xmlreader.c

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/*
 * xmlreader.c: implements the xmlTextReader streaming node API
 *
 * NOTE: 
 *   XmlTextReader.Normalization Property won't be supported, since
 *     it makes the parser non compliant to the XML recommendation
 *
 * See Copyright for the status of this software.
 *
 * [e-mail]
 */

/*
 * TODOs:
 *   - XML Schemas validation
 */
#define IN_LIBXML
#include "libxml.h"

#ifdef LIBXML_READER_ENABLED
#include <string.h> /* for memset() only ! */
#include <stdarg.h>

#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include <libxml/xmlmemory.h>
#include <libxml/xmlIO.h>
#include <libxml/xmlreader.h>
#include <libxml/parserInternals.h>
#ifdef LIBXML_SCHEMAS_ENABLED
#include <libxml/relaxng.h>
#include <libxml/xmlschemas.h>
#endif
#include <libxml/uri.h>
#ifdef LIBXML_XINCLUDE_ENABLED
#include <libxml/xinclude.h>
#endif
#ifdef LIBXML_PATTERN_ENABLED
#include <libxml/pattern.h>
#endif

/* #define DEBUG_CALLBACKS */
/* #define DEBUG_READER */

/**
 * TODO:
 *
 * macro to flag unimplemented blocks
 */
#define TODO 								\
    xmlGenericError(xmlGenericErrorContext,				\
	    "Unimplemented block at %s:%d\n",				\
            __FILE__, __LINE__);

#ifdef DEBUG_READER
#define DUMP_READER xmlTextReaderDebug(reader);
#else
#define DUMP_READER
#endif

#define CHUNK_SIZE 512
/************************************************************************
 *									*
 *	The parser: maps the Text Reader API on top of the existing	*
 *		parsing routines building a tree			*
 *									*
 ************************************************************************/

#define XML_TEXTREADER_INPUT	1
#define XML_TEXTREADER_CTXT	2

typedef enum {
    XML_TEXTREADER_NONE = -1,
    XML_TEXTREADER_START= 0,
    XML_TEXTREADER_ELEMENT= 1,
    XML_TEXTREADER_END= 2,
    XML_TEXTREADER_EMPTY= 3,
    XML_TEXTREADER_BACKTRACK= 4,
    XML_TEXTREADER_DONE= 5,
    XML_TEXTREADER_ERROR= 6
} xmlTextReaderState;

typedef enum {
    XML_TEXTREADER_NOT_VALIDATE = 0,
    XML_TEXTREADER_VALIDATE_DTD = 1,
    XML_TEXTREADER_VALIDATE_RNG = 2,
    XML_TEXTREADER_VALIDATE_XSD = 4
} xmlTextReaderValidate;

struct _xmlTextReader {
    int				mode;	/* the parsing mode */
    xmlDocPtr			doc;    /* when walking an existing doc */
    xmlTextReaderValidate       validate;/* is there any validation */
    int				allocs;	/* what structure were deallocated */
    xmlTextReaderState		state;
    xmlParserCtxtPtr		ctxt;	/* the parser context */
    xmlSAXHandlerPtr		sax;	/* the parser SAX callbacks */
    xmlParserInputBufferPtr	input;	/* the input */
    startElementSAXFunc		startElement;/* initial SAX callbacks */
    endElementSAXFunc		endElement;  /* idem */
    startElementNsSAX2Func	startElementNs;/* idem */
    endElementNsSAX2Func	endElementNs;  /* idem */
    charactersSAXFunc		characters;
    cdataBlockSAXFunc		cdataBlock;
    unsigned int 		base;	/* base of the segment in the input */
    unsigned int 		cur;	/* current position in the input */
    xmlNodePtr			node;	/* current node */
    xmlNodePtr			curnode;/* current attribute node */
    int				depth;  /* depth of the current node */
    xmlNodePtr			faketext;/* fake xmlNs chld */
    int				preserve;/* preserve the resulting document */
    xmlBufferPtr		buffer; /* used to return const xmlChar * */
    xmlDictPtr			dict;	/* the context dictionnary */

    /* entity stack when traversing entities content */
    xmlNodePtr         ent;          /* Current Entity Ref Node */
    int                entNr;        /* Depth of the entities stack */
    int                entMax;       /* Max depth of the entities stack */
    xmlNodePtr        *entTab;       /* array of entities */

    /* error handling */
    xmlTextReaderErrorFunc errorFunc;    /* callback function */
    void                  *errorFuncArg; /* callback function user argument */

#ifdef LIBXML_SCHEMAS_ENABLED
    /* Handling of RelaxNG validation */
    xmlRelaxNGPtr          rngSchemas;	/* The Relax NG schemas */
    xmlRelaxNGValidCtxtPtr rngValidCtxt;/* The Relax NG validation context */
    int                  rngValidErrors;/* The number of errors detected */
    xmlNodePtr             rngFullNode;	/* the node if RNG not progressive */
    /* Handling of Schemas validation */
    xmlSchemaPtr          xsdSchemas;	/* The Schemas schemas */
    xmlSchemaValidCtxtPtr xsdValidCtxt;/* The Schemas validation context */
    int                  xsdValidErrors;/* The number of errors detected */
    xmlSchemaSAXPlugPtr   xsdPlug;	/* the schemas plug in SAX pipeline */
#endif
#ifdef LIBXML_XINCLUDE_ENABLED
    /* Handling of XInclude processing */
    int                xinclude;	/* is xinclude asked for */
    const xmlChar *    xinclude_name;	/* the xinclude name from dict */
    xmlXIncludeCtxtPtr xincctxt;	/* the xinclude context */
    int                in_xinclude;	/* counts for xinclude */
#endif
#ifdef LIBXML_PATTERN_ENABLED
    int                patternNr;       /* number of preserve patterns */
    int                patternMax;      /* max preserve patterns */
    xmlPatternPtr     *patternTab;      /* array of preserve patterns */
#endif
    int                preserves;	/* level of preserves */
    int                parserFlags;	/* the set of options set */
    /* Structured error handling */
    xmlStructuredErrorFunc sErrorFunc;  /* callback function */
};

#define NODE_IS_EMPTY		0x1
#define NODE_IS_PRESERVED	0x2
#define NODE_IS_SPRESERVED	0x4

/**
 * CONSTSTR:
 *
 * Macro used to return an interned string
 */
#define CONSTSTR(str) xmlDictLookup(reader->dict, (str), -1)
#define CONSTQSTR(p, str) xmlDictQLookup(reader->dict, (p), (str))

static int xmlTextReaderReadTree(xmlTextReaderPtr reader);
static int xmlTextReaderNextTree(xmlTextReaderPtr reader);

/************************************************************************
 *									*
 *	Our own version of the freeing routines as we recycle nodes	*
 *									*
 ************************************************************************/
/**
 * DICT_FREE:
 * @str:  a string
 *
 * Free a string if it is not owned by the "dict" dictionnary in the
 * current scope
 */
#define DICT_FREE(str)						\
	if ((str) && ((!dict) || 				\
	    (xmlDictOwns(dict, (const xmlChar *)(str)) == 0)))	\
	    xmlFree((char *)(str));

static void xmlTextReaderFreeNode(xmlTextReaderPtr reader, xmlNodePtr cur);
static void xmlTextReaderFreeNodeList(xmlTextReaderPtr reader, xmlNodePtr cur);

/**
 * xmlFreeID:
 * @not:  A id
 *
 * Deallocate the memory used by an id definition
 */
static void
xmlFreeID(xmlIDPtr id) {
    xmlDictPtr dict = NULL;

    if (id == NULL) return;

    if (id->doc != NULL)
        dict = id->doc->dict;

    if (id->value != NULL)
	DICT_FREE(id->value)
    xmlFree(id);
}

/**
 * xmlTextReaderRemoveID:
 * @doc:  the document
 * @attr:  the attribute
 *
 * Remove the given attribute from the ID table maintained internally.
 *
 * Returns -1 if the lookup failed and 0 otherwise
 */
static int
xmlTextReaderRemoveID(xmlDocPtr doc, xmlAttrPtr attr) {
    xmlIDTablePtr table;
    xmlIDPtr id;
    xmlChar *ID;

    if (doc == NULL) return(-1);
    if (attr == NULL) return(-1);
    table = (xmlIDTablePtr) doc->ids;
    if (table == NULL) 
        return(-1);

    if (attr == NULL)
	return(-1);
    ID = xmlNodeListGetString(doc, attr->children, 1);
    if (ID == NULL)
	return(-1);
    id = xmlHashLookup(table, ID);
    xmlFree(ID);
    if (id == NULL || id->attr != attr) {
	return(-1);
    }
    id->name = attr->name;
    id->attr = NULL;
    return(0);
}

/**
 * xmlTextReaderFreeProp:
 * @reader:  the xmlTextReaderPtr used
 * @cur:  the node
 *
 * Free a node.
 */
static void
xmlTextReaderFreeProp(xmlTextReaderPtr reader, xmlAttrPtr cur) {
    xmlDictPtr dict;

    dict = reader->ctxt->dict;
    if (cur == NULL) return;

    if ((__xmlRegisterCallbacks) && (xmlDeregisterNodeDefaultValue))
	xmlDeregisterNodeDefaultValue((xmlNodePtr) cur);

    /* Check for ID removal -> leading to invalid references ! */
    if ((cur->parent != NULL) && (cur->parent->doc != NULL) &&
	((cur->parent->doc->intSubset != NULL) ||
	 (cur->parent->doc->extSubset != NULL))) {
        if (xmlIsID(cur->parent->doc, cur->parent, cur))
	    xmlTextReaderRemoveID(cur->parent->doc, cur);
    }
    if (cur->children != NULL)
        xmlTextReaderFreeNodeList(reader, cur->children);

    DICT_FREE(cur->name);
    if ((reader != NULL) && (reader->ctxt != NULL) &&
        (reader->ctxt->freeAttrsNr < 100)) {
        cur->next = reader->ctxt->freeAttrs;
	reader->ctxt->freeAttrs = cur;
	reader->ctxt->freeAttrsNr++;
    } else {
	xmlFree(cur);
    }
}

/**
 * xmlTextReaderFreePropList:
 * @reader:  the xmlTextReaderPtr used
 * @cur:  the first property in the list
 *
 * Free a property and all its siblings, all the children are freed too.
 */
static void
xmlTextReaderFreePropList(xmlTextReaderPtr reader, xmlAttrPtr cur) {
    xmlAttrPtr next;
    if (cur == NULL) return;
    while (cur != NULL) {
        next = cur->next;
        xmlTextReaderFreeProp(reader, cur);
	cur = next;
    }
}

/**
 * xmlTextReaderFreeNodeList:
 * @reader:  the xmlTextReaderPtr used
 * @cur:  the first node in the list
 *
 * Free a node and all its siblings, this is a recursive behaviour, all
 * the children are freed too.
 */
static void
xmlTextReaderFreeNodeList(xmlTextReaderPtr reader, xmlNodePtr cur) {
    xmlNodePtr next;
    xmlDictPtr dict;

    dict = reader->ctxt->dict;
    if (cur == NULL) return;
    if (cur->type == XML_NAMESPACE_DECL) {
	xmlFreeNsList((xmlNsPtr) cur);
	return;
    }
    if ((cur->type == XML_DOCUMENT_NODE) ||
	(cur->type == XML_HTML_DOCUMENT_NODE)) {
	xmlFreeDoc((xmlDocPtr) cur);
	return;
    }
    while (cur != NULL) {
        next = cur->next;
	/* unroll to speed up freeing the document */
	if (cur->type != XML_DTD_NODE) {

	    if ((cur->children != NULL) &&
		(cur->type != XML_ENTITY_REF_NODE)) {
		if (cur->children->parent == cur)
		    xmlTextReaderFreeNodeList(reader, cur->children);
		cur->children = NULL;
	    }

	    if ((__xmlRegisterCallbacks) && (xmlDeregisterNodeDefaultValue))
		xmlDeregisterNodeDefaultValue(cur);

	    if (((cur->type == XML_ELEMENT_NODE) ||
		 (cur->type == XML_XINCLUDE_START) ||
		 (cur->type == XML_XINCLUDE_END)) &&
		(cur->properties != NULL))
		xmlTextReaderFreePropList(reader, cur->properties);
	    if ((cur->type != XML_ELEMENT_NODE) &&
		(cur->type != XML_XINCLUDE_START) &&
		(cur->type != XML_XINCLUDE_END) &&
		(cur->type != XML_ENTITY_REF_NODE)) {
		DICT_FREE(cur->content);
	    }
	    if (((cur->type == XML_ELEMENT_NODE) ||
	         (cur->type == XML_XINCLUDE_START) ||
		 (cur->type == XML_XINCLUDE_END)) &&
		(cur->nsDef != NULL))
		xmlFreeNsList(cur->nsDef);

	    /*
	     * we don't free element names here they are interned now
	     */
	    if ((cur->type != XML_TEXT_NODE) &&
		(cur->type != XML_COMMENT_NODE))
		DICT_FREE(cur->name);
	    if (((cur->type == XML_ELEMENT_NODE) ||
		 (cur->type == XML_TEXT_NODE)) &&
	        (reader != NULL) && (reader->ctxt != NULL) &&
		(reader->ctxt->freeElemsNr < 100)) {
	        cur->next = reader->ctxt->freeElems;
		reader->ctxt->freeElems = cur;
		reader->ctxt->freeElemsNr++;
	    } else {
		xmlFree(cur);
	    }
	}
	cur = next;
    }
}

/**
 * xmlTextReaderFreeNode:
 * @reader:  the xmlTextReaderPtr used
 * @cur:  the node
 *
 * Free a node, this is a recursive behaviour, all the children are freed too.
 * This doesn't unlink the child from the list, use xmlUnlinkNode() first.
 */
static void
xmlTextReaderFreeNode(xmlTextReaderPtr reader, xmlNodePtr cur) {
    xmlDictPtr dict;

    dict = reader->ctxt->dict;
    if (cur->type == XML_DTD_NODE) {
	xmlFreeDtd((xmlDtdPtr) cur);
	return;
    }
    if (cur->type == XML_NAMESPACE_DECL) {
	xmlFreeNs((xmlNsPtr) cur);
        return;
    }
    if (cur->type == XML_ATTRIBUTE_NODE) {
	xmlTextReaderFreeProp(reader, (xmlAttrPtr) cur);
	return;
    }

    if ((cur->children != NULL) &&
	(cur->type != XML_ENTITY_REF_NODE)) {
	if (cur->children->parent == cur)
	    xmlTextReaderFreeNodeList(reader, cur->children);
	cur->children = NULL;
    }

    if ((__xmlRegisterCallbacks) && (xmlDeregisterNodeDefaultValue))
	xmlDeregisterNodeDefaultValue(cur);

    if (((cur->type == XML_ELEMENT_NODE) ||
	 (cur->type == XML_XINCLUDE_START) ||
	 (cur->type == XML_XINCLUDE_END)) &&
	(cur->properties != NULL))
	xmlTextReaderFreePropList(reader, cur->properties);
    if ((cur->type != XML_ELEMENT_NODE) &&
	(cur->type != XML_XINCLUDE_START) &&
	(cur->type != XML_XINCLUDE_END) &&
	(cur->type != XML_ENTITY_REF_NODE)) {
	DICT_FREE(cur->content);
    }
    if (((cur->type == XML_ELEMENT_NODE) ||
	 (cur->type == XML_XINCLUDE_START) ||
	 (cur->type == XML_XINCLUDE_END)) &&
	(cur->nsDef != NULL))
	xmlFreeNsList(cur->nsDef);

    /*
     * we don't free names here they are interned now
     */