First libxml2 implementation

* XPath node search
* Applied for shared memory area parsing
* Should we use it here (CPU consumption)?
* TODO: exception handling!

src/framework/Libxml2Adapter.cpp

@@ -20,15 +20,71 @@
 
 #include "Libxml2Adapter.h"
 
+#include <iostream>
+#include <sstream>
+
+#include <libxml/xpath.h>
+
 Libxml2Adapter::Libxml2Adapter()
 {
+	m_xmlDocument = NULL;
 }
 
 Libxml2Adapter::~Libxml2Adapter()
 {
 }
 
-string Libxml2Adapter::getAttributeBySingleElementXPath(const string xml, const string xpath)
+void Libxml2Adapter::setXmlDocument(const string xml, const string url)
 {
-	//TODO
+	xmlDocPtr doc = xmlReadMemory(xml.c_str(), xml.size(), url.c_str(), NULL, 0);
+	if(doc) {
+		m_xmlDocument = doc;
+	}
+	else {
+		cerr << "Document couldn't be parsed!" << endl;
+	}
+}
+
+string Libxml2Adapter::getSingleNodeContentByXPath(const string xpath)
+{
+	// no document available!
+	if(!m_xmlDocument) return("");
+
+	// prepare xpath search
+	stringstream buffer;
+    xmlXPathContextPtr xpathCtx = xmlXPathNewContext(m_xmlDocument);
+    xmlChar* xpathExpr = xmlCharStrdup(xpath.c_str());
+
+    // run xpath query
+    xmlXPathObjectPtr xpathObj = xmlXPathEvalExpression(xpathExpr, xpathCtx);
+    xmlNodeSetPtr nodes = xpathObj->nodesetval;
+
+    // how many nodes did we find?
+    int size = (nodes) ? nodes->nodeNr : 0;
+
+    if(size == 0) {
+    	cerr << "No node found using XPath expression: " << xpath << endl;
+    	return("");
     }
+    else if(size < 1) {
+    	cerr << "More than node found using XPath expression: " << xpath << endl;
+    	return("");
+    }
+
+    // convert xml contents
+    buffer << xmlNodeListGetString(m_xmlDocument, nodes->nodeTab[0]->xmlChildrenNode, 1);
+
+    // clean up
+    xmlXPathFreeObject(xpathObj);
+    xmlXPathFreeContext(xpathCtx);
+
+    return(buffer.str());
+}
+
+string Libxml2Adapter::getSingleNodeContentByXPath(const string xml, const string url, const string xpath)
+{
+	setXmlDocument(xml, url);
+	return(getSingleNodeContentByXPath(xpath));
+}
+
+

src/framework/Libxml2Adapter.h

@@ -25,6 +25,8 @@
 
 #include "XMLProcessorInterface.h"
 
+#include <libxml/parser.h>
+
 using namespace std;
 
 /**
@@ -55,19 +57,46 @@ public:
 	virtual ~Libxml2Adapter();
 
 	/**
-	 * \brief Retrieves a single element's attribute value
+	 * \brief Sets the XML document to be processed
+	 *
+	 * \param xml The XML document to be used for processing
+	 * \param url The base URL of the document
+	 */
+	void setXmlDocument(const string xml, const string url);
+
+	/**
+	 * \brief Retrieves a single node's (element or attribute) content
 	 *
 	 * This method takes a XPath expression that properly defines how to search
-	 * for a specific attribute of a single element. If the XPath search results
-	 * in more than one element or if the attribute can't be found the return
-	 * value is NULL.
+	 * for a specific node (element or attribute). If the XPath search results
+	 * in more than one instance or if the node (or its content) can't be found
+	 * the return value is NULL.
+	 *
+	 * \param xpath The XPath expression to be used for seaching
+	 *
+	 * \return The node's content or NULL in case of an error
+	 */
+	string getSingleNodeContentByXPath(const string xpath);
+
+	/**
+	 * \brief Retrieves a single node's (element or attribute) content
+	 *
+	 * This method takes a XPath expression that properly defines how to search
+	 * for a specific node (element or attribute). If the XPath search results
+	 * in more than one instance or if the node (or its content) can't be found
+	 * the return value is NULL.
 	 *
 	 * \param xml The XML document to be used for processing
+	 * \param url The base URL of the document
 	 * \param xpath The XPath expression to be used for seaching
 	 *
-	 * \return The attribute value or NULL in case of an error
+	 * \return The node's content or NULL in case of an error
 	 */
-	string getAttributeBySingleElementXPath(const string xml, const string xpath);
+	string getSingleNodeContentByXPath(const string xml, const string url, const string xpath);
+
+private:
+	/// The current XML document instance
+	xmlDocPtr m_xmlDocument;
 };
 
 /**

src/framework/Makefile

@@ -28,6 +28,7 @@ CXX?=g++
 # variables
 CPPFLAGS = $(shell $(FRAMEWORK_INSTALL)/bin/sdl-config --cflags)
 CPPFLAGS += $(shell $(FRAMEWORK_INSTALL)/bin/freetype-config --cflags)
+CPPFLAGS += $(shell $(FRAMEWORK_INSTALL)/bin/xml2-config --cflags)
 CPPFLAGS += -I$(FRAMEWORK_INSTALL)/include/BOINC -I/usr/include
 
 DEPS = Makefile

src/framework/XMLProcessorInterface.h

@@ -51,19 +51,42 @@ public:
 	virtual ~XMLProcessorInterface() {};
 
 	/**
-	 * \brief Retrieves a single element's attribute value
+	 * \brief Sets the XML document to be processed
+	 *
+	 * \param xml The XML document to be used for processing
+	 * \param url The base URL of the document
+	 */
+	virtual void setXmlDocument(const string xml, const string url) = 0;
+
+	/**
+	 * \brief Retrieves a single node's (element or attribute) content
+	 *
+	 * This method takes a XPath expression that properly defines how to search
+	 * for a specific node (element or attribute). If the XPath search results
+	 * in more than one instance or if the node (or its content) can't be found
+	 * the return value is NULL.
+	 *
+	 * \param xpath The XPath expression to be used for seaching
+	 *
+	 * \return The node's content or NULL in case of an error
+	 */
+	virtual string getSingleNodeContentByXPath(const string xpath) = 0;
+
+	/**
+	 * \brief Retrieves a single node's (element or attribute) content
 	 *
 	 * This method takes a XPath expression that properly defines how to search
-	 * for a specific attribute of a single element. If the XPath search results
-	 * in more than one element or if the attribute can't be found the return
-	 * value is NULL.
+	 * for a specific node (element or attribute). If the XPath search results
+	 * in more than one instance or if the node (or its content) can't be found
+	 * the return value is NULL.
 	 *
 	 * \param xml The XML document to be used for processing
+	 * \param url The base URL of the document
 	 * \param xpath The XPath expression to be used for seaching
 	 *
-	 * \return The attribute value or NULL in case of an error
+	 * \return The node's content or NULL in case of an error
 	 */
-	virtual string getAttributeBySingleElementXPath(const string xml, const string xpath) = 0;
+	virtual string getSingleNodeContentByXPath(const string xml, const string url, const string xpath) = 0;
 };
 
 /**

src/starsphere/EinsteinRadioAdapter.cpp

@@ -19,6 +19,9 @@
  ***************************************************************************/
 
 #include "EinsteinRadioAdapter.h"
+#include "Libxml2Adapter.h"
+
+#include <cstdlib>
 
 const string EinsteinRadioAdapter::SharedMemoryIdentifier = "EinsteinRadio";
 
@@ -26,6 +29,7 @@ EinsteinRadioAdapter::EinsteinRadioAdapter(BOINCClientAdapter *boincClient) :
 	m_WUTemplatePowerSpectrum(POWERSPECTRUM_BINS, 0)
 {
 	this->boincClient = boincClient;
+	m_xmlIFace = new Libxml2Adapter();
 
 	m_WUSkyPosRightAscension = 0.0;
 	m_WUSkyPosDeclination = 0.0;
@@ -35,6 +39,7 @@ EinsteinRadioAdapter::EinsteinRadioAdapter(BOINCClientAdapter *boincClient) :
 
 EinsteinRadioAdapter::~EinsteinRadioAdapter()
 {
+	if(m_xmlIFace) delete m_xmlIFace;
 }
 
 void EinsteinRadioAdapter::refresh()
@@ -45,46 +50,42 @@ void EinsteinRadioAdapter::refresh()
 
 void EinsteinRadioAdapter::parseApplicationInformation()
 {
-	char spectrumArray[POWERSPECTRUM_BIN_BYTES + 1] = {0};
+	string spectrumString;
 
 	// get updated application information
 	string info = boincClient->applicationInformation();
 
 	// do we have any data?
 	if(info.length() > 0) {
+		string temp;
 
 		// parse data into members
-		// TODO: this is soon going to be replaced by true XML parsing!
-		if(9 != sscanf(info.c_str(),
-				"<graphics_info>\n"
-				"  <skypos_rac>%lf</skypos_rac>\n"
-				"  <skypos_dec>%lf</skypos_dec>\n"
-				"  <dispersion>%lf</dispersion>\n"
-				"  <orb_radius>%lf</orb_radius>\n"
-				"  <orb_period>%lf</orb_period\n"
-				"  <orb_phase>%lf</orb_phase>\n"
-				"  <power_spectrum>%80c</power_spectrum>\n"
-				"  <fraction_done>%lf</fraction_done>\n"
-				"  <cpu_time>%lf</cpu_time>\n",
-				&m_WUSkyPosRightAscension,
-				&m_WUSkyPosDeclination,
-				&m_WUDispersionMeasure,
-				&m_WUTemplateOrbitalRadius,
-				&m_WUTemplateOrbitalPeriod,
-				&m_WUTemplateOrbitalPhase,
-				spectrumArray,
-				&m_WUFractionDone,
-				&m_WUCPUTime))
-		{
-			cerr << "Incompatible shared memory data encountered!" << endl;
-		}
-		else {
+		m_xmlIFace->setXmlDocument(info, "http://einstein.phys.uwm.edu");
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/skypos_rac");
+		m_WUSkyPosRightAscension = strtod(temp.c_str(), NULL);
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/skypos_dec");
+		m_WUSkyPosDeclination = strtod(temp.c_str(), NULL);
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/dispersion");
+		m_WUDispersionMeasure = strtod(temp.c_str(), NULL);
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/orb_radius");
+		m_WUTemplateOrbitalRadius = strtod(temp.c_str(), NULL);
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/orb_period");
+		m_WUTemplateOrbitalPeriod = strtod(temp.c_str(), NULL);
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/orb_phase");
+		m_WUTemplateOrbitalPhase = strtod(temp.c_str(), NULL);
+		spectrumString = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/power_spectrum");
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/fraction_done");
+		m_WUFractionDone = strtod(temp.c_str(), NULL);
+		temp = m_xmlIFace->getSingleNodeContentByXPath("/graphics_info/cpu_time");
+		m_WUCPUTime = strtod(temp.c_str(), NULL);
+
+		// TODO: make sure parsing worked flawlessly (only spectrum is checked below!)
+
 		// convert radians to degrees
 		m_WUSkyPosRightAscension *= 180/PI;
 		m_WUSkyPosDeclination *= 180/PI;
 
 		// deserialize power spectrum data
-			string spectrumString(spectrumArray);
 		if(spectrumString.length() == POWERSPECTRUM_BIN_BYTES) {
 			int spectrumBinValue;
 			// prepare hex to int conversion stream
@@ -109,7 +110,7 @@ void EinsteinRadioAdapter::parseApplicationInformation()
 		else {
 			cerr << "Invalid power spectrum shared memory data encountered!" << endl;
 		}
-		}
+
 	}
 }
 

src/starsphere/EinsteinRadioAdapter.h

@@ -26,6 +26,7 @@
 #include <iomanip>
 
 #include "BOINCClientAdapter.h"
+#include "XMLProcessorInterface.h"
 
 using namespace std;
 
@@ -152,6 +153,9 @@ private:
 	/// Pointer to the (parent) BOINC client adapter
 	BOINCClientAdapter *boincClient;
 
+	/// Pointer to the XML processor
+	XMLProcessorInterface* m_xmlIFace;
+
 	/// Right ascension of the currently searched sky position (in degrees)
 	double m_WUSkyPosRightAscension;
 

src/starsphere/Makefile

@@ -28,12 +28,14 @@ CXX ?= g++
 # variables
 LIBS = -Wl,-Bstatic -lframework -loglft -L$(STARSPHERE_INSTALL)/lib
 LIBS += $(shell $(STARSPHERE_INSTALL)/bin/freetype-config --libs)
+LIBS += $(shell $(STARSPHERE_INSTALL)/bin/xml2-config --libs)
 LIBS += -lboinc_api -lboinc -L/usr/lib
 LIBS += -Wl,-Bdynamic $(shell $(STARSPHERE_INSTALL)/bin/sdl-config --static-libs) -lGL -lGLU
 
 CPPFLAGS = -I$(STARSPHERE_INSTALL)/include
 CPPFLAGS += $(shell $(STARSPHERE_INSTALL)/bin/sdl-config --cflags)
 CPPFLAGS += $(shell $(STARSPHERE_INSTALL)/bin/freetype-config --cflags)
+CPPFLAGS += $(shell $(STARSPHERE_INSTALL)/bin/xml2-config --cflags)
 CPPFLAGS += -I$(STARSPHERE_INSTALL)/include/BOINC -I/usr/include
 
 DEPS = Makefile