homescreenpluginsrv/hspsdom/src/hspsdomdepthiterator.cpp
changeset 0 79c6a41cd166
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     1 /*
       
     2 * Copyright (c) 2005,2006 Nokia Corporation and/or its subsidiary(-ies).
       
     3 * All rights reserved.
       
     4 * This component and the accompanying materials are made available
       
     5 * under the terms of "Eclipse Public License v1.0"
       
     6 * which accompanies this distribution, and is available
       
     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     8 *
       
     9 * Initial Contributors:
       
    10 * Nokia Corporation - initial contribution.
       
    11 *
       
    12 * Contributors:
       
    13 *
       
    14 * Description:  Depth iterator walks the dom tree using depth first principle.
       
    15 *
       
    16 */
       
    17 
       
    18 
       
    19 
       
    20 // INCLUDE FILES
       
    21 #include    "hspsdomdepthiterator.h"
       
    22 #include    "hspsdomlist.h"
       
    23 #include    "hspsdomnode.h"
       
    24 
       
    25 // ============================ LOCAL FUNCTIONS ===============================
       
    26  
       
    27 
       
    28 // ============================ MEMBER FUNCTIONS ===============================
       
    29 
       
    30 // -----------------------------------------------------------------------------
       
    31 // ChspsDomDepthIterator::ChspsDomDepthIterator
       
    32 // C++ default constructor can NOT contain any code, that
       
    33 // might leave.
       
    34 // -----------------------------------------------------------------------------
       
    35 //
       
    36 ChspsDomDepthIterator::ChspsDomDepthIterator( ChspsDomNode& aRootNode  ):
       
    37     iFirst(&aRootNode), iCurrent(&aRootNode)
       
    38     {
       
    39     }
       
    40 
       
    41 // -----------------------------------------------------------------------------
       
    42 // ChspsDomDepthIterator::ConstructL
       
    43 // Symbian 2nd phase constructor can leave.
       
    44 // -----------------------------------------------------------------------------
       
    45 //
       
    46 void ChspsDomDepthIterator::ConstructL()
       
    47     {
       
    48     }
       
    49 
       
    50 // -----------------------------------------------------------------------------
       
    51 // ChspsDomDepthIterator::NewL
       
    52 // Two-phased constructor.
       
    53 // -----------------------------------------------------------------------------
       
    54 //
       
    55 EXPORT_C ChspsDomDepthIterator* ChspsDomDepthIterator::NewL( ChspsDomNode& aRootNode )
       
    56     {
       
    57     ChspsDomDepthIterator* self = new( ELeave ) ChspsDomDepthIterator( aRootNode );
       
    58     
       
    59     CleanupStack::PushL( self );
       
    60     self->ConstructL();
       
    61     CleanupStack::Pop( self );
       
    62 
       
    63     return self;
       
    64     }
       
    65 
       
    66     
       
    67 // Destructor
       
    68 EXPORT_C ChspsDomDepthIterator::~ChspsDomDepthIterator()
       
    69     {
       
    70     iDepthLevel.Close();
       
    71     }
       
    72 
       
    73 // -----------------------------------------------------------------------------
       
    74 // ChspsDomDepthIterator::First
       
    75 // -----------------------------------------------------------------------------
       
    76 //
       
    77 EXPORT_C ChspsDomNode* ChspsDomDepthIterator::First()
       
    78     {
       
    79     return iFirst;
       
    80     }
       
    81     
       
    82 // -----------------------------------------------------------------------------
       
    83 // ChspsDomDepthIterator::Next
       
    84 // -----------------------------------------------------------------------------
       
    85 //
       
    86 EXPORT_C ChspsDomNode* ChspsDomDepthIterator::NextL()
       
    87     {
       
    88     ChspsDomNode* sibling = NULL; 
       
    89     ChspsDomNode* firstChild = NULL;     
       
    90     
       
    91     //Initialise iCurrent if the whole tree has been walked through 
       
    92     if (!iCurrent) 
       
    93         {
       
    94         iCurrent = iFirst;
       
    95         }
       
    96         
       
    97     firstChild = static_cast<ChspsDomNode*>( iCurrent->ChildNodes().First() );
       
    98         
       
    99     // Current node has childs left
       
   100     if (firstChild)
       
   101         {
       
   102         //Keep count of depth level
       
   103         PushL( *iCurrent );
       
   104         iCurrent = firstChild;
       
   105         }
       
   106     else //If current node has siblings left
       
   107         {
       
   108         sibling = NextSibling(*iCurrent);
       
   109         if(sibling)
       
   110             {
       
   111             iCurrent = sibling;    
       
   112             }
       
   113         else //Current node don't have any childs or siblings left
       
   114             {
       
   115             // Reverse the tree by moving up in hierarchy
       
   116             // Move up one level in hierarchy and check if siblings exists or we are in a 
       
   117             // root level
       
   118             TBool stop( EFalse );
       
   119             while( !stop && iDepthLevel.Count() )  
       
   120                 {
       
   121                 iCurrent = Pop();                   //Reach the previous level
       
   122                 sibling = NextSibling( *iCurrent ); //Check if siblings exist
       
   123                 if ( sibling && iDepthLevel.Count() )
       
   124                     {
       
   125                     iCurrent = sibling;
       
   126                     stop = ETrue;
       
   127                     }
       
   128                 else                                //We didn't find any siblings
       
   129                     {
       
   130                     iCurrent = NULL;
       
   131                     }
       
   132                 }    
       
   133             }
       
   134         }
       
   135     return iCurrent;
       
   136     }
       
   137 
       
   138 // -----------------------------------------------------------------------------
       
   139 // NextSibling Find next sibling.
       
   140 // Returns NULL if there is no siblings left or there is no parent i.e this is a
       
   141 // root node
       
   142 // Returns: ChspsDomNode* Pointer to the node or NULL
       
   143 //          
       
   144 // -----------------------------------------------------------------------------
       
   145 //
       
   146 
       
   147 EXPORT_C ChspsDomNode* ChspsDomDepthIterator::NextSibling( ChspsDomNode& aNode )
       
   148     {
       
   149     ChspsDomNode* left = NULL;
       
   150     ChspsDomNode* parent = aNode.Parent();
       
   151     if ( parent )
       
   152         {
       
   153         ChspsDomList& nodeList = parent->ChildNodes();
       
   154         TInt currentIndex( nodeList.ItemIndex( aNode ) );
       
   155         TInt nextIndex( ++currentIndex );
       
   156         TInt length( nodeList.Length() );
       
   157         if ( nextIndex < length )  
       
   158             {
       
   159             left = static_cast<ChspsDomNode*>( nodeList.Item( nextIndex ) );
       
   160             }
       
   161         }
       
   162     return left;     
       
   163     }
       
   164 
       
   165 // -----------------------------------------------------------------------------
       
   166 // ChspsDomDepthIterator::PushL
       
   167 // -----------------------------------------------------------------------------
       
   168 //
       
   169 void ChspsDomDepthIterator::PushL( ChspsDomNode& aNode )
       
   170     {
       
   171     iDepthLevel.AppendL( &aNode );
       
   172     }
       
   173 
       
   174 // -----------------------------------------------------------------------------
       
   175 // ChspsDomDepthIterator::Pop
       
   176 // -----------------------------------------------------------------------------
       
   177 //
       
   178 ChspsDomNode* ChspsDomDepthIterator::Pop()
       
   179     {
       
   180     ChspsDomNode* pop = NULL;
       
   181     TInt count( iDepthLevel.Count() );
       
   182     if ( count )
       
   183         {
       
   184         pop = iDepthLevel[ count-1 ];
       
   185         iDepthLevel.Remove( count-1 );
       
   186         }
       
   187     return pop;    
       
   188     }
       
   189     
       
   190 //  End of File