From 43e5414039186a2f9f40d91868d37a4bed8cd3fc Mon Sep 17 00:00:00 2001
From: Lee Shombert <shombert@google.com>
Date: Wed, 24 Apr 2024 17:02:15 -0700
Subject: Small reflow of the AnrTimer class

The AnrTimer class is now abstract and requires two methods when
instantiated with a type V.  The methods extract a Linux pid and uid
from an object of type V.  The public start() method, which used to
take an explicit pid and uid now computes the necessary pid/uid from
the supplied instance of V.

It is permitted to for the pid/uid methods to simply return 0, to
indicate that there is no value.

This change allows AnrTimer clients to compute pid/uid as necessary,
without storing the information in the AnTimer system itself.

Test: atest
 * FrameworksServicesTests:com.android.server.am
 * FrameworksMockingServicesTests:com.android.server.am
 * FrameworksServicesTests:AnrTimerTest

Flag: com.android.server.utils.anr_timer_service
Bug: 325594551

Change-Id: Ifc7779ce23d0884a7943b52d16aadc1419db96b7
---
 .../java/com/android/server/am/ActiveServices.java | 23 ++++++++++++------
 .../server/am/BroadcastQueueModernImpl.java        | 10 ++++++--
 .../java/com/android/server/utils/AnrTimer.java    | 28 +++++++++++++++++-----
 .../src/com/android/server/utils/AnrTimerTest.java | 10 ++++++--
 4 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/services/core/java/com/android/server/am/ActiveServices.java b/services/core/java/com/android/server/am/ActiveServices.java
index eec22c92b5dc..93beb647df97 100644
--- a/services/core/java/com/android/server/am/ActiveServices.java
+++ b/services/core/java/com/android/server/am/ActiveServices.java
@@ -7560,8 +7560,14 @@ public final class ActiveServices {
             super(Objects.requireNonNull(am).mHandler, msg, label);
         }
 
-        void start(@NonNull ProcessRecord proc, long millis) {
-            start(proc, proc.getPid(), proc.uid, millis);
+        @Override
+        public int getPid(@NonNull ProcessRecord proc) {
+            return proc.getPid();
+        }
+
+        @Override
+        public int getUid(@NonNull ProcessRecord proc) {
+            return proc.uid;
         }
     }
 
@@ -7571,11 +7577,14 @@ public final class ActiveServices {
             super(Objects.requireNonNull(am).mHandler, msg, label);
         }
 
-        void start(@NonNull ServiceRecord service, long millis) {
-            start(service,
-                    (service.app != null) ? service.app.getPid() : 0,
-                    service.appInfo.uid,
-                    millis);
+        @Override
+        public int getPid(@NonNull ServiceRecord service) {
+            return (service.app != null) ? service.app.getPid() : 0;
+        }
+
+        @Override
+        public int getUid(@NonNull ServiceRecord service) {
+            return (service.appInfo != null) ? service.appInfo.uid : 0;
         }
     }
 
diff --git a/services/core/java/com/android/server/am/BroadcastQueueModernImpl.java b/services/core/java/com/android/server/am/BroadcastQueueModernImpl.java
index 48dd03922479..4425a388e9e1 100644
--- a/services/core/java/com/android/server/am/BroadcastQueueModernImpl.java
+++ b/services/core/java/com/android/server/am/BroadcastQueueModernImpl.java
@@ -1339,8 +1339,14 @@ class BroadcastQueueModernImpl extends BroadcastQueue {
                     MSG_DELIVERY_TIMEOUT, "BROADCAST_TIMEOUT", true);
         }
 
-        void start(@NonNull BroadcastProcessQueue queue, long timeoutMillis) {
-            start(queue, queue.app.getPid(), queue.app.uid, timeoutMillis);
+        @Override
+        public int getPid(@NonNull BroadcastProcessQueue queue) {
+            return (queue.app != null) ? queue.app.getPid() : 0;
+        }
+
+        @Override
+        public int getUid(@NonNull BroadcastProcessQueue queue) {
+            return (queue.app != null) ? queue.app.uid : 0;
         }
     }
 
diff --git a/services/core/java/com/android/server/utils/AnrTimer.java b/services/core/java/com/android/server/utils/AnrTimer.java
index e944eca63144..592d0396b349 100644
--- a/services/core/java/com/android/server/utils/AnrTimer.java
+++ b/services/core/java/com/android/server/utils/AnrTimer.java
@@ -47,7 +47,7 @@ import java.util.Objects;
  * mode, the timer just sends a delayed message.  In modern mode, the timer is implemented in
  * native code; on expiration, the message is sent without delay.
  *
- * <p>There are four external operations on a timer:
+ * <p>There are five external operations on a timer:
  * <ul>
  *
  * <li>{@link #start} starts a timer.  The timer is started with an object that the message
@@ -74,9 +74,13 @@ import java.util.Objects;
  * exit. (So, instances in system server generally need not be explicitly closed since they are
  * created during process start and will last until process exit.)
  *
+ * <p>AnrTimer parameterized by the type <code>V</code>.  The public methods on AnrTimer require
+ * an instance of <code>V</code>; the instance of <code>V</code> is a key that identifies a
+ * specific timer.
+ *
  * @hide
  */
-public class AnrTimer<V> implements AutoCloseable {
+public abstract class AnrTimer<V> implements AutoCloseable {
 
     /**
      * The log tag.
@@ -100,6 +104,20 @@ public class AnrTimer<V> implements AutoCloseable {
      */
     private static final long TRACE_TAG = Trace.TRACE_TAG_ACTIVITY_MANAGER;
 
+    /**
+     * Fetch the Linux pid from the object. The returned value may be zero to indicate that there
+     * is no valid pid available.
+     * @return a valid pid or zero.
+     */
+    public abstract int getPid(V obj);
+
+    /**
+     * Fetch the Linux uid from the object. The returned value may be zero to indicate that there
+     * is no valid uid available.
+     * @return a valid uid or zero.
+     */
+    public abstract int getUid(V obj);
+
     /**
      * Return true if the feature is enabled.  By default, the value is take from the Flags class
      * but it can be changed for local testing.
@@ -564,13 +582,11 @@ public class AnrTimer<V> implements AutoCloseable {
      * allows a client to deliver an immediate timeout via the AnrTimer.
      *
      * @param arg The key by which the timer is known.  This is never examined or modified.
-     * @param pid The Linux process ID of the target being timed.
-     * @param uid The Linux user ID of the target being timed.
      * @param timeoutMs The timer timeout, in milliseconds.
      */
-    public void start(@NonNull V arg, int pid, int uid, long timeoutMs) {
+    public void start(@NonNull V arg, long timeoutMs) {
         if (timeoutMs < 0) timeoutMs = 0;
-        mFeature.start(arg, pid, uid, timeoutMs);
+        mFeature.start(arg, getPid(arg), getUid(arg), timeoutMs);
     }
 
     /**
diff --git a/services/tests/servicestests/src/com/android/server/utils/AnrTimerTest.java b/services/tests/servicestests/src/com/android/server/utils/AnrTimerTest.java
index 44d116181be5..06c3db87ed2d 100644
--- a/services/tests/servicestests/src/com/android/server/utils/AnrTimerTest.java
+++ b/services/tests/servicestests/src/com/android/server/utils/AnrTimerTest.java
@@ -136,8 +136,14 @@ public class AnrTimerTest {
             this(helper.mHandler, MSG_TIMEOUT, caller());
         }
 
-        void start(TestArg arg, long millis) {
-            start(arg, arg.pid, arg.uid, millis);
+        @Override
+        public int getPid(TestArg arg) {
+            return arg.pid;
+        }
+
+        @Override
+        public int getUid(TestArg arg) {
+            return arg.uid;
         }
 
         // Return the name of method that called the constructor, assuming that this function is
-- 
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