blob: b59670e849f43379c0ce974cfcc7021e05a90888 [file] [log] [blame]
/*
* 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.google.dexmaker;
import java.io.File;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
/**
* Uses heuristics to guess the application's private data directory.
*/
class AppDataDirGuesser {
public File guess() {
try {
ClassLoader classLoader = guessSuitableClassLoader();
// Check that we have an instance of the PathClassLoader.
Class<?> clazz = Class.forName("dalvik.system.PathClassLoader");
clazz.cast(classLoader);
// Use the toString() method to calculate the data directory.
String pathFromThisClassLoader = getPathFromThisClassLoader(classLoader, clazz);
File[] results = guessPath(pathFromThisClassLoader);
if (results.length > 0) {
return results[0];
}
} catch (ClassCastException ignored) {
} catch (ClassNotFoundException ignored) {
}
return null;
}
private ClassLoader guessSuitableClassLoader() {
return AppDataDirGuesser.class.getClassLoader();
}
private String getPathFromThisClassLoader(ClassLoader classLoader,
Class<?> pathClassLoaderClass) {
// Prior to ICS, we can simply read the "path" field of the
// PathClassLoader.
try {
Field pathField = pathClassLoaderClass.getDeclaredField("path");
pathField.setAccessible(true);
return (String) pathField.get(classLoader);
} catch (NoSuchFieldException ignored) {
} catch (IllegalAccessException ignored) {
} catch (ClassCastException ignored) {
}
// Parsing toString() method: yuck. But no other way to get the path.
// Strip out the bit between angle brackets, that's our path.
String result = classLoader.toString();
int index = result.lastIndexOf('[');
result = (index == -1) ? result : result.substring(index + 1);
index = result.indexOf(']');
return (index == -1) ? result : result.substring(0, index);
}
File[] guessPath(String input) {
List<File> results = new ArrayList<File>();
// Post JB, the system property is set to the applications private data cache
// directory.
File tmpDir = new File(System.getProperty("java.io.tmpdir"));
if (isWriteableDirectory(tmpDir)) {
results.add(tmpDir);
}
for (String potential : input.split(":")) {
if (!potential.startsWith("/data/app/")) {
continue;
}
int start = "/data/app/".length();
int end = potential.lastIndexOf(".apk");
if (end != potential.length() - 4) {
continue;
}
int dash = potential.indexOf("-");
if (dash != -1) {
end = dash;
}
String packageName = potential.substring(start, end);
File dataDir = new File("/data/data/" + packageName);
if (isWriteableDirectory(dataDir)) {
File cacheDir = new File(dataDir, "cache");
// The cache directory might not exist -- create if necessary
if (fileOrDirExists(cacheDir) || cacheDir.mkdir()) {
if (isWriteableDirectory(cacheDir)) {
results.add(cacheDir);
}
}
}
}
return results.toArray(new File[results.size()]);
}
boolean fileOrDirExists(File file) {
return file.exists();
}
boolean isWriteableDirectory(File file) {
return file.isDirectory() && file.canWrite();
}
}