sdklib/src/main/java/com/android/sdklib/internal/repository/SdkStats.java - platform/tools/base - Git at Google

 /*
  * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.sdklib.internal.repository;

 import com.android.annotations.VisibleForTesting;
 import com.android.annotations.VisibleForTesting.Visibility;
 import com.android.io.NonClosingInputStream;
 import com.android.io.NonClosingInputStream.CloseBehavior;
 import com.android.sdklib.repository.SdkStatsConstants;
 import com.android.utils.SparseArray;

 import org.w3c.dom.Document;
 import org.w3c.dom.NamedNodeMap;
 import org.w3c.dom.Node;
 import org.xml.sax.ErrorHandler;
 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
 import org.xml.sax.SAXParseException;

 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.UnknownHostException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 import javax.net.ssl.SSLKeyException;
 import javax.xml.XMLConstants;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.transform.stream.StreamSource;
 import javax.xml.validation.Schema;
 import javax.xml.validation.SchemaFactory;
 import javax.xml.validation.Validator;


 /**
  * Retrieves stats on platforms.
  * <p/>
  * This returns information stored on the repository in a different XML file
  * and isn't directly tied to the existence of the listed platforms.
  *
  * @deprecated
  * com.android.sdklib.internal.repository has moved into Studio as
  * com.android.tools.idea.sdk.remote.internal.
  */
 @Deprecated
 public class SdkStats {

     public static class PlatformStatBase {
         private final int mApiLevel;
         private final String mVersionName;
         private final String mCodeName;
         private final float mShare;

         public PlatformStatBase(int apiLevel,
                 String versionName,
                 String codeName,
                 float share) {
             mApiLevel = apiLevel;
             mVersionName = versionName;
             mCodeName = codeName;
             mShare = share;
         }

         /** The Android API Level for the platform. An int > 0. */
         public int getApiLevel() {
             return mApiLevel;
         }

         /** The official codename for this platform, for example "Cupcake". */
         public String getCodeName() {
             return mCodeName;
         }

         /** The official version name of this platform, for example "Android 1.5". */
         public String getVersionName() {
             return mVersionName;
         }

         /** An approximate share percentage of this platform and all the
          *  platforms of lower API level. */
         public float getShare() {
             return mShare;
         }

         /** Returns a string representation of this object, for debugging purposes. */
         @Override
         public String toString() {
             return String.format("api=%d, code=%s, vers=%s, share=%.1f%%",  //$NON-NLS-1$
                     mApiLevel, mCodeName, mVersionName, mShare);
         }
     }

     public static class PlatformStat extends PlatformStatBase {
         private final float mAccumShare;

         public PlatformStat(int apiLevel,
                 String versionName,
                 String codeName,
                 float share,
                 float accumShare) {
             super(apiLevel, versionName, codeName, share);
             mAccumShare = accumShare;
         }

         public PlatformStat(PlatformStatBase base, float accumShare) {
             super(base.getApiLevel(),
                     base.getVersionName(),
                     base.getCodeName(),
                     base.getShare());
             mAccumShare = accumShare;
         }

         /** The accumulated approximate share percentage of that platform. */
         public float getAccumShare() {
             return mAccumShare;
         }

         /** Returns a string representation of this object, for debugging purposes. */
         @Override
         public String toString() {
             return String.format("<Stat %s, accum=%.1f%%>", super.toString(), mAccumShare);
         }
     }

     private final SparseArray<PlatformStat> mStats = new SparseArray<SdkStats.PlatformStat>();

     public SdkStats() {
     }

     public SparseArray<PlatformStat> getStats() {
         return mStats;
     }

     public void load(DownloadCache cache, boolean forceHttp, ITaskMonitor monitor) {

         String url = SdkStatsConstants.URL_STATS;

         if (forceHttp) {
             url = url.replaceAll("https://", "http://");  //$NON-NLS-1$ //$NON-NLS-2$
         }

         monitor.setProgressMax(5);
         monitor.setDescription("Fetching %1$s", url);
         monitor.incProgress(1);

         Exception[] exception = new Exception[] { null };
         Boolean[] validatorFound = new Boolean[] { Boolean.FALSE };
         String[] validationError = new String[] { null };
         Document validatedDoc = null;
         String validatedUri = null;

         InputStream xml = fetchXmlUrl(url, cache, monitor.createSubMonitor(1), exception);

         if (xml != null) {
             monitor.setDescription("Validate XML");

             // Explore the XML to find the potential XML schema version
             int version = getXmlSchemaVersion(xml);

             if (version >= 1 && version <= SdkStatsConstants.NS_LATEST_VERSION) {
                 // This should be a version we can handle. Try to validate it
                 // and report any error as invalid XML syntax,

                 String uri = validateXml(xml, url, version, validationError, validatorFound);
                 if (uri != null) {
                     // Validation was successful
                     validatedDoc = getDocument(xml, monitor);
                     validatedUri = uri;

                 }
             } else if (version > SdkStatsConstants.NS_LATEST_VERSION) {
                 // The schema used is more recent than what is supported by this tool.
                 // We don't have an upgrade-path support yet, so simply ignore the document.
                 closeStream(xml);
                 return;
             }
         }

         // If any exception was handled during the URL fetch, display it now.
         if (exception[0] != null) {
             String reason = null;
             if (exception[0] instanceof FileNotFoundException) {
                 // FNF has no useful getMessage, so we need to special handle it.
                 reason = "File not found";
             } else if (exception[0] instanceof UnknownHostException &&
                     exception[0].getMessage() != null) {
                 // This has no useful getMessage yet could really use one
                 reason = String.format("Unknown Host %1$s", exception[0].getMessage());
             } else if (exception[0] instanceof SSLKeyException) {
                 // That's a common error and we have a pref for it.
                 reason = "HTTPS SSL error. You might want to force download through HTTP in the settings.";
             } else if (exception[0].getMessage() != null) {
                 reason = exception[0].getMessage();
             } else {
                 // We don't know what's wrong. Let's give the exception class at least.
                 reason = String.format("Unknown (%1$s)", exception[0].getClass().getName());
             }

             monitor.logError("Failed to fetch URL %1$s, reason: %2$s", url, reason);
         }

         if (validationError[0] != null) {
             monitor.logError("%s", validationError[0]);  //$NON-NLS-1$
         }

         // Stop here if we failed to validate the XML. We don't want to load it.
         if (validatedDoc == null) {
             closeStream(xml);
             return;
         }

         monitor.incProgress(1);

         if (xml != null) {
             monitor.setDescription("Parse XML");
             monitor.incProgress(1);
             parseStatsDocument(validatedDoc, validatedUri, monitor);
         }

         // done
         monitor.incProgress(1);
         closeStream(xml);
     }

     /**
      * Fetches the document at the given URL and returns it as a stream. Returns
      * null if anything wrong happens.
      *
      * @param urlString The URL to load, as a string.
      * @param monitor {@link ITaskMonitor} related to this URL.
      * @param outException If non null, where to store any exception that
      *            happens during the fetch.
      * @see UrlOpener UrlOpener, which handles all URL logic.
      */
     private InputStream fetchXmlUrl(String urlString,
             DownloadCache cache,
             ITaskMonitor monitor,
             Exception[] outException) {
         try {
             InputStream xml = cache.openCachedUrl(urlString, monitor);
             if (xml != null) {
                 xml.mark(500000);
                 xml = new NonClosingInputStream(xml);
                 ((NonClosingInputStream) xml).setCloseBehavior(CloseBehavior.RESET);
             }
             return xml;
         } catch (Exception e) {
             if (outException != null) {
                 outException[0] = e;
             }
         }

         return null;
     }

     /**
      * Closes the stream, ignore any exception from InputStream.close().
      * If the stream is a NonClosingInputStream, sets it to CloseBehavior.CLOSE first.
      */
     private void closeStream(InputStream is) {
         if (is != null) {
             if (is instanceof NonClosingInputStream) {
                 ((NonClosingInputStream) is).setCloseBehavior(CloseBehavior.CLOSE);
             }
             try {
                 is.close();
             } catch (IOException ignore) {}
         }
     }

     /**
      * Manually parses the root element of the XML to extract the schema version
      * at the end of the xmlns:sdk="http://schemas.android.com/sdk/android/addons-list/$N"
      * declaration.
      *
      * @return 1..{@link SdkStatsConstants#NS_LATEST_VERSION} for a valid schema version
      *         or 0 if no schema could be found.
      */
     @VisibleForTesting(visibility=Visibility.PRIVATE)
     protected int getXmlSchemaVersion(InputStream xml) {
         if (xml == null) {
             return 0;
         }

         // Get an XML document
         Document doc = null;
         try {
             xml.reset();

             DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
             factory.setIgnoringComments(false);
             factory.setValidating(false);

             // Parse the old document using a non namespace aware builder
             factory.setNamespaceAware(false);
             DocumentBuilder builder = factory.newDocumentBuilder();

             // We don't want the default handler which prints errors to stderr.
             builder.setErrorHandler(new ErrorHandler() {
                 @Override
                 public void warning(SAXParseException e) throws SAXException {
                 // pass
                 }
                 @Override
                 public void fatalError(SAXParseException e) throws SAXException {
                     throw e;
                 }
                 @Override
                 public void error(SAXParseException e) throws SAXException {
                     throw e;
                 }
             });

             doc = builder.parse(xml);

             // Prepare a new document using a namespace aware builder
             factory.setNamespaceAware(true);
             builder = factory.newDocumentBuilder();

         } catch (Exception e) {
             // Failed to reset XML stream
             // Failed to get builder factor
             // Failed to create XML document builder
             // Failed to parse XML document
             // Failed to read XML document
         }

         if (doc == null) {
             return 0;
         }

         // Check the root element is an XML with at least the following properties:
         // <sdk:sdk-addons-list
         //    xmlns:sdk="http://schemas.android.com/sdk/android/addons-list/$N">
         //
         // Note that we don't have namespace support enabled, we just do it manually.

         Pattern nsPattern = Pattern.compile(SdkStatsConstants.NS_PATTERN);

         String prefix = null;
         for (Node child = doc.getFirstChild(); child != null; child = child.getNextSibling()) {
             if (child.getNodeType() == Node.ELEMENT_NODE) {
                 prefix = null;
                 String name = child.getNodeName();
                 int pos = name.indexOf(':');
                 if (pos > 0 && pos < name.length() - 1) {
                     prefix = name.substring(0, pos);
                     name = name.substring(pos + 1);
                 }
                 if (SdkStatsConstants.NODE_SDK_STATS.equals(name)) {
                     NamedNodeMap attrs = child.getAttributes();
                     String xmlns = "xmlns";                                         //$NON-NLS-1$
                     if (prefix != null) {
                         xmlns += ":" + prefix;                                      //$NON-NLS-1$
                     }
                     Node attr = attrs.getNamedItem(xmlns);
                     if (attr != null) {
                         String uri = attr.getNodeValue();
                         if (uri != null) {
                             Matcher m = nsPattern.matcher(uri);
                             if (m.matches()) {
                                 String version = m.group(1);
                                 try {
                                     return Integer.parseInt(version);
                                 } catch (NumberFormatException e) {
                                     return 0;
                                 }
                             }
                         }
                     }
                 }
             }
         }

         return 0;
     }

     /**
      * Validates this XML against one of the requested SDK Repository schemas.
      * If the XML was correctly validated, returns the schema that worked.
      * If it doesn't validate, returns null and stores the error in outError[0].
      * If we can't find a validator, returns null and set validatorFound[0] to false.
      */
     @VisibleForTesting(visibility=Visibility.PRIVATE)
     protected String validateXml(InputStream xml, String url, int version,
             String[] outError, Boolean[] validatorFound) {

         if (xml == null) {
             return null;
         }

         try {
             Validator validator = getValidator(version);

             if (validator == null) {
                 validatorFound[0] = Boolean.FALSE;
                 outError[0] = String.format(
                         "XML verification failed for %1$s.\nNo suitable XML Schema Validator could be found in your Java environment. Please consider updating your version of Java.",
                         url);
                 return null;
             }

             validatorFound[0] = Boolean.TRUE;

             // Reset the stream if it supports that operation.
             xml.reset();

             // Validation throws a bunch of possible Exceptions on failure.
             validator.validate(new StreamSource(xml));
             return SdkStatsConstants.getSchemaUri(version);

         } catch (SAXParseException e) {
             outError[0] = String.format(
                     "XML verification failed for %1$s.\nLine %2$d:%3$d, Error: %4$s",
                     url,
                     e.getLineNumber(),
                     e.getColumnNumber(),
                     e.toString());

         } catch (Exception e) {
             outError[0] = String.format(
                     "XML verification failed for %1$s.\nError: %2$s",
                     url,
                     e.toString());
         }
         return null;
     }

     /**
      * Helper method that returns a validator for our XSD, or null if the current Java
      * implementation can't process XSD schemas.
      *
      * @param version The version of the XML Schema.
      *        See {@link SdkStatsConstants#getXsdStream(int)}
      */
     private Validator getValidator(int version) throws SAXException {
         InputStream xsdStream = SdkStatsConstants.getXsdStream(version);
         try {
             SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);

             if (factory == null) {
                 return null;
             }

             // This may throw a SAX Exception if the schema itself is not a valid XSD
             Schema schema = factory.newSchema(new StreamSource(xsdStream));

             Validator validator = schema == null ? null : schema.newValidator();

             return validator;
         } finally {
             if (xsdStream != null) {
                 try {
                     xsdStream.close();
                 } catch (IOException ignore) {}
             }
         }
     }

     /**
      * Takes an XML document as a string as parameter and returns a DOM for it.
      *
      * On error, returns null and prints a (hopefully) useful message on the monitor.
      */
     @VisibleForTesting(visibility=Visibility.PRIVATE)
     protected Document getDocument(InputStream xml, ITaskMonitor monitor) {
         try {
             DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
             factory.setIgnoringComments(true);
             factory.setNamespaceAware(true);

             DocumentBuilder builder = factory.newDocumentBuilder();
             xml.reset();
             Document doc = builder.parse(new InputSource(xml));

             return doc;
         } catch (ParserConfigurationException e) {
             monitor.logError("Failed to create XML document builder");

         } catch (SAXException e) {
             monitor.logError("Failed to parse XML document");

         } catch (IOException e) {
             monitor.logError("Failed to read XML document");
         }

         return null;
     }

     /**
      * Parses all valid platforms found in the XML.
      * Changes the stats array returned by {@link #getStats()}
      * (also returns the value directly, useful for unit tests.)
      */
     @VisibleForTesting(visibility=Visibility.PRIVATE)
     protected SparseArray<PlatformStat> parseStatsDocument(
             Document doc,
             String nsUri,
             ITaskMonitor monitor) {

         String baseUrl = System.getenv("SDK_TEST_BASE_URL");            //$NON-NLS-1$
         if (baseUrl != null) {
             if (baseUrl.length() <= 0 || !baseUrl.endsWith("/")) {      //$NON-NLS-1$
                 baseUrl = null;
             }
         }

         SparseArray<PlatformStatBase> platforms = new SparseArray<SdkStats.PlatformStatBase>();
         int maxApi = 0;

         Node root = getFirstChild(doc, nsUri, SdkStatsConstants.NODE_SDK_STATS);
         if (root != null) {
             for (Node child = root.getFirstChild();
                  child != null;
                  child = child.getNextSibling()) {
                 if (child.getNodeType() == Node.ELEMENT_NODE &&
                         nsUri.equals(child.getNamespaceURI()) &&
                         child.getLocalName().equals(SdkStatsConstants.NODE_PLATFORM)) {

                     try {
                         Node node = getFirstChild(child, nsUri, SdkStatsConstants.NODE_API_LEVEL);
                         int apiLevel = Integer.parseInt(node.getTextContent().trim());

                         if (apiLevel < 1) {
                             // bad API level, ignore it.
                             continue;
                         }

                         if (platforms.indexOfKey(apiLevel) >= 0) {
                             // if we already loaded that API, ignore duplicates
                             continue;
                         }

                         String codeName =
                             getFirstChild(child, nsUri, SdkStatsConstants.NODE_CODENAME).
                                 getTextContent().trim();
                         String versName =
                             getFirstChild(child, nsUri, SdkStatsConstants.NODE_VERSION).
                                 getTextContent().trim();

                         if (codeName == null || versName == null ||
                                 codeName.length() == 0 || versName.length() == 0) {
                             // bad names. ignore.
                             continue;
                         }

                         node = getFirstChild(child, nsUri, SdkStatsConstants.NODE_SHARE);
                         float percent = Float.parseFloat(node.getTextContent().trim());

                         if (percent < 0 || percent > 100) {
                             // invalid percentage. ignore.
                             continue;
                         }

                         PlatformStatBase p = new PlatformStatBase(
                                 apiLevel, versName, codeName, percent);
                         platforms.put(apiLevel, p);

                         maxApi = apiLevel > maxApi ? apiLevel : maxApi;

                     } catch (Exception ignore) {
                         // Error parsing this platform. Ignore it.
                         continue;
                     }
                 }
             }
         }

         mStats.clear();

         // Compute cumulative share percents & fill in final map
         for (int api = 1; api <= maxApi; api++) {
             PlatformStatBase p = platforms.get(api);
             if (p == null) {
                 continue;
             }

             float sum = p.getShare();
             for (int j = api + 1; j <= maxApi; j++) {
                 PlatformStatBase pj = platforms.get(j);
                 if (pj != null) {
                     sum += pj.getShare();
                 }
             }

             mStats.put(api, new PlatformStat(p, sum));
         }

         return mStats;
     }

     /**
      * Returns the first child element with the given XML local name.
      * If xmlLocalName is null, returns the very first child element.
      */
     private Node getFirstChild(Node node, String nsUri, String xmlLocalName) {

         for(Node child = node.getFirstChild(); child != null; child = child.getNextSibling()) {
             if (child.getNodeType() == Node.ELEMENT_NODE &&
                     nsUri.equals(child.getNamespaceURI())) {
                 if (xmlLocalName == null || child.getLocalName().equals(xmlLocalName)) {
                     return child;
                 }
             }
         }

         return null;
     }

 }
	/*
	* Copyright (C) 2012 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.sdklib.internal.repository;

	import com.android.annotations.VisibleForTesting;
	import com.android.annotations.VisibleForTesting.Visibility;
	import com.android.io.NonClosingInputStream;
	import com.android.io.NonClosingInputStream.CloseBehavior;
	import com.android.sdklib.repository.SdkStatsConstants;
	import com.android.utils.SparseArray;

	import org.w3c.dom.Document;
	import org.w3c.dom.NamedNodeMap;
	import org.w3c.dom.Node;
	import org.xml.sax.ErrorHandler;
	import org.xml.sax.InputSource;
	import org.xml.sax.SAXException;
	import org.xml.sax.SAXParseException;

	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.io.InputStream;
	import java.net.UnknownHostException;
	import java.util.regex.Matcher;
	import java.util.regex.Pattern;

	import javax.net.ssl.SSLKeyException;
	import javax.xml.XMLConstants;
	import javax.xml.parsers.DocumentBuilder;
	import javax.xml.parsers.DocumentBuilderFactory;
	import javax.xml.parsers.ParserConfigurationException;
	import javax.xml.transform.stream.StreamSource;
	import javax.xml.validation.Schema;
	import javax.xml.validation.SchemaFactory;
	import javax.xml.validation.Validator;


	/**
	* Retrieves stats on platforms.
	* <p/>
	* This returns information stored on the repository in a different XML file
	* and isn't directly tied to the existence of the listed platforms.
	*
	* @deprecated
	* com.android.sdklib.internal.repository has moved into Studio as
	* com.android.tools.idea.sdk.remote.internal.
	*/
	@Deprecated
	public class SdkStats {

	public static class PlatformStatBase {
	private final int mApiLevel;
	private final String mVersionName;
	private final String mCodeName;
	private final float mShare;

	public PlatformStatBase(int apiLevel,
	String versionName,
	String codeName,
	float share) {
	mApiLevel = apiLevel;
	mVersionName = versionName;
	mCodeName = codeName;
	mShare = share;
	}

	/** The Android API Level for the platform. An int > 0. */
	public int getApiLevel() {
	return mApiLevel;
	}

	/** The official codename for this platform, for example "Cupcake". */
	public String getCodeName() {
	return mCodeName;
	}

	/** The official version name of this platform, for example "Android 1.5". */
	public String getVersionName() {
	return mVersionName;
	}

	/** An approximate share percentage of this platform and all the
	* platforms of lower API level. */
	public float getShare() {
	return mShare;
	}

	/** Returns a string representation of this object, for debugging purposes. */
	@Override
	public String toString() {
	return String.format("api=%d, code=%s, vers=%s, share=%.1f%%", //$NON-NLS-1$
	mApiLevel, mCodeName, mVersionName, mShare);
	}
	}

	public static class PlatformStat extends PlatformStatBase {
	private final float mAccumShare;

	public PlatformStat(int apiLevel,
	String versionName,
	String codeName,
	float share,
	float accumShare) {
	super(apiLevel, versionName, codeName, share);
	mAccumShare = accumShare;
	}

	public PlatformStat(PlatformStatBase base, float accumShare) {
	super(base.getApiLevel(),
	base.getVersionName(),
	base.getCodeName(),
	base.getShare());
	mAccumShare = accumShare;
	}

	/** The accumulated approximate share percentage of that platform. */
	public float getAccumShare() {
	return mAccumShare;
	}

	/** Returns a string representation of this object, for debugging purposes. */
	@Override
	public String toString() {
	return String.format("<Stat %s, accum=%.1f%%>", super.toString(), mAccumShare);
	}
	}

	private final SparseArray<PlatformStat> mStats = new SparseArray<SdkStats.PlatformStat>();

	public SdkStats() {
	}

	public SparseArray<PlatformStat> getStats() {
	return mStats;
	}

	public void load(DownloadCache cache, boolean forceHttp, ITaskMonitor monitor) {

	String url = SdkStatsConstants.URL_STATS;

	if (forceHttp) {
	url = url.replaceAll("https://", "http://"); //$NON-NLS-1$ //$NON-NLS-2$
	}

	monitor.setProgressMax(5);
	monitor.setDescription("Fetching %1$s", url);
	monitor.incProgress(1);

	Exception[] exception = new Exception[] { null };
	Boolean[] validatorFound = new Boolean[] { Boolean.FALSE };
	String[] validationError = new String[] { null };
	Document validatedDoc = null;
	String validatedUri = null;

	InputStream xml = fetchXmlUrl(url, cache, monitor.createSubMonitor(1), exception);

	if (xml != null) {
	monitor.setDescription("Validate XML");

	// Explore the XML to find the potential XML schema version
	int version = getXmlSchemaVersion(xml);

	if (version >= 1 && version <= SdkStatsConstants.NS_LATEST_VERSION) {
	// This should be a version we can handle. Try to validate it
	// and report any error as invalid XML syntax,

	String uri = validateXml(xml, url, version, validationError, validatorFound);
	if (uri != null) {
	// Validation was successful
	validatedDoc = getDocument(xml, monitor);
	validatedUri = uri;

	}
	} else if (version > SdkStatsConstants.NS_LATEST_VERSION) {
	// The schema used is more recent than what is supported by this tool.
	// We don't have an upgrade-path support yet, so simply ignore the document.
	closeStream(xml);
	return;
	}
	}

	// If any exception was handled during the URL fetch, display it now.
	if (exception[0] != null) {
	String reason = null;
	if (exception[0] instanceof FileNotFoundException) {
	// FNF has no useful getMessage, so we need to special handle it.
	reason = "File not found";
	} else if (exception[0] instanceof UnknownHostException &&
	exception[0].getMessage() != null) {
	// This has no useful getMessage yet could really use one
	reason = String.format("Unknown Host %1$s", exception[0].getMessage());
	} else if (exception[0] instanceof SSLKeyException) {
	// That's a common error and we have a pref for it.
	reason = "HTTPS SSL error. You might want to force download through HTTP in the settings.";
	} else if (exception[0].getMessage() != null) {
	reason = exception[0].getMessage();
	} else {
	// We don't know what's wrong. Let's give the exception class at least.
	reason = String.format("Unknown (%1$s)", exception[0].getClass().getName());
	}

	monitor.logError("Failed to fetch URL %1$s, reason: %2$s", url, reason);
	}

	if (validationError[0] != null) {
	monitor.logError("%s", validationError[0]); //$NON-NLS-1$
	}

	// Stop here if we failed to validate the XML. We don't want to load it.
	if (validatedDoc == null) {
	closeStream(xml);
	return;
	}

	monitor.incProgress(1);

	if (xml != null) {
	monitor.setDescription("Parse XML");
	monitor.incProgress(1);
	parseStatsDocument(validatedDoc, validatedUri, monitor);
	}

	// done
	monitor.incProgress(1);
	closeStream(xml);
	}

	/**
	* Fetches the document at the given URL and returns it as a stream. Returns
	* null if anything wrong happens.
	*
	* @param urlString The URL to load, as a string.
	* @param monitor {@link ITaskMonitor} related to this URL.
	* @param outException If non null, where to store any exception that
	* happens during the fetch.
	* @see UrlOpener UrlOpener, which handles all URL logic.
	*/
	private InputStream fetchXmlUrl(String urlString,
	DownloadCache cache,
	ITaskMonitor monitor,
	Exception[] outException) {
	try {
	InputStream xml = cache.openCachedUrl(urlString, monitor);
	if (xml != null) {
	xml.mark(500000);
	xml = new NonClosingInputStream(xml);
	((NonClosingInputStream) xml).setCloseBehavior(CloseBehavior.RESET);
	}
	return xml;
	} catch (Exception e) {
	if (outException != null) {
	outException[0] = e;
	}
	}

	return null;
	}

	/**
	* Closes the stream, ignore any exception from InputStream.close().
	* If the stream is a NonClosingInputStream, sets it to CloseBehavior.CLOSE first.
	*/
	private void closeStream(InputStream is) {
	if (is != null) {
	if (is instanceof NonClosingInputStream) {
	((NonClosingInputStream) is).setCloseBehavior(CloseBehavior.CLOSE);
	}
	try {
	is.close();
	} catch (IOException ignore) {}
	}
	}

	/**
	* Manually parses the root element of the XML to extract the schema version
	* at the end of the xmlns:sdk="http://schemas.android.com/sdk/android/addons-list/$N"
	* declaration.
	*
	* @return 1..{@link SdkStatsConstants#NS_LATEST_VERSION} for a valid schema version
	* or 0 if no schema could be found.
	*/
	@VisibleForTesting(visibility=Visibility.PRIVATE)
	protected int getXmlSchemaVersion(InputStream xml) {
	if (xml == null) {
	return 0;
	}

	// Get an XML document
	Document doc = null;
	try {
	xml.reset();

	DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
	factory.setIgnoringComments(false);
	factory.setValidating(false);

	// Parse the old document using a non namespace aware builder
	factory.setNamespaceAware(false);
	DocumentBuilder builder = factory.newDocumentBuilder();

	// We don't want the default handler which prints errors to stderr.
	builder.setErrorHandler(new ErrorHandler() {
	@Override
	public void warning(SAXParseException e) throws SAXException {
	// pass
	}
	@Override
	public void fatalError(SAXParseException e) throws SAXException {
	throw e;
	}
	@Override
	public void error(SAXParseException e) throws SAXException {
	throw e;
	}
	});

	doc = builder.parse(xml);

	// Prepare a new document using a namespace aware builder
	factory.setNamespaceAware(true);
	builder = factory.newDocumentBuilder();

	} catch (Exception e) {
	// Failed to reset XML stream
	// Failed to get builder factor
	// Failed to create XML document builder
	// Failed to parse XML document
	// Failed to read XML document
	}

	if (doc == null) {
	return 0;
	}

	// Check the root element is an XML with at least the following properties:
	// <sdk:sdk-addons-list
	// xmlns:sdk="http://schemas.android.com/sdk/android/addons-list/$N">
	//
	// Note that we don't have namespace support enabled, we just do it manually.

	Pattern nsPattern = Pattern.compile(SdkStatsConstants.NS_PATTERN);

	String prefix = null;
	for (Node child = doc.getFirstChild(); child != null; child = child.getNextSibling()) {
	if (child.getNodeType() == Node.ELEMENT_NODE) {
	prefix = null;
	String name = child.getNodeName();
	int pos = name.indexOf(':');
	if (pos > 0 && pos < name.length() - 1) {
	prefix = name.substring(0, pos);
	name = name.substring(pos + 1);
	}
	if (SdkStatsConstants.NODE_SDK_STATS.equals(name)) {
	NamedNodeMap attrs = child.getAttributes();
	String xmlns = "xmlns"; //$NON-NLS-1$
	if (prefix != null) {
	xmlns += ":" + prefix; //$NON-NLS-1$
	}
	Node attr = attrs.getNamedItem(xmlns);
	if (attr != null) {
	String uri = attr.getNodeValue();
	if (uri != null) {
	Matcher m = nsPattern.matcher(uri);
	if (m.matches()) {
	String version = m.group(1);
	try {
	return Integer.parseInt(version);
	} catch (NumberFormatException e) {
	return 0;
	}
	}
	}
	}
	}
	}
	}

	return 0;
	}

	/**
	* Validates this XML against one of the requested SDK Repository schemas.
	* If the XML was correctly validated, returns the schema that worked.
	* If it doesn't validate, returns null and stores the error in outError[0].
	* If we can't find a validator, returns null and set validatorFound[0] to false.
	*/
	@VisibleForTesting(visibility=Visibility.PRIVATE)
	protected String validateXml(InputStream xml, String url, int version,
	String[] outError, Boolean[] validatorFound) {

	if (xml == null) {
	return null;
	}

	try {
	Validator validator = getValidator(version);

	if (validator == null) {
	validatorFound[0] = Boolean.FALSE;
	outError[0] = String.format(
	"XML verification failed for %1$s.\nNo suitable XML Schema Validator could be found in your Java environment. Please consider updating your version of Java.",
	url);
	return null;
	}

	validatorFound[0] = Boolean.TRUE;

	// Reset the stream if it supports that operation.
	xml.reset();

	// Validation throws a bunch of possible Exceptions on failure.
	validator.validate(new StreamSource(xml));
	return SdkStatsConstants.getSchemaUri(version);

	} catch (SAXParseException e) {
	outError[0] = String.format(
	"XML verification failed for %1$s.\nLine %2$d:%3$d, Error: %4$s",
	url,
	e.getLineNumber(),
	e.getColumnNumber(),
	e.toString());

	} catch (Exception e) {
	outError[0] = String.format(
	"XML verification failed for %1$s.\nError: %2$s",
	url,
	e.toString());
	}
	return null;
	}

	/**
	* Helper method that returns a validator for our XSD, or null if the current Java
	* implementation can't process XSD schemas.
	*
	* @param version The version of the XML Schema.
	* See {@link SdkStatsConstants#getXsdStream(int)}
	*/
	private Validator getValidator(int version) throws SAXException {
	InputStream xsdStream = SdkStatsConstants.getXsdStream(version);
	try {
	SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);

	if (factory == null) {
	return null;
	}

	// This may throw a SAX Exception if the schema itself is not a valid XSD
	Schema schema = factory.newSchema(new StreamSource(xsdStream));

	Validator validator = schema == null ? null : schema.newValidator();

	return validator;
	} finally {
	if (xsdStream != null) {
	try {
	xsdStream.close();
	} catch (IOException ignore) {}
	}
	}
	}

	/**
	* Takes an XML document as a string as parameter and returns a DOM for it.
	*
	* On error, returns null and prints a (hopefully) useful message on the monitor.
	*/
	@VisibleForTesting(visibility=Visibility.PRIVATE)
	protected Document getDocument(InputStream xml, ITaskMonitor monitor) {
	try {
	DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
	factory.setIgnoringComments(true);
	factory.setNamespaceAware(true);

	DocumentBuilder builder = factory.newDocumentBuilder();
	xml.reset();
	Document doc = builder.parse(new InputSource(xml));

	return doc;
	} catch (ParserConfigurationException e) {
	monitor.logError("Failed to create XML document builder");

	} catch (SAXException e) {
	monitor.logError("Failed to parse XML document");

	} catch (IOException e) {
	monitor.logError("Failed to read XML document");
	}

	return null;
	}

	/**
	* Parses all valid platforms found in the XML.
	* Changes the stats array returned by {@link #getStats()}
	* (also returns the value directly, useful for unit tests.)
	*/
	@VisibleForTesting(visibility=Visibility.PRIVATE)
	protected SparseArray<PlatformStat> parseStatsDocument(
	Document doc,
	String nsUri,
	ITaskMonitor monitor) {

	String baseUrl = System.getenv("SDK_TEST_BASE_URL"); //$NON-NLS-1$
	if (baseUrl != null) {
	if (baseUrl.length() <= 0 \|\| !baseUrl.endsWith("/")) { //$NON-NLS-1$
	baseUrl = null;
	}
	}

	SparseArray<PlatformStatBase> platforms = new SparseArray<SdkStats.PlatformStatBase>();
	int maxApi = 0;

	Node root = getFirstChild(doc, nsUri, SdkStatsConstants.NODE_SDK_STATS);
	if (root != null) {
	for (Node child = root.getFirstChild();
	child != null;
	child = child.getNextSibling()) {
	if (child.getNodeType() == Node.ELEMENT_NODE &&
	nsUri.equals(child.getNamespaceURI()) &&
	child.getLocalName().equals(SdkStatsConstants.NODE_PLATFORM)) {

	try {
	Node node = getFirstChild(child, nsUri, SdkStatsConstants.NODE_API_LEVEL);
	int apiLevel = Integer.parseInt(node.getTextContent().trim());

	if (apiLevel < 1) {
	// bad API level, ignore it.
	continue;
	}

	if (platforms.indexOfKey(apiLevel) >= 0) {
	// if we already loaded that API, ignore duplicates
	continue;
	}

	String codeName =
	getFirstChild(child, nsUri, SdkStatsConstants.NODE_CODENAME).
	getTextContent().trim();
	String versName =
	getFirstChild(child, nsUri, SdkStatsConstants.NODE_VERSION).
	getTextContent().trim();

	if (codeName == null \|\| versName == null \|\|
	codeName.length() == 0 \|\| versName.length() == 0) {
	// bad names. ignore.
	continue;
	}

	node = getFirstChild(child, nsUri, SdkStatsConstants.NODE_SHARE);
	float percent = Float.parseFloat(node.getTextContent().trim());

	if (percent < 0 \|\| percent > 100) {
	// invalid percentage. ignore.
	continue;
	}

	PlatformStatBase p = new PlatformStatBase(
	apiLevel, versName, codeName, percent);
	platforms.put(apiLevel, p);

	maxApi = apiLevel > maxApi ? apiLevel : maxApi;

	} catch (Exception ignore) {
	// Error parsing this platform. Ignore it.
	continue;
	}
	}
	}
	}

	mStats.clear();

	// Compute cumulative share percents & fill in final map
	for (int api = 1; api <= maxApi; api++) {
	PlatformStatBase p = platforms.get(api);
	if (p == null) {
	continue;
	}

	float sum = p.getShare();
	for (int j = api + 1; j <= maxApi; j++) {
	PlatformStatBase pj = platforms.get(j);
	if (pj != null) {
	sum += pj.getShare();
	}
	}

	mStats.put(api, new PlatformStat(p, sum));
	}

	return mStats;
	}

	/**
	* Returns the first child element with the given XML local name.
	* If xmlLocalName is null, returns the very first child element.
	*/
	private Node getFirstChild(Node node, String nsUri, String xmlLocalName) {

	for(Node child = node.getFirstChild(); child != null; child = child.getNextSibling()) {
	if (child.getNodeType() == Node.ELEMENT_NODE &&
	nsUri.equals(child.getNamespaceURI())) {
	if (xmlLocalName == null \|\| child.getLocalName().equals(xmlLocalName)) {
	return child;
	}
	}
	}

	return null;
	}

	}