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/*
* Copyright (C) 2009 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 android.app.backup;
import android.annotation.UnsupportedAppUsage;
import android.os.ParcelFileDescriptor;
import android.util.Log;
import java.io.FileDescriptor;
import java.io.IOException;
import java.util.Map;
import java.util.TreeMap;
/** @hide */
public class BackupHelperDispatcher {
private static final String TAG = "BackupHelperDispatcher";
private static class Header {
@UnsupportedAppUsage
int chunkSize; // not including the header
@UnsupportedAppUsage
String keyPrefix;
}
TreeMap<String,BackupHelper> mHelpers = new TreeMap<String,BackupHelper>();
public BackupHelperDispatcher() {
}
public void addHelper(String keyPrefix, BackupHelper helper) {
mHelpers.put(keyPrefix, helper);
}
public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
ParcelFileDescriptor newState) throws IOException {
// First, do the helpers that we've already done, since they're already in the state
// file.
int err;
Header header = new Header();
TreeMap<String,BackupHelper> helpers = (TreeMap<String,BackupHelper>)mHelpers.clone();
FileDescriptor oldStateFD = null;
if (oldState != null) {
oldStateFD = oldState.getFileDescriptor();
while ((err = readHeader_native(header, oldStateFD)) >= 0) {
if (err == 0) {
BackupHelper helper = helpers.get(header.keyPrefix);
Log.d(TAG, "handling existing helper '" + header.keyPrefix + "' " + helper);
if (helper != null) {
doOneBackup(oldState, data, newState, header, helper);
helpers.remove(header.keyPrefix);
} else {
skipChunk_native(oldStateFD, header.chunkSize);
}
}
}
}
// Then go through and do the rest that we haven't done.
for (Map.Entry<String,BackupHelper> entry: helpers.entrySet()) {
header.keyPrefix = entry.getKey();
Log.d(TAG, "handling new helper '" + header.keyPrefix + "'");
BackupHelper helper = entry.getValue();
doOneBackup(oldState, data, newState, header, helper);
}
}
private void doOneBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
ParcelFileDescriptor newState, Header header, BackupHelper helper)
throws IOException {
int err;
FileDescriptor newStateFD = newState.getFileDescriptor();
// allocate space for the header in the file
int pos = allocateHeader_native(header, newStateFD);
if (pos < 0) {
throw new IOException("allocateHeader_native failed (error " + pos + ")");
}
data.setKeyPrefix(header.keyPrefix);
// do the backup
helper.performBackup(oldState, data, newState);
// fill in the header (seeking back to pos). The file pointer will be returned to
// where it was at the end of performBackup. Header.chunkSize will not be filled in.
err = writeHeader_native(header, newStateFD, pos);
if (err != 0) {
throw new IOException("writeHeader_native failed (error " + err + ")");
}
}
public void performRestore(BackupDataInput input, int appVersionCode,
ParcelFileDescriptor newState)
throws IOException {
boolean alreadyComplained = false;
BackupDataInputStream stream = new BackupDataInputStream(input);
while (input.readNextHeader()) {
String rawKey = input.getKey();
int pos = rawKey.indexOf(':');
if (pos > 0) {
String prefix = rawKey.substring(0, pos);
BackupHelper helper = mHelpers.get(prefix);
if (helper != null) {
stream.dataSize = input.getDataSize();
stream.key = rawKey.substring(pos+1);
helper.restoreEntity(stream);
} else {
if (!alreadyComplained) {
Log.w(TAG, "Couldn't find helper for: '" + rawKey + "'");
alreadyComplained = true;
}
}
} else {
if (!alreadyComplained) {
Log.w(TAG, "Entity with no prefix: '" + rawKey + "'");
alreadyComplained = true;
}
}
input.skipEntityData(); // In case they didn't consume the data.
}
// Write out the state files -- mHelpers is a TreeMap, so the order is well defined.
for (BackupHelper helper: mHelpers.values()) {
helper.writeNewStateDescription(newState);
}
}
private static native int readHeader_native(Header h, FileDescriptor fd);
private static native int skipChunk_native(FileDescriptor fd, int bytesToSkip);
private static native int allocateHeader_native(Header h, FileDescriptor fd);
private static native int writeHeader_native(Header h, FileDescriptor fd, int pos);
}
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