+/*
+ * Copyright (C) 2014 - Jonathan Rajotte <jonathan.r.julien@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ */
+
+/*
+ * Usage: extract_xml [-v] xml_path xpath_expression
+ * Evaluate XPath expression and prints result node set.
+ * args[1] path to the xml file
+ * args[2] xpath expression to extract
+ * If -v is set the name of the node will appear with his value delimited by
+ * a semicolon(;)
+ * Ex:
+ * Command:extract_xml ../file.xml /test/node/text()
+ * Output:
+ * a
+ * b
+ * c
+ * With -v
+ * node;a;
+ * node;b;
+ * node;c;
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <unistd.h>
+
+#include <libxml/tree.h>
+#include <libxml/parser.h>
+#include <libxml/xpath.h>
+#include <libxml/xpathInternals.h>
+
+#if defined(LIBXML_XPATH_ENABLED)
+
+
+int opt_verbose;
+/**
+ * print_xpath_nodes:
+ * nodes: the nodes set.
+ * output: the output file handle.
+ *
+ * Print the node content to the file
+ */
+static int print_xpath_nodes(xmlDocPtr doc, xmlNodeSetPtr nodes, FILE *output)
+{
+ int ret;
+ int size;
+ int i;
+
+ xmlNodePtr cur;
+ xmlChar *node_child_value_string = NULL;
+
+ assert(output);
+ size = (nodes) ? nodes->nodeNr : 0;
+
+ for (i = 0; i < size; ++i) {
+ assert(nodes->nodeTab[i]);
+
+ if (nodes->nodeTab[i]->type == XML_NAMESPACE_DECL) {
+ fprintf(stderr, "ERR:%s\n",
+ "This executable does not support xml namespacing\n");
+ ret = -1;
+ goto end;
+ } else if (nodes->nodeTab[i]->type == XML_ELEMENT_NODE) {
+ cur = nodes->nodeTab[i];
+
+ if (xmlChildElementCount(cur) == 0) {
+ if (xmlNodeIsText(cur->children)) {
+ node_child_value_string = xmlNodeListGetString(doc,
+ cur->children, 1);
+ if (opt_verbose) {
+ fprintf(output, "%s;%s;\n", cur->name,
+ node_child_value_string);
+ } else {
+ fprintf(output, "%s\n",
+ node_child_value_string);
+ }
+ xmlFree(node_child_value_string);
+ } else {
+ /* We don't want to print non-final element */
+ fprintf(stderr, "ERR:%s\n",
+ "Xpath expression return non-final xml element");
+ ret = -1;
+ goto end;
+ }
+ } else {
+ /* We don't want to print non-final element */
+ fprintf(stderr, "ERR:%s\n",
+ "Xpath expression return non-final xml element");
+ ret = -1;
+ goto end;
+ }
+
+ } else {
+ cur = nodes->nodeTab[i];
+ if (opt_verbose) {
+ fprintf(output, "%s;%s;\n", cur->parent->name, cur->content);
+ } else {
+ fprintf(output, "%s\n", cur->content);
+
+ }
+ }
+ }
+ /* Command Success */
+ ret = 0;
+
+end:
+ return ret;
+}
+
+/*
+ * Extract element corresponding to xpath
+ * xml_path The path to the xml file
+ * xpath: The xpath to evaluate.
+ *
+ * Evaluate an xpath expression onto an xml file.
+ * and print the result one by line.
+ *
+ * Returns 0 on success and a negative value otherwise.
+ */
+static int extract_xpath(const char *xml_path, const xmlChar *xpath)
+{
+ xmlDocPtr doc = NULL;
+ xmlXPathContextPtr xpathCtx = NULL;
+ xmlXPathObjectPtr xpathObj = NULL;
+
+ assert(xml_path);
+ assert(xpath);
+
+ /* Parse the xml file */
+ doc = xmlParseFile(xml_path);
+ if (!doc) {
+ fprintf(stderr, "ERR parsing: xml file invalid \"%s\"\n", xml_path);
+ return -1;
+ }
+
+ /* Initialize a xpath context */
+ xpathCtx = xmlXPathNewContext(doc);
+ if (!xpathCtx) {
+ fprintf(stderr, "ERR: XPath context invalid\n");
+ xmlFreeDoc(doc);
+ return -1;
+ }
+
+ /* Evaluate xpath expression */
+ xpathObj = xmlXPathEvalExpression(xpath, xpathCtx);
+ if (!xpathObj) {
+ fprintf(stderr, "ERR: invalid xpath expression \"%s\"\n", xpath);
+ xmlXPathFreeContext(xpathCtx);
+ xmlFreeDoc(doc);
+ return -1;
+ }
+
+ /* Print results */
+ if (print_xpath_nodes(doc, xpathObj->nodesetval, stdout)) {
+ xmlXPathFreeObject(xpathObj);
+ xmlXPathFreeContext(xpathCtx);
+ xmlFreeDoc(doc);
+ return -1;
+ }
+
+ /* Cleanup */
+ xmlXPathFreeObject(xpathObj);
+ xmlXPathFreeContext(xpathCtx);
+ xmlFreeDoc(doc);
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int opt;
+
+ /* Parse command line and process file */
+ while ((opt = getopt(argc, argv, "v")) != -1) {
+ switch (opt) {
+ case 'v':
+ opt_verbose = 1;
+ break;
+ default:
+ abort();
+ }
+ }
+
+ if (!(optind + 1 < argc)) {
+ fprintf(stderr, "ERR:%s\n", "Arguments missing");
+ return -1;
+ }
+
+ /* Init libxml */
+ xmlInitParser();
+ xmlKeepBlanksDefault(0);
+ if (access(argv[optind], F_OK)) {
+ fprintf(stderr, "ERR:%s\n", "Xml path not valid");
+ return -1;
+ }
+ /* Do the main job */
+ if (extract_xpath(argv[optind], (xmlChar *)argv[optind+1])) {
+ return -1;
+ }
+
+ /* Shutdown libxml */
+ xmlCleanupParser();
+
+ return 0;
+}
+
+#else
+int main(void)
+{
+ fprintf(stderr, "XPath support not compiled in\n");
+ return -1;
+}
+#endif
projects / lttng-tools.git / commitdiff
