Photo Picker Dialog: Use sandboxed utility process for decoding images.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/DecoderServiceHost.java

Index: chrome/android/java/src/org/chromium/chrome/browser/photo_picker/DecoderServiceHost.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/DecoderServiceHost.java b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/DecoderServiceHost.java
new file mode 100644
index 0000000000000000000000000000000000000000..ae83641d55fa713814cf056836969bc6a8377405
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/DecoderServiceHost.java
@@ -0,0 +1,294 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.photo_picker;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.ServiceConnection;
+import android.graphics.Bitmap;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.IBinder;
+import android.os.Message;
+import android.os.Messenger;
+import android.os.ParcelFileDescriptor;
+import android.os.RemoteException;
+import android.os.StrictMode;
+
+import org.chromium.base.Log;
+
+import java.io.File;
+import java.io.FileDescriptor;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.lang.ref.WeakReference;
+import java.util.LinkedHashMap;
+
+/**
+ * A class to communicate with the {@link DecoderService}.
+ */
+public class DecoderServiceHost {
+    // A tag for logging error messages.
+    private static final String TAG = "ImageDecoderHost";
+
+    /**
+     * Interface for notifying clients of the service being ready.
+     */
+    public interface ServiceReadyCallback {
+        /**
+         * A function to define to receive a notification once the service is up and running.
+         */
+        void serviceReady();
+    }
+
+    /**
+     * An interface notifying clients when an image has finished decoding.
+     */
+    public interface ImageDecodedCallback {
+        /**
+         * A function to define to receive a notification that an image has been decoded.
+         * @param filePath The file path for the newly decoded image.
+         * @param bitmap The results of the decoding (or placeholder image, if failed).
+         */
+        void imageDecodedCallback(String filePath, Bitmap bitmap);
+    }
+
+    /**
+     * Class for interacting with the main interface of the service.
+     */
+    private class DecoderServiceConnection implements ServiceConnection {
+        // The callback to use to notify the service being ready.
+        private ServiceReadyCallback mCallback;
+
+        public DecoderServiceConnection(ServiceReadyCallback callback) {
+            mCallback = callback;
+        }
+
+        // Called when a connection to the service has been established.
+        public void onServiceConnected(ComponentName name, IBinder service) {
+            mService = new Messenger(service);
+            mBound = true;
+            mCallback.serviceReady();
+        }
+
+        // Called when a connection to the service has been lost.
+        public void onServiceDisconnected(ComponentName name) {
+            mBound = false;
+        }
+    }
+
+    /**
+     * Class for keeping track of the data involved with each request.
+     */
+    private static class DecoderServiceParams {
+        // The path to the file containing the bitmap to decode.
+        public String mFilePath;
+
+        // The requested size (width and height) of the bitmap, once decoded.
+        public int mSize;
+
+        // The callback to use to communicate the results of the decoding.
+        ImageDecodedCallback mCallback;
+
+        public DecoderServiceParams(String filePath, int size, ImageDecodedCallback callback) {
+            mFilePath = filePath;
+            mSize = size;
+            mCallback = callback;
+        }
+    }
+
+    // Map of file paths to decoder parameters in order of request.
+    private LinkedHashMap<String, DecoderServiceParams> mRequests = new LinkedHashMap<>();
+    LinkedHashMap<String, DecoderServiceParams> getRequests() {
+        return mRequests;
+    }
+
+    // The callback used to notify the client when the service is ready.
+    private ServiceReadyCallback mCallback;
+
+    // Messenger for communicating with the remote service.
+    Messenger mService = null;
+
+    // Our service connection to the {@link DecoderService}.
+    private DecoderServiceConnection mConnection;
+
+    // Flag indicating whether we are bound to the service.
+    boolean mBound;
+
+    // The inbound messenger used by the remote service to communicate with us.
+    final Messenger mMessenger = new Messenger(new IncomingHandler(this));
+
+    /**
+     * The DecoderServiceHost constructor.
+     * @param callback The callback to use when communicating back to the client.
+     */
+    public DecoderServiceHost(ServiceReadyCallback callback) {
+        mCallback = callback;
+    }
+
+    /**
+     * Initiate binding with the {@link DecoderService}.
+     * @param context The context to use.
+     */
+    public void bind(Context context) {
+        mConnection = new DecoderServiceConnection(mCallback);
+        Intent intent = new Intent(context, DecoderService.class);
+        context.bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
+    }
+
+    /**
+     * Unbind from the {@link DecoderService}.
+     * @param context The context to use.
+     */
+    public void unbind(Context context) {
+        if (mBound) {
+            context.unbindService(mConnection);
+            mBound = false;
+        }
+    }
+
+    /**
+     * Accepts a request to decode a single image. Queues up the request and reports back
+     * asynchronously on |callback|.
+     * @param filePath The path to the file to decode.
+     * @param size The requested size (width and height) of the resulting bitmap.
+     * @param callback The callback to use to communicate the decoding results.
+     */
+    public void decodeImage(String filePath, int size, ImageDecodedCallback callback) {
+        DecoderServiceParams params = new DecoderServiceParams(filePath, size, callback);
+        mRequests.put(filePath, params);
+        if (mRequests.size() == 1) dispatchNextDecodeImageRequest();
+    }
+
+    /**
+     * Dispatches the next image for decoding (from the queue).
+     */
+    private void dispatchNextDecodeImageRequest() {
+        if (mRequests.entrySet().iterator().hasNext()) {
+            DecoderServiceParams params = mRequests.entrySet().iterator().next().getValue();
+            dispatchDecodeImageRequest(params.mFilePath, params.mSize);
+        }
+    }
+
+    /**
+     * Ties up all the loose ends from the decoding request (communicates the results of the
+     * decoding process back to the client, and takes care of house-keeping chores regarding
+     * the request queue).
+     * @param filePath The path to the image that was just decoded.
+     * @param bitmap The resulting decoded bitmap.
+     */
+    public void closeRequest(String filePath, Bitmap bitmap) {
+        DecoderServiceParams params = getRequests().get(filePath);
+        if (params != null) {
+            params.mCallback.imageDecodedCallback(filePath, bitmap);
+            getRequests().remove(filePath);
+        }
+        dispatchNextDecodeImageRequest();
+    }
+
+    /**
+     * Communicates with the server to decode a single bitmap.
+     * @param filePath The path to the image on disk.
+     * @param size The requested width and height of the resulting bitmap.
+     */
+    private void dispatchDecodeImageRequest(String filePath, int size) {
+        // Obtain a file descriptor to send over to the sandboxed process.
+        File file = new File(filePath);
+        FileInputStream inputFile = null;
+        ParcelFileDescriptor pfd = null;
+        Bundle bundle = new Bundle();
+
+        // The restricted utility process can't open the file to read the
+        // contents, so we need to obtain a file descriptor to pass over.
+        StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
+        try {
+            try {
+                inputFile = new FileInputStream(file);
+                FileDescriptor fd = inputFile.getFD();
+                pfd = ParcelFileDescriptor.dup(fd);
+                bundle.putParcelable(DecoderService.KEY_FILE_DESCRIPTOR, pfd);
+            } catch (IOException e) {
+                Log.e(TAG, "Unable to obtain FileDescriptor: " + e);
+                closeRequest(filePath, null);
+            }
+        } finally {
+            try {
+                if (inputFile != null) inputFile.close();
+            } catch (IOException e) {
+                Log.e(TAG, "Unable to close inputFile: " + e);
+            }
+            StrictMode.setThreadPolicy(oldPolicy);
+        }
+
+        if (pfd == null) return;
+
+        // Prepare and send the data over.
+        Message payload = Message.obtain(null, DecoderService.MSG_DECODE_IMAGE);
+        payload.replyTo = mMessenger;
+        bundle.putString(DecoderService.KEY_FILE_PATH, filePath);
+        bundle.putInt(DecoderService.KEY_SIZE, size);
+        payload.setData(bundle);
+        try {
+            mService.send(payload);
+            pfd.close();
+        } catch (RemoteException e) {
+            Log.e(TAG, "Communications failed (Remote): " + e);
+            closeRequest(filePath, null);
+        } catch (IOException e) {
+            Log.e(TAG, "Communications failed (IO): " + e);
+            closeRequest(filePath, null);
+        }
+    }
+
+    /**
+     * Cancels a request to decode an image (if it hasn't already been dispatched).
+     * @param filePath The path to the image to cancel decoding.
+     */
+    public void cancelDecodeImage(String filePath) {
+        mRequests.remove(filePath);
+    }
+
+    /**
+     * A class for handling communications from the service to us.
+     */
+    static class IncomingHandler extends Handler {
+        // The DecoderServiceHost object to communicate with.
+        private final WeakReference<DecoderServiceHost> mHost;
+
+        /**
+         * Constructor for IncomingHandler.
+         * @param host The DecoderServiceHost object to communicate with.
+         */
+        IncomingHandler(DecoderServiceHost host) {
+            mHost = new WeakReference<DecoderServiceHost>(host);
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            DecoderServiceHost host = mHost.get();
+            if (host == null) {
+                super.handleMessage(msg);
+                return;
+            }
+
+            switch (msg.what) {
+                case DecoderService.MSG_IMAGE_DECODED_REPLY:
+                    Bundle payload = msg.getData();
+
+                    // Read the reply back from the service.
+                    String filePath = payload.getString(DecoderService.KEY_FILE_PATH);
+                    Boolean success = payload.getBoolean(DecoderService.KEY_SUCCESS);
+                    Bitmap bitmap = success
+                            ? (Bitmap) payload.getParcelable(DecoderService.KEY_IMAGE_BITMAP)
+                            : null;
+                    host.closeRequest(filePath, bitmap);
+                    break;
+                default:
+                    super.handleMessage(msg);
+            }
+        }
+    }
+}