Add initial multi-display support.

Split the DisplayManager into two parts.  One part is bound
to a Context and takes care of Display compatibility and
caching Display objects on behalf of the Context.  The other
part is global and takes care of communicating with the
DisplayManagerService, handling callbacks, and caching
DisplayInfo objects on behalf of the process.

Implemented support for enumerating Displays and getting
callbacks when displays are added, removed or changed.

Elaborated the roles of DisplayManagerService, DisplayAdapter,
and DisplayDevice.  We now support having multiple display
adapters registered, each of which can register multiple display
devices and configure them dynamically.

Added an OverlayDisplayAdapter which is used to simulate
secondary displays by means of overlay windows.  Different
configurations of overlays can be selected using a new
setting in the Developer Settings panel.  The overlays can
be repositioned and resized by the user for convenience.

At the moment, all displays are mirrors of display 0 and
no display transformations are applied.  This will be improved
in future patches.

Refactored the way that the window manager creates its threads.
The OverlayDisplayAdapter needs to be able to use hardware
acceleration so it must share the same UI thread as the Keyguard
and window manager policy.  We now handle this explicitly as
part of starting up the system server.  This puts us in a
better position to consider how we might want to share (or not
share) Loopers among components.

Overlay displays are disabled when in safe mode or in only-core
mode to reduce the number of dependencies started in these modes.

Change-Id: Ic2a661d5448dde01b095ab150697cb6791d69bb5

1 files changed, 55 insertions, 8 deletions

diff --git a/core/java/android/view/Display.java b/core/java/android/view/Display.java
index 6f8ca13f1c76..ec635a2156fe 100644
--- a/core/java/android/view/Display.java
+++ b/core/java/android/view/Display.java
@@ -19,7 +19,7 @@ package android.view;
 import android.graphics.PixelFormat;
 import android.graphics.Point;
 import android.graphics.Rect;
-import android.hardware.display.DisplayManager;
+import android.hardware.display.DisplayManagerGlobal;
 import android.os.SystemClock;
 import android.util.DisplayMetrics;
 import android.util.Log;
@@ -49,10 +49,14 @@ import android.util.Log;
  */
 public final class Display {
     private static final String TAG = "Display";
+    private static final boolean DEBUG = false;
 
+    private final DisplayManagerGlobal mGlobal;
     private final int mDisplayId;
     private final CompatibilityInfoHolder mCompatibilityInfo;
-    private final DisplayInfo mDisplayInfo = new DisplayInfo();
+
+    private DisplayInfo mDisplayInfo; // never null
+    private boolean mIsValid;
 
     // Temporary display metrics structure used for compatibility mode.
     private final DisplayMetrics mTempMetrics = new DisplayMetrics();
@@ -80,9 +84,14 @@ public final class Display {
      *
      * @hide
      */
-    public Display(int displayId, CompatibilityInfoHolder compatibilityInfo) {
+    public Display(DisplayManagerGlobal global,
+            int displayId, DisplayInfo displayInfo /*not null*/,
+            CompatibilityInfoHolder compatibilityInfo) {
+        mGlobal = global;
         mDisplayId = displayId;
+        mDisplayInfo = displayInfo;
         mCompatibilityInfo = compatibilityInfo;
+        mIsValid = true;
     }
 
     /**
@@ -97,15 +106,37 @@ public final class Display {
     }
 
     /**
+     * Returns true if this display is still valid, false if the display has been removed.
+     *
+     * If the display is invalid, then the methods of this class will
+     * continue to report the most recently observed display information.
+     * However, it is unwise (and rather fruitless) to continue using a
+     * {@link Display} object after the display's demise.
+     *
+     * It's possible for a display that was previously invalid to become
+     * valid again if a display with the same id is reconnected.
+     *
+     * @return True if the display is still valid.
+     */
+    public boolean isValid() {
+        synchronized (this) {
+            updateDisplayInfoLocked();
+            return mIsValid;
+        }
+    }
+
+    /**
      * Gets a full copy of the display information.
      *
      * @param outDisplayInfo The object to receive the copy of the display information.
+     * @return True if the display is still valid.
      * @hide
      */
-    public void getDisplayInfo(DisplayInfo outDisplayInfo) {
+    public boolean getDisplayInfo(DisplayInfo outDisplayInfo) {
         synchronized (this) {
             updateDisplayInfoLocked();
             outDisplayInfo.copyFrom(mDisplayInfo);
+            return mIsValid;
         }
     }
 
@@ -366,9 +397,25 @@ public final class Display {
     }
 
     private void updateDisplayInfoLocked() {
-        // TODO: only refresh the display information when needed
-        if (!DisplayManager.getInstance().getDisplayInfo(mDisplayId, mDisplayInfo)) {
-            Log.e(TAG, "Could not get information about logical display " + mDisplayId);
+        // Note: The display manager caches display info objects on our behalf.
+        DisplayInfo newInfo = mGlobal.getDisplayInfo(mDisplayId);
+        if (newInfo == null) {
+            // Preserve the old mDisplayInfo after the display is removed.
+            if (mIsValid) {
+                mIsValid = false;
+                if (DEBUG) {
+                    Log.d(TAG, "Logical display " + mDisplayId + " was removed.");
+                }
+            }
+        } else {
+            // Use the new display info.  (It might be the same object if nothing changed.)
+            mDisplayInfo = newInfo;
+            if (!mIsValid) {
+                mIsValid = true;
+                if (DEBUG) {
+                    Log.d(TAG, "Logical display " + mDisplayId + " was recreated.");
+                }
+            }
         }
     }
 
@@ -390,7 +437,7 @@ public final class Display {
             updateDisplayInfoLocked();
             mDisplayInfo.getAppMetrics(mTempMetrics, mCompatibilityInfo);
             return "Display id " + mDisplayId + ": " + mDisplayInfo
-                    + ", " + mTempMetrics;
+                    + ", " + mTempMetrics + ", isValid=" + mIsValid;
         }
     }
 }