Use reentrant lock for main dictionaries.

Bug: 10964805
Change-Id: Iaa9b79fc770d8ae2ec9d7c362c90c28bc9f65ea8

1 files changed, 120 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/ReadOnlyBinaryDictionary.java b/java/src/com/android/inputmethod/latin/ReadOnlyBinaryDictionary.java
new file mode 100644
index 000000000..68505ce38
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/ReadOnlyBinaryDictionary.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2013 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 com.android.inputmethod.keyboard.ProximityInfo;
+import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
+
+import java.util.ArrayList;
+import java.util.Locale;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+/**
+ * This class provides binary dictionary reading operations with locking. An instance of this class
+ * can be used by multiple threads. Note that different session IDs must be used when multiple
+ * threads get suggestions using this class.
+ */
+public final class ReadOnlyBinaryDictionary extends Dictionary {
+    /**
+     * A lock for accessing binary dictionary. Only closing binary dictionary is the operation
+     * that change the state of dictionary.
+     */
+    private final ReentrantReadWriteLock mLock = new ReentrantReadWriteLock();
+
+    private final BinaryDictionary mBinaryDictionary;
+
+    public ReadOnlyBinaryDictionary(final String filename, final long offset, final long length,
+            final boolean useFullEditDistance, final Locale locale, final String dictType) {
+        super(dictType);
+        mBinaryDictionary = new BinaryDictionary(filename, offset, length, useFullEditDistance,
+                locale, dictType, false /* isUpdatable */);
+    }
+
+    public boolean isValidDictionary() {
+        return mBinaryDictionary.isValidDictionary();
+    }
+
+    @Override
+    public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer composer,
+            final String prevWord, final ProximityInfo proximityInfo,
+            final boolean blockOffensiveWords, final int[] additionalFeaturesOptions) {
+        return getSuggestionsWithSessionId(composer, prevWord, proximityInfo, blockOffensiveWords,
+                additionalFeaturesOptions, 0 /* sessionId */);
+    }
+
+    @Override
+    public ArrayList<SuggestedWordInfo> getSuggestionsWithSessionId(final WordComposer composer,
+            final String prevWord, final ProximityInfo proximityInfo,
+            final boolean blockOffensiveWords, final int[] additionalFeaturesOptions,
+            final int sessionId) {
+        if (mLock.readLock().tryLock()) {
+            try {
+                return mBinaryDictionary.getSuggestions(composer, prevWord, proximityInfo,
+                        blockOffensiveWords, additionalFeaturesOptions);
+            } finally {
+                mLock.readLock().unlock();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public boolean isValidWord(final String word) {
+        if (mLock.readLock().tryLock()) {
+            try {
+                return mBinaryDictionary.isValidWord(word);
+            } finally {
+                mLock.readLock().unlock();
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public boolean shouldAutoCommit(final SuggestedWordInfo candidate) {
+        if (mLock.readLock().tryLock()) {
+            try {
+                return mBinaryDictionary.shouldAutoCommit(candidate);
+            } finally {
+                mLock.readLock().unlock();
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public int getFrequency(final String word) {
+        if (mLock.readLock().tryLock()) {
+            try {
+                return mBinaryDictionary.getFrequency(word);
+            } finally {
+                mLock.readLock().unlock();
+            }
+        }
+        return NOT_A_PROBABILITY;
+    }
+
+    @Override
+    public void close() {
+        mLock.writeLock().lock();
+        try {
+            mBinaryDictionary.close();
+        } finally {
+            mLock.writeLock().unlock();
+        }
+    }
+}