commit 8bec7e8744342a97cac606f3da8436c285e5b8fe
author Yiwei Zhang <zzyiwei@google.com> Mon Oct 07 18:08:26 2019 -0700
committer Yiwei Zhang <zzyiwei@google.com> Tue Oct 08 14:59:53 2019 -0700
tree 7ebb76c697263e37223b298faab290ae063efbfd
parent 8f2b750d93ab2e4ef70ae335efbd7ecd68635f2f

TimeStats: remove the regex checks on layer name

This change removes the regex validation on the layer name. Instead, now we just
check if the layer name meets the minimum length requirement set in TimeStats,
as well as filtering out the PopupWindow layer names.

This change also removes the regex extraction for the package name. It's not
making sense to do that in the platform. After we have the authenticated package
name from WindowManager, we can upload the package name info again.

Bug: 140266250
Test: atest libsurfaceflinger_unittest:TimeStatsTest
Change-Id: I476bb2a81c2a0d1e99663f4e0fe78cc3e6cf7f6b

services/surfaceflinger/TimeStats/TimeStats.cpp

diff --git a/services/surfaceflinger/TimeStats/TimeStats.cpp b/services/surfaceflinger/TimeStats/TimeStats.cpp
index 3df8360..3e47ec6 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.cpp
+++ b/services/surfaceflinger/TimeStats/TimeStats.cpp
@@ -28,7 +28,6 @@
 #include <utils/Trace.h>
 
 #include <algorithm>
-#include <regex>
 
 namespace android {
 
@@ -156,22 +155,6 @@
     return static_cast<int32_t>(delta);
 }
 
-// This regular expression captures the following for instance:
-// StatusBar in StatusBar#0
-// com.appname in com.appname/com.appname.activity#0
-// com.appname in SurfaceView - com.appname/com.appname.activity#0
-static const std::regex packageNameRegex("(?:SurfaceView[-\\s\\t]+)?([^/]+).*#\\d+");
-
-static std::string getPackageName(const std::string& layerName) {
-    std::smatch match;
-    if (std::regex_match(layerName.begin(), layerName.end(), match, packageNameRegex)) {
-        // There must be a match for group 1 otherwise the whole string is not
-        // matched and the above will return false
-        return match[1];
-    }
-    return "";
-}
-
 void TimeStats::flushAvailableRecordsToStatsLocked(int32_t layerID) {
     ATRACE_CALL();
 
@@ -187,7 +170,6 @@
             const std::string& layerName = layerRecord.layerName;
             if (!mTimeStats.stats.count(layerName)) {
                 mTimeStats.stats[layerName].layerName = layerName;
-                mTimeStats.stats[layerName].packageName = getPackageName(layerName);
             }
             TimeStatsHelper::TimeStatsLayer& timeStatsLayer = mTimeStats.stats[layerName];
             timeStatsLayer.totalFrames++;
@@ -236,19 +218,13 @@
     }
 }
 
-// This regular expression captures the following layer names for instance:
-// 1) StatusBat#0
-// 2) NavigationBar#1
-// 3) co(m).*#0
-// 4) SurfaceView - co(m).*#0
-// Using [-\\s\t]+ for the conjunction part between SurfaceView and co(m).*
-// is a bit more robust in case there's a slight change.
-// The layer name would only consist of . / $ _ 0-9 a-z A-Z in most cases.
-static const std::regex layerNameRegex(
-        "(((SurfaceView[-\\s\\t]+)?com?\\.[./$\\w]+)|((Status|Navigation)Bar))#\\d+");
+static constexpr const char* kPopupWindowPrefix = "PopupWindow";
+static const size_t kMinLenLayerName = std::strlen(kPopupWindowPrefix);
 
+// Avoid tracking the "PopupWindow:<random hash>#<number>" layers
 static bool layerNameIsValid(const std::string& layerName) {
-    return std::regex_match(layerName.begin(), layerName.end(), layerNameRegex);
+    return layerName.length() >= kMinLenLayerName &&
+            layerName.compare(0, kMinLenLayerName, kPopupWindowPrefix) != 0;
 }
 
 void TimeStats::setPostTime(int32_t layerID, uint64_t frameNumber, const std::string& layerName,