/*
* Copyright (C) 2014 Dominik Schürmann <dominik@dominikschuermann.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.util;
import android.content.Context;
import android.os.Parcel;
import android.os.Parcelable;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.KeychainApplication;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Iterator;
/**
* When sending large data (over 1MB) through Androids Binder IPC you get
* JavaBinder E !!! FAILED BINDER TRANSACTION !!!
* <p/>
* To overcome this problem, we cache large Parcelables into a file in our private cache directory
* instead of sending them through IPC.
*/
public class ParcelableFileCache<E extends Parcelable> {
private Context mContext;
private final String mFilename;
public ParcelableFileCache(Context context, String filename) {
mContext = context;
mFilename = filename;
}
public void writeCache(IteratorWithSize<E> it) throws IOException {
writeCache(it.getSize(), it);
}
public void writeCache(int numEntries, Iterator<E> it) throws IOException {
File cacheDir = mContext.getCacheDir();
if (cacheDir == null) {
// https://groups.google.com/forum/#!topic/android-developers/-694j87eXVU
throw new IOException("cache dir is null!");
}
File tempFile = new File(mContext.getCacheDir(), mFilename);
DataOutputStream oos = new DataOutputStream(new FileOutputStream(tempFile));
try {
oos.writeInt(numEntries);
while (it.hasNext()) {
Parcel p = Parcel.obtain(); // creating empty parcel object
p.writeParcelable(it.next(), 0); // saving bundle as parcel
byte[] buf = p.marshall();
oos.writeInt(buf.length);
oos.write(buf);
p.recycle();
}
} finally {
oos.close();
}
}
/**
* Reads from cache file and deletes it afterward. Convenience function for readCache(boolean).
* @return an IteratorWithSize object containing entries read from the cache file
* @throws IOException
*/
public IteratorWithSize<E> readCache() throws IOException {
return readCache(true);
}
/**
* Reads entries from a cache file and returns an IteratorWithSize object containing the entries
* @param deleteAfterRead if true, the cache file will be deleted after being read
* @return an IteratorWithSize object containing entries read from the cache file
* @throws IOException if cache directory/parcel import file does not exist, or a read error
* occurs
*/
public IteratorWithSize<E> readCache(final boolean deleteAfterRead) throws IOException {
File cacheDir = mContext.getCacheDir();
if (cacheDir == null) {
// https://groups.google.com/forum/#!topic/android-developers/-694j87eXVU
throw new IOException("cache dir is null!");
}
final File tempFile = new File(cacheDir, mFilename);
final DataInputStream ois;
try {
ois = new DataInputStream(new FileInputStream(tempFile));
} catch (FileNotFoundException e) {
Log.e(Constants.TAG, "parcel import file not existing", e);
throw new IOException(e);
}
final int numEntries = ois.readInt();
return new IteratorWithSize<E>() {
E mRing = null;
boolean closed = false;
byte[] buf = new byte[512];
public int getSize() {
return numEntries;
}
private void readNext() {
if (mRing != null || closed) {
return;
}
try {
int length = ois.readInt();
while (buf.length < length) {
buf = new byte[buf.length * 2];
}
ois.readFully(buf, 0, length);
Parcel parcel = Parcel.obtain(); // creating empty parcel object
parcel.unmarshall(buf, 0, length);
parcel.setDataPosition(0);
mRing = parcel.readParcelable(KeychainApplication.class.getClassLoader());
parcel.recycle();
} catch (EOFException e) {
// aight
close();
} catch (IOException e) {
Log.e(Constants.TAG, "Encountered IOException during cache read!", e);
}
}
@Override
public boolean hasNext() {
readNext();
return mRing != null;
}
@Override
public E next() {
readNext();
try {
return mRing;
} finally {
mRing = null;
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public void finalize() throws Throwable {
close();
super.finalize();
}
private void close() {
if (!closed) {
try {
ois.close();
if (deleteAfterRead) {
//noinspection ResultOfMethodCallIgnored
tempFile.delete();
}
} catch (IOException e) {
// nvm
}
}
closed = true;
}
};
}
public boolean delete() throws IOException {
File cacheDir = mContext.getCacheDir();
if (cacheDir == null) {
// https://groups.google.com/forum/#!topic/android-developers/-694j87eXVU
throw new IOException("cache dir is null!");
}
final File tempFile = new File(cacheDir, mFilename);
return tempFile.delete();
}
/** As the name implies, this is an extended iterator interface, which
* knows the total number of its entries beforehand.
*/
public static interface IteratorWithSize<E> extends Iterator<E> {
/** Returns the number of total entries in this iterator. */
int getSize();
}
}