added this new file.

2003-06-25 Dodji Seketeli <dodji at seketeli dot org>

* docs/examples/sac-example-2.c: added this new file.

Dodji.

1 files changed, 348 insertions, 0 deletions

diff --git a/docs/examples/sac-example-2.c b/docs/examples/sac-example-2.c
new file mode 100644
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+++ b/docs/examples/sac-example-2.c
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+/* -*- Mode: C; indent-tabs-mode:nil; c-basic-offset:8 -*- */
+/**
+ *This test example shows how to use the SAC api.
+ *
+ *This features a simple parser that prints the selector list
+ *and the properties list of each CSS ruleset found.
+ *It also prints the number of properties found in each CSS ruleset.
+ *
+ *At the end of the parsing, it a prints the number of rulesets found
+ *in the CSS document.
+ *
+ *To to this, several handler callbacks have been registered.
+ *We have also created a data structure that we call a parsing context.
+ *This parsing context stores the data necessary to achieve the calculation
+ *done during the parsing (count the number of rulesets and the number
+ *of properties per ruleset)
+ *The parsing context itself is stored in the "app_data" field of the sac handler.
+ *This field is there to provide applications with a
+ *place to store the custom data they want to be able to get/set during the parsing.
+ *
+ *To compile this file, type:
+ *
+ *gcc -g  -o sac-example-2 `pkg-config --cflags --libs libcroco` sac-example-1.c
+ *
+ *Make sure you have compiled and installed libcroco prior to trying to
+ *compile this file :)
+ *
+ *Once you have compiled it, type:
+ *
+ *./sac-example-2 <a-path-to-a-css-file>
+ *
+ *to try it on a CSS file of your choice.
+ *
+ *Initial Author: Dodji Seketeli <Dodji 47 seketeli dot org>
+ */
+
+#include <libcroco.h>
+
+/**
+ *A Context that will hold the
+ *variables necessary to count the number
+ *of rulesets and the number of properties
+ *per ruleset.
+ */
+struct MyFooContext
+{
+        /**the total number of rulesets in the stylesheet.*/
+        unsigned long nb_rulesets ;
+        
+        /**the number of property per ruleset.*/
+        unsigned long nb_props_per_ruleset ;
+} ;
+
+/**
+ *This callback is called only once, at the begining of
+ *the CSS Document.
+ *So here, we will allocate a custom parsing context
+ *where we will store data necessary for us to
+ *count the number of rulesets and properties found in
+ *the CSS document.
+ *@param a_handler the sac handler.
+ */
+static void
+start_document_cb (CRDocHandler *a_handler)
+{
+        struct MyFooContext * parsing_context = NULL ;
+
+        /*
+         *Allocate the parsing context.
+         *Our custom parsing context.
+         */
+        parsing_context = malloc (sizeof (struct MyFooContext)) ;
+        if (!parsing_context)
+        {
+                /*
+                 *the system ran out of memory. Advertise it and
+                 *stop the program.
+                 */
+                fprintf (stderr, "progam ran out of memory") ;
+                exit (-1) ;
+        }
+
+        /*
+         *Initialize the newly allocated custom parsing context
+         *to zero.
+         */
+        memset (parsing_context, 0, sizeof (struct MyFooContext)) ;
+
+        /*
+         *Store the parsing context in the document handler.
+         *The app_data field CRDocHandler is especially there
+         *for that: give applications a place to store some data 
+         *during the parsing.
+         */
+        a_handler->app_data = parsing_context ;
+}
+
+/**
+ *This callback function will
+ *be called at the begining of each css ruleset.
+ *@param a_handler a pointer to the current sac
+ *document handler
+ *@param a_selector a pointer to the selector.
+ *of the current ruleset.
+ */
+static void
+start_selector_cb (CRDocHandler *a_handler,
+		   CRSelector *a_selector)
+{
+	struct MyFooContext *context = NULL ;
+        
+        context = a_handler->app_data ;
+        if (!context)
+                return ;
+        context->nb_props_per_ruleset = 0 ;
+        
+        cr_selector_dump (a_selector, stdout) ;
+        printf (" {\n") ;
+                
+}
+
+/**
+ *This callback function is called when
+ *the parser encounters a CSS property.
+ *@param a_handler the SAC handler.
+ *@param a_name string that contains the
+ *name of the property.
+ *@param a_value the value of the property.
+ */
+static void
+property_cb (CRDocHandler *a_handler,
+             GString *a_name,
+             CRTerm *a_value)
+{
+        struct MyFooContext *context = NULL ;
+        
+        context = a_handler->app_data ;
+
+        if (!context || !a_name || !a_name->str)
+                return ;
+        context->nb_props_per_ruleset ++ ;
+        
+        printf ("%s : ", a_name->str) ;
+        cr_term_dump (a_value, stdout) ;
+        printf ("\n") ;
+}
+
+
+/**
+ *This is a callback function that will be called at the end
+ *of the each css ruleset.
+ */
+static void
+end_selector_cb (CRDocHandler *a_handler,
+		 CRSelector *a_selector)
+{
+        struct MyFooContext *context = NULL ;
+
+	context = a_handler->app_data ;
+        if (!context)
+                return ;
+        context->nb_rulesets ++ ;
+        printf ("\n}\n") ;
+        printf ("**Number of properties in this ruleset: %d\n\n\n",
+                context->nb_props_per_ruleset) ;
+}
+
+/**
+ *This callback is called only once at the end
+ *of the CSS document.
+ *@param a_handler the SAC handler.
+ */
+static void
+end_document_cb (CRDocHandler *a_handler)
+{
+        struct MyFooContext *context = NULL ;
+
+        context = a_handler->app_data ;
+        if (!context)
+                return ;
+
+        printf ("\nTotal number of rulesets: %d\n", 
+                context->nb_rulesets) ;
+        
+        free (context) ;
+        a_handler->app_data = NULL ;
+}
+
+/**
+ *Displays some information about how to use this program.
+ *@param a_prog_name the name of the current program.
+ */
+void
+display_usage (unsigned char *a_prog_name)
+{
+	unsigned char *prog_name = a_prog_name ;
+
+	if (!prog_name)
+	{
+		prog_name = "sac-example-1" ;
+	}
+
+	printf ("usage: %s [--help] | <css file name>\n", prog_name) ;	
+}
+
+int
+main (int argc, char **argv)
+{	
+	unsigned short i = 0 ;
+	unsigned char * file_path = NULL ;
+	CRParser * parser = NULL ;
+	CRDocHandler *sac_handler = NULL ;
+
+	if (argc <= 1)
+	{
+		display_usage (argv[0]) ;
+		return -1 ;
+	}
+
+	/*
+	 *Let's parse the
+	 *command line arguments of this 
+	 *program in this loop.
+	 */
+	for (i=1 ; i < argc ;i++)
+	{
+		if (*argv[i] != '-')
+			break ;
+
+		if (!strcmp (argv[i], "--help")
+		    || !strcmp (argv[i], "-h"))
+		{
+			display_usage (argv[0]) ;
+			return ;
+		}
+		else
+		{
+			/*
+			 *no other option is
+			 *available now, so this is
+			 *a bit redundant...
+			 */
+			display_usage (argv[0]) ;
+		}
+	}
+
+	if (i > argc)
+	{
+		/*
+		 *no file name has been given
+		 *in parameter, go out.
+		 */
+		return ;
+	}
+	
+	/****************************************
+	 *Now, the real libcroco related stuffs...
+	 ****************************************/
+
+	file_path = argv[i] ;
+	
+	/*
+	 *Instanciate the libcroco parser.
+	 */
+	parser = cr_parser_new_from_file (file_path,
+					  CR_ASCII) ;
+	if (!parser)
+	{
+		/*
+		 *Damned, something bad happened ...
+		 */
+		return ;
+	}
+
+	/*
+	 *Instanciates the SAC document handler.
+	 */
+	sac_handler = cr_doc_handler_new () ;
+	if (!sac_handler)
+	{
+		/*
+		 *Argh, something bad happened here :-\
+		 *Let's release the resources we allocated 
+		 *and let's get out.
+		 */
+
+		cr_parser_destroy (parser) ;
+		return ;
+	}
+
+	/****************************************
+	 *Set some of the sac document handlers.
+	 ****************************************/
+
+        /*
+         *This callback function will be called by the parser
+         *only once, at the beginning of the CSS Document.
+         */
+        sac_handler->start_document = start_document_cb ;
+
+        /*
+         *This callback function will be called by the parser
+         *only once, at the end of the CSS Document.
+         */
+        sac_handler->end_document =end_document_cb ;
+
+	/*
+	 *This callback function will be called by the parser
+	 *each time it encounters the beginning of a ruleset.
+	 */
+	sac_handler->start_selector = start_selector_cb ;
+
+        /*
+	 *This callback function will be called by the parser
+	 *each time it encounters the beginning of a ruleset.
+	 */
+        sac_handler->property = property_cb ;
+
+	/*
+	 *This sac handler callback function will be called by the parser
+	 *each time it encounters the end of a ruleset.
+	 */
+	sac_handler->end_selector = end_selector_cb ;
+
+	/*
+	 *Let's register our sac handler into the parser.
+	 */
+	cr_parser_set_sac_handler (parser, sac_handler) ;
+
+	/*
+	 *Now, let's do the parsing !!!
+	 */
+	cr_parser_parse (parser) ;
+	
+	/*******************************************************
+	 *End of the parsing. A Couple of CSS rulesets must have
+         *been printed on the screen...
+	 ***********************************************/
+
+	/*
+	 *Time to free the resources we allocated.
+	 */
+	cr_parser_destroy (parser) ;
+
+	cr_doc_handler_unref (sac_handler) ;
+
+	return 0 ;
+}