312 lines
14 KiB
Java
312 lines
14 KiB
Java
/*
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* Copyright (C) 2011 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.android.inputmethod.latin;
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import android.content.ContentResolver;
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import android.content.Context;
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import android.content.res.AssetFileDescriptor;
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import android.database.Cursor;
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import android.net.Uri;
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import android.text.TextUtils;
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import android.util.Log;
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import java.io.BufferedInputStream;
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collections;
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import java.util.List;
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import java.util.Locale;
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/**
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* Group class for static methods to help with creation and getting of the binary dictionary
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* file from the dictionary provider
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*/
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public class BinaryDictionaryFileDumper {
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private static final String TAG = BinaryDictionaryFileDumper.class.getSimpleName();
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private static final boolean DEBUG = false;
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/**
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* The size of the temporary buffer to copy files.
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*/
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private static final int FILE_READ_BUFFER_SIZE = 1024;
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// TODO: make the following data common with the native code
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private static final byte[] MAGIC_NUMBER_VERSION_1 =
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new byte[] { (byte)0x78, (byte)0xB1, (byte)0x00, (byte)0x00 };
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private static final byte[] MAGIC_NUMBER_VERSION_2 =
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new byte[] { (byte)0x9B, (byte)0xC1, (byte)0x3A, (byte)0xFE };
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private static final String DICTIONARY_PROJECTION[] = { "id" };
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public static final String QUERY_PARAMETER_MAY_PROMPT_USER = "mayPrompt";
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public static final String QUERY_PARAMETER_TRUE = "true";
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public static final String QUERY_PARAMETER_DELETE_RESULT = "result";
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public static final String QUERY_PARAMETER_SUCCESS = "success";
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public static final String QUERY_PARAMETER_FAILURE = "failure";
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// Prevents this class to be accidentally instantiated.
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private BinaryDictionaryFileDumper() {
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}
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/**
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* Returns a URI builder pointing to the dictionary pack.
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*
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* This creates a URI builder able to build a URI pointing to the dictionary
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* pack content provider for a specific dictionary id.
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*/
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private static Uri.Builder getProviderUriBuilder(final String path) {
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return new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT)
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.authority(BinaryDictionary.DICTIONARY_PACK_AUTHORITY).appendPath(
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path);
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}
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/**
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* Queries a content provider for the list of word lists for a specific locale
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* available to copy into Latin IME.
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*/
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private static List<WordListInfo> getWordListWordListInfos(final Locale locale,
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final Context context, final boolean hasDefaultWordList) {
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final ContentResolver resolver = context.getContentResolver();
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final Uri.Builder builder = getProviderUriBuilder(locale.toString());
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if (!hasDefaultWordList) {
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builder.appendQueryParameter(QUERY_PARAMETER_MAY_PROMPT_USER, QUERY_PARAMETER_TRUE);
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}
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final Uri dictionaryPackUri = builder.build();
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final Cursor c = resolver.query(dictionaryPackUri, DICTIONARY_PROJECTION, null, null, null);
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if (null == c) return Collections.<WordListInfo>emptyList();
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if (c.getCount() <= 0 || !c.moveToFirst()) {
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c.close();
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return Collections.<WordListInfo>emptyList();
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}
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try {
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final List<WordListInfo> list = new ArrayList<WordListInfo>();
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do {
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final String wordListId = c.getString(0);
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final String wordListLocale = c.getString(1);
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if (TextUtils.isEmpty(wordListId)) continue;
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list.add(new WordListInfo(wordListId, wordListLocale));
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} while (c.moveToNext());
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c.close();
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return list;
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} catch (Exception e) {
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// Just in case we hit a problem in communication with the dictionary pack.
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// We don't want to die.
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Log.e(TAG, "Exception communicating with the dictionary pack : " + e);
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return Collections.<WordListInfo>emptyList();
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}
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}
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/**
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* Helper method to encapsulate exception handling.
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*/
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private static AssetFileDescriptor openAssetFileDescriptor(final ContentResolver resolver,
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final Uri uri) {
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try {
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return resolver.openAssetFileDescriptor(uri, "r");
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} catch (FileNotFoundException e) {
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// I don't want to log the word list URI here for security concerns
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Log.e(TAG, "Could not find a word list from the dictionary provider.");
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return null;
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}
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}
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/**
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* Caches a word list the id of which is passed as an argument. This will write the file
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* to the cache file name designated by its id and locale, overwriting it if already present
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* and creating it (and its containing directory) if necessary.
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*/
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private static AssetFileAddress cacheWordList(final String id, final String locale,
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final ContentResolver resolver, final Context context) {
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final int COMPRESSED_CRYPTED_COMPRESSED = 0;
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final int CRYPTED_COMPRESSED = 1;
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final int COMPRESSED_CRYPTED = 2;
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final int COMPRESSED_ONLY = 3;
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final int CRYPTED_ONLY = 4;
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final int NONE = 5;
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final int MODE_MIN = COMPRESSED_CRYPTED_COMPRESSED;
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final int MODE_MAX = NONE;
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final Uri.Builder wordListUriBuilder = getProviderUriBuilder(id);
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final String finalFileName = BinaryDictionaryGetter.getCacheFileName(id, locale, context);
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final String tempFileName = finalFileName + ".tmp";
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for (int mode = MODE_MIN; mode <= MODE_MAX; ++mode) {
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InputStream originalSourceStream = null;
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InputStream inputStream = null;
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File outputFile = null;
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FileOutputStream outputStream = null;
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AssetFileDescriptor afd = null;
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final Uri wordListUri = wordListUriBuilder.build();
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try {
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// Open input.
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afd = openAssetFileDescriptor(resolver, wordListUri);
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// If we can't open it at all, don't even try a number of times.
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if (null == afd) return null;
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originalSourceStream = afd.createInputStream();
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// Open output.
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outputFile = new File(tempFileName);
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// Just to be sure, delete the file. This may fail silently, and return false: this
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// is the right thing to do, as we just want to continue anyway.
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outputFile.delete();
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outputStream = new FileOutputStream(outputFile);
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// Get the appropriate decryption method for this try
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switch (mode) {
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case COMPRESSED_CRYPTED_COMPRESSED:
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inputStream = FileTransforms.getUncompressedStream(
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FileTransforms.getDecryptedStream(
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FileTransforms.getUncompressedStream(
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originalSourceStream)));
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break;
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case CRYPTED_COMPRESSED:
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inputStream = FileTransforms.getUncompressedStream(
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FileTransforms.getDecryptedStream(originalSourceStream));
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break;
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case COMPRESSED_CRYPTED:
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inputStream = FileTransforms.getDecryptedStream(
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FileTransforms.getUncompressedStream(originalSourceStream));
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break;
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case COMPRESSED_ONLY:
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inputStream = FileTransforms.getUncompressedStream(originalSourceStream);
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break;
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case CRYPTED_ONLY:
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inputStream = FileTransforms.getDecryptedStream(originalSourceStream);
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break;
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case NONE:
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inputStream = originalSourceStream;
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break;
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}
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checkMagicAndCopyFileTo(new BufferedInputStream(inputStream), outputStream);
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outputStream.flush();
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outputStream.close();
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final File finalFile = new File(finalFileName);
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if (!outputFile.renameTo(finalFile)) {
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throw new IOException("Can't move the file to its final name");
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}
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wordListUriBuilder.appendQueryParameter(QUERY_PARAMETER_DELETE_RESULT,
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QUERY_PARAMETER_SUCCESS);
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if (0 >= resolver.delete(wordListUriBuilder.build(), null, null)) {
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Log.e(TAG, "Could not have the dictionary pack delete a word list");
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}
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BinaryDictionaryGetter.removeFilesWithIdExcept(context, id, finalFile);
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// Success! Close files (through the finally{} clause) and return.
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return AssetFileAddress.makeFromFileName(finalFileName);
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} catch (Exception e) {
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if (DEBUG) {
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Log.i(TAG, "Can't open word list in mode " + mode + " : " + e);
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}
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if (null != outputFile) {
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// This may or may not fail. The file may not have been created if the
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// exception was thrown before it could be. Hence, both failure and
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// success are expected outcomes, so we don't check the return value.
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outputFile.delete();
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}
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// Try the next method.
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} finally {
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// Ignore exceptions while closing files.
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try {
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// inputStream.close() will close afd, we should not call afd.close().
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if (null != inputStream) inputStream.close();
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} catch (Exception e) {
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Log.e(TAG, "Exception while closing a cross-process file descriptor : " + e);
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}
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try {
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if (null != outputStream) outputStream.close();
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} catch (Exception e) {
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Log.e(TAG, "Exception while closing a file : " + e);
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}
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}
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}
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// We could not copy the file at all. This is very unexpected.
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// I'd rather not print the word list ID to the log out of security concerns
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Log.e(TAG, "Could not copy a word list. Will not be able to use it.");
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// If we can't copy it we should warn the dictionary provider so that it can mark it
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// as invalid.
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wordListUriBuilder.appendQueryParameter(QUERY_PARAMETER_DELETE_RESULT,
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QUERY_PARAMETER_FAILURE);
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if (0 >= resolver.delete(wordListUriBuilder.build(), null, null)) {
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Log.e(TAG, "In addition, we were unable to delete it.");
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}
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return null;
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}
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/**
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* Queries a content provider for word list data for some locale and cache the returned files
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*
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* This will query a content provider for word list data for a given locale, and copy the
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* files locally so that they can be mmap'ed. This may overwrite previously cached word lists
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* with newer versions if a newer version is made available by the content provider.
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* @returns the addresses of the word list files, or null if no data could be obtained.
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* @throw FileNotFoundException if the provider returns non-existent data.
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* @throw IOException if the provider-returned data could not be read.
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*/
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public static List<AssetFileAddress> cacheWordListsFromContentProvider(final Locale locale,
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final Context context, final boolean hasDefaultWordList) {
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final ContentResolver resolver = context.getContentResolver();
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final List<WordListInfo> idList = getWordListWordListInfos(locale, context,
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hasDefaultWordList);
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final List<AssetFileAddress> fileAddressList = new ArrayList<AssetFileAddress>();
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for (WordListInfo id : idList) {
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final AssetFileAddress afd = cacheWordList(id.mId, id.mLocale, resolver, context);
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if (null != afd) {
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fileAddressList.add(afd);
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}
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}
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return fileAddressList;
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}
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/**
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* Copies the data in an input stream to a target file if the magic number matches.
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*
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* If the magic number does not match the expected value, this method throws an
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* IOException. Other usual conditions for IOException or FileNotFoundException
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* also apply.
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*
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* @param input the stream to be copied.
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* @param output an output stream to copy the data to.
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*/
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private static void checkMagicAndCopyFileTo(final BufferedInputStream input,
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final FileOutputStream output) throws FileNotFoundException, IOException {
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// Check the magic number
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final int length = MAGIC_NUMBER_VERSION_2.length;
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final byte[] magicNumberBuffer = new byte[length];
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final int readMagicNumberSize = input.read(magicNumberBuffer, 0, length);
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if (readMagicNumberSize < length) {
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throw new IOException("Less bytes to read than the magic number length");
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}
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if (!Arrays.equals(MAGIC_NUMBER_VERSION_2, magicNumberBuffer)) {
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if (!Arrays.equals(MAGIC_NUMBER_VERSION_1, magicNumberBuffer)) {
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throw new IOException("Wrong magic number for downloaded file");
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}
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}
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output.write(magicNumberBuffer);
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// Actually copy the file
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final byte[] buffer = new byte[FILE_READ_BUFFER_SIZE];
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for (int readBytes = input.read(buffer); readBytes >= 0; readBytes = input.read(buffer))
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output.write(buffer, 0, readBytes);
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input.close();
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}
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}
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