Merge "Add different ways of reading the dictionary file."

1 files changed, 96 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/BinaryDictionaryGetter.java b/java/src/com/android/inputmethod/latin/BinaryDictionaryGetter.java
new file mode 100644
index 000000000..72512c7e1
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/BinaryDictionaryGetter.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2011 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.Context;
+import android.content.res.AssetFileDescriptor;
+import android.util.Log;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.Locale;
+
+/**
+ * Helper class to get the address of a mmap'able dictionary file.
+ */
+class BinaryDictionaryGetter {
+
+    /**
+     * Used for Log actions from this class
+     */
+    private static final String TAG = BinaryDictionaryGetter.class.getSimpleName();
+
+    // Prevents this from being instantiated
+    private BinaryDictionaryGetter() {}
+
+    /**
+     * Returns a file address from a resource, or null if it cannot be opened.
+     */
+    private static AssetFileAddress loadFallbackResource(Context context, int fallbackResId) {
+        final AssetFileDescriptor afd = context.getResources().openRawResourceFd(fallbackResId);
+        if (afd == null) {
+            Log.e(TAG, "Found the resource but cannot read it. Is it compressed? resId="
+                    + fallbackResId);
+            return null;
+        }
+        return AssetFileAddress.makeFromFileNameAndOffset(
+                context.getApplicationInfo().sourceDir, afd.getStartOffset(), afd.getLength());
+    }
+
+    /**
+     * Returns a file address for a given locale, trying relevant methods in order.
+     *
+     * Tries to get a binary dictionary from various sources, in order:
+     * - Uses a private method of getting a private dictionary, as implemented by the
+     *   PrivateBinaryDictionaryGetter class.
+     * If that fails:
+     * - Uses a content provider to get a public dictionary, as per the protocol described
+     *   in BinaryDictionaryFileDumper.
+     * If that fails:
+     * - Gets a file name from the fallback resource passed as an argument.
+     * If that fails:
+     * - Returns null.
+     * @return The address of a valid file, or null.
+     * @throws FileNotFoundException if a dictionary provider returned a file name, but the
+     *                               file cannot be found.
+     * @throws IOException if there was an I/O problem reading or copying a file.
+     */
+    public static AssetFileAddress getDictionaryFile(Locale locale, Context context,
+            int fallbackResId) {
+        // Try first to query a private file signed the same way.
+        final AssetFileAddress privateFile =
+                PrivateBinaryDictionaryGetter.getDictionaryFile(locale, context);
+        if (null != privateFile) {
+            return privateFile;
+        } else {
+            try {
+                // If that was no-go, try to find a publicly exported dictionary.
+                final String fileName = BinaryDictionaryFileDumper.
+                        getDictionaryFileFromContentProvider(locale, context);
+                return AssetFileAddress.makeFromFileName(fileName);
+            } catch (FileNotFoundException e) {
+                Log.e(TAG, "Unable to create dictionary file from provider for locale "
+                        + locale.toString() + ": falling back to internal dictionary");
+                return loadFallbackResource(context, fallbackResId);
+            } catch (IOException e) {
+                Log.e(TAG, "Unable to read source data for locale "
+                        + locale.toString() + ": falling back to internal dictionary");
+                return loadFallbackResource(context, fallbackResId);
+            }
+        }
+    }
+}