From a6e912cf9849f5c979303042ce83820a8dc560d0 Mon Sep 17 00:00:00 2001
From: Jean Chalard <jchalard@google.com>
Date: Tue, 23 Aug 2011 14:30:26 +0900
Subject: [PATCH] Fix a bug with the string pool.
This also adds some optional debug code to detect more easily possible
future occurrences of the same problem.
Bug: 5195017
Change-Id: I2558b468e46f7090de868f1ec2dc9e24895d670f
---
.../inputmethod/latin/StringBuilderPool.java | 16 +++++++++++++++-
.../com/android/inputmethod/latin/Suggest.java | 9 ++++++++-
2 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/java/src/com/android/inputmethod/latin/StringBuilderPool.java b/java/src/com/android/inputmethod/latin/StringBuilderPool.java
index 66f123731e..a663ed43e3 100644
--- a/java/src/com/android/inputmethod/latin/StringBuilderPool.java
+++ b/java/src/com/android/inputmethod/latin/StringBuilderPool.java
@@ -26,12 +26,20 @@ import java.util.List;
public class StringBuilderPool {
// Singleton
private static final StringBuilderPool sInstance = new StringBuilderPool();
+ private static final boolean DEBUG = false;
private StringBuilderPool() {}
- // TODO: Make this a normal array with a size of 20
+ // TODO: Make this a normal array with a size of 20, or a ConcurrentQueue
private final List<StringBuilder> mPool =
Collections.synchronizedList(new ArrayList<StringBuilder>());
public static StringBuilder getStringBuilder(final int initialSize) {
+ // TODO: although the pool is synchronized, the following is not thread-safe.
+ // Two threads entering this at the same time could take the same size of the pool and the
+ // second to attempt removing this index from the pool would crash with an
+ // IndexOutOfBoundsException.
+ // At the moment this pool is only used in Suggest.java and only in one thread so it's
+ // okay. The simplest thing to do here is probably to replace the ArrayList with a
+ // ConcurrentQueue.
final int poolSize = sInstance.mPool.size();
final StringBuilder sb = poolSize > 0 ? (StringBuilder) sInstance.mPool.remove(poolSize - 1)
: new StringBuilder(initialSize);
@@ -40,6 +48,12 @@ public class StringBuilderPool {
}
public static void recycle(final StringBuilder garbage) {
+ if (DEBUG) {
+ final int gid = garbage.hashCode();
+ for (final StringBuilder q : sInstance.mPool) {
+ if (gid == q.hashCode()) throw new RuntimeException("Duplicate id " + gid);
+ }
+ }
sInstance.mPool.add(garbage);
}
diff --git a/java/src/com/android/inputmethod/latin/Suggest.java b/java/src/com/android/inputmethod/latin/Suggest.java
index e3cb6987a6..29b629576b 100644
--- a/java/src/com/android/inputmethod/latin/Suggest.java
+++ b/java/src/com/android/inputmethod/latin/Suggest.java
@@ -284,7 +284,14 @@ public class Suggest implements Dictionary.WordCallback {
}
protected void addBigramToSuggestions(CharSequence bigram) {
- mSuggestions.add(bigram);
+ // TODO: Try to be a little more shrewd with resource allocation.
+ // At the moment we copy this object because the StringBuilders are pooled (see
+ // StringBuilderPool.java) and when we are finished using mSuggestions and
+ // mBigramSuggestions we will take everything from both and insert them back in the
+ // pool, so we can't allow the same object to be in both lists at the same time.
+ final StringBuilder sb = StringBuilderPool.getStringBuilder(getApproxMaxWordLength());
+ sb.append(bigram);
+ mSuggestions.add(sb);
}
// TODO: cleanup dictionaries looking up and suggestions building with SuggestedWords.Builder
--
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