/* * This file is part of LibDOM. * Licensed under the MIT License, * http://www.opensource.org/licenses/mit-license.php * * Copyright 2010 - 2011 Michael Drake */ /* * 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: *

NetSurf

NetSurf is awesome!

Hubbub

Hubbub is too.

Big time.

* * Example output: * * HTML * +-BODY * | +-H1 class="woo" * | +-P * | | +-EM * | +-DIV * | | +-H2 * | | +-P * | | +-P * */ #include #include #include #include #include #include #include #include #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, test_msg, 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 * \return true on success, or false on error */ bool dump_dom_element_attribute(dom_node_internal *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((uint8_t *)attribute, 5, &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"); return false; } else if (attr_value == NULL) { /* Element lacks required attribute */ 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_internal *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); /* Finished with the node_name dom_string */ dom_string_unref(node_name); /* Print the element's class, if it has one */ if (dump_dom_element_attribute(node, "class") == false) { 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_internal *node, int depth) { dom_exception exc; dom_node_internal *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 { /* Visit node's descendents */ if (dump_dom_structure(child, depth) == false) { /* There was an error; return */ return false; } /* Go to next sibling */ exc = dom_node_get_next_sibling(child, &child); if (exc != DOM_NO_ERR) { printf("Exception raised for " "node_get_next_sibling\n"); return false; } } 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_internal *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"); return EXIT_FAILURE; } else if (root == NULL) { printf("Broken: root == NULL\n"); return EXIT_FAILURE; } /* Dump DOM structure */ if (dump_dom_structure(root, 0) == false) { printf("Failed to complete DOM structure dump.\n"); return EXIT_FAILURE; } /* Finished with the dom_document */ dom_node_unref(doc); return EXIT_SUCCESS; }