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@mlcollard mlcollard/srcMLXPathCount.cpp Secret
Created Feb 27, 2019

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Implementation of file from SEComplexity that does not use std::unique_ptr<>
/*
srcMLXPathCount.cpp
Implementation file for srcMLXPathCount()
*/
#include "srcMLXPathCount.hpp"
#include "memory"
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
/** Count of the result of applying the xpath to the srcML file
*
* XPath expression must result in a numeric, integer result.
* In general, this means it needs to use the XPath count() function
*
* @param srcMLfile filename of srcML file
* @param xpath XPath expression as string
* @retval Number of conditions in the srcMLfile
* @retval -1 Error in apply XPath
* @retval -2 Invalid argument
*/
int srcMLXPathCount(const char* srcMLfile, const char* xpath) {
// precondition on parameters
if (srcMLfile == nullptr || xpath == nullptr)
return -2;
xmlInitParser();
// open the srcML file with no encoding change and no options
xmlDoc* srcMLdoc(xmlReadFile(srcMLfile, nullptr, 0));
if (!srcMLdoc) {
return -1;
}
// create xpath evaluation context
xmlXPathContext* xpathCtx(xmlXPathNewContext(srcMLdoc));
if (!xpathCtx) {
xmlFreeDoc(srcMLdoc);
return -1;
}
// register srcML namespaces
if (xmlXPathRegisterNs(xpathCtx, BAD_CAST "src", BAD_CAST "http://www.srcML.org/srcML/src")) {
xmlFreeDoc(srcMLdoc);
xmlXPathFreeContext(xpathCtx);
return -1;
}
if (xmlXPathRegisterNs(xpathCtx, BAD_CAST "cpp", BAD_CAST "http://www.srcML.org/srcML/cpp")) {
xmlFreeDoc(srcMLdoc);
xmlXPathFreeContext(xpathCtx);
return -1;
}
// evaluate xpath expression
xmlXPathObject* xpathResults(xmlXPathEvalExpression(BAD_CAST xpath, xpathCtx));
if (!xpathResults) {
xmlFreeDoc(srcMLdoc);
xmlXPathFreeContext(xpathCtx);
return -1;
}
// extract the count
int count = xmlXPathCastToNumber(xpathResults);
if (count < 0) {
xmlFreeDoc(srcMLdoc);
xmlXPathFreeContext(xpathCtx);
xmlXPathFreeObject(xpathResults);
return -1;
}
xmlFreeDoc(srcMLdoc);
xmlXPathFreeContext(xpathCtx);
xmlXPathFreeObject(xpathResults);
return count;
}
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