Show MTP device as root when it has multiple/zero storages.

The CL updates MtpDocumentsProvider#queryRoots so that it fetches
devices from Database as well as storages when we don't have storages
under the device, or when we have multiple storages under the device.

BUG=26120019
Change-Id: Id2b140f00a1d49fa4da7e17d2564dbbaa1795e1e
diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/Mapper.java b/packages/MtpDocumentsProvider/src/com/android/mtp/Mapper.java
index cb49535e..ac47067 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/Mapper.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/Mapper.java
@@ -66,10 +66,13 @@
         database.beginTransaction();
         try {
             final ContentValues[] valuesList = new ContentValues[1];
+            final ContentValues[] extraValuesList = new ContentValues[1];
             valuesList[0] = new ContentValues();
-            MtpDatabase.getDeviceDocumentValues(valuesList[0], device);
+            extraValuesList[0] = new ContentValues();
+            MtpDatabase.getDeviceDocumentValues(valuesList[0], extraValuesList[0], device);
             final boolean changed = putDocuments(
                     valuesList,
+                    extraValuesList,
                     COLUMN_PARENT_DOCUMENT_ID + " IS NULL",
                     EMPTY_ARGS,
                     /* heuristic */ false,
@@ -88,7 +91,7 @@
      * @param roots List of root information.
      * @return If roots are added or removed from the database.
      */
-    synchronized boolean putRootDocuments(
+    synchronized boolean putStorageDocuments(
             String parentDocumentId, Resources resources, MtpRoot[] roots) {
         final SQLiteDatabase database = mDatabase.getSQLiteDatabase();
         database.beginTransaction();
@@ -109,36 +112,21 @@
                     throw new Error("Unexpected map mode.");
             }
             final ContentValues[] valuesList = new ContentValues[roots.length];
+            final ContentValues[] extraValuesList = new ContentValues[roots.length];
             for (int i = 0; i < roots.length; i++) {
                 valuesList[i] = new ContentValues();
+                extraValuesList[i] = new ContentValues();
                 MtpDatabase.getStorageDocumentValues(
-                        valuesList[i], resources, parentDocumentId, roots[i]);
+                        valuesList[i], extraValuesList[i], resources, parentDocumentId, roots[i]);
             }
             final boolean changed = putDocuments(
                     valuesList,
+                    extraValuesList,
                     COLUMN_PARENT_DOCUMENT_ID + "=?",
                     strings(parentDocumentId),
                     heuristic,
                     mapColumn);
-            final ContentValues values = new ContentValues();
-            int i = 0;
-            for (final MtpRoot root : roots) {
-                // Use the same value for the root ID and the corresponding document ID.
-                final String documentId = valuesList[i++].getAsString(Document.COLUMN_DOCUMENT_ID);
-                // If it fails to insert/update documents, the document ID will be set with -1.
-                // In this case we don't insert/update root extra information neither.
-                if (documentId == null) {
-                    continue;
-                }
-                values.put(Root.COLUMN_ROOT_ID, documentId);
-                values.put(
-                        Root.COLUMN_FLAGS,
-                        Root.FLAG_SUPPORTS_IS_CHILD | Root.FLAG_SUPPORTS_CREATE);
-                values.put(Root.COLUMN_AVAILABLE_BYTES, root.mFreeSpace);
-                values.put(Root.COLUMN_CAPACITY_BYTES, root.mMaxCapacity);
-                values.put(Root.COLUMN_MIME_TYPES, "");
-                database.replace(TABLE_ROOT_EXTRA, null, values);
-            }
+
             database.setTransactionSuccessful();
             return changed;
         } finally {
@@ -176,6 +164,7 @@
         }
         putDocuments(
                 valuesList,
+                null,
                 COLUMN_PARENT_DOCUMENT_ID + "=?",
                 strings(parentId),
                 heuristic,
@@ -257,6 +246,7 @@
      * rows. If the methods adds rows to database, it updates valueList with correct document ID.
      *
      * @param valuesList Values for documents to be stored in the database.
+     * @param rootExtraValuesList Values for root extra to be stored in the database.
      * @param selection SQL where closure to select rows that shares the same parent.
      * @param args Argument for selection SQL.
      * @param heuristic Whether the mapping mode is heuristic.
@@ -264,6 +254,7 @@
      */
     private boolean putDocuments(
             ContentValues[] valuesList,
+            @Nullable ContentValues[] rootExtraValuesList,
             String selection,
             String[] args,
             boolean heuristic,
@@ -272,7 +263,14 @@
         boolean added = false;
         database.beginTransaction();
         try {
-            for (final ContentValues values : valuesList) {
+            for (int i = 0; i < valuesList.length; i++) {
+                final ContentValues values = valuesList[i];
+                final ContentValues rootExtraValues;
+                if (rootExtraValuesList != null) {
+                    rootExtraValues = rootExtraValuesList[i];
+                } else {
+                    rootExtraValues = null;
+                }
                 final Cursor candidateCursor = database.query(
                         TABLE_DOCUMENTS,
                         strings(Document.COLUMN_DOCUMENT_ID),
@@ -290,25 +288,26 @@
                     final long rowId;
                     if (candidateCursor.getCount() == 0) {
                         rowId = database.insert(TABLE_DOCUMENTS, null, values);
-                        if (rowId == -1) {
-                            throw new SQLiteException("Failed to put a document into database.");
-                        }
                         added = true;
                     } else if (!heuristic) {
                         candidateCursor.moveToNext();
-                        final String documentId = candidateCursor.getString(0);
-                        rowId = database.update(
+                        rowId = candidateCursor.getLong(0);
+                        database.update(
                                 TABLE_DOCUMENTS,
                                 values,
                                 SELECTION_DOCUMENT_ID,
-                                strings(documentId));
+                                strings(rowId));
                     } else {
                         values.put(COLUMN_ROW_STATE, ROW_STATE_PENDING);
-                        rowId = database.insert(TABLE_DOCUMENTS, null, values);
+                        rowId = database.insertOrThrow(TABLE_DOCUMENTS, null, values);
                     }
                     // Document ID is a primary integer key of the table. So the returned row
                     // IDs should be same with the document ID.
                     values.put(Document.COLUMN_DOCUMENT_ID, rowId);
+                    if (rootExtraValues != null) {
+                        rootExtraValues.put(Root.COLUMN_ROOT_ID, rowId);
+                        database.replace(TABLE_ROOT_EXTRA, null, rootExtraValues);
+                    }
                 } finally {
                     candidateCursor.close();
                 }
diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java
index 10941eb..112914e 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java
@@ -23,6 +23,9 @@
 import android.content.Context;
 import android.content.res.Resources;
 import android.database.Cursor;
+import android.database.DatabaseUtils;
+import android.database.MatrixCursor;
+import android.database.MatrixCursor.RowBuilder;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.database.sqlite.SQLiteQueryBuilder;
@@ -106,17 +109,93 @@
      * @return Database cursor.
      */
     Cursor queryRoots(String[] columnNames) {
-        final SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
-        builder.setTables(JOIN_ROOTS);
-        builder.setProjectionMap(COLUMN_MAP_ROOTS);
-        return builder.query(
-                mDatabase,
-                columnNames,
-                COLUMN_ROW_STATE + " IN (?, ?) AND " + COLUMN_DOCUMENT_TYPE + " = ?",
-                strings(ROW_STATE_VALID, ROW_STATE_INVALIDATED, DOCUMENT_TYPE_STORAGE),
+        final String selection =
+                COLUMN_ROW_STATE + " IN (?, ?) AND " + COLUMN_DOCUMENT_TYPE + " = ?";
+        final Cursor deviceCursor = mDatabase.query(
+                TABLE_DOCUMENTS,
+                strings(COLUMN_DEVICE_ID),
+                selection,
+                strings(ROW_STATE_VALID, ROW_STATE_INVALIDATED, DOCUMENT_TYPE_DEVICE),
+                COLUMN_DEVICE_ID,
                 null,
                 null,
                 null);
+
+        try {
+            final SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
+            builder.setTables(JOIN_ROOTS);
+            builder.setProjectionMap(COLUMN_MAP_ROOTS);
+            final MatrixCursor result = new MatrixCursor(columnNames);
+            final ContentValues values = new ContentValues();
+
+            while (deviceCursor.moveToNext()) {
+                final int deviceId = deviceCursor.getInt(0);
+                final Cursor storageCursor = builder.query(
+                        mDatabase,
+                        columnNames,
+                        selection + " AND " + COLUMN_DEVICE_ID + " = ?",
+                        strings(ROW_STATE_VALID,
+                                ROW_STATE_INVALIDATED,
+                                DOCUMENT_TYPE_STORAGE,
+                                deviceId),
+                        null,
+                        null,
+                        null);
+                try {
+                    values.clear();
+                    if (storageCursor.getCount() == 1) {
+                        storageCursor.moveToNext();
+                        DatabaseUtils.cursorRowToContentValues(storageCursor, values);
+                    } else {
+                        final Cursor cursor = builder.query(
+                                mDatabase,
+                                columnNames,
+                                selection + " AND " + COLUMN_DEVICE_ID + " = ?",
+                                strings(ROW_STATE_VALID,
+                                        ROW_STATE_INVALIDATED,
+                                        DOCUMENT_TYPE_DEVICE,
+                                        deviceId),
+                                null,
+                                null,
+                                null);
+                        try {
+                            cursor.moveToNext();
+                            DatabaseUtils.cursorRowToContentValues(cursor, values);
+                        } finally {
+                            cursor.close();
+                        }
+
+                        long capacityBytes = 0;
+                        long availableBytes = 0;
+                        int capacityIndex = cursor.getColumnIndex(Root.COLUMN_CAPACITY_BYTES);
+                        int availableIndex = cursor.getColumnIndex(Root.COLUMN_AVAILABLE_BYTES);
+                        while (storageCursor.moveToNext()) {
+                            // If requested columnNames does not include COLUMN_XXX_BYTES, we don't
+                            // calculate corresponding values.
+                            if (capacityIndex != -1) {
+                                capacityBytes += cursor.getLong(capacityIndex);
+                            }
+                            if (availableIndex != -1) {
+                                availableBytes += cursor.getLong(availableIndex);
+                            }
+                        }
+                        values.put(Root.COLUMN_CAPACITY_BYTES, capacityBytes);
+                        values.put(Root.COLUMN_AVAILABLE_BYTES, availableBytes);
+                    }
+                } finally {
+                    storageCursor.close();
+                }
+
+                final RowBuilder row = result.newRow();
+                for (final String key : values.keySet()) {
+                    row.add(key, values.get(key));
+                }
+            }
+
+            return result;
+        } finally {
+            deviceCursor.close();
+        }
     }
 
     /**
@@ -380,7 +459,10 @@
         context.deleteDatabase(DATABASE_NAME);
     }
 
-    static void getDeviceDocumentValues(ContentValues values, MtpDeviceRecord device) {
+    static void getDeviceDocumentValues(
+            ContentValues values,
+            ContentValues extraValues,
+            MtpDeviceRecord device) {
         values.clear();
         values.put(COLUMN_DEVICE_ID, device.deviceId);
         values.putNull(COLUMN_STORAGE_ID);
@@ -394,11 +476,15 @@
         values.putNull(Document.COLUMN_LAST_MODIFIED);
         values.put(Document.COLUMN_ICON, R.drawable.ic_root_mtp);
         values.put(Document.COLUMN_FLAGS, 0);
-        long size = 0;
-        for (final MtpRoot root : device.roots) {
-            size += root.mMaxCapacity - root.mFreeSpace;
-        }
-        values.put(Document.COLUMN_SIZE, size);
+        values.putNull(Document.COLUMN_SIZE);
+
+        extraValues.clear();
+        extraValues.put(
+                Root.COLUMN_FLAGS,
+                Root.FLAG_SUPPORTS_IS_CHILD | Root.FLAG_SUPPORTS_CREATE);
+        extraValues.putNull(Root.COLUMN_AVAILABLE_BYTES);
+        extraValues.putNull(Root.COLUMN_CAPACITY_BYTES);
+        extraValues.put(Root.COLUMN_MIME_TYPES, "");
     }
 
     /**
@@ -408,7 +494,11 @@
      * @param root Root to be converted {@link ContentValues}.
      */
     static void getStorageDocumentValues(
-            ContentValues values, Resources resources, String parentDocumentId, MtpRoot root) {
+            ContentValues values,
+            ContentValues extraValues,
+            Resources resources,
+            String parentDocumentId,
+            MtpRoot root) {
         values.clear();
         values.put(COLUMN_DEVICE_ID, root.mDeviceId);
         values.put(COLUMN_STORAGE_ID, root.mStorageId);
@@ -424,6 +514,13 @@
         values.put(Document.COLUMN_FLAGS, 0);
         values.put(Document.COLUMN_SIZE,
                 (int) Math.min(root.mMaxCapacity - root.mFreeSpace, Integer.MAX_VALUE));
+
+        extraValues.put(
+                Root.COLUMN_FLAGS,
+                Root.FLAG_SUPPORTS_IS_CHILD | Root.FLAG_SUPPORTS_CREATE);
+        extraValues.put(Root.COLUMN_AVAILABLE_BYTES, root.mFreeSpace);
+        extraValues.put(Root.COLUMN_CAPACITY_BYTES, root.mMaxCapacity);
+        extraValues.put(Root.COLUMN_MIME_TYPES, "");
     }
 
     /**
diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabaseConstants.java b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabaseConstants.java
index a233589..f252e0f 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabaseConstants.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabaseConstants.java
@@ -126,14 +126,14 @@
             Document.COLUMN_LAST_MODIFIED + " INTEGER," +
             Document.COLUMN_ICON + " INTEGER," +
             Document.COLUMN_FLAGS + " INTEGER NOT NULL," +
-            Document.COLUMN_SIZE + " INTEGER NOT NULL);";
+            Document.COLUMN_SIZE + " INTEGER);";
 
     static final String QUERY_CREATE_ROOT_EXTRA =
             "CREATE TABLE " + TABLE_ROOT_EXTRA + " (" +
             Root.COLUMN_ROOT_ID + " INTEGER PRIMARY KEY," +
             Root.COLUMN_FLAGS + " INTEGER NOT NULL," +
-            Root.COLUMN_AVAILABLE_BYTES + " INTEGER NOT NULL," +
-            Root.COLUMN_CAPACITY_BYTES + " INTEGER NOT NULL," +
+            Root.COLUMN_AVAILABLE_BYTES + " INTEGER," +
+            Root.COLUMN_CAPACITY_BYTES + " INTEGER," +
             Root.COLUMN_MIME_TYPES + " TEXT NOT NULL);";
 
     /**
@@ -145,18 +145,26 @@
         COLUMN_MAP_ROOTS = new HashMap<>();
         COLUMN_MAP_ROOTS.put(Root.COLUMN_ROOT_ID, TABLE_ROOT_EXTRA + "." + Root.COLUMN_ROOT_ID);
         COLUMN_MAP_ROOTS.put(Root.COLUMN_FLAGS, TABLE_ROOT_EXTRA + "." + Root.COLUMN_FLAGS);
-        COLUMN_MAP_ROOTS.put(Root.COLUMN_ICON, TABLE_DOCUMENTS + "." + Document.COLUMN_ICON);
         COLUMN_MAP_ROOTS.put(
-                Root.COLUMN_TITLE, TABLE_DOCUMENTS + "." + Document.COLUMN_DISPLAY_NAME);
-        COLUMN_MAP_ROOTS.put(Root.COLUMN_SUMMARY, TABLE_DOCUMENTS + "." + Document.COLUMN_SUMMARY);
+                Root.COLUMN_ICON,
+                TABLE_DOCUMENTS + "." + Document.COLUMN_ICON + " AS " + Root.COLUMN_ICON);
         COLUMN_MAP_ROOTS.put(
-                Root.COLUMN_DOCUMENT_ID, TABLE_DOCUMENTS + "." + Document.COLUMN_DOCUMENT_ID);
+                Root.COLUMN_TITLE,
+                TABLE_DOCUMENTS + "." + Document.COLUMN_DISPLAY_NAME + " AS " + Root.COLUMN_TITLE);
+        COLUMN_MAP_ROOTS.put(
+                Root.COLUMN_SUMMARY,
+                TABLE_DOCUMENTS + "." + Document.COLUMN_SUMMARY + " AS " + Root.COLUMN_SUMMARY);
+        COLUMN_MAP_ROOTS.put(
+                Root.COLUMN_DOCUMENT_ID,
+                TABLE_DOCUMENTS + "." + Document.COLUMN_DOCUMENT_ID +
+                " AS " + Root.COLUMN_DOCUMENT_ID);
         COLUMN_MAP_ROOTS.put(
                 Root.COLUMN_AVAILABLE_BYTES, TABLE_ROOT_EXTRA + "." + Root.COLUMN_AVAILABLE_BYTES);
         COLUMN_MAP_ROOTS.put(
                 Root.COLUMN_CAPACITY_BYTES, TABLE_ROOT_EXTRA + "." + Root.COLUMN_CAPACITY_BYTES);
         COLUMN_MAP_ROOTS.put(
                 Root.COLUMN_MIME_TYPES, TABLE_ROOT_EXTRA + "." + Root.COLUMN_MIME_TYPES);
+        COLUMN_MAP_ROOTS.put(COLUMN_DEVICE_ID, COLUMN_DEVICE_ID);
     }
 
     private static String createJoinFromClosure(
diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/RootScanner.java b/packages/MtpDocumentsProvider/src/com/android/mtp/RootScanner.java
index e6c2726..619ef54 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/RootScanner.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/RootScanner.java
@@ -127,7 +127,7 @@
                         continue;
                     }
                     mDatabase.getMapper().startAddingDocuments(documentId);
-                    if (mDatabase.getMapper().putRootDocuments(
+                    if (mDatabase.getMapper().putStorageDocuments(
                             documentId, mResources, device.roots)) {
                         changed = true;
                     }