search for a valid journal
there are too many bytes, so we need to find the valid subset,
without stepping past the end!
Bug: 12489602
Change-Id: Ic9d7c804c199740ff50d0864f99632ae68619369
diff --git a/src/com/android/launcher3/LauncherBackupHelper.java b/src/com/android/launcher3/LauncherBackupHelper.java
index 556d4af..7268b08 100644
--- a/src/com/android/launcher3/LauncherBackupHelper.java
+++ b/src/com/android/launcher3/LauncherBackupHelper.java
@@ -858,7 +858,7 @@
* in that case, do a full backup.
*
* @param oldState the read-0only file descriptor pointing to the old journal
- * @return a Journal protocol bugffer
+ * @return a Journal protocol buffer
*/
private Journal readJournal(ParcelFileDescriptor oldState) {
Journal journal = new Journal();
@@ -867,38 +867,50 @@
}
FileInputStream inStream = new FileInputStream(oldState.getFileDescriptor());
try {
- int remaining = inStream.available();
- if (DEBUG) Log.d(TAG, "available " + remaining);
- if (remaining < MAX_JOURNAL_SIZE) {
- byte[] buffer = new byte[remaining];
+ int availableBytes = inStream.available();
+ if (DEBUG) Log.d(TAG, "available " + availableBytes);
+ if (availableBytes < MAX_JOURNAL_SIZE) {
+ byte[] buffer = new byte[availableBytes];
int bytesRead = 0;
- while (remaining > 0) {
+ boolean valid = false;
+ while (availableBytes > 0) {
try {
- int result = inStream.read(buffer, bytesRead, remaining);
+ // OMG what are you doing? This is crazy inefficient!
+ // If we read a byte that is not ours, we will cause trouble: b/12491813
+ // However, we don't know how many bytes to expect (oops).
+ // So we have to step through *slowly*, watching for the end.
+ int result = inStream.read(buffer, bytesRead, 1);
if (result > 0) {
- if (DEBUG) Log.d(TAG, "read some bytes: " + result);
- remaining -= result;
+ availableBytes -= result;
bytesRead += result;
+ if (DEBUG && (bytesRead % 100 == 0)) {
+ Log.d(TAG, "read some bytes: " + bytesRead);
+ }
} else {
- // stop reading ands see what there is to parse
- Log.w(TAG, "read error: " + result);
- remaining = 0;
+ Log.w(TAG, "unexpected end of file while reading journal.");
+ // stop reading and see what there is to parse
+ availableBytes = 0;
}
} catch (IOException e) {
- Log.w(TAG, "failed to read the journal", e);
+ Log.e(TAG, "failed to read the journal", e);
buffer = null;
- remaining = 0;
+ availableBytes = 0;
+ }
+
+ // check the buffer to see if we have a valid journal
+ try {
+ MessageNano.mergeFrom(journal, readCheckedBytes(buffer, 0, bytesRead));
+ // if we are here, then we have read a valid, checksum-verified journal
+ valid = true;
+ availableBytes = 0;
+ } catch (InvalidProtocolBufferNanoException e) {
+ // if we don't have the whole journal yet, mergeFrom will throw. keep going.
+ journal.clear();
}
}
if (DEBUG) Log.d(TAG, "journal bytes read: " + bytesRead);
-
- if (buffer != null) {
- try {
- MessageNano.mergeFrom(journal, readCheckedBytes(buffer, 0, bytesRead));
- } catch (InvalidProtocolBufferNanoException e) {
- Log.d(TAG, "failed to read the journal", e);
- journal.clear();
- }
+ if (!valid) {
+ Log.w(TAG, "failed to read the journal: could not find a valid journal");
}
}
} catch (IOException e) {
@@ -968,7 +980,9 @@
FileOutputStream outStream = null;
try {
outStream = new FileOutputStream(newState.getFileDescriptor());
- outStream.write(writeCheckedBytes(journal));
+ final byte[] journalBytes = writeCheckedBytes(journal);
+ if (DEBUG) Log.d(TAG, "writing " + journalBytes.length + " bytes of journal");
+ outStream.write(journalBytes);
outStream.close();
} catch (IOException e) {
Log.d(TAG, "failed to write backup journal", e);