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Diffstat (limited to 'java/src/com/android/inputmethod/latin/UserDictionaryLookup.java')
| -rw-r--r-- | java/src/com/android/inputmethod/latin/UserDictionaryLookup.java | 518 |
1 files changed, 518 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/latin/UserDictionaryLookup.java b/java/src/com/android/inputmethod/latin/UserDictionaryLookup.java new file mode 100644 index 000000000..2569723b0 --- /dev/null +++ b/java/src/com/android/inputmethod/latin/UserDictionaryLookup.java @@ -0,0 +1,518 @@ +/* + * Copyright (C) 2015 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.android.inputmethod.latin; + +import android.content.ContentResolver; +import android.content.Context; +import android.database.ContentObserver; +import android.database.Cursor; +import android.net.Uri; +import android.provider.UserDictionary; +import android.text.TextUtils; +import android.util.Log; + +import com.android.inputmethod.annotations.UsedForTesting; +import com.android.inputmethod.latin.common.CollectionUtils; +import com.android.inputmethod.latin.common.LocaleUtils; +import com.android.inputmethod.latin.utils.ExecutorUtils; + +import java.io.Closeable; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.Locale; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.ScheduledFuture; +import java.util.concurrent.TimeUnit; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +/** + * UserDictionaryLookup provides the ability to lookup into the system-wide "Personal dictionary". + * + * Note, that the initial dictionary loading happens asynchronously so it is possible (hopefully + * rarely) that isValidWord is called before the initial load has started. + * + * The caller should explicitly call close() when the object is no longer needed, in order to + * release any resources and references to this object. A service should create this object in + * onCreate and close() it in onDestroy. + */ +public class UserDictionaryLookup implements Closeable { + + /** + * This guards the execution of any Log.d() logging, so that if false, they are not even + */ + private static final boolean DEBUG = false; + + /** + * To avoid loading too many dictionary entries in memory, we cap them at this number. If + * that number is exceeded, the lowest-frequency items will be dropped. Note, there is no + * explicit cap on the number of locales in every entry. + */ + private static final int MAX_NUM_ENTRIES = 1000; + + /** + * The delay (in milliseconds) to impose on reloads. Previously scheduled reloads will be + * cancelled if a new reload is scheduled before the delay expires. Thus, only the last + * reload in the series of frequent reloads will execute. + * + * Note, this value should be low enough to allow the "Add to dictionary" feature in the + * TextView correction (red underline) drop-down menu to work properly in the following case: + * + * 1. User types OOV (out-of-vocabulary) word. + * 2. The OOV is red-underlined. + * 3. User selects "Add to dictionary". The red underline disappears while the OOV is + * in a composing span. + * 4. The user taps space. The red underline should NOT reappear. If this value is very + * high and the user performs the space tap fast enough, the red underline may reappear. + */ + @UsedForTesting + static final int RELOAD_DELAY_MS = 200; + + @UsedForTesting + static final Locale ANY_LOCALE = new Locale(""); + + private final String mTag; + private final ContentResolver mResolver; + private final String mServiceName; + + /** + * Runnable that calls loadUserDictionary(). + */ + private class UserDictionaryLoader implements Runnable { + @Override + public void run() { + if (DEBUG) { + Log.d(mTag, "Executing (re)load"); + } + loadUserDictionary(); + } + } + + /** + * Content observer for UserDictionary changes. It has the following properties: + * 1. It spawns off a UserDictionary reload in another thread, after some delay. + * 2. It cancels previously scheduled reloads, and only executes the latest. + * 3. It may be called multiple times quickly in succession (and is in fact called so + * when UserDictionary is edited through its settings UI, when sometimes multiple + * notifications are sent for the edited entry, but also for the entire UserDictionary). + */ + private class UserDictionaryContentObserver extends ContentObserver { + public UserDictionaryContentObserver() { + super(null); + } + + @Override + public boolean deliverSelfNotifications() { + return true; + } + + // Support pre-API16 platforms. + @Override + public void onChange(boolean selfChange) { + onChange(selfChange, null); + } + + @Override + public void onChange(boolean selfChange, Uri uri) { + if (DEBUG) { + Log.d(mTag, "Received content observer onChange notification for URI: " + uri); + } + // Cancel (but don't interrupt) any pending reloads (except the initial load). + if (mReloadFuture != null && !mReloadFuture.isCancelled() && + !mReloadFuture.isDone()) { + // Note, that if already cancelled or done, this will do nothing. + boolean isCancelled = mReloadFuture.cancel(false); + if (DEBUG) { + if (isCancelled) { + Log.d(mTag, "Successfully canceled previous reload request"); + } else { + Log.d(mTag, "Unable to cancel previous reload request"); + } + } + } + + if (DEBUG) { + Log.d(mTag, "Scheduling reload in " + RELOAD_DELAY_MS + " ms"); + } + + // Schedule a new reload after RELOAD_DELAY_MS. + mReloadFuture = ExecutorUtils.getBackgroundExecutor(mServiceName) + .schedule(new UserDictionaryLoader(), RELOAD_DELAY_MS, TimeUnit.MILLISECONDS); + } + } + private final ContentObserver mObserver = new UserDictionaryContentObserver(); + + /** + * Indicates that a load is in progress, so no need for another. + */ + private AtomicBoolean mIsLoading = new AtomicBoolean(false); + + /** + * Indicates that this lookup object has been close()d. + */ + private AtomicBoolean mIsClosed = new AtomicBoolean(false); + + /** + * We store a map from a dictionary word to the set of locales it belongs + * in. We then iterate over the set of locales to find a match using + * LocaleUtils. + */ + private volatile HashMap<String, ArrayList<Locale>> mDictWords; + + /** + * We store a map from a shortcut to a word for each locale. + * Shortcuts that apply to any locale are keyed by {@link #ANY_LOCALE}. + */ + private volatile HashMap<Locale, HashMap<String, String>> mShortcutsPerLocale; + + /** + * The last-scheduled reload future. Saved in order to cancel a pending reload if a new one + * is coming. + */ + private volatile ScheduledFuture<?> mReloadFuture; + + /** + * @param context the context from which to obtain content resolver + */ + public UserDictionaryLookup(@Nonnull final Context context, @Nonnull final String serviceName) { + mTag = serviceName + ".UserDictionaryLookup"; + + Log.i(mTag, "create()"); + + mServiceName = serviceName; + + // Obtain a content resolver. + mResolver = context.getContentResolver(); + } + + public void open() { + Log.i(mTag, "open()"); + + // Schedule the initial load to run immediately. It's possible that the first call to + // isValidWord occurs before the dictionary has actually loaded, so it should not + // assume that the dictionary has been loaded. + loadUserDictionary(); + + // Register the observer to be notified on changes to the UserDictionary and all individual + // items. + // + // If the user is interacting with the UserDictionary settings UI, or with the + // "Add to dictionary" drop-down option, duplicate notifications will be sent for the same + // edit: if a new entry is added, there is a notification for the entry itself, and + // separately for the entire dictionary. However, when used programmatically, + // only notifications for the specific edits are sent. Thus, the observer is registered to + // receive every possible notification, and instead has throttling logic to avoid doing too + // many reloads. + mResolver.registerContentObserver( + UserDictionary.Words.CONTENT_URI, true /* notifyForDescendents */, mObserver); + } + + /** + * To be called by the garbage collector in the off chance that the service did not clean up + * properly. Do not rely on this getting called, and make sure close() is called explicitly. + */ + @Override + public void finalize() throws Throwable { + try { + if (DEBUG) { + Log.d(mTag, "Finalize called, calling close()"); + } + close(); + } finally { + super.finalize(); + } + } + + /** + * Cleans up UserDictionaryLookup: shuts down any extra threads and unregisters the observer. + * + * It is safe, but not advised to call this multiple times, and isValidWord would continue to + * work, but no data will be reloaded any longer. + */ + @Override + public void close() { + if (DEBUG) { + Log.d(mTag, "Close called (no pun intended), cleaning up executor and observer"); + } + if (mIsClosed.compareAndSet(false, true)) { + // Unregister the content observer. + mResolver.unregisterContentObserver(mObserver); + } + } + + /** + * Returns true if the initial load has been performed. + * + * @return true if the initial load is successful + */ + public boolean isLoaded() { + return mDictWords != null && mShortcutsPerLocale != null; + } + + /** + * Determines if the given word is a valid word in the given locale based on the UserDictionary. + * It tries hard to find a match: for example, casing is ignored and if the word is present in a + * more general locale (e.g. en or all locales), and isValidWord is asking for a more specific + * locale (e.g. en_US), it will be considered a match. + * + * @param word the word to match + * @param locale the locale in which to match the word + * @return true iff the word has been matched for this locale in the UserDictionary. + */ + public boolean isValidWord(@Nonnull final String word, @Nonnull final Locale locale) { + if (!isLoaded()) { + // This is a corner case in the event the initial load of UserDictionary has not + // been loaded. In that case, we assume the word is not a valid word in + // UserDictionary. + if (DEBUG) { + Log.d(mTag, "isValidWord invoked, but initial load not complete"); + } + return false; + } + + // Atomically obtain the current copy of mDictWords; + final HashMap<String, ArrayList<Locale>> dictWords = mDictWords; + + if (DEBUG) { + Log.d(mTag, "isValidWord invoked for word [" + word + + "] in locale " + locale); + } + // Lowercase the word using the given locale. Note, that dictionary + // words are lowercased using their locale, and theoretically the + // lowercasing between two matching locales may differ. For simplicity + // we ignore that possibility. + final String lowercased = word.toLowerCase(locale); + final ArrayList<Locale> dictLocales = dictWords.get(lowercased); + if (null == dictLocales) { + if (DEBUG) { + Log.d(mTag, "isValidWord=false, since there is no entry for " + + "lowercased word [" + lowercased + "]"); + } + return false; + } else { + if (DEBUG) { + Log.d(mTag, "isValidWord found an entry for lowercased word [" + lowercased + + "]; examining locales"); + } + // Iterate over the locales this word is in. + for (final Locale dictLocale : dictLocales) { + final int matchLevel = LocaleUtils.getMatchLevel(dictLocale.toString(), + locale.toString()); + if (DEBUG) { + Log.d(mTag, "matchLevel for dictLocale=" + dictLocale + ", locale=" + + locale + " is " + matchLevel); + } + if (LocaleUtils.isMatch(matchLevel)) { + if (DEBUG) { + Log.d(mTag, "isValidWord=true, since matchLevel " + matchLevel + + " is a match"); + } + return true; + } + if (DEBUG) { + Log.d(mTag, "matchLevel " + matchLevel + " is not a match"); + } + } + if (DEBUG) { + Log.d(mTag, "isValidWord=false, since none of the locales matched"); + } + return false; + } + } + + /** + * Expands the given shortcut for the given locale. + * + * @param shortcut the shortcut to expand + * @param inputLocale the locale in which to expand the shortcut + * @return expanded shortcut iff the word is a shortcut in the UserDictionary. + */ + @Nullable public String expandShortcut( + @Nonnull final String shortcut, @Nonnull final Locale inputLocale) { + if (DEBUG) { + Log.d(mTag, "expandShortcut() : Shortcut [" + shortcut + "] for [" + inputLocale + "]"); + } + + // Atomically obtain the current copy of mShortcuts; + final HashMap<Locale, HashMap<String, String>> shortcutsPerLocale = mShortcutsPerLocale; + + // Exit as early as possible. Most users don't use shortcuts. + if (CollectionUtils.isNullOrEmpty(shortcutsPerLocale)) { + return null; + } + + if (!TextUtils.isEmpty(inputLocale.getCountry())) { + // First look for the country-specific shortcut: en_US, en_UK, fr_FR, etc. + final String expansionForCountry = expandShortcut( + shortcutsPerLocale, shortcut, inputLocale); + if (!TextUtils.isEmpty(expansionForCountry)) { + return expansionForCountry; + } + } + + // Next look for the language-specific shortcut: en, fr, etc. + final Locale languageOnlyLocale = + LocaleUtils.constructLocaleFromString(inputLocale.getLanguage()); + final String expansionForLanguage = expandShortcut( + shortcutsPerLocale, shortcut, languageOnlyLocale); + if (!TextUtils.isEmpty(expansionForLanguage)) { + return expansionForLanguage; + } + + // If all else fails, loof for a global shortcut. + return expandShortcut(shortcutsPerLocale, shortcut, ANY_LOCALE); + } + + @Nullable private String expandShortcut( + @Nullable final HashMap<Locale, HashMap<String, String>> shortcutsPerLocale, + @Nonnull final String shortcut, + @Nonnull final Locale locale) { + if (CollectionUtils.isNullOrEmpty(shortcutsPerLocale)) { + return null; + } + final HashMap<String, String> localeShortcuts = shortcutsPerLocale.get(locale); + if (CollectionUtils.isNullOrEmpty(localeShortcuts)) { + return null; + } + final String word = localeShortcuts.get(shortcut); + if (DEBUG && word != null) { + Log.d(mTag, "expandShortcut() : Shortcut [" + shortcut + "] for [" + locale + + "] expands to [" + word + "]"); + } + return word; + } + + /** + * Loads the UserDictionary in the current thread. + * + * Only one reload can happen at a time. If already running, will exit quickly. + */ + private void loadUserDictionary() { + // Bail out if already in the process of loading. + if (!mIsLoading.compareAndSet(false, true)) { + Log.i(mTag, "loadUserDictionary() : Already Loading (exit)"); + return; + } + Log.i(mTag, "loadUserDictionary() : Start Loading"); + HashMap<String, ArrayList<Locale>> dictWords = new HashMap<>(); + HashMap<Locale, HashMap<String, String>> shortcutsPerLocale = new HashMap<>(); + // Load the UserDictionary. Request that items be returned in the default sort order + // for UserDictionary, which is by frequency. + Cursor cursor = mResolver.query(UserDictionary.Words.CONTENT_URI, + null, null, null, UserDictionary.Words.DEFAULT_SORT_ORDER); + if (null == cursor || cursor.getCount() < 1) { + Log.i(mTag, "loadUserDictionary() : Empty"); + } else { + // Iterate over the entries in the UserDictionary. Note, that iteration is in + // descending frequency by default. + while (dictWords.size() < MAX_NUM_ENTRIES && cursor.moveToNext()) { + // If there is no column for locale, skip this entry. An empty + // locale on the other hand will not be skipped. + final int dictLocaleIndex = cursor.getColumnIndex(UserDictionary.Words.LOCALE); + if (dictLocaleIndex < 0) { + if (DEBUG) { + Log.d(mTag, "Encountered UserDictionary entry without LOCALE, skipping"); + } + continue; + } + // If there is no column for word, skip this entry. + final int dictWordIndex = cursor.getColumnIndex(UserDictionary.Words.WORD); + if (dictWordIndex < 0) { + if (DEBUG) { + Log.d(mTag, "Encountered UserDictionary entry without WORD, skipping"); + } + continue; + } + // If the word is null, skip this entry. + final String rawDictWord = cursor.getString(dictWordIndex); + if (null == rawDictWord) { + if (DEBUG) { + Log.d(mTag, "Encountered null word"); + } + continue; + } + // If the locale is null, that's interpreted to mean all locales. Note, the special + // zz locale for an Alphabet (QWERTY) layout will not match any actual language. + String localeString = cursor.getString(dictLocaleIndex); + if (null == localeString) { + if (DEBUG) { + Log.d(mTag, "Encountered null locale for word [" + + rawDictWord + "], assuming all locales"); + } + // For purposes of LocaleUtils, an empty locale matches everything. + localeString = ""; + } + final Locale dictLocale = LocaleUtils.constructLocaleFromString(localeString); + // Lowercase the word before storing it. + final String dictWord = rawDictWord.toLowerCase(dictLocale); + if (DEBUG) { + Log.d(mTag, "Incorporating UserDictionary word [" + dictWord + + "] for locale " + dictLocale); + } + // Check if there is an existing entry for this word. + ArrayList<Locale> dictLocales = dictWords.get(dictWord); + if (null == dictLocales) { + // If there is no entry for this word, create one. + if (DEBUG) { + Log.d(mTag, "Word [" + dictWord + + "] not seen for other locales, creating new entry"); + } + dictLocales = new ArrayList<>(); + dictWords.put(dictWord, dictLocales); + } + // Append the locale to the list of locales this word is in. + dictLocales.add(dictLocale); + + // If there is no column for a shortcut, we're done. + final int shortcutIndex = cursor.getColumnIndex(UserDictionary.Words.SHORTCUT); + if (shortcutIndex < 0) { + if (DEBUG) { + Log.d(mTag, "Encountered UserDictionary entry without SHORTCUT, done"); + } + continue; + } + // If the shortcut is null, we're done. + final String shortcut = cursor.getString(shortcutIndex); + if (shortcut == null) { + if (DEBUG) { + Log.d(mTag, "Encountered null shortcut"); + } + continue; + } + // Else, save the shortcut. + HashMap<String, String> localeShortcuts = shortcutsPerLocale.get(dictLocale); + if (localeShortcuts == null) { + localeShortcuts = new HashMap<>(); + shortcutsPerLocale.put(dictLocale, localeShortcuts); + } + // Map to the raw input, which might be capitalized. + // This lets the user create a shortcut from "gm" to "General Motors". + localeShortcuts.put(shortcut, rawDictWord); + } + } + + // Atomically replace the copy of mDictWords and mShortcuts. + mDictWords = dictWords; + mShortcutsPerLocale = shortcutsPerLocale; + + // Allow other calls to loadUserDictionary to execute now. + mIsLoading.set(false); + + Log.i(mTag, "loadUserDictionary() : Loaded " + mDictWords.size() + " words"); + } +} |