Track crashing during migration to avoid crash loop.

Bug: 16213554
Bug: 16235703
Change-Id: Ib29b1a84b4c6ebae06d3dc6448f3c274ec6a7aab

java/src/com/android/inputmethod/latin/BinaryDictionary.java

@@ -80,6 +80,7 @@ public final class BinaryDictionary extends Dictionary {
     public static final int FORMAT_WORD_PROPERTY_COUNT_INDEX = 3;
 
     public static final String DICT_FILE_NAME_SUFFIX_FOR_MIGRATION = ".migrate";
+    public static final String DIR_NAME_SUFFIX_FOR_RECORD_MIGRATION = ".migrating";
 
     private long mNativeDict;
     private final Locale mLocale;
@@ -559,6 +560,20 @@ public final class BinaryDictionary extends Dictionary {
         if (!isValidDictionary()) {
             return false;
         }
+        final File isMigratingDir =
+                new File(mDictFilePath + DIR_NAME_SUFFIX_FOR_RECORD_MIGRATION);
+        if (isMigratingDir.exists()) {
+            isMigratingDir.delete();
+            Log.e(TAG, "Previous migration attempt failed probably due to a crash. "
+                        + "Giving up using the old dictionary (" + mDictFilePath + ").");
+            return false;
+        }
+        if (!isMigratingDir.mkdir()) {
+            Log.e(TAG, "Cannot create a dir (" + isMigratingDir.getAbsolutePath()
+                    + ") to record migration.");
+            return false;
+        }
+        try {
             final String tmpDictFilePath = mDictFilePath + DICT_FILE_NAME_SUFFIX_FOR_MIGRATION;
             if (!migrateNative(mNativeDict, tmpDictFilePath, newFormatVersion)) {
                 return false;
@@ -575,6 +590,9 @@ public final class BinaryDictionary extends Dictionary {
             loadDictionary(dictFile.getAbsolutePath(), 0 /* startOffset */,
                     dictFile.length(), mIsUpdatable);
             return true;
+        } finally {
+            isMigratingDir.delete();
+        }
     }
 
     @UsedForTesting