Index Data to build Slices in Settings

The indexing is done by taking the indexable fragments from
search, grabbing their XML via SearchIndexableResources, and
then looking for controllers defined in preferences.

For each controller found, we take the combination of the
fragment providing the XML and the Preference info to create
an indexable row.

Buiding a Slice will be handled in a subsquent CL, but a
prototype can be found here: ag/3324435

Test: robotests
Bug: 67996923
Change-Id: I48668618079bcc3da55ab77b7323ee8e467073af

src/com/android/settings/slices/SlicesDatabaseHelper.java

@@ -1,12 +1,30 @@
+/*
+ * Copyright (C) 2017 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.settings.slices;
 
 import android.content.Context;
 
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
+import android.os.Build;
+import android.support.annotation.VisibleForTesting;
 import android.util.Log;
 
-import com.android.internal.annotations.VisibleForTesting;
+import java.util.Locale;
 
 /**
  * Defines the schema for the Slices database.
@@ -38,7 +56,7 @@ public class SlicesDatabaseHelper extends SQLiteOpenHelper {
         /**
          * Summary / Subtitle for the setting.
          */
-        String SUBTITLE = "subtitle";
+        String SUMMARY = "summary";
 
         /**
          * Title of the Setting screen on which the Setting lives.
@@ -69,7 +87,7 @@ public class SlicesDatabaseHelper extends SQLiteOpenHelper {
                     ", " +
                     IndexColumns.TITLE +
                     ", " +
-                    IndexColumns.SUBTITLE +
+                    IndexColumns.SUMMARY +
                     ", " +
                     IndexColumns.SCREENTITLE +
                     ", " +
@@ -82,7 +100,16 @@ public class SlicesDatabaseHelper extends SQLiteOpenHelper {
 
     private final Context mContext;
 
-    public SlicesDatabaseHelper(Context context) {
+    private static SlicesDatabaseHelper sSingleton;
+
+    public static synchronized SlicesDatabaseHelper getInstance(Context context) {
+        if (sSingleton == null) {
+            sSingleton = new SlicesDatabaseHelper(context);
+        }
+        return sSingleton;
+    }
+
+    private SlicesDatabaseHelper(Context context) {
         super(context, DATABASE_NAME, null /* CursorFactor */, DATABASE_VERSION);
         mContext = context;
     }
@@ -100,7 +127,11 @@ public class SlicesDatabaseHelper extends SQLiteOpenHelper {
         }
     }
 
-    @VisibleForTesting
+    /**
+     * Drops the currently stored databases rebuilds them.
+     * Also un-marks the state of the data such that any subsequent call to
+     * {@link#isNewIndexingState(Context)} will return {@code true}.
+     */
     void reconstruct(SQLiteDatabase db) {
         mContext.getSharedPreferences(SHARED_PREFS_TAG, Context.MODE_PRIVATE)
                 .edit()
@@ -110,13 +141,61 @@ public class SlicesDatabaseHelper extends SQLiteOpenHelper {
         createDatabases(db);
     }
 
+    /**
+     * Marks the current state of the device for the validity of the data. Should be called after
+     * a full index of the TABLE_SLICES_INDEX.
+     */
+    public void setIndexedState() {
+        setBuildIndexed();
+        setLocaleIndexed();
+    }
+
+    /**
+     * Indicates if the indexed slice data reflects the current state of the phone.
+     *
+     * @return {@code true} if database should be rebuilt, {@code false} otherwise.
+     */
+    public boolean isSliceDataIndexed() {
+        return isBuildIndexed() && isLocaleIndexed();
+    }
+
     private void createDatabases(SQLiteDatabase db) {
         db.execSQL(CREATE_SLICES_TABLE);
         Log.d(TAG, "Created databases");
     }
 
-
     private void dropTables(SQLiteDatabase db) {
         db.execSQL("DROP TABLE IF EXISTS " + Tables.TABLE_SLICES_INDEX);
     }
+
+    private void setBuildIndexed() {
+        mContext.getSharedPreferences(SHARED_PREFS_TAG, 0 /* mode */)
+                .edit()
+                .putBoolean(getBuildTag(), true /* value */)
+                .apply();
+    }
+
+    private void setLocaleIndexed() {
+        mContext.getSharedPreferences(SHARED_PREFS_TAG, Context.MODE_PRIVATE)
+                .edit()
+                .putBoolean(Locale.getDefault().toString(), true /* value */)
+                .apply();
+    }
+
+    private boolean isBuildIndexed() {
+        return mContext.getSharedPreferences(SHARED_PREFS_TAG,
+                Context.MODE_PRIVATE)
+                .getBoolean(getBuildTag(), false /* default */);
+    }
+
+    private boolean isLocaleIndexed() {
+        return mContext.getSharedPreferences(SHARED_PREFS_TAG,
+                Context.MODE_PRIVATE)
+                .getBoolean(Locale.getDefault().toString(), false /* default */);
+    }
+
+    @VisibleForTesting
+    String getBuildTag() {
+        return Build.FINGERPRINT;
+    }
 }