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