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

1 files changed, 141 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/BinaryDictionaryFileDumper.java b/java/src/com/android/inputmethod/latin/BinaryDictionaryFileDumper.java
new file mode 100644
index 000000000..d0464dd94
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/BinaryDictionaryFileDumper.java
@@ -0,0 +1,141 @@
+/*
+ * 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.ContentResolver;
+import android.content.Context;
+import android.net.Uri;
+import android.text.TextUtils;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Locale;
+
+/**
+ * Group class for static methods to help with creation and getting of the binary dictionary
+ * file from the dictionary provider
+ */
+public class BinaryDictionaryFileDumper {
+    /**
+     * The size of the temporary buffer to copy files.
+     */
+    static final int FILE_READ_BUFFER_SIZE = 1024;
+
+    // Prevents this class to be accidentally instantiated.
+    private BinaryDictionaryFileDumper() {
+    }
+
+    /**
+     * Generates a file name that matches the locale passed as an argument.
+     * The file name is basically the result of the .toString() method, except we replace
+     * any @File.separator with an underscore to avoid generating a file name that may not
+     * be created.
+     * @param locale the locale for which to get the file name
+     * @param context the context to use for getting the directory
+     * @return the name of the file to be created
+     */
+    private static String getCacheFileNameForLocale(Locale locale, Context context) {
+        // The following assumes two things :
+        // 1. That File.separator is not the same character as "_"
+        //    I don't think any android system will ever use "_" as a path separator
+        // 2. That no two locales differ by only a File.separator versus a "_"
+        //    Since "_" can't be part of locale components this should be safe.
+        // Examples:
+        // en -> en
+        // en_US_POSIX -> en_US_POSIX
+        // en__foo/bar -> en__foo_bar
+        final String[] separator = { File.separator };
+        final String[] empty = { "_" };
+        final CharSequence basename = TextUtils.replace(locale.toString(), separator, empty);
+        return context.getFilesDir() + File.separator + basename;
+    }
+
+    /**
+     * Return for a given locale the provider URI to query to get the dictionary.
+     */
+    public static Uri getProviderUri(Locale locale) {
+        return new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT)
+                .authority(BinaryDictionary.DICTIONARY_PACK_AUTHORITY).appendPath(
+                        locale.toString()).build();
+    }
+
+    /**
+     * Queries a content provider for dictionary data for some locale and returns it as a file name.
+     *
+     * This will query a content provider for dictionary data for a given locale, and return
+     * the name of a file suitable to be mmap'ed. It will copy it to local storage if needed.
+     * It should also check the dictionary version to avoid unnecessary copies but this is
+     * still in TODO state.
+     * This will make the data from the content provider the cached dictionary for this locale,
+     * overwriting any previous cached data.
+     * @returns the name of the file, or null if no data could be obtained.
+     * @throw FileNotFoundException if the provider returns non-existent data.
+     * @throw IOException if the provider-returned data could not be read.
+     */
+    public static String getDictionaryFileFromContentProvider(Locale locale, Context context)
+            throws FileNotFoundException, IOException {
+        // TODO: check whether the dictionary is the same or not and if it is, return the cached
+        // file.
+        final ContentResolver resolver = context.getContentResolver();
+        final Uri dictionaryPackUri = getProviderUri(locale);
+        final InputStream stream = resolver.openInputStream(dictionaryPackUri);
+        if (null == stream) return null;
+        return copyFileTo(stream, getCacheFileNameForLocale(locale, context));
+    }
+
+    /**
+     * Accepts a file as dictionary data for some locale and returns the name of a file.
+     *
+     * This will make the data in the input file the cached dictionary for this locale, overwriting
+     * any previous cached data.
+     */
+    public static String getDictionaryFileFromFile(String fileName, Locale locale,
+            Context context) throws FileNotFoundException, IOException {
+        return copyFileTo(new FileInputStream(fileName), getCacheFileNameForLocale(locale,
+                context));
+    }
+
+    /**
+     * Accepts a resource number as dictionary data for some locale and returns the name of a file.
+     *
+     * This will make the resource the cached dictionary for this locale, overwriting any previous
+     * cached data.
+     */
+    public static String getDictionaryFileFromResource(int resource, Locale locale,
+            Context context) throws FileNotFoundException, IOException {
+        return copyFileTo(context.getResources().openRawResource(resource),
+                getCacheFileNameForLocale(locale, context));
+    }
+
+    /**
+     * Copies the data in an input stream to a target file, creating the file if necessary and
+     * overwriting it if it already exists.
+     */
+    private static String copyFileTo(final InputStream input, final String outputFileName)
+            throws FileNotFoundException, IOException {
+        final byte[] buffer = new byte[FILE_READ_BUFFER_SIZE];
+        final FileOutputStream output = new FileOutputStream(outputFileName);
+        for (int readBytes = input.read(buffer); readBytes >= 0; readBytes = input.read(buffer))
+            output.write(buffer, 0, readBytes);
+        input.close();
+        return outputFileName;
+    }
+}