xml/xmlexpatparser/src/xmlparserplugin.cpp
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     1 // Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
       
     2 // All rights reserved.
       
     3 // This component and the accompanying materials are made available
       
     4 // under the terms of "Eclipse Public License v1.0"
       
     5 // which accompanies this distribution, and is available
       
     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     7 //
       
     8 // Initial Contributors:
       
     9 // Nokia Corporation - initial contribution.
       
    10 //
       
    11 // Contributors:
       
    12 //
       
    13 // Description:
       
    14 //
       
    15 
       
    16 #include <e32std.h>
       
    17 #include <ecom/implementationproxy.h>
       
    18 
       
    19 #include <xml/contenthandler.h>
       
    20 #include <xml/stringdictionarycollection.h>
       
    21 
       
    22 #include "xmlparserplugin.h"
       
    23 
       
    24 using namespace Xml;
       
    25 
       
    26 const TInt KExpatBufferSize = 2048;
       
    27 
       
    28 MParser* CXmlParserPlugin::EcomNewL(TAny* aInitParams)
       
    29 	{
       
    30 	// The cast to the MParser interface is a particular to the Xml Framework.  Ecom plug-ins usually
       
    31 	// return the pointer to the C class.
       
    32 	return static_cast<MParser*>(CXmlParserPlugin::NewL(aInitParams));
       
    33 	}
       
    34 
       
    35 /*
       
    36 CXmlParserPlugin::NewL is for testing and can only be accessed by linking directly to XmlParser.o
       
    37 
       
    38 aDebugFailCount is used to configure parser heap failure during construction testing - the
       
    39 usual heap failure macros do not work for our purposes here as it is a private heap.  See
       
    40 CExpat for details.
       
    41 */
       
    42 CXmlParserPlugin* CXmlParserPlugin::NewL(TAny* aInitParams, TInt aDebugFailCount)
       
    43 	{
       
    44 	TParserInitParams* p = reinterpret_cast<TParserInitParams*>(aInitParams);
       
    45 
       
    46 	CXmlParserPlugin* self = new(ELeave) CXmlParserPlugin(p->iContentHandler);
       
    47 	
       
    48 	CleanupStack::PushL(self);
       
    49 	self->ConstructL(p->iStringDictionaryCollection, p->iCharSetConverter, p->iElementStack, aDebugFailCount);
       
    50 	CleanupStack::Pop(self);
       
    51 
       
    52 	return self;
       
    53 	}
       
    54 
       
    55 CXmlParserPlugin::CXmlParserPlugin(MContentHandler* aContentHandler) :
       
    56 	iContentHandler(*aContentHandler)
       
    57 	{
       
    58 	}
       
    59 
       
    60 void CXmlParserPlugin::ConstructL(RStringDictionaryCollection* aStringDictionaryCollection, CCharSetConverter* aCharSetConverter,
       
    61 							RElementStack* aElementStack, TInt aDebugFailCount)
       
    62 	{
       
    63 	iExpat = CExpat::NewL(iContentHandler, aStringDictionaryCollection->StringPool(), *aCharSetConverter, *aElementStack, aDebugFailCount);
       
    64 	}
       
    65 
       
    66 /*
       
    67 Used by framework to delete this object
       
    68 */
       
    69 void CXmlParserPlugin::Release()
       
    70 	{
       
    71 	delete this;
       
    72 	}
       
    73 
       
    74 /*
       
    75 Private destructor - only accessible from Release method
       
    76 */
       
    77 CXmlParserPlugin::~CXmlParserPlugin()
       
    78 	{
       
    79 	delete iExpat;
       
    80 	}
       
    81 
       
    82 
       
    83 TInt CXmlParserPlugin::EnableFeature(TInt aParseMode)
       
    84 	{
       
    85 	return iExpat->EnableFeature(aParseMode);
       
    86 	}
       
    87 
       
    88 TInt CXmlParserPlugin::DisableFeature(TInt aParseMode)
       
    89 	{
       
    90 	return iExpat->DisableFeature(aParseMode);
       
    91 	}
       
    92 
       
    93 TBool CXmlParserPlugin::IsFeatureEnabled(TInt aParseMode) const
       
    94 	{
       
    95 	return iExpat->IsFeatureEnabled(aParseMode);
       
    96 	}
       
    97 
       
    98 
       
    99 void CXmlParserPlugin::ParseChunkL(const TDesC8& aChunk)
       
   100 	{
       
   101 	// If a Reset failed, iExpatResetError will have been set.  Here we report it by leaving with the error,
       
   102 	// which will in turn be passed to MContentHandler::OnError.
       
   103 	User::LeaveIfError(iExpatResetError);
       
   104 	ParseChunkInPartsL(aChunk);
       
   105 	}
       
   106 
       
   107 void CXmlParserPlugin::ParseLastChunkL(const TDesC8& aFinalChunk)
       
   108 	{
       
   109 	// If a Reset failed, iExpatResetError will have been set.  Here we report it by leaving with the error,
       
   110 	// which will in turn be passed to MContentHandler::OnError.
       
   111 	User::LeaveIfError(iExpatResetError);
       
   112 
       
   113 	// Could be that there is some enourmous piece of data here.
       
   114 	ParseChunkInPartsL(aFinalChunk);
       
   115 	
       
   116 	// We need a buffer even though we have nothing to parse,
       
   117 	// as any previous buffers are destroyed.
       
   118 	// We are just going through the sequence of completing the parsing gracefully.
       
   119 	TDes8& buf = iExpat->GetBufferL(1);
       
   120 	buf = _L8("");
       
   121 	iExpat->ParseLastL();
       
   122 
       
   123 	// TRAP doesn't set its result variable unless a leave occurs - so reset it first.
       
   124 	iExpatResetError = KErrNone;
       
   125 
       
   126 	// The Reset interface of the Xml Framework provides no mechanism for failure reporting.  If iExpat.ResetL
       
   127 	// fails we set iExpatResetError.  The error will be reported to MContentHandler::OnError when an attempt
       
   128 	// is made by the client to begin parsing (see RunL).
       
   129 	TRAP(iExpatResetError, iExpat->ResetL());
       
   130 	}
       
   131 
       
   132 void CXmlParserPlugin::ParseChunkInPartsL(const TDesC8& aChunk)
       
   133 	{
       
   134 	// The Expat parser has a buffer of 64k that it stores its state variables in 
       
   135 	// and allocates its heap memory from.
       
   136 	// We do this because we may need to upgrade the version of Expat later and this
       
   137 	// makes it easier.
       
   138 	// Beacuse of this we copy the buffer that could have a performance issue, 
       
   139 	// we will address this if it later arises.
       
   140 	// We parse the descriptor in parts as we do not want to blow the buffer.
       
   141 	// Even though the descriptor may already be passed in chunks they may be too big.
       
   142 	
       
   143 	if (aChunk.Length() == 0)
       
   144 		{
       
   145 		return;
       
   146 		}
       
   147 
       
   148 	TPtrC8 part;
       
   149 	TInt offset = 0;
       
   150 	TInt size = aChunk.Size();
       
   151 	TInt partSize = size;
       
   152 
       
   153 	do
       
   154 		{
       
   155 		TDes8& buf = iExpat->GetBufferL(KExpatBufferSize);
       
   156 
       
   157 		if (partSize > KExpatBufferSize) 
       
   158 			{	
       
   159 			partSize = KExpatBufferSize;
       
   160 			}
       
   161 			
       
   162 		part.Set (aChunk.Mid(offset, partSize));
       
   163 
       
   164 		buf = part;
       
   165 		iExpat->ParseL();
       
   166 
       
   167 		// The remaining part stats.
       
   168 		offset += part.Length();
       
   169 		partSize = size - offset;
       
   170 
       
   171 		} while (partSize);
       
   172 	}
       
   173 
       
   174 void CXmlParserPlugin::SetContentSink(class MContentHandler &aContentSink)
       
   175 	{
       
   176 	iExpat->SetContentSink(aContentSink);
       
   177 	}
       
   178 
       
   179 RHeap* CXmlParserPlugin::GetInternalHeap() const
       
   180 	{
       
   181 	return iExpat->GetInternalHeap();
       
   182 	}
       
   183 
       
   184 //
       
   185 // Ecom implementation infrastructure
       
   186 //
       
   187 
       
   188 // KUidXmlParserPlugin is the unique UID for our implementation of the MParser interface.  This interface is
       
   189 // 'published' as KParserInterfaceUid defined in Xml/FrameworkConstants.h.  KUidXmlParserPlugin must be
       
   190 // the same as the value of implementation_uid in the file 101faa0a.rss
       
   191 const TInt KUidXmlParserPlugin = 0x101FAA0C;
       
   192 
       
   193 const TImplementationProxy ImplementationTable[] = {
       
   194 	IMPLEMENTATION_PROXY_ENTRY(KUidXmlParserPlugin, CXmlParserPlugin::EcomNewL)
       
   195 };
       
   196 
       
   197 EXPORT_C const TImplementationProxy* ImplementationGroupProxy(TInt& aTableCount)
       
   198 	{
       
   199 	aTableCount = sizeof(ImplementationTable) / sizeof(TImplementationProxy);
       
   200 
       
   201 	return ImplementationTable;
       
   202 	}
       
   203