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/*
* This file is part of LibDOM.
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
*
* Copyright 2010 - 2011 Michael Drake <tlsa@netsurf-browser.org>
*/
/*
* Load an HTML file into LibDOM with Hubbub and print out the DOM structure.
*
* This example demonstrates the following:
*
* 1. Using LibDOM's Hubbub binding to read an HTML file into LibDOM.
* 2. Walking around the DOM tree.
* 3. Accessing DOM node attributes.
*
* Example input:
* <html><body><h1 class="woo">NetSurf</h1>
* <p>NetSurf is <em>awesome</em>!</p>
* <div><h2>Hubbub</h2><p>Hubbub is too.</p>
* <p>Big time.</p></div></body></html>
*
* Example output:
*
* HTML
* +-BODY
* | +-H1 class="woo"
* | +-P
* | | +-EM
* | +-DIV
* | | +-H2
* | | +-P
* | | +-P
*
*/
#include <assert.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dom/dom.h>
#include <dom/bindings/hubbub/parser.h>
#define UNUSED(x) ((x)=(x))
void test_msg(uint32_t severity, void *ctx, const char *msg, ...)
{
va_list l;
UNUSED(ctx);
va_start(l, msg);
fprintf(stderr, "%d: ", severity);
vfprintf(stderr, msg, l);
fprintf(stderr, "\n");
}
/**
* Generate a LibDOM document DOM from an HTML file
*
* \param file The file path
* \return pointer to DOM document, or NULL on error
*/
dom_document *create_doc_dom_from_file(char *file)
{
size_t buffer_size = 1024;
dom_hubbub_parser *parser = NULL;
FILE *handle;
int chunk_length;
dom_hubbub_error error;
dom_document *doc;
unsigned char buffer[buffer_size];
/* Create Hubbub parser */
parser = dom_hubbub_parser_create(NULL, true, false, test_msg, NULL,
NULL, NULL);
if (parser == NULL) {
printf("Can't create Hubbub Parser\n");
return NULL;
}
/* Open input file */
handle = fopen(file, "rb");
if (handle == NULL) {
dom_hubbub_parser_destroy(parser);
printf("Can't open test input file: %s\n", file);
return NULL;
}
/* Parse input file in chunks */
chunk_length = buffer_size;
while (chunk_length == buffer_size) {
chunk_length = fread(buffer, 1, buffer_size, handle);
error = dom_hubbub_parser_parse_chunk(parser, buffer,
chunk_length);
if (error != DOM_HUBBUB_OK) {
dom_hubbub_parser_destroy(parser);
printf("Parsing errors occur\n");
return NULL;
}
}
/* Done parsing file */
error = dom_hubbub_parser_completed(parser);
if (error != DOM_HUBBUB_OK) {
dom_hubbub_parser_destroy(parser);
printf("Parsing error when construct DOM\n");
return NULL;
}
/* Get the document */
doc = dom_hubbub_parser_get_document(parser);
/* Finished with parser */
dom_hubbub_parser_destroy(parser);
/* Close input file */
if (fclose(handle) != 0) {
printf("Can't close test input file: %s\n", file);
return NULL;
}
return doc;
}
/**
* Dump attribute/value for an element node
*
* \param node The element node to dump attribute details for
* \param attribute The attribute to dump
* \return true on success, or false on error
*/
bool dump_dom_element_attribute(dom_node *node, char *attribute)
{
dom_exception exc;
dom_string *attr = NULL;
dom_string *attr_value = NULL;
dom_node_type type;
const char *string;
size_t length;
/* Should only have element nodes here */
exc = dom_node_get_node_type(node, &type);
if (exc != DOM_NO_ERR) {
printf(" Exception raised for node_get_node_type\n");
return false;
}
assert(type == DOM_ELEMENT_NODE);
/* Create a dom_string containing required attribute name. */
exc = dom_string_create_interned((uint8_t *)attribute,
strlen(attribute), &attr);
if (exc != DOM_NO_ERR) {
printf(" Exception raised for dom_string_create\n");
return false;
}
/* Get class attribute's value */
exc = dom_element_get_attribute(node, attr, &attr_value);
if (exc != DOM_NO_ERR) {
printf(" Exception raised for element_get_attribute\n");
dom_string_unref(attr);
return false;
} else if (attr_value == NULL) {
/* Element lacks required attribute */
dom_string_unref(attr);
return true;
}
/* Finished with the attr dom_string */
dom_string_unref(attr);
/* Get attribute value's string data */
string = dom_string_data(attr_value);
length = dom_string_byte_length(attr_value);
/* Print attribute info */
printf(" %s=\"%.*s\"", attribute, (int)length, string);
/* Finished with the attr_value dom_string */
dom_string_unref(attr_value);
return true;
}
/**
* Print a line in a DOM structure dump for an element
*
* \param node The node to dump
* \param depth The node's depth
* \return true on success, or false on error
*/
bool dump_dom_element(dom_node *node, int depth)
{
dom_exception exc;
dom_string *node_name = NULL;
dom_node_type type;
int i;
const char *string;
size_t length;
/* Only interested in element nodes */
exc = dom_node_get_node_type(node, &type);
if (exc != DOM_NO_ERR) {
printf("Exception raised for node_get_node_type\n");
return false;
} else if (type != DOM_ELEMENT_NODE) {
/* Nothing to print */
return true;
}
/* Get element name */
exc = dom_node_get_node_name(node, &node_name);
if (exc != DOM_NO_ERR) {
printf("Exception raised for get_node_name\n");
return false;
} else if (node_name == NULL) {
printf("Broken: root_name == NULL\n");
return false;
}
/* Print ASCII tree structure for current node */
if (depth > 0) {
for (i = 0; i < depth; i++) {
printf("| ");
}
printf("+-");
}
/* Get string data and print element name */
string = dom_string_data(node_name);
length = dom_string_byte_length(node_name);
printf("[%.*s]", (int)length, string);
if (length == 5 && strncmp(string, "title", 5) == 0) {
/* Title tag, gather the title */
dom_string *str;
exc = dom_node_get_text_content(node, &str);
if (exc == DOM_NO_ERR && str != NULL) {
printf(" $%.*s$", (int)dom_string_byte_length(str),
dom_string_data(str));
dom_string_unref(str);
}
}
/* Finished with the node_name dom_string */
dom_string_unref(node_name);
/* Print the element's id & class, if it has them */
if (dump_dom_element_attribute(node, "id") == false ||
dump_dom_element_attribute(node, "class") == false) {
/* Error occured */
printf("\n");
return false;
}
printf("\n");
return true;
}
/**
* Walk though a DOM (sub)tree, in depth first order, printing DOM structure.
*
* \param node The root node to start from
* \param depth The depth of 'node' in the (sub)tree
*/
bool dump_dom_structure(dom_node *node, int depth)
{
dom_exception exc;
dom_node *child;
/* Print this node's entry */
if (dump_dom_element(node, depth) == false) {
/* There was an error; return */
return false;
}
/* Get the node's first child */
exc = dom_node_get_first_child(node, &child);
if (exc != DOM_NO_ERR) {
printf("Exception raised for node_get_first_child\n");
return false;
} else if (child != NULL) {
/* node has children; decend to children's depth */
depth++;
/* Loop though all node's children */
do {
dom_node *next_child;
/* Visit node's descendents */
if (dump_dom_structure(child, depth) == false) {
/* There was an error; return */
dom_node_unref(child);
return false;
}
/* Go to next sibling */
exc = dom_node_get_next_sibling(child, &next_child);
if (exc != DOM_NO_ERR) {
printf("Exception raised for "
"node_get_next_sibling\n");
dom_node_unref(child);
return false;
}
dom_node_unref(child);
child = next_child;
} while (child != NULL); /* No more children */
}
return true;
}
/**
* Main entry point from OS.
*/
int main(int argc, char **argv)
{
dom_exception exc; /* returned by libdom functions */
dom_document *doc = NULL; /* document, loaded into libdom */
dom_node *root = NULL; /* root element of document */
/* Load up the input HTML file */
doc = create_doc_dom_from_file("files/test.html");
if (doc == NULL) {
printf("Failed to load document.\n");
return EXIT_FAILURE;
}
/* Get root element */
exc = dom_document_get_document_element(doc, &root);
if (exc != DOM_NO_ERR) {
printf("Exception raised for get_document_element\n");
dom_node_unref(doc);
return EXIT_FAILURE;
} else if (root == NULL) {
printf("Broken: root == NULL\n");
dom_node_unref(doc);
return EXIT_FAILURE;
}
/* Dump DOM structure */
if (dump_dom_structure(root, 0) == false) {
printf("Failed to complete DOM structure dump.\n");
dom_node_unref(root);
dom_node_unref(doc);
return EXIT_FAILURE;
}
dom_node_unref(root);
/* Finished with the dom_document */
dom_node_unref(doc);
return EXIT_SUCCESS;
}
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