com.android.tools.lint.client.api.JarFileIssueRegistry Maven / Gradle / Ivy
/*
* Copyright (C) 2013 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.tools.lint.client.api;
import static com.android.SdkConstants.DOT_CLASS;
import com.android.annotations.NonNull;
import com.android.tools.lint.detector.api.Issue;
import com.android.tools.lint.detector.api.Severity;
import com.android.utils.SdkUtils;
import com.google.common.collect.Lists;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.JarInputStream;
import java.util.jar.Manifest;
import java.util.zip.ZipEntry;
/**
* An {@link IssueRegistry} for a custom lint rule jar file. The rule jar should provide a
* manifest entry with the key {@code Lint-Registry} and the value of the fully qualified name of an
* implementation of {@link IssueRegistry} (with a default constructor).
*
* NOTE: The custom issue registry should not extend this file; it should be a plain
* IssueRegistry! This file is used internally to wrap the given issue registry.
*/
class JarFileIssueRegistry extends IssueRegistry {
/**
* Manifest constant for declaring an issue provider. Example: Lint-Registry:
* foo.bar.CustomIssueRegistry
*/
private static final String MF_LINT_REGISTRY = "Lint-Registry"; //$NON-NLS-1$
private static Map> sCache;
private final List myIssues;
@NonNull
static IssueRegistry get(@NonNull LintClient client, @NonNull File jarFile) throws IOException,
ClassNotFoundException, IllegalAccessException, InstantiationException {
if (sCache == null) {
sCache = new HashMap>();
} else {
SoftReference reference = sCache.get(jarFile);
if (reference != null) {
JarFileIssueRegistry registry = reference.get();
if (registry != null) {
return registry;
}
}
}
// Ensure that the scope-to-detector map doesn't return stale results
IssueRegistry.reset();
JarFileIssueRegistry registry = new JarFileIssueRegistry(client, jarFile);
sCache.put(jarFile, new SoftReference(registry));
return registry;
}
private JarFileIssueRegistry(@NonNull LintClient client, @NonNull File file)
throws IOException, ClassNotFoundException, IllegalAccessException,
InstantiationException {
myIssues = Lists.newArrayList();
JarFile jarFile = null;
try {
//noinspection IOResourceOpenedButNotSafelyClosed
jarFile = new JarFile(file);
Manifest manifest = jarFile.getManifest();
Attributes attrs = manifest.getMainAttributes();
Object object = attrs.get(new Attributes.Name(MF_LINT_REGISTRY));
if (object instanceof String) {
String className = (String) object;
// Make a class loader for this jar
URL url = SdkUtils.fileToUrl(file);
ClassLoader loader = client.createUrlClassLoader(new URL[]{url},
JarFileIssueRegistry.class.getClassLoader());
Class registryClass = Class.forName(className, true, loader);
IssueRegistry registry = (IssueRegistry) registryClass.newInstance();
myIssues.addAll(registry.getIssues());
if (loader instanceof URLClassLoader) {
loadAndCloseURLClassLoader(client, file, (URLClassLoader)loader);
}
} else {
client.log(Severity.ERROR, null,
"Custom lint rule jar %1$s does not contain a valid registry manifest key " +
"(%2$s).\n" +
"Either the custom jar is invalid, or it uses an outdated API not supported " +
"this lint client", file.getPath(), MF_LINT_REGISTRY);
}
} finally {
if (jarFile != null) {
jarFile.close();
}
}
}
/**
* Work around http://bugs.java.com/bugdatabase/view_bug.do?bug_id=5041014 :
* URLClassLoader, on Windows, locks the .jar file forever.
* As of Java 7, there's a workaround: you can call close() when you're "done"
* with the file. We'll do that here. However, the whole point of the
* {@linkplain JarFileIssueRegistry} is that when lint is run over and over again
* as the user is editing in the IDE and we're background checking the code, we
* don't to keep loading the custom view classes over and over again: we want to
* cache them. Therefore, just closing the URLClassLoader right away isn't great
* either. However, it turns out it's safe to close the URLClassLoader once you've
* loaded the classes you need, since the URLClassLoader will continue to serve
* those classes even after its close() methods has been called.
*
* Therefore, if we can call close() on this URLClassLoader, we'll proactively load
* all class files we find in the .jar file, then close it.
*
* @param client the client to report errors to
* @param file the .jar file
* @param loader the URLClassLoader we should close
*/
private static void loadAndCloseURLClassLoader(
@NonNull LintClient client,
@NonNull File file,
@NonNull URLClassLoader loader) {
try {
// Proactively close out the .jar file. This is only available on Java 7.
Method closeMethod = loader.getClass().getDeclaredMethod("close");
// But first, proactively load all classes:
try {
InputStream inputStream = new FileInputStream(file);
try {
JarInputStream jarInputStream = new JarInputStream(inputStream);
try {
ZipEntry entry = jarInputStream.getNextEntry();
while (entry != null) {
String name = entry.getName();
// Load non-inner-classes
if (name.endsWith(DOT_CLASS) && name.indexOf('$') == -1) {
// Strip .class suffix and change .jar file path (/)
// to class name (.'s).
name = name.substring(0,
name.length() - DOT_CLASS.length());
name = name.replace('/', '.');
try {
Class.forName(name, true, loader);
} catch (Throwable e) {
client.log(Severity.ERROR, e,
"Failed to prefetch " + name + " from " + file);
}
}
entry = jarInputStream.getNextEntry();
}
} finally {
jarInputStream.close();
}
} finally {
inputStream.close();
}
} catch (Throwable ignore) {
} finally {
// Finally close the URL class loader
try {
closeMethod.invoke(loader);
} catch (Throwable ignore) {
// Couldn't close. This is unlikely.
}
}
} catch (NoSuchMethodException ignore) {
// No close method - we're on 1.6
}
}
@NonNull
@Override
public List getIssues() {
return myIssues;
}
}