/*
* Copyright (C) 2011 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 com.sugree.inputmethod.latin;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.AssetFileDescriptor;
import android.content.res.Resources;
import android.util.Log;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import com.sugree.inputmethod.latin.R;
/**
* Helper class to get the address of a mmap'able dictionary file.
*/
class BinaryDictionaryGetter {
/**
* Used for Log actions from this class
*/
private static final String TAG = BinaryDictionaryGetter.class.getSimpleName();
/**
* Used to return empty lists
*/
private static final File[] EMPTY_FILE_ARRAY = new File[0];
/**
* Name of the common preferences name to know which word list are on and which are off.
*/
private static final String COMMON_PREFERENCES_NAME = "LatinImeDictPrefs";
// Prevents this from being instantiated
private BinaryDictionaryGetter() {}
/**
* Returns whether we may want to use this character as part of a file name.
*
* This basically only accepts ascii letters and numbers, and rejects everything else.
*/
private static boolean isFileNameCharacter(int codePoint) {
if (codePoint >= 0x30 && codePoint <= 0x39) return true; // Digit
if (codePoint >= 0x41 && codePoint <= 0x5A) return true; // Uppercase
if (codePoint >= 0x61 && codePoint <= 0x7A) return true; // Lowercase
return codePoint == '_'; // Underscore
}
/**
* Escapes a string for any characters that may be suspicious for a file or directory name.
*
* Concretely this does a sort of URL-encoding except it will encode everything that's not
* alphanumeric or underscore. (true URL-encoding leaves alone characters like '*', which
* we cannot allow here)
*/
// TODO: create a unit test for this method
private static String replaceFileNameDangerousCharacters(final String name) {
// This assumes '%' is fully available as a non-separator, normal
// character in a file name. This is probably true for all file systems.
final StringBuilder sb = new StringBuilder();
for (int i = 0; i < name.length(); ++i) {
final int codePoint = name.codePointAt(i);
if (isFileNameCharacter(codePoint)) {
sb.appendCodePoint(codePoint);
} else {
// 6 digits - unicode is limited to 21 bits
sb.append(String.format((Locale)null, "%%%1$06x", codePoint));
}
}
return sb.toString();
}
/**
* Reverse escaping done by replaceFileNameDangerousCharacters.
*/
private static String getWordListIdFromFileName(final String fname) {
final StringBuilder sb = new StringBuilder();
for (int i = 0; i < fname.length(); ++i) {
final int codePoint = fname.codePointAt(i);
if ('%' != codePoint) {
sb.appendCodePoint(codePoint);
} else {
final int encodedCodePoint = Integer.parseInt(fname.substring(i + 1, i + 7), 16);
i += 6;
sb.appendCodePoint(encodedCodePoint);
}
}
return sb.toString();
}
/**
* Helper method to get the top level cache directory.
*/
private static String getWordListCacheDirectory(final Context context) {
return context.getFilesDir() + File.separator + "dicts";
}
/**
* Find out the cache directory associated with a specific locale.
*/
private static String getCacheDirectoryForLocale(final String locale, final Context context) {
final String relativeDirectoryName = replaceFileNameDangerousCharacters(locale);
final String absoluteDirectoryName = getWordListCacheDirectory(context) + File.separator
+ relativeDirectoryName;
final File directory = new File(absoluteDirectoryName);
if (!directory.exists()) {
if (!directory.mkdirs()) {
Log.e(TAG, "Could not create the directory for locale" + locale);
}
}
return absoluteDirectoryName;
}
/**
* Generates a file name for the id and locale passed as an argument.
*
* In the current implementation the file name returned will always be unique for
* any id/locale pair, but please do not expect that the id can be the same for
* different dictionaries with different locales. An id should be unique for any
* dictionary.
* The file name is pretty much an URL-encoded version of the id inside a directory
* named like the locale, except it will also escape characters that look dangerous
* to some file systems.
* @param id the id of the dictionary for which to get a file name
* @param locale the locale for which to get the file name as a string
* @param context the context to use for getting the directory
* @return the name of the file to be created
*/
public static String getCacheFileName(String id, String locale, Context context) {
final String fileName = replaceFileNameDangerousCharacters(id);
return getCacheDirectoryForLocale(locale, context) + File.separator + fileName;
}
/**
* Returns a file address from a resource, or null if it cannot be opened.
*/
private static AssetFileAddress loadFallbackResource(final Context context,
final int fallbackResId, final Locale locale) {
final Resources res = context.getResources();
final Locale savedLocale = LocaleUtils.setSystemLocale(res, locale);
final AssetFileDescriptor afd = res.openRawResourceFd(fallbackResId);
LocaleUtils.setSystemLocale(res, savedLocale);
if (afd == null) {
Log.e(TAG, "Found the resource but cannot read it. Is it compressed? resId="
+ fallbackResId);
return null;
}
return AssetFileAddress.makeFromFileNameAndOffset(
context.getApplicationInfo().sourceDir, afd.getStartOffset(), afd.getLength());
}
static private class DictPackSettings {
final SharedPreferences mDictPreferences;
public DictPackSettings(final Context context) {
Context dictPackContext = null;
try {
final String dictPackName =
context.getString(R.string.dictionary_pack_package_name);
dictPackContext = context.createPackageContext(dictPackName, 0);
} catch (NameNotFoundException e) {
// The dictionary pack is not installed...
// TODO: fallback on the built-in dict, see the TODO above
Log.e(TAG, "Could not find a dictionary pack");
}
mDictPreferences = null == dictPackContext ? null
: dictPackContext.getSharedPreferences(COMMON_PREFERENCES_NAME,
Context.MODE_WORLD_READABLE | Context.MODE_MULTI_PROCESS);
}
public boolean isWordListActive(final String dictId) {
if (null == mDictPreferences) {
// If we don't have preferences it basically means we can't find the dictionary
// pack - either it's not installed, or it's disabled, or there is some strange
// bug. Either way, a word list with no settings should be on by default: default
// dictionaries in LatinIME are on if there is no settings at all, and if for some
// reason some dictionaries have been installed BUT the dictionary pack can't be
// found anymore it's safer to actually supply installed dictionaries.
return true;
} else {
// The default is true here for the same reasons as above. We got the dictionary
// pack but if we don't have any settings for it it means the user has never been
// to the settings yet. So by default, the main dictionaries should be on.
return mDictPreferences.getBoolean(dictId, true);
}
}
}
/**
* Helper method to the list of cache directories, one for each distinct locale.
*/
private static File[] getCachedDirectoryList(final Context context) {
return new File(getWordListCacheDirectory(context)).listFiles();
}
/**
* Returns the list of cached files for a specific locale.
*
* @param locale the locale to find the dictionary files for, as a string.
* @param context the context on which to open the files upon.
* @return an array of binary dictionary files, which may be empty but may not be null.
*/
private static File[] getCachedWordLists(final String locale,
final Context context) {
final File[] directoryList = getCachedDirectoryList(context);
if (null == directoryList) return EMPTY_FILE_ARRAY;
final ArrayList<File> cacheFiles = new ArrayList<File>();
for (File directory : directoryList) {
if (!directory.isDirectory()) continue;
final String dirLocale = getWordListIdFromFileName(directory.getName());
if (LocaleUtils.isMatch(LocaleUtils.getMatchLevel(dirLocale, locale))) {
final File[] wordLists = directory.listFiles();
if (null != wordLists) {
for (File wordList : wordLists) {
cacheFiles.add(wordList);
}
}
}
}
if (cacheFiles.isEmpty()) return EMPTY_FILE_ARRAY;
return cacheFiles.toArray(EMPTY_FILE_ARRAY);
}
/**
* Returns the id associated with the main word list for a specified locale.
*
* Word lists stored in Android Keyboard's resources are referred to as the "main"
* word lists. Since they can be updated like any other list, we need to assign a
* unique ID to them. This ID is just the name of the language (locale-wise) they
* are for, and this method returns this ID.
*/
private static String getMainDictId(final Locale locale) {
// This works because we don't include by default different dictionaries for
// different countries. This actually needs to return the id that we would
// like to use for word lists included in resources, and the following is okay.
return locale.getLanguage().toString();
}
/**
* Returns a list of file addresses for a given locale, trying relevant methods in order.
*
* Tries to get binary dictionaries from various sources, in order:
* - Uses a content provider to get a public dictionary set, as per the protocol described
* in BinaryDictionaryFileDumper.
* If that fails:
* - Gets a file name from the fallback resource passed as an argument.
* If that fails:
* - Returns null.
* @return The address of a valid file, or null.
*/
public static List<AssetFileAddress> getDictionaryFiles(final Locale locale,
final Context context, final int fallbackResId) {
// cacheWordListsFromContentProvider returns the list of files it copied to local
// storage, but we don't really care about what was copied NOW: what we want is the
// list of everything we ever cached, so we ignore the return value.
BinaryDictionaryFileDumper.cacheWordListsFromContentProvider(locale, context);
final File[] cachedWordLists = getCachedWordLists(locale.toString(), context);
final String mainDictId = getMainDictId(locale);
final DictPackSettings dictPackSettings = new DictPackSettings(context);
boolean foundMainDict = false;
final ArrayList<AssetFileAddress> fileList = new ArrayList<AssetFileAddress>();
// cachedWordLists may not be null, see doc for getCachedDictionaryList
for (final File f : cachedWordLists) {
final String wordListId = getWordListIdFromFileName(f.getName());
if (wordListId.equals(mainDictId)) {
foundMainDict = true;
}
if (!dictPackSettings.isWordListActive(wordListId)) continue;
if (f.canRead()) {
fileList.add(AssetFileAddress.makeFromFileName(f.getPath()));
} else {
Log.e(TAG, "Found a cached dictionary file but cannot read it");
}
}
if (!foundMainDict && dictPackSettings.isWordListActive(mainDictId)) {
final AssetFileAddress fallbackAsset = loadFallbackResource(context, fallbackResId,
locale);
if (null != fallbackAsset) {
fileList.add(fallbackAsset);
}
}
return fileList;
}
}