Make informational queries respect requested projection

Fixed:
- DisplayPhoto.CONTENT_MAX_DIMENSIONS_URI
- StreamItems.CONTENT_LIMIT_URI

Also now ProviderStatus now throws when a non-existent column is requested.

Change-Id: I03c82c31fe78a30d4929335dfb8efc3bff3bc76b
diff --git a/src/com/android/providers/contacts/ContactsProvider2.java b/src/com/android/providers/contacts/ContactsProvider2.java
index 6de16df..8822c44 100644
--- a/src/com/android/providers/contacts/ContactsProvider2.java
+++ b/src/com/android/providers/contacts/ContactsProvider2.java
@@ -57,6 +57,7 @@
 import com.google.android.collect.Maps;
 import com.google.android.collect.Sets;
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
 
 import android.accounts.Account;
 import android.accounts.AccountManager;
@@ -5253,9 +5254,8 @@
             }
 
             case STREAM_ITEMS_LIMIT: {
-                MatrixCursor cursor = new MatrixCursor(new String[]{StreamItems.MAX_ITEMS}, 1);
-                cursor.addRow(new Object[]{MAX_STREAM_ITEMS_PER_RAW_CONTACT});
-                return cursor;
+                return buildSingleRowResult(projection, new String[] {StreamItems.MAX_ITEMS},
+                        new Object[] {MAX_STREAM_ITEMS_PER_RAW_CONTACT});
             }
 
             case STREAM_ITEMS_PHOTOS: {
@@ -5283,11 +5283,9 @@
             }
 
             case PHOTO_DIMENSIONS: {
-                MatrixCursor cursor = new MatrixCursor(
-                        new String[]{DisplayPhoto.DISPLAY_MAX_DIM, DisplayPhoto.THUMBNAIL_MAX_DIM},
-                        1);
-                cursor.addRow(new Object[]{mMaxDisplayPhotoDim, mMaxThumbnailPhotoDim});
-                return cursor;
+                return buildSingleRowResult(projection,
+                        new String[] {DisplayPhoto.DISPLAY_MAX_DIM, DisplayPhoto.THUMBNAIL_MAX_DIM},
+                        new Object[] {mMaxDisplayPhotoDim, mMaxThumbnailPhotoDim});
             }
 
             case PHONES:
@@ -5848,7 +5846,9 @@
             }
 
             case PROVIDER_STATUS: {
-                return queryProviderStatus(uri, projection);
+                return buildSingleRowResult(projection,
+                        new String[] {ProviderStatus.STATUS, ProviderStatus.DATA1},
+                        new Object[] {mProviderStatus, mEstimatedStorageRequirement});
             }
 
             case DIRECTORIES : {
@@ -5908,21 +5908,6 @@
         return c;
     }
 
-    /**
-     * Creates a single-row cursor containing the current status of the provider.
-     */
-    private Cursor queryProviderStatus(Uri uri, String[] projection) {
-        MatrixCursor cursor = new MatrixCursor(projection);
-        RowBuilder row = cursor.newRow();
-        for (int i = 0; i < projection.length; i++) {
-            if (ProviderStatus.STATUS.equals(projection[i])) {
-                row.add(mProviderStatus);
-            } else if (ProviderStatus.DATA1.equals(projection[i])) {
-                row.add(mEstimatedStorageRequirement);
-            }
-        }
-        return cursor;
-    }
 
     /**
      * Runs the query with the supplied contact ID and lookup ID.  If the query succeeds,
@@ -8131,6 +8116,39 @@
     }
 
     /**
+     * Create a single row cursor for a simple, informational queries, such as
+     * {@link ProviderStatus#CONTENT_URI}.
+     */
+    @VisibleForTesting
+    static Cursor buildSingleRowResult(String[] projection, String[] availableColumns,
+            Object[] data) {
+        Preconditions.checkArgument(availableColumns.length == data.length);
+        if (projection == null) {
+            projection = availableColumns;
+        }
+        final MatrixCursor c = new MatrixCursor(projection, 1);
+        final RowBuilder row = c.newRow();
+
+        // It's O(n^2), but it's okay because we only have a few columns.
+        for (int i = 0; i < c.getColumnCount(); i++) {
+            final String column = c.getColumnName(i);
+
+            boolean found = false;
+            for (int j = 0; j < availableColumns.length; j++) {
+                if (availableColumns[j].equals(column)) {
+                    row.add(data[j]);
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) {
+                throw new IllegalArgumentException("Invalid column " + projection[i]);
+            }
+        }
+        return c;
+    }
+
+    /**
      * @return the currently active {@link ContactsDatabaseHelper} for the current thread.
      */
     @NeededForTesting
diff --git a/tests/src/com/android/providers/contacts/ContactsProvider2Test.java b/tests/src/com/android/providers/contacts/ContactsProvider2Test.java
index bef077c..c7f7dcb 100644
--- a/tests/src/com/android/providers/contacts/ContactsProvider2Test.java
+++ b/tests/src/com/android/providers/contacts/ContactsProvider2Test.java
@@ -6393,6 +6393,53 @@
         cursor.close();
     }
 
+    public void testBuildSingleRowResult() {
+        checkBuildSingleRowResult(
+                new String[] {"b"},
+                new String[] {"a", "b"},
+                new Integer[] {1, 2},
+                new Integer[] {2}
+                );
+
+        checkBuildSingleRowResult(
+                new String[] {"b", "a", "b"},
+                new String[] {"a", "b"},
+                new Integer[] {1, 2},
+                new Integer[] {2, 1, 2}
+                );
+
+        checkBuildSingleRowResult(
+                null, // all columns
+                new String[] {"a", "b"},
+                new Integer[] {1, 2},
+                new Integer[] {1, 2}
+                );
+
+        try {
+            // Access non-existent column
+            ContactsProvider2.buildSingleRowResult(new String[] {"a"}, new String[] {"b"},
+                    new Object[] {1});
+            fail();
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    private void checkBuildSingleRowResult(String[] projection, String[] availableColumns,
+            Object[] data, Integer[] expectedValues) {
+        final Cursor c = ContactsProvider2.buildSingleRowResult(projection, availableColumns, data);
+        try {
+            assertTrue(c.moveToFirst());
+            assertEquals(1, c.getCount());
+            assertEquals(expectedValues.length, c.getColumnCount());
+
+            for (int i = 0; i < expectedValues.length; i++) {
+                assertEquals("column " + i, expectedValues[i], (Integer) c.getInt(i));
+            }
+        } finally {
+            c.close();
+        }
+    }
+
     private Cursor queryGroupMemberships(Account account) {
         Cursor c = mResolver.query(maybeAddAccountQueryParameters(Data.CONTENT_URI, account),
                 new String[]{GroupMembership.GROUP_ROW_ID, GroupMembership.RAW_CONTACT_ID},