Recursive search example for issue #14

test/CMakeLists.txt

@@ -96,3 +96,29 @@ add_test(
 	COMMAND valgrind --tool=memcheck --leak-check=full --track-origins=yes -v "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}-test-cpp"
 )
 
+
+
+# Test huitre39
+add_executable(
+	"${PROJECT_NAME}-test-huitre39"
+	"${CMAKE_CURRENT_LIST_DIR}/test-huitre39.c"
+)
+
+target_compile_options(
+	"${PROJECT_NAME}-test-huitre39"
+	PRIVATE
+		-std=c11
+)
+
+target_link_libraries(
+	"${PROJECT_NAME}-test-huitre39"
+	PRIVATE
+		xml
+)
+
+
+add_test(
+	NAME "${PROJECT_NAME}-test-huitre39"
+	COMMAND "${PROJECT_NAME}-test-huitre39"
+)
+

test/test-huitre39.c

@@ -0,0 +1,181 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "./xml.h"
+
+
+
+
+
+/**
+ * Will halt the program iff assertion fails
+ */
+static void _assert_that(_Bool condition, char const* message, char const* func, char const* file, int line) {
+	if (!condition) {
+		fprintf(stderr, "Assertion failed: %s, in %s (%s:%i)\n", message, func, file, line);
+		exit(EXIT_FAILURE);
+	}
+}
+
+#define assert_that(condition, message)					\
+	_assert_that(condition, message, __func__, __FILE__, __LINE__)	
+
+
+
+
+
+/**
+ * Behaves similar to `getElementsByTagName`, however returns just the first and
+ * not all elements with a given tag name
+ *
+ * @param base Node in tree which should be the start of te recursive search
+ * @param 0-terminated tag name, case sensitive
+ *
+ * @return First node below `base` iff found, otherwise 0
+ * @warning Depth-First search!
+ *
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Element/getElementsByTagName
+ */
+static struct xml_node* get_node_by_name(struct xml_node* base, uint8_t* name) {
+
+
+	/* Check whether `base` already has the tag name we are searching for
+	 */
+	size_t const name_length = strlen(name);
+
+	uint8_t* base_name = xml_easy_name(base);
+	size_t const base_name_length = strlen(base_name);
+
+
+	/* Length of `name` and `base_name` do match, we should now do a real
+	 * comparison
+	 */
+	if (name_length == base_name_length) {
+		int const rs = memcmp(name, base_name, name_length);
+
+		/* Names match! We have found an element which fullfills our
+		 * search criteria
+		 */
+		if (!rs) {
+			free(base_name);
+			return base;
+		}
+	}
+
+
+	/* Unfortunately, `base` is not the element we are looking for :-(
+	 */
+	free(base_name);
+
+
+	/* Let's take a look at the children of `base`
+	 */
+	size_t const number_of_children = xml_node_children(base);
+
+
+	/* No children → No luck with base
+	 */
+	if (!number_of_children) {
+		return 0;
+	}
+
+
+	/* Recursivly look through all children
+	 */
+	size_t child = 0; for (; child < number_of_children; ++child) {
+		struct xml_node* child_node = xml_node_child(base, child);
+
+		/* Maybe this child does contain the element we are looking for?
+		 */
+		struct xml_node* search_result = get_node_by_name(
+			child_node, name
+		);
+
+		/* We are lucky!
+		 */
+		if (search_result) {
+			return search_result;
+		}
+	}
+
+
+	/* No luck :-(
+	 */
+	return 0;
+}
+
+
+
+
+
+int main(int argc, char** argv) {
+
+	/* XML source, could be read from disk
+	 */
+	uint8_t* source = ""
+		"<Root>"
+			"<Hello>World</Hello>"
+
+			"<Functions>"
+				"<Function>"
+					"<as>testas one</as>"
+					"<os>testos</os>"
+				"</Function>"
+
+				"<Function>"
+					"<is>testis</is>"
+					"<us>testus</us>"
+					"<ls>testls</ls>"
+				"</Function>"
+
+				"<Function>"
+					"<mn>testmn</mn>"
+					"<as>testas two</as>"
+				"</Function>"
+			"</Functions>"
+		"</Root>"
+	;
+
+	struct xml_document* document = xml_parse_document(source, strlen(source));
+
+	if (!document) {
+		printf("Could parse document\n");
+		exit(EXIT_FAILURE);
+	}
+	struct xml_node* root = xml_document_root(document);
+
+
+
+	/* We expect to find Root / Functions / Function#1 / us
+	 */
+	struct xml_node* us = get_node_by_name(root, "us");
+	assert_that(us, "Did not find element by tag name `us'");
+
+	uint8_t* us_content = xml_easy_content(us);
+	assert_that(us_content, "`us' should have content");
+	assert_that(!strcmp(us_content, "testus"), "Unexpected content for node `us'");
+	free(us_content);
+
+
+	/* We expect to find Root / Functions / Function#0 / as
+	 */
+	struct xml_node* as = get_node_by_name(root, "as");
+	assert_that(as, "Did not find element by tag name `as'");
+
+	uint8_t* as_content = xml_easy_content(as);
+	assert_that(as_content, "`as' should have content");
+	assert_that(!strcmp(as_content, "testas one"), "Unexpected content for first `as' node");
+	free(as_content);
+
+
+	/* We do not expect do find a node with tag name `does_not_exist'
+	 */
+	struct xml_node* does_not_exist = get_node_by_name(root, "does_not_exist");
+	assert_that(!does_not_exist, "Found node that should not exist");
+
+	
+
+	xml_document_free(document, false);
+}
+