commit d308b0127b45f1ec9498793a4f2b580057e297cf
author Jason Macnak <natsu@google.com> Fri Jul 16 13:57:41 2021 -0700
committer Alistair Delva <adelva@google.com> Thu Jul 22 16:17:03 2021 +0000
tree 571b775b29d41e87d1fdf8bbeb4ad02f5e9cb575
parent 1888932b8ee090dee07704856f587d43b6da8a47

Make display unique id stable across x86 and x86_64 builds

... by using a minimal version of CityHash64 for the hash function.
std::hash differs between x86 and x86_64 and also:

"Hash functions are only required to produce the same result for the
same input within a single execution of a program;"

This is problematic for input device configuration files which
reference the display unique id.

Bug: b/186150820
Test: libsurfaceflinger_unittest
Change-Id: If15b66775fa48f14cc56bbd23536b61844b7ae37
Merged-In: If15b66775fa48f14cc56bbd23536b61844b7ae37

services/surfaceflinger/Android.bp

diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index e669e45..eb31e92 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -146,6 +146,7 @@
         "DisplayHardware/ComposerHal.cpp",
         "DisplayHardware/DisplayIdentification.cpp",
         "DisplayHardware/FramebufferSurface.cpp",
+        "DisplayHardware/Hash.cpp",
         "DisplayHardware/HWC2.cpp",
         "DisplayHardware/HWComposer.cpp",
         "DisplayHardware/PowerAdvisor.cpp",