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Merge "Check the magic number of a decoded file"

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Jean Chalard 2011-08-30 22:58:29 -07:00 committed by Android (Google) Code Review
parent b8dc674663 7a408431fe
commit fcee70ea92
1 changed files with 36 additions and 6 deletions
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42
java/src/com/android/inputmethod/latin/BinaryDictionaryFileDumper.java
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@ -25,12 +25,15 @@ import android.net.Uri;
import android.text.TextUtils;
import android.util.Log;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
@ -46,7 +49,9 @@ public class BinaryDictionaryFileDumper {
/**
* The size of the temporary buffer to copy files.
*/
static final int FILE_READ_BUFFER_SIZE = 1024;
private static final int FILE_READ_BUFFER_SIZE = 1024;
// TODO: make the following data common with the native code
private static final byte[] MAGIC_NUMBER = new byte[] { 0x78, (byte)0xB1 };
private static final String DICTIONARY_PROJECTION[] = { "id" };
@ -135,6 +140,7 @@ public class BinaryDictionaryFileDumper {
for (int mode = MODE_MIN; mode <= MODE_MAX; ++mode) {
InputStream originalSourceStream = null;
InputStream inputStream = null;
File outputFile = null;
FileOutputStream outputStream = null;
AssetFileDescriptor afd = null;
try {
@ -144,7 +150,8 @@ public class BinaryDictionaryFileDumper {
if (null == afd) return null;
originalSourceStream = afd.createInputStream();
// Open output.
outputStream = new FileOutputStream(outputFileName);
outputFile = new File(outputFileName);
outputStream = new FileOutputStream(outputFile);
// Get the appropriate decryption method for this try
switch (mode) {
case COMPRESSED_CRYPTED_COMPRESSED:
@ -171,7 +178,7 @@ public class BinaryDictionaryFileDumper {
inputStream = originalSourceStream;
break;
}
copyFileTo(inputStream, outputStream);
checkMagicAndCopyFileTo(new BufferedInputStream(inputStream), outputStream);
if (0 >= resolver.delete(wordListUri, null, null)) {
Log.e(TAG, "Could not have the dictionary pack delete a word list");
}
@ -181,6 +188,12 @@ public class BinaryDictionaryFileDumper {
if (DEBUG) {
Log.i(TAG, "Can't open word list in mode " + mode + " : " + e);
}
if (null != outputFile) {
// This may or may not fail. The file may not have been created if the
// exception was thrown before it could be. Hence, both failure and
// success are expected outcomes, so we don't check the return value.
outputFile.delete();
}
// Try the next method.
} finally {
// Ignore exceptions while closing files.
@ -234,12 +247,29 @@ public class BinaryDictionaryFileDumper {
}
/**
* Copies the data in an input stream to a target file.
* Copies the data in an input stream to a target file if the magic number matches.
*
* If the magic number does not match the expected value, this method throws an
* IOException. Other usual conditions for IOException or FileNotFoundException
* also apply.
*
* @param input the stream to be copied.
* @param outputFile an outputstream to copy the data to.
*/
private static void copyFileTo(final InputStream input, final FileOutputStream output)
throws FileNotFoundException, IOException {
private static void checkMagicAndCopyFileTo(final BufferedInputStream input,
final FileOutputStream output) throws FileNotFoundException, IOException {
// Check the magic number
final byte[] magicNumberBuffer = new byte[MAGIC_NUMBER.length];
final int readMagicNumberSize = input.read(magicNumberBuffer, 0, MAGIC_NUMBER.length);
if (readMagicNumberSize < MAGIC_NUMBER.length) {
throw new IOException("Less bytes to read than the magic number length");
}
if (!Arrays.equals(MAGIC_NUMBER, magicNumberBuffer)) {
throw new IOException("Wrong magic number for downloaded file");
}
output.write(MAGIC_NUMBER);
// Actually copy the file
final byte[] buffer = new byte[FILE_READ_BUFFER_SIZE];
for (int readBytes = input.read(buffer); readBytes >= 0; readBytes = input.read(buffer))
output.write(buffer, 0, readBytes);