From 0bceb84773882b796d9dacbaf96167cb15928d78 Mon Sep 17 00:00:00 2001
From: Jamie Gennis <jgennis@google.com>
Date: Thu, 23 Aug 2012 20:19:38 -0700
Subject: [PATCH] surfaceflinger: fix display id selection

This change fixes display ID selection so that it never chooses negative
numbers as display IDs.

Change-Id: I5af1acc7b1270b371595e096b18e2a6ad250c7ba
---
 services/surfaceflinger/SurfaceFlinger.cpp | 21 ++++++++++++++++++++-
 services/surfaceflinger/SurfaceFlinger.h   |  5 +++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e6e258f4e..7b070bac9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -162,6 +162,24 @@ sp<ISurfaceComposerClient> SurfaceFlinger::createConnection()
     return bclient;
 }
 
+int32_t SurfaceFlinger::chooseNewDisplayIdLocked() const
+{
+    int32_t id = DisplayDevice::DISPLAY_ID_COUNT - 1;
+    bool available;
+    do {
+        id++;
+        available = true;
+        for (size_t i = 0; i < mCurrentState.displays.size(); i++) {
+            const DisplayDeviceState& dds(mCurrentState.displays.valueAt(i));
+            if (dds.id == id) {
+                available = false;
+                break;
+            }
+        }
+    } while (!available);
+    return id;
+}
+
 sp<IBinder> SurfaceFlinger::createDisplay()
 {
     class DisplayToken : public BBinder {
@@ -181,7 +199,8 @@ sp<IBinder> SurfaceFlinger::createDisplay()
     sp<BBinder> token = new DisplayToken(this);
 
     Mutex::Autolock _l(mStateLock);
-    DisplayDeviceState info(intptr_t(token.get())); // FIXME: we shouldn't use the address for the id
+    int32_t id = chooseNewDisplayIdLocked();
+    DisplayDeviceState info(id);
     mCurrentState.displays.add(token, info);
 
     return token;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 1f799068d..754a2cc20 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -363,6 +363,11 @@ private:
         return mProtectedTexName;
     }
 
+    /* ------------------------------------------------------------------------
+     * Display management
+     */
+    int32_t chooseNewDisplayIdLocked() const;
+
     /* ------------------------------------------------------------------------
      * Debugging & dumpsys
      */