c14n.c

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    if (str1 == str2) return(1);
    if (str1 == NULL) return((*str2) == '\0');
    if (str2 == NULL) return((*str1) == '\0');
    do {
	if (*str1++ != *str2) return(0);
    } while (*str2++);
    return(1);
}

/**
 * xmlC14NVisibleNsStackFind:
 * @ctx:		the C14N context 
 * @ns:			the namespace to check
 *
 * Checks whether the given namespace was already rendered or not
 *
 * Returns 1 if we already wrote this namespace or 0 otherwise
 */
static int
xmlC14NVisibleNsStackFind(xmlC14NVisibleNsStackPtr cur, xmlNsPtr ns)
{
    int i;
    const xmlChar *prefix;
    const xmlChar *href;
    int has_empty_ns;
        
    if(cur == NULL) {
        xmlC14NErrParam("searching namespaces stack (c14n)");
        return (0);
    }

    /*
     * if the default namespace xmlns="" is not defined yet then 
     * we do not want to print it out
     */
    prefix = ((ns == NULL) || (ns->prefix == NULL)) ? BAD_CAST "" : ns->prefix;
    href = ((ns == NULL) || (ns->href == NULL)) ? BAD_CAST "" : ns->href;
    has_empty_ns = (xmlC14NStrEqual(prefix, NULL) && xmlC14NStrEqual(href, NULL));

    if (cur->nsTab != NULL) {
	int start = (has_empty_ns) ? 0 : cur->nsPrevStart;
        for (i = cur->nsCurEnd - 1; i >= start; --i) {
            xmlNsPtr ns1 = cur->nsTab[i];
	    
	    if(xmlC14NStrEqual(prefix, (ns1 != NULL) ? ns1->prefix : NULL)) {
		return(xmlC14NStrEqual(href, (ns1 != NULL) ? ns1->href : NULL));
	    }
        }
    }
    return(has_empty_ns);
}

static int			
xmlExcC14NVisibleNsStackFind(xmlC14NVisibleNsStackPtr cur, xmlNsPtr ns, xmlC14NCtxPtr ctx) {
    int i;
    const xmlChar *prefix;
    const xmlChar *href;
    int has_empty_ns;
        
    if(cur == NULL) {
        xmlC14NErrParam("searching namespaces stack (exc c14n)");
        return (0);
    }

    /*
     * if the default namespace xmlns="" is not defined yet then 
     * we do not want to print it out
     */
    prefix = ((ns == NULL) || (ns->prefix == NULL)) ? BAD_CAST "" : ns->prefix;
    href = ((ns == NULL) || (ns->href == NULL)) ? BAD_CAST "" : ns->href;
    has_empty_ns = (xmlC14NStrEqual(prefix, NULL) && xmlC14NStrEqual(href, NULL));

    if (cur->nsTab != NULL) {
	int start = 0;
        for (i = cur->nsCurEnd - 1; i >= start; --i) {
            xmlNsPtr ns1 = cur->nsTab[i];
	    
	    if(xmlC14NStrEqual(prefix, (ns1 != NULL) ? ns1->prefix : NULL)) {
		if(xmlC14NStrEqual(href, (ns1 != NULL) ? ns1->href : NULL)) {
	    	    return(xmlC14NIsVisible(ctx, ns1, cur->nodeTab[i]));
		} else {
		    return(0);
		}
	    }
        }
    }
    return(has_empty_ns);
}




/**
 * xmlC14NIsXmlNs:
 * @ns: 		the namespace to check
 *  		
 * Checks whether the given namespace is a default "xml:" namespace
 * with href="http://www.w3.org/XML/1998/namespace"
 *
 * Returns 1 if the node is default or 0 otherwise
 */

/* todo: make it a define? */
static int
xmlC14NIsXmlNs(xmlNsPtr ns)
{
    return ((ns != NULL) &&
            (xmlStrEqual(ns->prefix, BAD_CAST "xml")) &&
            (xmlStrEqual(ns->href,
                         BAD_CAST
                         "http://www.w3.org/XML/1998/namespace")));
}


/**
 * xmlC14NNsCompare:
 * @ns1:		the pointer to first namespace
 * @ns2: 		the pointer to second namespace
 *
 * Compares the namespaces by names (prefixes).
 *
 * Returns -1 if ns1 < ns2, 0 if ns1 == ns2 or 1 if ns1 > ns2.
 */
static int
xmlC14NNsCompare(xmlNsPtr ns1, xmlNsPtr ns2)
{
    if (ns1 == ns2)
        return (0);
    if (ns1 == NULL)
        return (-1);
    if (ns2 == NULL)
        return (1);

    return (xmlStrcmp(ns1->prefix, ns2->prefix));
}


/**
 * xmlC14NPrintNamespaces:
 * @ns:			the pointer to namespace
 * @ctx: 		the C14N context
 *
 * Prints the given namespace to the output buffer from C14N context.
 *
 * Returns 1 on success or 0 on fail.
 */
static int
xmlC14NPrintNamespaces(const xmlNsPtr ns, xmlC14NCtxPtr ctx)
{

    if ((ns == NULL) || (ctx == NULL)) {
        xmlC14NErrParam("writing namespaces");
        return 0;
    }

    if (ns->prefix != NULL) {
        xmlOutputBufferWriteString(ctx->buf, " xmlns:");
        xmlOutputBufferWriteString(ctx->buf, (const char *) ns->prefix);
        xmlOutputBufferWriteString(ctx->buf, "=\"");
    } else {
        xmlOutputBufferWriteString(ctx->buf, " xmlns=\"");
    }
    if(ns->href != NULL) {
	xmlOutputBufferWriteString(ctx->buf, (const char *) ns->href);
    }
    xmlOutputBufferWriteString(ctx->buf, "\"");
    return (1);
}

/**
 * xmlC14NProcessNamespacesAxis:
 * @ctx: 		the C14N context
 * @node:		the current node
 *
 * Prints out canonical namespace axis of the current node to the
 * buffer from C14N context as follows 
 *
 * Canonical XML v 1.0 (http://www.w3.org/TR/xml-c14n)
 *
 * Namespace Axis
 * Consider a list L containing only namespace nodes in the 
 * axis and in the node-set in lexicographic order (ascending). To begin 
 * processing L, if the first node is not the default namespace node (a node 
 * with no namespace URI and no local name), then generate a space followed 
 * by xmlns="" if and only if the following conditions are met:
 *    - the element E that owns the axis is in the node-set
 *    - The nearest ancestor element of E in the node-set has a default 
 *	    namespace node in the node-set (default namespace nodes always 
 *      have non-empty values in XPath)
 * The latter condition eliminates unnecessary occurrences of xmlns="" in 
 * the canonical form since an element only receives an xmlns="" if its 
 * default namespace is empty and if it has an immediate parent in the 
 * canonical form that has a non-empty default namespace. To finish 
 * processing  L, simply process every namespace node in L, except omit 
 * namespace node with local name xml, which defines the xml prefix, 
 * if its string value is http://www.w3.org/XML/1998/namespace.
 *
 * Exclusive XML Canonicalization v 1.0 (http://www.w3.org/TR/xml-exc-c14n)
 * Canonical XML applied to a document subset requires the search of the 
 * ancestor nodes of each orphan element node for attributes in the xml 
 * namespace, such as xml:lang and xml:space. These are copied into the 
 * element node except if a declaration of the same attribute is already 
 * in the attribute axis of the element (whether or not it is included in 
 * the document subset). This search and copying are omitted from the 
 * Exclusive XML Canonicalization method.
 *
 * Returns 0 on success or -1 on fail.
 */
static int
xmlC14NProcessNamespacesAxis(xmlC14NCtxPtr ctx, xmlNodePtr cur, int visible)
{
    xmlNodePtr n;
    xmlNsPtr ns, tmp;
    xmlListPtr list;
    int already_rendered;
    int has_empty_ns = 0;
    
    if ((ctx == NULL) || (cur == NULL) || (cur->type != XML_ELEMENT_NODE)) {
        xmlC14NErrParam("processing namespaces axis (c14n)");
        return (-1);
    }

    /*
     * Create a sorted list to store element namespaces
     */
    list = xmlListCreate(NULL, (xmlListDataCompare) xmlC14NNsCompare);
    if (list == NULL) {
        xmlC14NErrInternal("creating namespaces list (c14n)");
        return (-1);
    }

    /* check all namespaces */
    for(n = cur; n != NULL; n = n->parent) {
	for(ns = n->nsDef; ns != NULL; ns = ns->next) {
	    tmp = xmlSearchNs(cur->doc, cur, ns->prefix);
	    
	    if((tmp == ns) && !xmlC14NIsXmlNs(ns) && xmlC14NIsVisible(ctx, ns, cur)) {
		already_rendered = xmlC14NVisibleNsStackFind(ctx->ns_rendered, ns);
		if(visible) {
        	    xmlC14NVisibleNsStackAdd(ctx->ns_rendered, ns, cur);
		}
		if(!already_rendered) {
		    xmlListInsert(list, ns); 
		}
    		if(xmlStrlen(ns->prefix) == 0) {
		    has_empty_ns = 1;
		}
	    }
	}
    }
	
    /**
     * if the first node is not the default namespace node (a node with no 
     * namespace URI and no local name), then generate a space followed by 
     * xmlns="" if and only if the following conditions are met:
     *  - the element E that owns the axis is in the node-set
     *  - the nearest ancestor element of E in the node-set has a default 
     *     namespace node in the node-set (default namespace nodes always 
     *     have non-empty values in XPath)
     */
    if(visible && !has_empty_ns) {
        static xmlNs ns_default;

        memset(&ns_default, 0, sizeof(ns_default));
        if(!xmlC14NVisibleNsStackFind(ctx->ns_rendered, &ns_default)) {
    	    xmlC14NPrintNamespaces(&ns_default, ctx);
	}
    }
	
    
    /* 
     * print out all elements from list 
     */
    xmlListWalk(list, (xmlListWalker) xmlC14NPrintNamespaces, (const void *) ctx);

    /* 
     * Cleanup
     */
    xmlListDelete(list);
    return (0);
}


/**
 * xmlExcC14NProcessNamespacesAxis:
 * @ctx: 		the C14N context
 * @node:		the current node
 *
 * Prints out exclusive canonical namespace axis of the current node to the
 * buffer from C14N context as follows 
 *
 * Exclusive XML Canonicalization
 * http://www.w3.org/TR/xml-exc-c14n
 *
 * If the element node is in the XPath subset then output the node in 
 * accordance with Canonical XML except for namespace nodes which are 
 * rendered as follows:
 *
 * 1. Render each namespace node iff:
 *    * it is visibly utilized by the immediate parent element or one of 
 *      its attributes, or is present in InclusiveNamespaces PrefixList, and
 *    * its prefix and value do not appear in ns_rendered. ns_rendered is 
 *      obtained by popping the state stack in order to obtain a list of 
 *      prefixes and their values which have already been rendered by 
 *      an output ancestor of the namespace node's parent element.
 * 2. Append the rendered namespace node to the list ns_rendered of namespace 
 * nodes rendered by output ancestors. Push ns_rendered on state stack and 
 * recurse.
 * 3. After the recursion returns, pop thestate stack.
 *
 *
 * Returns 0 on success or -1 on fail.
 */
static int
xmlExcC14NProcessNamespacesAxis(xmlC14NCtxPtr ctx, xmlNodePtr cur, int visible)
{
    xmlNsPtr ns;
    xmlListPtr list;
    xmlAttrPtr attr;
    int already_rendered;
    int has_empty_ns = 0;
    int has_visibly_utilized_empty_ns = 0;
    int has_empty_ns_in_inclusive_list = 0;
        
    if ((ctx == NULL) || (cur == NULL) || (cur->type != XML_ELEMENT_NODE)) {
        xmlC14NErrParam("processing namespaces axis (exc c14n)");
        return (-1);
    }

    if(!ctx->exclusive) {
        xmlC14NErrParam("processing namespaces axis (exc c14n)");
        return (-1);

    }

    /*
     * Create a sorted list to store element namespaces
     */
    list = xmlListCreate(NULL, (xmlListDataCompare) xmlC14NNsCompare);
    if (list == NULL) {
        xmlC14NErrInternal("creating namespaces list (exc c14n)");
        return (-1);
    }

    /* 
     * process inclusive namespaces:
     * All namespace nodes appearing on inclusive ns list are 
     * handled as provided in Canonical XML
     */
    if(ctx->inclusive_ns_prefixes != NULL) {
	xmlChar *prefix; 
	int i;
	
	for (i = 0; ctx->inclusive_ns_prefixes[i] != NULL; ++i) {
	    prefix = ctx->inclusive_ns_prefixes[i];
	    /*
	     * Special values for namespace with empty prefix
	     */
            if (xmlStrEqual(prefix, BAD_CAST "#default")
                || xmlStrEqual(prefix, BAD_CAST "")) {
                prefix = NULL;
		has_empty_ns_in_inclusive_list = 1;
            }
	
	    ns = xmlSearchNs(cur->doc, cur, prefix);	    
	    if((ns != NULL) && !xmlC14NIsXmlNs(ns) && xmlC14NIsVisible(ctx, ns, cur)) {
		already_rendered = xmlC14NVisibleNsStackFind(ctx->ns_rendered, ns);
		if(visible) {
    	    	    xmlC14NVisibleNsStackAdd(ctx->ns_rendered, ns, cur);
		}
		if(!already_rendered) {
	    	    xmlListInsert(list, ns); 
		}
    		if(xmlStrlen(ns->prefix) == 0) {
		    has_empty_ns = 1;
		}
	    }
	}
    }
    
    /* add node namespace */
    if(cur->ns != NULL) {
	ns = cur->ns;
    } else {
        ns = xmlSearchNs(cur->doc, cur, NULL);
	has_visibly_utilized_empty_ns = 1;