1 files changed, 42 insertions, 30 deletions

diff --git a/java/src/com/android/inputmethod/research/FixedLogBuffer.java b/java/src/com/android/inputmethod/research/FixedLogBuffer.java
index 78dc59562..8b64de8ae 100644
--- a/java/src/com/android/inputmethod/research/FixedLogBuffer.java
+++ b/java/src/com/android/inputmethod/research/FixedLogBuffer.java
@@ -51,38 +51,36 @@ public class FixedLogBuffer extends LogBuffer {
         mNumActualWords = 0;
     }
 
-    protected int getNumActualWords() {
-        return mNumActualWords;
-    }
-
     /**
      * Adds a new LogUnit to the front of the LIFO queue, evicting existing LogUnit's
      * (oldest first) if word capacity is reached.
      */
     @Override
     public void shiftIn(final LogUnit newLogUnit) {
-        if (!newLogUnit.hasWord()) {
-            // This LogUnit isn't a word, so it doesn't count toward the word-limit.
+        if (!newLogUnit.hasOneOrMoreWords()) {
+            // This LogUnit doesn't contain any word, so it doesn't count toward the word-limit.
             super.shiftIn(newLogUnit);
             return;
         }
+        final int numWordsIncoming = newLogUnit.getNumWords();
         if (mNumActualWords >= mWordCapacity) {
             // Give subclass a chance to handle the buffer full condition by shifting out logUnits.
+            // TODO: Tell onBufferFull() how much space it needs to make to avoid forced eviction.
             onBufferFull();
             // If still full, evict.
             if (mNumActualWords >= mWordCapacity) {
-                shiftOutWords(1);
+                shiftOutWords(numWordsIncoming);
             }
         }
         super.shiftIn(newLogUnit);
-        mNumActualWords++; // Must be a word, or we wouldn't be here.
+        mNumActualWords += numWordsIncoming;
     }
 
     @Override
     public LogUnit unshiftIn() {
         final LogUnit logUnit = super.unshiftIn();
-        if (logUnit != null && logUnit.hasWord()) {
-            mNumActualWords--;
+        if (logUnit != null && logUnit.hasOneOrMoreWords()) {
+            mNumActualWords -= logUnit.getNumWords();
         }
         return logUnit;
     }
@@ -113,18 +111,28 @@ public class FixedLogBuffer extends LogBuffer {
     @Override
     public LogUnit shiftOut() {
         final LogUnit logUnit = super.shiftOut();
-        if (logUnit != null && logUnit.hasWord()) {
-            mNumActualWords--;
+        if (logUnit != null && logUnit.hasOneOrMoreWords()) {
+            mNumActualWords -= logUnit.getNumWords();
         }
         return logUnit;
     }
 
-    protected void shiftOutWords(final int numWords) {
-        final int targetNumWords = mNumActualWords - numWords;
-        final LinkedList<LogUnit> logUnits = getLogUnits();
-        while (mNumActualWords > targetNumWords && !logUnits.isEmpty()) {
-            shiftOut();
-        }
+    /**
+     * Remove LogUnits from the front of the LogBuffer until {@code numWords} have been removed.
+     *
+     * If there are less than {@code numWords} in the buffer, shifts out all {@code LogUnit}s.
+     *
+     * @param numWords the minimum number of words in {@link LogUnit}s to shift out
+     * @return the number of actual words LogUnit}s shifted out
+     */
+    protected int shiftOutWords(final int numWords) {
+        int numWordsShiftedOut = 0;
+        do {
+            final LogUnit logUnit = shiftOut();
+            if (logUnit == null) break;
+            numWordsShiftedOut += logUnit.getNumWords();
+        } while (numWordsShiftedOut < numWords);
+        return numWordsShiftedOut;
     }
 
     public void shiftOutAll() {
@@ -136,27 +144,31 @@ public class FixedLogBuffer extends LogBuffer {
     }
 
     /**
-     * Returns a list of {@link LogUnit}s at the front of the buffer that have associated words.  No
-     * more than {@code n} LogUnits will have words associated with them.  If there are not enough
-     * LogUnits in the buffer to meet the word requirement, returns the all LogUnits.
+     * Returns a list of {@link LogUnit}s at the front of the buffer that have words associated with
+     * them.
+     *
+     * There will be no more than {@code n} words in the returned list.  So if 2 words are
+     * requested, and the first LogUnit has 3 words, it is not returned.  If 2 words are requested,
+     * and the first LogUnit has only 1 word, and the next LogUnit 2 words, only the first LogUnit
+     * is returned.  If the first LogUnit has no words associated with it, and the second LogUnit
+     * has three words, then only the first LogUnit (which has no associated words) is returned.  If
+     * there are not enough LogUnits in the buffer to meet the word requirement, then all LogUnits
+     * will be returned.
      *
      * @param n The maximum number of {@link LogUnit}s with words to return.
      * @return The list of the {@link LogUnit}s containing the first n words
      */
     public ArrayList<LogUnit> peekAtFirstNWords(int n) {
         final LinkedList<LogUnit> logUnits = getLogUnits();
-        final int length = logUnits.size();
         // Allocate space for n*2 logUnits.  There will be at least n, one for each word, and
         // there may be additional for punctuation, between-word commands, etc.  This should be
         // enough that reallocation won't be necessary.
-        final ArrayList<LogUnit> list = new ArrayList<LogUnit>(n * 2);
-        for (int i = 0; i < length && n > 0; i++) {
-            final LogUnit logUnit = logUnits.get(i);
-            list.add(logUnit);
-            if (logUnit.hasWord()) {
-                n--;
-            }
+        final ArrayList<LogUnit> resultList = new ArrayList<LogUnit>(n * 2);
+        for (final LogUnit logUnit : logUnits) {
+            n -= logUnit.getNumWords();
+            if (n < 0) break;
+            resultList.add(logUnit);
         }
-        return list;
+        return resultList;
     }
 }