/*
* Copyright (C) 2010 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.sdklib.repository.SdkAddonsListConstants;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import java.io.ByteArrayInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
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;
/**
* Fetches and loads an sdk-addons-list XML.
* <p/>
* Such an XML contains a simple list of add-ons site that are to be loaded by default by the
* SDK Manager. <br/>
* The XML must conform to the sdk-addons-list-N.xsd. <br/>
* Constants used in the XML are defined in {@link SdkAddonsListConstants}.
*/
public class AddonsListFetcher {
/**
* An immutable structure representing an add-on site.
*/
public static class Site {
private final String mUrl;
private final String mUiName;
private Site(String url, String uiName) {
mUrl = url.trim();
mUiName = uiName;
}
public String getUrl() {
return mUrl;
}
public String getUiName() {
return mUiName;
}
}
/**
* Fetches the addons list from the given URL.
*
* @param monitor A monitor to report errors. Cannot be null.
* @param url The URL of an XML file resource that conforms to the latest sdk-addons-list-N.xsd.
* For the default operation, use {@link SdkAddonsListConstants#URL_ADDON_LIST}.
* Cannot be null.
* @return An array of {@link Site} on success (possibly empty), or null on error.
*/
public Site[] fetch(ITaskMonitor monitor, String url) {
url = url == null ? "" : url.trim();
monitor.setProgressMax(4);
monitor.setDescription("Fetching %1$s", url);
monitor.incProgress(1);
Exception[] exception = new Exception[] { null };
Boolean[] validatorFound = new Boolean[] { Boolean.FALSE };
String[] validationError = new String[] { null };
Document validatedDoc = null;
String validatedUri = null;
ByteArrayInputStream xml = fetchUrl(url, exception);
if (xml != null) {
monitor.setDescription("Validate XML");
// Explore the XML to find the potential XML schema version
int version = getXmlSchemaVersion(xml);
if (version >= 1 && version <= SdkAddonsListConstants.NS_LATEST_VERSION) {
// This should be a version we can handle. Try to validate it
// and report any error as invalid XML syntax,
String uri = validateXml(xml, url, version, validationError, validatorFound);
if (uri != null) {
// Validation was successful
validatedDoc = getDocument(xml, monitor);
validatedUri = uri;
}
} else if (version > SdkAddonsListConstants.NS_LATEST_VERSION) {
// The schema used is more recent than what is supported by this tool.
// We don't have an upgrade-path support yet, so simply ignore the document.
return null;
}
}
// If any exception was handled during the URL fetch, display it now.
if (exception[0] != null) {
String reason = null;
if (exception[0] instanceof FileNotFoundException) {
// FNF has no useful getMessage, so we need to special handle it.
reason = "File not found";
} else if (exception[0] instanceof SSLKeyException) {
// That's a common error and we have a pref for it.
reason = "HTTPS SSL error. You might want to force download through HTTP in the settings.";
} else if (exception[0].getMessage() != null) {
reason = exception[0].getMessage();
} else {
// We don't know what's wrong. Let's give the exception class at least.
reason = String.format("Unknown (%1$s)", exception[0].getClass().getName());
}
monitor.setResult("Failed to fetch URL %1$s, reason: %2$s", url, reason);
}
if (validationError[0] != null) {
monitor.setResult("%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) {
return null;
}
monitor.incProgress(1);
Site[] result = null;
if (xml != null) {
monitor.setDescription("Parse XML");
monitor.incProgress(1);
result = parseAddonsList(validatedDoc, validatedUri, monitor);
}
// done
monitor.incProgress(1);
return result;
}
/**
* Fetches the document at the given URL and returns it as a stream.
* Returns null if anything wrong happens.
*
* References: <br/>
* Java URL Connection: http://java.sun.com/docs/books/tutorial/networking/urls/readingWriting.html <br/>
* Java URL Reader: http://java.sun.com/docs/books/tutorial/networking/urls/readingURL.html <br/>
* Java set Proxy: http://java.sun.com/docs/books/tutorial/networking/urls/_setProxy.html <br/>
*
* @param urlString The URL to load, as a string.
* @param outException If non null, where to store any exception that happens during the fetch.
*/
private ByteArrayInputStream fetchUrl(String urlString, Exception[] outException) {
URL url;
try {
url = new URL(urlString);
InputStream is = null;
int inc = 65536;
int curr = 0;
byte[] result = new byte[inc];
try {
is = url.openStream();
int n;
while ((n = is.read(result, curr, result.length - curr)) != -1) {
curr += n;
if (curr == result.length) {
byte[] temp = new byte[curr + inc];
System.arraycopy(result, 0, temp, 0, curr);
result = temp;
}
}
return new ByteArrayInputStream(result, 0, curr);
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
// pass
}
}
}
} catch (Exception e) {
if (outException != null) {
outException[0] = e;
}
}
return null;
}
/**
* 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/$N"
* declaration.
*
* @return 1..{@link SdkAddonsListConstants#NS_LATEST_VERSION} for a valid schema version
* or 0 if no schema could be found.
*/
@VisibleForTesting(visibility=Visibility.PRIVATE)
protected int getXmlSchemaVersion(InputStream xml) {
if (xml == null) {
return 0;
}
// Get an XML document
Document doc = null;
try {
xml.reset();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setIgnoringComments(false);
factory.setValidating(false);
// Parse the old document using a non namespace aware builder
factory.setNamespaceAware(false);
DocumentBuilder builder = factory.newDocumentBuilder();
doc = builder.parse(xml);
// Prepare a new document using a namespace aware builder
factory.setNamespaceAware(true);
builder = factory.newDocumentBuilder();
} catch (Exception e) {
// Failed to reset XML stream
// Failed to get builder factor
// Failed to create XML document builder
// Failed to parse XML document
// Failed to read XML document
}
if (doc == null) {
return 0;
}
// Check the root element is an XML with at least the following properties:
// <sdk:sdk-addons-list
// xmlns:sdk="http://schemas.android.com/sdk/android/addons-list/$N">
//
// Note that we don't have namespace support enabled, we just do it manually.
Pattern nsPattern = Pattern.compile(SdkAddonsListConstants.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 (SdkAddonsListConstants.NODE_SDK_ADDONS_LIST.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$s.\nNo suitable XML Schema Validator could be found in your Java environment. Please consider updating your version of Java.",
url);
return null;
}
validatorFound[0] = Boolean.TRUE;
// Reset the stream if it supports that operation.
xml.reset();
// Validation throws a bunch of possible Exceptions on failure.
validator.validate(new StreamSource(xml));
return SdkAddonsListConstants.getSchemaUri(version);
} catch (SAXParseException e) {
outError[0] = String.format(
"XML verification failed for %1$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 SdkAddonsListConstants#getXsdStream(int)}
*/
private Validator getValidator(int version) throws SAXException {
InputStream xsdStream = SdkAddonsListConstants.getXsdStream(version);
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;
}
/**
* 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.setResult("Failed to create XML document builder");
} catch (SAXException e) {
monitor.setResult("Failed to parse XML document");
} catch (IOException e) {
monitor.setResult("Failed to read XML document");
}
return null;
}
/**
* Parse all sites defined in the Addaons list XML and returns an array of sites.
*/
@VisibleForTesting(visibility=Visibility.PRIVATE)
protected Site[] parseAddonsList(Document doc, String nsUri, ITaskMonitor monitor) {
Node root = getFirstChild(doc, nsUri, SdkAddonsListConstants.NODE_SDK_ADDONS_LIST);
if (root != null) {
ArrayList<Site> sites = new ArrayList<Site>();
for (Node child = root.getFirstChild();
child != null;
child = child.getNextSibling()) {
if (child.getNodeType() == Node.ELEMENT_NODE &&
nsUri.equals(child.getNamespaceURI()) &&
child.getLocalName().equals(SdkAddonsListConstants.NODE_ADDON_SITE)) {
Node url = getFirstChild(child, nsUri, SdkAddonsListConstants.NODE_URL);
Node name = getFirstChild(child, nsUri, SdkAddonsListConstants.NODE_NAME);
if (name != null && url != null) {
String strUrl = url.getTextContent().trim();
String strName = name.getTextContent().trim();
if (strUrl.length() > 0 && strName.length() > 0) {
sites.add(new Site(strUrl, strName));
}
}
}
}
return sites.toArray(new Site[sites.size()]);
}
return null;
}
/**
* 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;
}
}