// =================================================================================================

// Copyright 2005-2008 Adobe Systems Incorporated

// All Rights Reserved.

//

// NOTICE:  Adobe permits you to use, modify, and distribute this file in accordance with the terms

// of the Adobe license agreement accompanying it.

// =================================================================================================

#include "XMP_Environment.h"  // ! Must be the first #include!

#include "XMPCore_Impl.hpp"

#include "ExpatAdapter.hpp"

#include "XMPMeta.hpp"

#include "expat.h"

#include <string.h>

using namespace std;

#if XMP_WinBuild

#   ifdef _MSC_VER

        #pragma warning ( disable : 4996 )  // '...' was declared deprecated

#   endif

#endif

// *** Set memory handlers.

#ifndef DumpXMLParseEvents

  #define DumpXMLParseEvents  0

#endif

#define FullNameSeparator '@'

// =================================================================================================

static void StartNamespaceDeclHandler    ( void * userData, XMP_StringPtr prefix, XMP_StringPtr uri );

static void EndNamespaceDeclHandler      ( void * userData, XMP_StringPtr prefix );

static void StartElementHandler          ( void * userData, XMP_StringPtr name, XMP_StringPtr* attrs );

static void EndElementHandler            ( void * userData, XMP_StringPtr name );

static void CharacterDataHandler         ( void * userData, XMP_StringPtr cData, int len );

static void StartCdataSectionHandler     ( void * userData );

static void EndCdataSectionHandler       ( void * userData );

static void ProcessingInstructionHandler ( void * userData, XMP_StringPtr target, XMP_StringPtr data );

static void CommentHandler               ( void * userData, XMP_StringPtr comment );

#if BanAllEntityUsage

  // For now we do this by banning DOCTYPE entirely. This is easy and consistent with what is

  // available in recent Java XML parsers. Another, somewhat less drastic, approach would be to 

  // ban all entity declarations. We can't allow declarations and ban references, Expat does not

  // call the SkippedEntityHandler for references in attribute values.

  // ! Standard entities (&, <, >, ", ', and numeric character references) are

  // ! not banned. Expat handles them transparently no matter what.

  static void StartDoctypeDeclHandler ( void * userData, XMP_StringPtr doctypeName,

                      XMP_StringPtr sysid, XMP_StringPtr pubid, int has_internal_subset );

#endif

// =================================================================================================

extern "C" ExpatAdapter * XMP_NewExpatAdapter()

{

  return new ExpatAdapter;

}  // XMP_NewExpatAdapter

// =================================================================================================

ExpatAdapter::ExpatAdapter() : parser(0)

{

  #if XMP_DebugBuild

    this->elemNesting = 0;

    #if DumpXMLParseEvents

      if ( this->parseLog == 0 ) this->parseLog = stdout;

    #endif

  #endif

  this->parser = XML_ParserCreateNS ( 0, FullNameSeparator );

  if ( this->parser == 0 ) XMP_Throw ( "Failure creating Expat parser", kXMPErr_ExternalFailure );

  XML_SetUserData ( this->parser, this );

  XML_SetNamespaceDeclHandler ( this->parser, StartNamespaceDeclHandler, EndNamespaceDeclHandler );

  XML_SetElementHandler ( this->parser, StartElementHandler, EndElementHandler );

  XML_SetCharacterDataHandler ( this->parser, CharacterDataHandler );

  XML_SetCdataSectionHandler ( this->parser, StartCdataSectionHandler, EndCdataSectionHandler );

  XML_SetProcessingInstructionHandler ( this->parser, ProcessingInstructionHandler );

  XML_SetCommentHandler ( this->parser, CommentHandler );

  #if BanAllEntityUsage

    XML_SetStartDoctypeDeclHandler ( this->parser, StartDoctypeDeclHandler );

    isAborted = false;

  #endif

  this->parseStack.push_back ( &this->tree ); // Push the XML root node.

}  // ExpatAdapter::ExpatAdapter

// =================================================================================================

ExpatAdapter::~ExpatAdapter()

{

  if ( this->parser != 0 ) XML_ParserFree ( this->parser );

  this->parser = 0;

}  // ExpatAdapter::~ExpatAdapter

// =================================================================================================

#if XMP_DebugBuild

  static XMP_VarString sExpatMessage;

#endif

static const char * kOneSpace = " ";

void ExpatAdapter::ParseBuffer ( const void * buffer, size_t length, bool last /* = true */ )

{

  enum XML_Status status;

  if ( length == 0 ) { // Expat does not like empty buffers.

    if ( ! last ) return;

    buffer = kOneSpace;

    length = 1;

  }

  status = XML_Parse ( this->parser, (const char *)buffer, length, last );

  #if BanAllEntityUsage

    if ( this->isAborted ) XMP_Throw ( "DOCTYPE is not allowed", kXMPErr_BadXML );

  #endif

  if ( status != XML_STATUS_OK ) {

    XMP_StringPtr errMsg = "XML parsing failure";

    #if 0 // XMP_DebugBuild // Disable for now to make test output uniform. Restore later with thread safety.

      // *** This is a good candidate for a callback error notification mechanism.

      // *** This code is not thread safe, the sExpatMessage isn't locked. But that's OK for debug usage.

      enum XML_Error expatErr = XML_GetErrorCode ( this->parser );

      const char *   expatMsg = XML_ErrorString ( expatErr );

      int errLine = XML_GetCurrentLineNumber ( this->parser );

      char msgBuffer[1000];

      // AUDIT: Use of sizeof(msgBuffer) for snprintf length is safe.

      snprintf ( msgBuffer, sizeof(msgBuffer), "# Expat error %d at line %d, \"%s\"", expatErr, errLine, expatMsg );

      sExpatMessage = msgBuffer;

      errMsg = sExpatMessage.c_str();

      #if  DumpXMLParseEvents

        if ( this->parseLog != 0 ) fprintf ( this->parseLog, "%s\n", errMsg, expatErr, errLine, expatMsg );

      #endif

    #endif

    XMP_Throw ( errMsg, kXMPErr_BadXML );

  }

}  // ExpatAdapter::ParseBuffer

// =================================================================================================

// =================================================================================================

#if XMP_DebugBuild & DumpXMLParseEvents

  static inline void PrintIndent ( FILE * file, size_t count )

  {

    for ( ; count > 0; --count ) fprintf ( file, "  " );

  }

#endif

// =================================================================================================

static void SetQualName ( XMP_StringPtr fullName, XML_Node * node )

{

  // Expat delivers the full name as a catenation of namespace URI, separator, and local name.

  // As a compatibility hack, an "about" or "ID" attribute of an rdf:Description element is

  // changed to "rdf:about" or rdf:ID. Easier done here than in the RDF recognizer.

  // As a bug fix hack, change a URI of "http://purl.org/dc/1.1/" to ""http://purl.org/dc/elements/1.1/.

  // Early versions of Flash that put XMP in SWF used a bad URI for the dc: namespace.

  // ! This code presumes the RDF namespace prefix is "rdf".

  size_t sepPos = strlen(fullName);

  for ( --sepPos; sepPos > 0; --sepPos ) {

    if ( fullName[sepPos] == FullNameSeparator ) break;

  }

  if ( fullName[sepPos] == FullNameSeparator ) {

    XMP_StringPtr prefix;

    XMP_StringLen prefixLen;

    XMP_StringPtr localPart = fullName + sepPos + 1;

    node->ns.assign ( fullName, sepPos );

    if ( node->ns == "http://purl.org/dc/1.1/" ) node->ns = "http://purl.org/dc/elements/1.1/";

    bool found = XMPMeta::GetNamespacePrefix ( node->ns.c_str(), &prefix, &prefixLen );

    if ( ! found ) XMP_Throw ( "Unknown URI in Expat full name", kXMPErr_ExternalFailure );

    node->nsPrefixLen = prefixLen;  // ! Includes the ':'.

    node->name = prefix;

    node->name += localPart;

  } else {

    node->name = fullName;  // The name is not in a namespace.

    if ( node->parent->name == "rdf:Description" ) {

      if ( node->name == "about" ) {

        node->ns   = kXMP_NS_RDF;

        node->name = "rdf:about";

        node->nsPrefixLen = 4;  // ! Include the ':'.

      } else if ( node->name == "ID" ) {

        node->ns   = kXMP_NS_RDF;

        node->name = "rdf:ID";

        node->nsPrefixLen = 4;  // ! Include the ':'.

      }

    }

  }

}  // SetQualName

// =================================================================================================

static void StartNamespaceDeclHandler ( void * userData, XMP_StringPtr prefix, XMP_StringPtr uri )

{

  IgnoreParam(userData);

  // As a bug fix hack, change a URI of "http://purl.org/dc/1.1/" to ""http://purl.org/dc/elements/1.1/.

  // Early versions of Flash that put XMP in SWF used a bad URI for the dc: namespace.

  #if XMP_DebugBuild & DumpXMLParseEvents   // Avoid unused variable warning.

    ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #endif

  if ( prefix == 0 ) prefix = "_dflt_"; // Have default namespace.

  if ( uri == 0 ) return;  // Ignore, have xmlns:pre="", no URI to register.

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "StartNamespace: %s - \"%s\"\n", prefix, uri );

    }

  #endif

  if ( XMP_LitMatch ( uri, "http://purl.org/dc/1.1/" ) ) uri = "http://purl.org/dc/elements/1.1/";

  XMPMeta::RegisterNamespace ( uri, prefix );

}  // StartNamespaceDeclHandler

// =================================================================================================

static void EndNamespaceDeclHandler ( void * userData, XMP_StringPtr prefix )

{

  IgnoreParam(userData);

  #if XMP_DebugBuild & DumpXMLParseEvents   // Avoid unused variable warning.

    ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #endif

  if ( prefix == 0 ) prefix = "_dflt_"; // Have default namespace.

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "EndNamespace: %s\n", prefix );

    }

  #endif

  // ! Nothing to do, Expat has done all of the XML processing.

}  // EndNamespaceDeclHandler

// =================================================================================================

static void StartElementHandler ( void * userData, XMP_StringPtr name, XMP_StringPtr* attrs )

{

  XMP_Assert ( attrs != 0 );

  ExpatAdapter * thiz = (ExpatAdapter*)userData;

  size_t attrCount = 0;

  for ( XMP_StringPtr* a = attrs; *a != 0; ++a ) ++attrCount;

  if ( (attrCount & 1) != 0 )  XMP_Throw ( "Expat attribute info has odd length", kXMPErr_ExternalFailure );

  attrCount = attrCount/2;  // They are name/value pairs.

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "StartElement: %s, %d attrs", name, attrCount );

      for ( XMP_StringPtr* attr = attrs; *attr != 0; attr += 2 ) {

        XMP_StringPtr attrName = *attr;

        XMP_StringPtr attrValue = *(attr+1);

        fprintf ( thiz->parseLog, ", %s = \"%s\"", attrName, attrValue );

      }

      fprintf ( thiz->parseLog, "\n" );

    }

  #endif

  XML_Node * parentNode = thiz->parseStack.back();

  XML_Node * elemNode   = new XML_Node ( parentNode, "", kElemNode );

  SetQualName ( name, elemNode );

  for ( XMP_StringPtr* attr = attrs; *attr != 0; attr += 2 ) {

    XMP_StringPtr attrName = *attr;

    XMP_StringPtr attrValue = *(attr+1);

    XML_Node * attrNode = new XML_Node ( elemNode, "", kAttrNode );

    SetQualName ( attrName, attrNode );

    attrNode->value = attrValue;

    if ( attrNode->name == "xml:lang" ) NormalizeLangValue ( &attrNode->value );

    elemNode->attrs.push_back ( attrNode );

  }

  parentNode->content.push_back ( elemNode );

  thiz->parseStack.push_back ( elemNode );

  if ( elemNode->name == "rdf:RDF" ) {

    thiz->rootNode = elemNode;

    ++thiz->rootCount;

  }

  #if XMP_DebugBuild

    ++thiz->elemNesting;

  #endif

}  // StartElementHandler

// =================================================================================================

static void EndElementHandler ( void * userData, XMP_StringPtr name )

{

  IgnoreParam(name);

  ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #if XMP_DebugBuild

    --thiz->elemNesting;

  #endif

  (void) thiz->parseStack.pop_back();

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "EndElement: %s\n", name );

    }

  #endif

}  // EndElementHandler

// =================================================================================================

static void CharacterDataHandler ( void * userData, XMP_StringPtr cData, int len )

{

  ExpatAdapter * thiz = (ExpatAdapter*)userData;

  if ( (cData == 0) || (len == 0) ) { cData = ""; len = 0; }

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "CharContent: \"" );

      for ( int i = 0; i < len; ++i ) fprintf ( thiz->parseLog, "%c", cData[i] );

      fprintf ( thiz->parseLog, "\"\n" );

    }

  #endif

  XML_Node * parentNode = thiz->parseStack.back();

  XML_Node * cDataNode  = new XML_Node ( parentNode, "", kCDataNode );

  cDataNode->value.assign ( cData, len );

  parentNode->content.push_back ( cDataNode );

}  // CharacterDataHandler

// =================================================================================================

static void StartCdataSectionHandler ( void * userData )

{

  IgnoreParam(userData);

  #if XMP_DebugBuild & DumpXMLParseEvents   // Avoid unused variable warning.

    ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #endif

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "StartCDATA\n" );

    }

  #endif

  // *** Since markup isn't recognized inside CDATA, this affects XMP's double escaping.

}  // StartCdataSectionHandler

// =================================================================================================

static void EndCdataSectionHandler ( void * userData )

{

  IgnoreParam(userData);

  #if XMP_DebugBuild & DumpXMLParseEvents   // Avoid unused variable warning.

    ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #endif

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "EndCDATA\n" );

    }

  #endif  

}  // EndCdataSectionHandler

// =================================================================================================

static void ProcessingInstructionHandler ( void * userData, XMP_StringPtr target, XMP_StringPtr data )

{

  XMP_Assert ( target != 0 );

  ExpatAdapter * thiz = (ExpatAdapter*)userData;

  if ( ! XMP_LitMatch ( target, "xpacket" ) ) return;  // Ignore all PIs except the XMP packet wrapper.

  if ( data == 0 ) data = "";

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "PI: %s - \"%s\"\n", target, data );

    }

  #endif

  XML_Node * parentNode = thiz->parseStack.back();

  XML_Node * piNode  = new XML_Node ( parentNode, target, kPINode );

  piNode->value.assign ( data );

  parentNode->content.push_back ( piNode );

}  // ProcessingInstructionHandler

// =================================================================================================

static void CommentHandler ( void * userData, XMP_StringPtr comment )

{

  IgnoreParam(userData);

  #if XMP_DebugBuild & DumpXMLParseEvents   // Avoid unused variable warning.

    ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #endif

  if ( comment == 0 ) comment = "";

  #if XMP_DebugBuild & DumpXMLParseEvents

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "Comment: \"%s\"\n", comment );

    }

  #endif

  // ! Comments are ignored.

}  // CommentHandler

// =================================================================================================

#if BanAllEntityUsage

static void StartDoctypeDeclHandler ( void * userData, XMP_StringPtr doctypeName,

                    XMP_StringPtr sysid, XMP_StringPtr pubid, int has_internal_subset )

{

  IgnoreParam(doctypeName);

  IgnoreParam(sysid);

  IgnoreParam(pubid);

  IgnoreParam(has_internal_subset);

  ExpatAdapter * thiz = (ExpatAdapter*)userData;

  #if XMP_DebugBuild & DumpXMLParseEvents   // Avoid unused variable warning.

    if ( thiz->parseLog != 0 ) {

      PrintIndent ( thiz->parseLog, thiz->elemNesting );

      fprintf ( thiz->parseLog, "DocType: \"%s\"\n", doctypeName );

    }

  #endif

  thiz->isAborted = true; // ! Can't throw an exception across the plain C Expat frames.

  (void) XML_StopParser ( thiz->parser, XML_FALSE /* not resumable */ );

}  // StartDoctypeDeclHandler

#endif

// =================================================================================================