c14n.c

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/*
 * "Canonical XML" implementation 
 * http://www.w3.org/TR/xml-c14n
 * 
 * "Exclusive XML Canonicalization" implementation
 * http://www.w3.org/TR/xml-exc-c14n
 *
 * See Copyright for the status of this software.
 * 
 * Author: Aleksey Sanin <[e-mail]>
 */
#define IN_LIBXML
#include "libxml.h"
#ifdef LIBXML_C14N_ENABLED
#ifdef LIBXML_OUTPUT_ENABLED

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <string.h>

#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/uri.h>
#include <libxml/xmlerror.h>
#include <libxml/globals.h>
#include <libxml/xpathInternals.h>
#include <libxml/c14n.h>

/************************************************************************
 *									*
 *		Some declaration better left private ATM		*
 *									*
 ************************************************************************/

typedef enum {
    XMLC14N_BEFORE_DOCUMENT_ELEMENT = 0,
    XMLC14N_INSIDE_DOCUMENT_ELEMENT = 1,
    XMLC14N_AFTER_DOCUMENT_ELEMENT = 2
} xmlC14NPosition;

typedef struct _xmlC14NVisibleNsStack {
    int nsCurEnd;           /* number of nodes in the set */
    int nsPrevStart;        /* the begginning of the stack for previous visible node */
    int nsPrevEnd;          /* the end of the stack for previous visible node */
    int nsMax;              /* size of the array as allocated */
    xmlNsPtr 	*nsTab;	    /* array of ns in no particular order */	      
    xmlNodePtr	*nodeTab;   /* array of nodes in no particular order */
} xmlC14NVisibleNsStack, *xmlC14NVisibleNsStackPtr;

typedef struct _xmlC14NCtx {
    /* input parameters */
    xmlDocPtr doc;
    xmlC14NIsVisibleCallback is_visible_callback;
    void* user_data;    
    int with_comments;
    xmlOutputBufferPtr buf;

    /* position in the XML document */
    xmlC14NPosition pos;
    int parent_is_doc;
    xmlC14NVisibleNsStackPtr ns_rendered;

    /* exclusive canonicalization */
    int exclusive;
    xmlChar **inclusive_ns_prefixes;

    /* error number */
    int error;
} xmlC14NCtx, *xmlC14NCtxPtr;

static xmlC14NVisibleNsStackPtr	xmlC14NVisibleNsStackCreate	(void);
static void     xmlC14NVisibleNsStackDestroy	(xmlC14NVisibleNsStackPtr cur);
static void     xmlC14NVisibleNsStackAdd	    (xmlC14NVisibleNsStackPtr cur, 
                                                 xmlNsPtr ns,
                                                 xmlNodePtr node);
static void 			xmlC14NVisibleNsStackSave	(xmlC14NVisibleNsStackPtr cur,
								 xmlC14NVisibleNsStackPtr state);
static void 			xmlC14NVisibleNsStackRestore	(xmlC14NVisibleNsStackPtr cur,
								 xmlC14NVisibleNsStackPtr state);
static void 			xmlC14NVisibleNsStackShift	(xmlC14NVisibleNsStackPtr cur);
static int			xmlC14NVisibleNsStackFind	(xmlC14NVisibleNsStackPtr cur, 
								 xmlNsPtr ns);
static int			xmlExcC14NVisibleNsStackFind	(xmlC14NVisibleNsStackPtr cur, 
								 xmlNsPtr ns,
								 xmlC14NCtxPtr ctx);

static int			xmlC14NIsNodeInNodeset		(xmlNodeSetPtr nodes,
								 xmlNodePtr node,
								 xmlNodePtr parent);



static int xmlC14NProcessNode(xmlC14NCtxPtr ctx, xmlNodePtr cur);
static int xmlC14NProcessNodeList(xmlC14NCtxPtr ctx, xmlNodePtr cur);
typedef enum {
    XMLC14N_NORMALIZE_ATTR = 0,
    XMLC14N_NORMALIZE_COMMENT = 1,
    XMLC14N_NORMALIZE_PI = 2,
    XMLC14N_NORMALIZE_TEXT = 3
} xmlC14NNormalizationMode;

static xmlChar *xmlC11NNormalizeString(const xmlChar * input,
                                       xmlC14NNormalizationMode mode);

#define 	xmlC11NNormalizeAttr( a ) \
    xmlC11NNormalizeString((a), XMLC14N_NORMALIZE_ATTR)
#define 	xmlC11NNormalizeComment( a ) \
    xmlC11NNormalizeString((a), XMLC14N_NORMALIZE_COMMENT)
#define 	xmlC11NNormalizePI( a )	\
    xmlC11NNormalizeString((a), XMLC14N_NORMALIZE_PI)
#define 	xmlC11NNormalizeText( a ) \
    xmlC11NNormalizeString((a), XMLC14N_NORMALIZE_TEXT)

#define 	xmlC14NIsVisible( ctx, node, parent ) \
     (((ctx)->is_visible_callback != NULL) ? \
	(ctx)->is_visible_callback((ctx)->user_data, \
		(xmlNodePtr)(node), (xmlNodePtr)(parent)) : 1)

/************************************************************************
 *									*
 * 		Some factorized error routines				*
 *									*
 ************************************************************************/

/**
 * xmlC14NErrMemory:
 * @extra:  extra informations
 *
 * Handle a redefinition of memory error
 */
static void
xmlC14NErrMemory(const char *extra)
{
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_C14N,
		    XML_ERR_NO_MEMORY, XML_ERR_ERROR, NULL, 0, extra,
		    NULL, NULL, 0, 0,
		    "Memory allocation failed : %s\n", extra);
}

/**
 * xmlC14NErrParam:
 * @extra:  extra informations
 *
 * Handle a redefinition of param error
 */
static void
xmlC14NErrParam(const char *extra)
{
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_C14N,
		    XML_ERR_INTERNAL_ERROR, XML_ERR_ERROR, NULL, 0, extra,
		    NULL, NULL, 0, 0,
		    "Invalid parameter : %s\n", extra);
}

/**
 * xmlC14NErrInternal:
 * @extra:  extra informations
 *
 * Handle a redefinition of internal error
 */
static void
xmlC14NErrInternal(const char *extra)
{
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_C14N,
		    XML_ERR_INTERNAL_ERROR, XML_ERR_ERROR, NULL, 0, extra,
		    NULL, NULL, 0, 0,
		    "Internal error : %s\n", extra);
}

/**
 * xmlC14NErrInvalidNode:
 * @extra:  extra informations
 *
 * Handle a redefinition of invalid node error
 */
static void
xmlC14NErrInvalidNode(const char *node_type, const char *extra)
{
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_C14N,
		    XML_C14N_INVALID_NODE, XML_ERR_ERROR, NULL, 0, extra,
		    NULL, NULL, 0, 0,
		    "Node %s is invalid here : %s\n", node_type, extra);
}

/**
 * xmlC14NErrUnknownNode:
 * @extra:  extra informations
 *
 * Handle a redefinition of unknown node error
 */
static void
xmlC14NErrUnknownNode(int node_type, const char *extra)
{
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_C14N,
		    XML_C14N_UNKNOW_NODE, XML_ERR_ERROR, NULL, 0, extra,
		    NULL, NULL, 0, 0,
		    "Unknown node type %d found : %s\n", node_type, extra);
}

/**
 * xmlC14NErrRelativeNamespace:
 * @extra:  extra informations
 *
 * Handle a redefinition of relative namespace error
 */
static void
xmlC14NErrRelativeNamespace(const char *ns_uri)
{
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_C14N,
		    XML_C14N_RELATIVE_NAMESPACE, XML_ERR_ERROR, NULL, 0, NULL,
		    NULL, NULL, 0, 0,
		    "Relative namespace UR is invalid here : %s\n", ns_uri);
}



/**
 * xmlC14NErr:
 * @ctxt:  a C14N evaluation context
 * @node:  the context node
 * @error:  the erorr code
 * @msg:  the message
 * @extra:  extra informations
 *
 * Handle a redefinition of attribute error
 */
static void
xmlC14NErr(xmlC14NCtxPtr ctxt, xmlNodePtr node, int error,
           const char * msg)
{
    if (ctxt != NULL)
        ctxt->error = error;
    __xmlRaiseError(NULL, NULL, NULL,
		    ctxt, node, XML_FROM_C14N, error,
		    XML_ERR_ERROR, NULL, 0,
		    NULL, NULL, NULL, 0, 0, msg);
}

/************************************************************************
 *									*
 *		The implementation internals				*
 *									*
 ************************************************************************/
#define XML_NAMESPACES_DEFAULT		16

static int			
xmlC14NIsNodeInNodeset(xmlNodeSetPtr nodes, xmlNodePtr node, xmlNodePtr parent) {
    if((nodes != NULL) && (node != NULL)) {
	if(node->type != XML_NAMESPACE_DECL) {
	    return(xmlXPathNodeSetContains(nodes, node));
	} else {
	    xmlNs ns;
	    
	    memcpy(&ns, node, sizeof(ns)); 
	    
	    /* this is a libxml hack! check xpath.c for details */
	    if((parent != NULL) && (parent->type == XML_ATTRIBUTE_NODE)) {
		ns.next = (xmlNsPtr)parent->parent;
	    } else {
		ns.next = (xmlNsPtr)parent; 
	    }

	    /* 
	     * If the input is an XPath node-set, then the node-set must explicitly 
	     * contain every node to be rendered to the canonical form.
	     */
	    return(xmlXPathNodeSetContains(nodes, (xmlNodePtr)&ns));
	}
    }
    return(1);
}

static xmlC14NVisibleNsStackPtr
xmlC14NVisibleNsStackCreate(void) {
    xmlC14NVisibleNsStackPtr ret;

    ret = (xmlC14NVisibleNsStackPtr) xmlMalloc(sizeof(xmlC14NVisibleNsStack));
    if (ret == NULL) {
        xmlC14NErrMemory("creating namespaces stack");
	return(NULL);
    }
    memset(ret, 0 , (size_t) sizeof(xmlC14NVisibleNsStack));
    return(ret);
}

static void
xmlC14NVisibleNsStackDestroy(xmlC14NVisibleNsStackPtr cur) {
    if(cur == NULL) {
        xmlC14NErrParam("destroying namespaces stack");
        return;
    }
    if(cur->nsTab != NULL) {
	memset(cur->nsTab, 0, cur->nsMax * sizeof(xmlNsPtr));
	xmlFree(cur->nsTab);
    }
    if(cur->nodeTab != NULL) {
	memset(cur->nodeTab, 0, cur->nsMax * sizeof(xmlNodePtr));
	xmlFree(cur->nodeTab);
    }
    memset(cur, 0, sizeof(xmlC14NVisibleNsStack));
    xmlFree(cur);
    
}

static void 
xmlC14NVisibleNsStackAdd(xmlC14NVisibleNsStackPtr cur, xmlNsPtr ns, xmlNodePtr node) {
    if((cur == NULL) || 
       ((cur->nsTab == NULL) && (cur->nodeTab != NULL)) ||
       ((cur->nsTab != NULL) && (cur->nodeTab == NULL))) {
        xmlC14NErrParam("adding namespace to stack");
	return;
    }

    if ((cur->nsTab == NULL) && (cur->nodeTab == NULL)) {
        cur->nsTab = (xmlNsPtr*) xmlMalloc(XML_NAMESPACES_DEFAULT * sizeof(xmlNsPtr));
        cur->nodeTab = (xmlNodePtr*) xmlMalloc(XML_NAMESPACES_DEFAULT * sizeof(xmlNodePtr));
	if ((cur->nsTab == NULL) || (cur->nodeTab == NULL)) {
	    xmlC14NErrMemory("adding node to stack");
	    return;
	}
	memset(cur->nsTab, 0 , XML_NAMESPACES_DEFAULT * sizeof(xmlNsPtr));
	memset(cur->nodeTab, 0 , XML_NAMESPACES_DEFAULT * sizeof(xmlNodePtr));
        cur->nsMax = XML_NAMESPACES_DEFAULT;
    } else if(cur->nsMax == cur->nsCurEnd) {
	void *tmp;	
	int tmpSize;
	
	tmpSize = 2 * cur->nsMax;
	tmp = xmlRealloc(cur->nsTab, tmpSize * sizeof(xmlNsPtr));
	if (tmp == NULL) {
	    xmlC14NErrMemory("adding node to stack");
	    return;
	}
	cur->nsTab = (xmlNsPtr*)tmp;

	tmp = xmlRealloc(cur->nodeTab, tmpSize * sizeof(xmlNodePtr));
	if (tmp == NULL) {
	    xmlC14NErrMemory("adding node to stack");
	    return;
	}
	cur->nodeTab = (xmlNodePtr*)tmp;

	cur->nsMax = tmpSize;
    }
    cur->nsTab[cur->nsCurEnd] = ns;
    cur->nodeTab[cur->nsCurEnd] = node;

    ++cur->nsCurEnd;
}

static void
xmlC14NVisibleNsStackSave(xmlC14NVisibleNsStackPtr cur, xmlC14NVisibleNsStackPtr state) {
    if((cur == NULL) || (state == NULL)) {
        xmlC14NErrParam("saving namespaces stack");
	return;
    }
    
    state->nsCurEnd = cur->nsCurEnd;
    state->nsPrevStart = cur->nsPrevStart;
    state->nsPrevEnd = cur->nsPrevEnd;
}

static void
xmlC14NVisibleNsStackRestore(xmlC14NVisibleNsStackPtr cur, xmlC14NVisibleNsStackPtr state) {
    if((cur == NULL) || (state == NULL)) {
        xmlC14NErrParam("restoring namespaces stack");
	return;
    }
    cur->nsCurEnd = state->nsCurEnd;
    cur->nsPrevStart = state->nsPrevStart;
    cur->nsPrevEnd = state->nsPrevEnd;
}

static void 
xmlC14NVisibleNsStackShift(xmlC14NVisibleNsStackPtr cur) {
    if(cur == NULL) {
        xmlC14NErrParam("shifting namespaces stack");
	return;
    }
    cur->nsPrevStart = cur->nsPrevEnd;
    cur->nsPrevEnd = cur->nsCurEnd;
}

static int
xmlC14NStrEqual(const xmlChar *str1, const xmlChar *str2) {