Adding content provider for exposing launcher grid settings

Bug: 122262084
Change-Id: I3e89e0a9400fb3e81f932af3606eb49c36d34894

src/com/android/launcher3/graphics/GridOptionsProvider.java

@@ -0,0 +1,157 @@
+package com.android.launcher3.graphics;
+
+import android.content.ContentProvider;
+import android.content.ContentValues;
+import android.content.res.XmlResourceParser;
+import android.database.Cursor;
+import android.database.MatrixCursor;
+import android.graphics.Bitmap;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.ParcelFileDescriptor;
+import android.os.ParcelFileDescriptor.AutoCloseOutputStream;
+import android.text.TextUtils;
+import android.util.Log;
+import android.util.Xml;
+
+import com.android.launcher3.InvariantDeviceProfile;
+import com.android.launcher3.InvariantDeviceProfile.GridOption;
+import com.android.launcher3.R;
+import com.android.launcher3.util.LooperExecutor;
+import com.android.launcher3.util.UiThreadHelper;
+
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.Future;
+
+/**
+ * Exposes various launcher grid options and allows the caller to change them.
+ * APIs:
+ *      /list_options: List the various available grip options, has following columns
+ *          name: name of the grid
+ *          rows: number of rows in the grid
+ *          cols: number of columns in the grid
+ *          preview_count: number of previews available for this grid option. The preview uri
+ *                         looks like /preview/<grid-name>/<preview index starting with 0>
+ *          is_default: true if this grid is currently active
+ *
+ *     /preview: Opens a file stream for the grid preview
+ */
+public class GridOptionsProvider extends ContentProvider {
+
+    private static final String TAG = "GridOptionsProvider";
+
+    private static final String KEY_NAME = "name";
+    private static final String KEY_ROWS = "rows";
+    private static final String KEY_COLS = "cols";
+    private static final String KEY_PREVIEW_COUNT = "preview_count";
+    private static final String KEY_IS_DEFAULT = "is_default";
+
+    private static final String KEY_PREVIEW = "preview";
+    private static final String MIME_TYPE_PNG = "image/png";
+
+    public static final PipeDataWriter<Future<Bitmap>> BITMAP_WRITER =
+            new PipeDataWriter<Future<Bitmap>>() {
+                @Override
+                public void writeDataToPipe(ParcelFileDescriptor output, Uri uri, String s,
+                        Bundle bundle, Future<Bitmap> bitmap) {
+                    try (AutoCloseOutputStream os = new AutoCloseOutputStream(output)) {
+                        bitmap.get().compress(Bitmap.CompressFormat.PNG, 100, os);
+                    } catch (Exception e) {
+                        Log.w(TAG, "fail to write to pipe", e);
+                    }
+                }
+            };
+
+    @Override
+    public boolean onCreate() {
+        return true;
+    }
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection,
+            String[] selectionArgs, String sortOrder) {
+        // TODO: Validate the query uri
+        MatrixCursor cursor = new MatrixCursor(new String[] {
+                KEY_NAME, KEY_ROWS, KEY_COLS, KEY_PREVIEW_COUNT, KEY_IS_DEFAULT});
+        InvariantDeviceProfile idp = InvariantDeviceProfile.INSTANCE.get(getContext());
+        try (XmlResourceParser parser = getContext().getResources().getXml(R.xml.device_profiles)) {
+            final int depth = parser.getDepth();
+            int type;
+            while (((type = parser.next()) != XmlPullParser.END_TAG ||
+                    parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {
+                if ((type == XmlPullParser.START_TAG) && "grid-option".equals(parser.getName())) {
+                    GridOption gridOption = new GridOption(
+                            getContext(), Xml.asAttributeSet(parser));
+
+                    cursor.newRow()
+                            .add(KEY_NAME, gridOption.name)
+                            .add(KEY_ROWS, gridOption.numRows)
+                            .add(KEY_COLS, gridOption.numColumns)
+                            .add(KEY_PREVIEW_COUNT, 1)
+                            .add(KEY_IS_DEFAULT, idp.numColumns == gridOption.numColumns
+                                    && idp.numRows == gridOption.numRows);
+                }
+            }
+        } catch (IOException | XmlPullParserException e) {
+            Log.e(TAG, "Error parsing device profile", e);
+        }
+
+        return cursor;
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        List<String> segments = uri.getPathSegments();
+        if (segments.size() > 0 && KEY_PREVIEW.equals(segments.get(0))) {
+            return MIME_TYPE_PNG;
+        }
+        return "vnd.android.cursor.dir/launcher_grid";
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues initialValues) {
+        return null;
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        return 0;
+    }
+
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        return 0;
+    }
+
+    @Override
+    public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+        List<String> segments = uri.getPathSegments();
+        if (segments.size() < 2 || !KEY_PREVIEW.equals(segments.get(0))) {
+            throw new FileNotFoundException("Invalid preview url");
+        }
+        String profileName = segments.get(1);
+        if (TextUtils.isEmpty(profileName)) {
+            throw new FileNotFoundException("Invalid preview url");
+        }
+
+        InvariantDeviceProfile idp;
+        try {
+            idp = new InvariantDeviceProfile(getContext(), profileName);
+        } catch (Exception e) {
+            throw new FileNotFoundException(e.getMessage());
+        }
+
+        LooperExecutor executor = new LooperExecutor(UiThreadHelper.getBackgroundLooper());
+        try {
+            return openPipeHelper(uri, MIME_TYPE_PNG, null,
+                    executor.submit(new LauncherPreviewRenderer(getContext(), idp)), BITMAP_WRITER);
+        } catch (Exception e) {
+            throw new FileNotFoundException(e.getMessage());
+        }
+    }
+}