Re: [libcroco-list] new example

[Dodji Seketeli <dodji seketeli org>]

Heya Stefan,

The example looks good to me.
I have commited in the CVS HEAD.
It's named selection-example-1.c.

Thank you very much for your time and effort.

Dodji.

On Wed, Dec 10, 2003 at 10:43:35PM -0500, Stefan Seefeld wrote:
> hi there,
> 
> in an attempt to familiarize myself with libcroco,
> I wrote a new example, which reports all properties
> for a given node.
> In the hope that it may be useful, may be even serve
> for unit testing, I'm posting it here. Feel free to
> include it into the repository.
> 
> It is run as
> 
> ./report report.xml report.css <xpath expression>
> 
> and it will report the properties that apply for
> the first matching node. The node path is reported
> for convenience.
> 
> With a variety of documents and stylesheets it
> can be used to test the selection mechanism of
> libcroco.
> 
> Regards,
> 		Stefan
> 
> PS: It is written with release 0.3, in case it needs
>     some adjustments for the latest CVS...

> /**
>  * This example looks up a node from a document with an
>  * xpath expression, then reports all properties that apply
>  * from a given stylesheet.
>  *
>  * To compile it using gcc, type
>  *
>  * gcc `croco-config --cflags`  `croco-config --libs` -o report report.c
>  *
>  * @author Stefan Seefeld <seefeld sympatico ca>
>  */
> 
> #include <libcroco.h>
> #include <libxml/tree.h>
> #include <libxml/xpath.h>
> 
> void usage_and_exit(char *progname)
> {
>   fprintf(stderr, "Usage: %s <xml doc> <stylesheet> <xpath>\n", progname);
>   exit(-1);
> }
> 
> struct workspace
> {
>   xmlDoc *document;
>   xmlXPathContext *xpath; 
>   xmlXPathObject *result; 
>   CRStyleSheet *stylesheet;
>   CRCascade *cascade;
>   CRSelEng *selector;
> };
> 
> // construct workspace members in order...
> //
> // return 0 on success and -1 on error
> //
> int init(struct workspace *ws, char **args)
> {
>   short i = 0;
>   enum CRStatus status = CR_OK;
> 
>   ws->document = 0;
>   ws->xpath = 0;
>   ws->result = 0;
>   ws->stylesheet = 0;
>   ws->cascade = 0;
>   ws->selector = 0;
> 
> 
>   ws->document = xmlParseFile(args[0]);
>   if (!ws->document)
>   {
>     fprintf(stderr, "could not parse the document %s", args[0]);
>     return -1;
>   }
>   ws->xpath = xmlXPathNewContext(ws->document);
>   if (!ws->xpath)
>   {
>     fprintf(stderr, "Error: unable to create new XPath context\n");
>     return -1;
>   }
>   ws->result = xmlXPathEvalExpression((xmlChar *)args[2], ws->xpath);
>   if (!ws->result)
>   {
>     fprintf(stderr, "Error: unable to evaluate xpath expression\n");
>     return -1;
>   }
>   if (ws->result->type != XPATH_NODESET || !ws->result->nodesetval)
>   {
>     fprintf(stderr, "Error: xpath does not evaluate to a node set\n");
>     return -1;
>   }
> 
>   status = cr_om_parser_simply_parse_file(args[1] /*sheet*/,
>                                           CR_ASCII /*the encoding*/,
>                                           &ws->stylesheet);
>   if (status != CR_OK || !ws->stylesheet)
>   {
>     fprintf(stderr, "could not parse the stylesheet %s", args[1]);
>     return -1;
>   }
>   ws->cascade = cr_cascade_new(ws->stylesheet, 0, 0);
>   ws->selector = cr_sel_eng_new();
> }
> 
> // ...and destruct in reverse order
> void fini(struct workspace *ws)
> {
>   if (ws->selector) cr_sel_eng_destroy(ws->selector);
>   if (ws->cascade) cr_cascade_destroy(ws->cascade);
>   if (ws->stylesheet) cr_stylesheet_destroy(ws->stylesheet);
>   if (ws->result) xmlXPathFreeObject(ws->result);
>   if (ws->xpath) xmlXPathFreeContext(ws->xpath); 
>   if (ws->document) xmlFreeDoc(ws->document);
> }
> 
> void print_property(gpointer name, gpointer decl, gpointer data)
> {
>   CRDeclaration *declaration = (CRDeclaration *)decl;
>   printf("%s\n", (char *)cr_declaration_to_string(declaration, 0));
> }
> 
> void print_properties(struct workspace *ws)
> {
>   enum CRStatus status;
>   GHashTable *table = g_hash_table_new(g_str_hash, g_str_equal);
>   xmlNode *node = ws->result->nodesetval->nodeTab[0];
>   if (!table)
>   {
>     fprintf(stderr, "unable to allocate a hash table\n");
>     return;
>   }
>   status = cr_sel_eng_get_matched_properties_from_cascade(ws->selector,
>                                                           ws->cascade,
>                                                           node,
>                                                           &table);
>   if (status != CR_OK)
>     fprintf(stderr, "Error retrieving properties\n");
>   else
>   {
>     printf("properties for node %s :\n", (char *)xmlGetNodePath(node));
>     g_hash_table_foreach(table, print_property, 0);
>   }
>   g_hash_table_destroy(table);
> }
> 
> int main(int argc, char **argv)
> {
>   struct workspace ws;
>   if (argc != 4) usage_and_exit(argv[0]);
>   if (!init(&ws, argv + 1)) fini(&ws);
> 
>   if (ws.result->nodesetval->nodeNr == 0)
>     printf("no matching nodes found\n");
>   else
>     print_properties(&ws);
> 
>   fini(&ws);
>   return 0;
> }