :     // @param item   The item to search for.
         161                 :     // @return       true if the element was found.
         162                 :     template<class Item>
         163            3186 :     bool Contains(const Item& item) const {
         164            3186 :       return IndexOf(item) != array_type::NoIndex;
         165                 :     }
         166                 :
         167                 :     // This method searches for the offset of the first element in this
         168                 :     // array that is equal to the given element.
         169                 :     // 'operator==' must be defined for elem_type.
         170                 :     // @param item   The item to search for.
         171                 :     // @param start  The index to start from.
         172                 :     // @return       The index of the found element or NoIndex if not found.
         173                 :     template<class Item>
         174            9571 :     index_type IndexOf(const Item& item, index_type start = 0) const {
         175            9571 :       return mArray.IndexOf(item, start);
         176                 :     }
         177                 :
         178                 :     //
         179                 :     // Mutation methods
         180                 :     //
         181                 :
         182                 :     // Prepend an element to the array unless it already exists in the array.
         183                 :     // 'operator==' must be defined for elem_type.
         184                 :     // @param item   The item to prepend.
         185                 :     // @return       true if the element was found, or inserted successfully.
         186                 :     template<class Item>
         187            1275 :     bool PrependElementUnlessExists(const Item& item) {
         188            1275 :       return Contains(item) || mArray.InsertElementAt(0, item) != nsnull;
         189                 :     }
         190                 :
         191                 :     // Append an element to the array.
         192                 :     // @param item   The item to append.
         193                 :     // @return A pointer to the newly appended element, or null on OOM.
         194                 :     template<class Item>
         195            8303 :     elem_type* AppendElement(const Item& item) {
         196            8303 :       return mArray.AppendElement(item);
         197                 :     }
         198                 :
         199                 :     // Same as above, but without copy-constructing. This is useful to avoid
         200                 :     // temporaries.
         201            4584 :     elem_type* AppendElement() {
         202            4584 :       return mArray.AppendElement();
         203                 :     }
         204                 :
         205                 :     // Append an element to the array unless it already exists in the array.
         206                 :     // 'operator==' must be defined for elem_type.
         207                 :     // @param item   The item to append.
         208                 :     // @return       true if the element was found, or inserted successfully.
         209                 :     template<class Item>
         210              29 :     bool AppendElementUnlessExists(const Item& item) {
         211              29 :       return Contains(item) || AppendElement(item) != nsnull;
         212                 :     }
         213                 :
         214                 :     // Remove an element from the array.
         215                 :     // @param index  The index of the item to remove.
         216              34 :     void RemoveElementAt(index_type index) {
         217              34 :       NS_ASSERTION(index < mArray.Length(), "invalid index");
         218              34 :       mArray.RemoveElementAt(index);
         219              34 :       AdjustIterators(index, -1);
         220              34 :     }
         221                 :
         222                 :     // This helper function combines IndexOf with RemoveElementAt to "search
         223                 :     // and destroy" the first element that is equal to the given element.
         224                 :     // 'operator==' must be defined for elem_type.
         225                 :     // @param item  The item to search for.
         226                 :     // @return true if the element was found and removed.
         227                 :     template<class Item>
         228            9064 :     bool RemoveElement(const Item& item) {
         229            9064 :       index_type index = mArray.IndexOf(item, 0);
         230            9064 :       if (index == array_type::NoIndex)
         231            2200 :         return false;
         232                 :
         233            6864 :       mArray.RemoveElementAt(index);
         234            6864 :       AdjustIterators(index, -1);
         235            6864 :       return true;
         236                 :     }
         237                 :
         238                 :     // Removes all observers and collapses all iterators to the beginning of
         239                 :     // the array. The result is that forward iterators will see all elements
         240                 :     // in the array.
         241           15132 :     void Clear() {
         242           15132 :       mArray.Clear();
         243           15132 :       ClearIterators();
         244           15132 :     }
         245                 :
         246                 :     // Returns the number of bytes on the heap taken up by this object, not
         247                 :     // including sizeof(*this).
         248               0 :     size_t SizeOfExcludingThis(nsMallocSizeOfFun mallocSizeOf) const {
         249               0 :       return mArray.SizeOfExcludingThis(mallocSizeOf);
         250                 :     }
         251                 :
         252                 :     //
         253                 :     // Iterators
         254                 :     //
         255                 :
         256                 :     // Base class for iterators. Do not use this directly.
         257                 :     class Iterator : public Iterator_base {
         258                 :       protected:
         259                 :         friend class nsAutoTObserverArray;
         260                 :         typedef nsAutoTObserverArray<T, N> array_type;
         261                 :
         262          385871 :         Iterator(index_type aPosition, const array_type& aArray)
         263                 :           : Iterator_base(aPosition, aArray.mIterators),
         264          385871 :             mArray(const_cast<array_type&>(aArray)) {
         265          385871 :           aArray.mIterators = this;
         266          385871 :         }
         267                 :
         268          385871 :         ~Iterator() {
         269          385871 :           NS_ASSERTION(mArray.mIterators == this,
         270                 :                        "Iterators must currently be destroyed in opposite order "
         271                 :                        "from the construction order. It is suggested that you "
         272                 :                        "simply put them on the stack");
         273          385871 :           mArray.mIterators = mNext;
         274          385871 :         }
         275                 :
         276                 :         // The array we're iterating
         277                 :         array_type& mArray;
         278                 :     };
         279                 :
         280                 :     // Iterates the array forward from beginning to end. mPosition points
         281                 :     // to the element that will be returned on next call to GetNext.
         282                 :     // Elements:
         283                 :     // - prepended to the array during iteration *will not* be traversed
         284                 :     // - appended during iteration *will* be traversed
         285                 :     // - removed during iteration *will not* be traversed.
         286                 :     // @see EndLimitedIterator
         287          385871 :     class ForwardIterator : protected Iterator {
         288                 :       public:
         289                 :         typedef nsAutoTObserverArray<T, N> array_type;
         290                 :         typedef Iterator                   base_type;
         291                 :
         292          377637 :         ForwardIterator(const array_type& aArray)
         293          377637 :           : Iterator(0, aArray) {
         294          377637 :         }
         295                 :
         296            8234 :         ForwardIterator(const array_type& aArray, index_type aPos)
         297            8234 :           : Iterator(aPos, aArray) {
         298            8234 :         }
         299                 :
         300           36392 :         bool operator <(const ForwardIterator& aOther) const {
         301           36392 :           NS_ASSERTION(&this->mArray == &aOther.mArray,
         302                 :                        "not iterating the same array");
         303           36392 :           return base_type::mPosition < aOther.mPosition;
         304                 :         }
         305                 :
         306                 :         // Returns true if there are more elements to iterate.
         307                 :         // This must precede a call to GetNext(). If false is
         308                 :         // returned, GetNext() must not be called.
         309         1105663 :         bool HasMore() const {
         310         1105663 :           return base_type::mPosition < base_type::mArray.Length();
         311                 :         }
         312                 :
         313                 :         // Returns the next element and steps one step. This must
         314                 :         // be preceded by a call to HasMore().
         315                 :         // @return The next observer.
         316          368125 :         elem_type& GetNext() {
         317          368125 :           NS_ASSERTION(HasMore(), "iterating beyond end of array");
         318          368125 :           return base_type::mArray.ElementAt(base_type::mPosition++);
         319                 :         }
         320                 :     };
         321                 :
         322                 :     // EndLimitedIterator works like ForwardIterator, but will not iterate new
         323                 :     // observers appended to the array after the iterator was created.
         324            8234 :     class EndLimitedIterator : protected ForwardIterator {
         325                 :       public:
         326                 :         typedef nsAutoTObserverArray<T, N> array_type;
         327                 :         typedef Iterator                   base_type;
         328                 :
         329            8234 :         EndLimitedIterator(const array_type& aArray)
         330                 :           : ForwardIterator(aArray),
         331            8234 :             mEnd(aArray, aArray.Length()) {
         332            8234 :         }
         333                 :
         334                 :         // Returns true if there are more elements to iterate.
         335                 :         // This must precede a call to GetNext(). If false is
         336                 :         // returned, GetNext() must not be called.
         337           36392 :         bool HasMore() const {
         338           36392 :           return *this < mEnd;
         339                 :         }
         340                 :
         341                 :         // Returns the next element and steps one step. This must
         342                 :         // be preceded by a call to HasMore().
         343                 :         // @return The next observer.
         344           14078 :         elem_type& GetNext() {
         345           14078 :           NS_ASSERTION(HasMore(), "iterating beyond end of array");
         346           14078 :           return base_type::mArray.ElementAt(base_type::mPosition++);
         347                 :         }
         348                 :
         349                 :       private:
         350                 :         ForwardIterator mEnd;
         351                 :     };
         352                 :
         353                 :   protected:
         354                 :     nsAutoTArray<T, N> mArray;
         355                 : };
         356                 :
         357                 : template<class T>
         358            7170 : class nsTObserverArray : public nsAutoTObserverArray<T, 0> {
         359                 :   public:
         360                 :     typedef nsAutoTObserverArray<T, 0>       base_type;
         361                 :     typedef nsTObserverArray_base::size_type size_type;
         362                 :
         363                 :     //
         364                 :     // Initialization methods
         365                 :     //
         366                 :
         367            7176 :     nsTObserverArray() {}
         368                 :
         369                 :     // Initialize this array and pre-allocate some number of elements.
         370                 :     explicit nsTObserverArray(size_type capacity) {
         371                 :       base_type::mArray.SetCapacity(capacity);
         372                 :     }
         373                 : };
         374                 :
         375                 : // XXXbz I wish I didn't have to pass in the observer type, but I
         376                 : // don't see a way to get it out of array_.
         377                 : // Note that this macro only works if the array holds pointers to XPCOM objects.
         378                 : #define NS_OBSERVER_ARRAY_NOTIFY_XPCOM_OBSERVERS(array_, obstype_, func_, params_) \
         379                 :   PR_BEGIN_MACRO                                                             \
         380                 :     nsTObserverArray<obstype_ *>::ForwardIterator iter_(array_);             \
         381                 :     nsCOMPtr<obstype_> obs_;                                                 \
         382                 :     while (iter_.HasMore()) {                                                 \
         383                 :       obs_ = iter_.GetNext();                                                \
         384                 :       obs_ -> func_ params_ ;                                                \
         385                 :     }                                                                        \
         386                 :   PR_END_MACRO
         387                 :
         388                 : // Note that this macro only works if the array holds pointers to XPCOM objects.
         389                 : #define NS_OBSERVER_ARRAY_NOTIFY_OBSERVERS(array_, obstype_, func_, params_) \
         390                 :   PR_BEGIN_MACRO                                                             \
         391                 :     nsTObserverArray<obstype_ *>::ForwardIterator iter_(array_);             \
         392                 :     obstype_* obs_;                                                          \
         393                 :     while (iter_.HasMore()) {                                                \
         394                 :       obs_ = iter_.GetNext();                                                \
         395                 :       obs_ -> func_ params_ ;                                                \
         396                 :     }                                                                        \
         397                 :   PR_END_MACRO
         398                 : #endif // nsTObserverArray_h___

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