Do not launch Somnambulator as a dock app.

Fixes a black flash that occurred when the device was docked
because the UiModeManagerService was launching the Somnambulator
to start the dream when docked.  This caused an unnecessary
activity transition and could in fact make dreaming less
reliable than if the UiModeManagerService started the dream itself.

Moved common code from UiModeManagerService and Somnambulator
to Sandman to ensure it is kept in sync.

Bug: 7328545
Change-Id: I46102784e2ab1acc0241d43a48abf0581278af24

1 files changed, 122 insertions, 0 deletions

diff --git a/core/java/android/service/dreams/Sandman.java b/core/java/android/service/dreams/Sandman.java
new file mode 100644
index 0000000..70142ce
--- /dev/null
+++ b/core/java/android/service/dreams/Sandman.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2012 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 android.service.dreams;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.os.PowerManager;
+import android.os.RemoteException;
+import android.os.ServiceManager;
+import android.os.SystemClock;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.util.Slog;
+
+/**
+ * Internal helper for launching dreams to ensure consistency between the
+ * <code>UiModeManagerService</code> system service and the <code>Somnambulator</code> activity.
+ *
+ * @hide
+ */
+public final class Sandman {
+    private static final String TAG = "Sandman";
+
+    private static final int DEFAULT_SCREENSAVER_ENABLED = 1;
+    private static final int DEFAULT_SCREENSAVER_ACTIVATED_ON_DOCK = 1;
+
+    // The component name of a special dock app that merely launches a dream.
+    // We don't want to launch this app when docked because it causes an unnecessary
+    // activity transition.  We just want to start the dream.
+    private static final ComponentName SOMNAMBULATOR_COMPONENT =
+            new ComponentName("com.android.systemui", "com.android.systemui.Somnambulator");
+
+
+    // The sandman is eternal.  No one instantiates him.
+    private Sandman() {
+    }
+
+    /**
+     * Returns true if the specified dock app intent should be started.
+     * False if we should dream instead, if appropriate.
+     */
+    public static boolean shouldStartDockApp(Context context, Intent intent) {
+        ComponentName name = intent.resolveActivity(context.getPackageManager());
+        return name != null && !name.equals(SOMNAMBULATOR_COMPONENT);
+    }
+
+    /**
+     * Starts a dream manually.
+     */
+    public static void startDreamByUserRequest(Context context) {
+        startDream(context, false);
+    }
+
+    /**
+     * Starts a dream when docked if the system has been configured to do so,
+     * otherwise does nothing.
+     */
+    public static void startDreamWhenDockedIfAppropriate(Context context) {
+        if (!isScreenSaverEnabled(context)
+                || !isScreenSaverActivatedOnDock(context)) {
+            Slog.i(TAG, "Dreams currently disabled for docks.");
+            return;
+        }
+
+        startDream(context, true);
+    }
+
+    private static void startDream(Context context, boolean docked) {
+        try {
+            IDreamManager dreamManagerService = IDreamManager.Stub.asInterface(
+                    ServiceManager.getService(DreamService.DREAM_SERVICE));
+            if (dreamManagerService != null && !dreamManagerService.isDreaming()) {
+                if (docked) {
+                    Slog.i(TAG, "Activating dream while docked.");
+
+                    // Wake up.
+                    // The power manager will wake up the system automatically when it starts
+                    // receiving power from a dock but there is a race between that happening
+                    // and the UI mode manager starting a dream.  We want the system to already
+                    // be awake by the time this happens.  Otherwise the dream may not start.
+                    PowerManager powerManager =
+                            (PowerManager)context.getSystemService(Context.POWER_SERVICE);
+                    powerManager.wakeUp(SystemClock.uptimeMillis());
+                } else {
+                    Slog.i(TAG, "Activating dream by user request.");
+                }
+
+                // Dream.
+                dreamManagerService.dream();
+            }
+        } catch (RemoteException ex) {
+            Slog.e(TAG, "Could not start dream when docked.", ex);
+        }
+    }
+
+    private static boolean isScreenSaverEnabled(Context context) {
+        return Settings.Secure.getIntForUser(context.getContentResolver(),
+                Settings.Secure.SCREENSAVER_ENABLED, DEFAULT_SCREENSAVER_ENABLED,
+                UserHandle.USER_CURRENT) != 0;
+    }
+
+    private static boolean isScreenSaverActivatedOnDock(Context context) {
+        return Settings.Secure.getIntForUser(context.getContentResolver(),
+                Settings.Secure.SCREENSAVER_ACTIVATE_ON_DOCK,
+                DEFAULT_SCREENSAVER_ACTIVATED_ON_DOCK, UserHandle.USER_CURRENT) != 0;
+    }
+}