Stop wifi display discovery when no longer needed.

Keep track of how many clients are requesting scans and scan
continuously until all of them are gone then explicitly terminate the
scan instead of letting it time out as before.

Suspend wifi display scans while connecting or connected to a remote
display.  This is handled by both the display manager and media router
since neither has complete information about what is happening.
Much of this code will no longer be needed once wifi display support
is integrated directly into the media router service.

Ensure that we don't attempt to scan or connect to wifi displays
while the wifi display feature is off.

Infer when a connection attempt fails and unselect the wifi display
route automatically so it doesn't appear to be connecting forever.

Fix issues around correctly canceling and retrying connection attempts.
Often we would cancel but not retry.

Improved connection reliability somewhat.  It seems that discovery must
already be in progress in order for a connection attempt to succeed.

Ensure QuickSettings uses exactly the same logic as the MediaRouteButton
to determine when the remote display tile should be made visible.

Bug: 11717053
Change-Id: I18afc977b0e8c26204b8c96adaa79f05225f7b6e

3 files changed, 59 insertions, 18 deletions

diff --git a/core/java/android/hardware/display/DisplayManager.java b/core/java/android/hardware/display/DisplayManager.java
index d5208d9..093e0e9 100644
--- a/core/java/android/hardware/display/DisplayManager.java
+++ b/core/java/android/hardware/display/DisplayManager.java
@@ -297,16 +297,31 @@ public final class DisplayManager {
     }
 
     /**
-     * Initiates a fresh scan of availble Wifi displays.
+     * Starts scanning for available Wifi displays.
      * The results are sent as a {@link #ACTION_WIFI_DISPLAY_STATUS_CHANGED} broadcast.
      * <p>
+     * Calls to this method nest and must be matched by an equal number of calls to
+     * {@link #stopWifiDisplayScan()}.
+     * </p><p>
+     * Requires {@link android.Manifest.permission#CONFIGURE_WIFI_DISPLAY}.
+     * </p>
+     *
+     * @hide
+     */
+    public void startWifiDisplayScan() {
+        mGlobal.startWifiDisplayScan();
+    }
+
+    /**
+     * Stops scanning for available Wifi displays.
+     * <p>
      * Requires {@link android.Manifest.permission#CONFIGURE_WIFI_DISPLAY}.
      * </p>
      *
      * @hide
      */
-    public void scanWifiDisplays() {
-        mGlobal.scanWifiDisplays();
+    public void stopWifiDisplayScan() {
+        mGlobal.stopWifiDisplayScan();
     }
 
     /**
diff --git a/core/java/android/hardware/display/DisplayManagerGlobal.java b/core/java/android/hardware/display/DisplayManagerGlobal.java
index 936a086..3417430 100644
--- a/core/java/android/hardware/display/DisplayManagerGlobal.java
+++ b/core/java/android/hardware/display/DisplayManagerGlobal.java
@@ -72,6 +72,8 @@ public final class DisplayManagerGlobal {
     private final SparseArray<DisplayInfo> mDisplayInfoCache = new SparseArray<DisplayInfo>();
     private int[] mDisplayIdCache;
 
+    private int mWifiDisplayScanNestCount;
+
     private DisplayManagerGlobal(IDisplayManager dm) {
         mDm = dm;
     }
@@ -267,11 +269,32 @@ public final class DisplayManagerGlobal {
         }
     }
 
-    public void scanWifiDisplays() {
-        try {
-            mDm.scanWifiDisplays();
-        } catch (RemoteException ex) {
-            Log.e(TAG, "Failed to scan for Wifi displays.", ex);
+    public void startWifiDisplayScan() {
+        synchronized (mLock) {
+            if (mWifiDisplayScanNestCount++ == 0) {
+                registerCallbackIfNeededLocked();
+                try {
+                    mDm.startWifiDisplayScan();
+                } catch (RemoteException ex) {
+                    Log.e(TAG, "Failed to scan for Wifi displays.", ex);
+                }
+            }
+        }
+    }
+
+    public void stopWifiDisplayScan() {
+        synchronized (mLock) {
+            if (--mWifiDisplayScanNestCount == 0) {
+                try {
+                    mDm.stopWifiDisplayScan();
+                } catch (RemoteException ex) {
+                    Log.e(TAG, "Failed to scan for Wifi displays.", ex);
+                }
+            } else if (mWifiDisplayScanNestCount < 0) {
+                Log.wtf(TAG, "Wifi display scan nest count became negative: "
+                        + mWifiDisplayScanNestCount);
+                mWifiDisplayScanNestCount = 0;
+            }
         }
     }
 
diff --git a/core/java/android/hardware/display/IDisplayManager.aidl b/core/java/android/hardware/display/IDisplayManager.aidl
index 6b2c887..68eb13f 100644
--- a/core/java/android/hardware/display/IDisplayManager.aidl
+++ b/core/java/android/hardware/display/IDisplayManager.aidl
@@ -29,11 +29,14 @@ interface IDisplayManager {
 
     void registerCallback(in IDisplayManagerCallback callback);
 
-    // No permissions required.
-    void scanWifiDisplays();
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    // The process must have previously registered a callback.
+    void startWifiDisplayScan();
 
-    // Requires CONFIGURE_WIFI_DISPLAY permission to connect to an unknown device.
-    // No permissions required to connect to a known device.
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    void stopWifiDisplayScan();
+
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
     void connectWifiDisplay(String address);
 
     // No permissions required.
@@ -45,6 +48,12 @@ interface IDisplayManager {
     // Requires CONFIGURE_WIFI_DISPLAY permission.
     void forgetWifiDisplay(String address);
 
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    void pauseWifiDisplay();
+
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    void resumeWifiDisplay();
+
     // No permissions required.
     WifiDisplayStatus getWifiDisplayStatus();
 
@@ -55,10 +64,4 @@ interface IDisplayManager {
 
     // No permissions required but must be same Uid as the creator.
     void releaseVirtualDisplay(in IBinder token);
-
-    // Requires CONFIGURE_WIFI_DISPLAY permission.
-    void pauseWifiDisplay();
-
-    // Requires CONFIGURE_WIFI_DISPLAY permission.
-    void resumeWifiDisplay();
 }