Revert "Revert "Speculative fix for concurrency SessionManager i..."

Revert submission 30287372-revert-30239784-spec_session_fix-ZAKHYQBVDW

Reason for revert: broken build due to automerger issue: b/377750579

Reverted changes: /q/submissionid:30287372-revert-30239784-spec_session_fix-ZAKHYQBVDW

Change-Id: I82785545a00ba98385e5cda279731170c979144d

2 files changed, 39 insertions, 14 deletions

diff --git a/telecomm/java/android/telecom/Log.java b/telecomm/java/android/telecom/Log.java
index a34094ce6452..98949d0c45cf 100644
--- a/telecomm/java/android/telecom/Log.java
+++ b/telecomm/java/android/telecom/Log.java
@@ -68,7 +68,7 @@ public class Log {
     // Used to synchronize singleton logging lazy initialization
     private static final Object sSingletonSync = new Object();
     private static EventManager sEventManager;
-    private static SessionManager sSessionManager;
+    private static volatile SessionManager sSessionManager;
     private static Object sLock = null;
 
     /**
@@ -379,6 +379,23 @@ public class Log {
         return sSessionManager;
     }
 
+    @VisibleForTesting
+    public static SessionManager setSessionManager(Context context,
+            java.lang.Runnable cleanSessionRunnable) {
+        // Checking for null again outside of synchronization because we only need to synchronize
+        // during the lazy loading of the session logger. We don't need to synchronize elsewhere.
+        if (sSessionManager == null) {
+            synchronized (sSingletonSync) {
+                if (sSessionManager == null) {
+                    sSessionManager = new SessionManager(cleanSessionRunnable);
+                    sSessionManager.setContext(context);
+                    return sSessionManager;
+                }
+            }
+        }
+        return sSessionManager;
+    }
+
     public static void setTag(String tag) {
         TAG = tag;
         DEBUG = isLoggable(android.util.Log.DEBUG);
diff --git a/telecomm/java/android/telecom/Logging/SessionManager.java b/telecomm/java/android/telecom/Logging/SessionManager.java
index 00e344c67cc5..ac1e69e92ec0 100644
--- a/telecomm/java/android/telecom/Logging/SessionManager.java
+++ b/telecomm/java/android/telecom/Logging/SessionManager.java
@@ -62,9 +62,7 @@ public class SessionManager {
 
     @VisibleForTesting
     public final ConcurrentHashMap<Integer, Session> mSessionMapper = new ConcurrentHashMap<>(64);
-    @VisibleForTesting
-    public java.lang.Runnable mCleanStaleSessions = () ->
-            cleanupStaleSessions(getSessionCleanupTimeoutMs());
+    private final java.lang.Runnable mCleanStaleSessions;
     private final Handler mSessionCleanupHandler = new Handler(Looper.getMainLooper());
 
     // Overridden in LogTest to skip query to ContentProvider
@@ -110,29 +108,39 @@ public class SessionManager {
     }
 
     public SessionManager() {
+        mCleanStaleSessions = () -> cleanupStaleSessions(getSessionCleanupTimeoutMs());
+    }
+
+    @VisibleForTesting
+    public SessionManager(java.lang.Runnable cleanStaleSessionsRunnable) {
+        mCleanStaleSessions = cleanStaleSessionsRunnable;
     }
 
     private long getSessionCleanupTimeoutMs() {
         return mSessionCleanupTimeoutMs.get();
     }
 
-    private synchronized void resetStaleSessionTimer() {
+    private void resetStaleSessionTimer() {
         if (!Flags.endSessionImprovements()) {
-            mSessionCleanupHandler.removeCallbacksAndMessages(null);
-            // Will be null in Log Testing
-            if (mCleanStaleSessions != null) {
-                mSessionCleanupHandler.postDelayed(mCleanStaleSessions,
-                        getSessionCleanupTimeoutMs());
-            }
-        } else {
-            if (mCleanStaleSessions != null
-                    && !mSessionCleanupHandler.hasCallbacks(mCleanStaleSessions)) {
+            resetStaleSessionTimerOld();
+            return;
+        }
+        // Will be null in Log Testing
+        if (mCleanStaleSessions == null) return;
+        synchronized (mSessionCleanupHandler) {
+            if (!mSessionCleanupHandler.hasCallbacks(mCleanStaleSessions)) {
                 mSessionCleanupHandler.postDelayed(mCleanStaleSessions,
                         getSessionCleanupTimeoutMs());
             }
         }
     }
 
+    private synchronized void resetStaleSessionTimerOld() {
+        if (mCleanStaleSessions == null) return;
+        mSessionCleanupHandler.removeCallbacksAndMessages(null);
+        mSessionCleanupHandler.postDelayed(mCleanStaleSessions, getSessionCleanupTimeoutMs());
+    }
+
     /**
      * Determines whether or not to start a new session or continue an existing session based on
      * the {@link Session.Info} info passed into startSession. If info is null, a new Session is