From 182908d216f27861d033f69398abff996caf8053 Mon Sep 17 00:00:00 2001
From: "Justin Clark-Casey (justincc)" <jjustincc@googlemail.com>
Date: Tue, 25 Oct 2011 23:16:01 +0100
Subject: [PATCH] In Watchdog, add ability to specific timeout for a thread.

This also changes the point of registration to the StartThread() call rather than the first Update()
---
 OpenSim/Framework/Watchdog.cs | 72 +++++++++++++++++++++++++++--------
 1 file changed, 56 insertions(+), 16 deletions(-)

diff --git a/OpenSim/Framework/Watchdog.cs b/OpenSim/Framework/Watchdog.cs
index 3ef9ccbba0..1374518b6e 100644
--- a/OpenSim/Framework/Watchdog.cs
+++ b/OpenSim/Framework/Watchdog.cs
@@ -40,18 +40,30 @@ namespace OpenSim.Framework
     {
         /// <summary>Timer interval in milliseconds for the watchdog timer</summary>
         const double WATCHDOG_INTERVAL_MS = 2500.0d;
+
         /// <summary>Maximum timeout in milliseconds before a thread is considered dead</summary>
         const int WATCHDOG_TIMEOUT_MS = 5000;
 
         [System.Diagnostics.DebuggerDisplay("{Thread.Name}")]
         public class ThreadWatchdogInfo
         {
-            public Thread Thread;
-            public int LastTick;
+            public Thread Thread { get; private set; }
+            public int LastTick { get; set; }
 
-            public ThreadWatchdogInfo(Thread thread)
+            /// <summary>
+            /// Number of seconds before we notify that the thread is having a problem.
+            /// </summary>
+            public int Timeout { get; set; }
+
+            /// <summary>
+            /// Is this thread considered timed out?
+            /// </summary>
+            public bool IsTimedOut { get; set; }
+
+            public ThreadWatchdogInfo(Thread thread, int timeout)
             {
                 Thread = thread;
+                Timeout = timeout;
                 LastTick = Environment.TickCount & Int32.MaxValue;
             }
         }
@@ -82,7 +94,7 @@ namespace OpenSim.Framework
         }
 
         /// <summary>
-        /// Start a new thread that is tracked by the watchdog timer
+        /// Start a new thread that is tracked by the watchdog timer.
         /// </summary>
         /// <param name="start">The method that will be executed in a new thread</param>
         /// <param name="name">A name to give to the new thread</param>
@@ -91,6 +103,24 @@ namespace OpenSim.Framework
         /// thread, otherwise false</param>
         /// <returns>The newly created Thread object</returns>
         public static Thread StartThread(ThreadStart start, string name, ThreadPriority priority, bool isBackground)
+        {
+            return StartThread(start, name, priority, isBackground, WATCHDOG_TIMEOUT_MS);
+        }
+
+        /// <summary>
+        /// Start a new thread that is tracked by the watchdog timer
+        /// </summary>
+        /// <param name="start">The method that will be executed in a new thread</param>
+        /// <param name="name">A name to give to the new thread</param>
+        /// <param name="priority">Priority to run the thread at</param>
+        /// <param name="isBackground">True to run this thread as a background
+        /// thread, otherwise false</param>
+        /// <param name="timeout">
+        /// Number of seconds to wait until we issue a warning about timeout.
+        /// </para>
+        /// <returns>The newly created Thread object</returns>
+        public static Thread StartThread(
+            ThreadStart start, string name, ThreadPriority priority, bool isBackground, int timeout)
         {
             Thread thread = new Thread(start);
             thread.Name = name;
@@ -98,6 +128,13 @@ namespace OpenSim.Framework
             thread.IsBackground = isBackground;
             thread.Start();
 
+            ThreadWatchdogInfo twi = new ThreadWatchdogInfo(thread, timeout);
+
+            m_log.Debug("[WATCHDOG]: Started tracking thread \"" + twi.Thread.Name + "\" (ID " + twi.Thread.ManagedThreadId + ")");
+
+            lock (m_threads)
+                m_threads.Add(twi.Thread.ManagedThreadId, twi);
+
             return thread;
         }
 
@@ -121,14 +158,6 @@ namespace OpenSim.Framework
             return RemoveThread(Thread.CurrentThread.ManagedThreadId);
         }
 
-        private static void AddThread(ThreadWatchdogInfo threadInfo)
-        {
-            m_log.Debug("[WATCHDOG]: Started tracking thread \"" + threadInfo.Thread.Name + "\" (ID " + threadInfo.Thread.ManagedThreadId + ")");
-
-            lock (m_threads)
-                m_threads.Add(threadInfo.Thread.ManagedThreadId, threadInfo);
-        }
-
         private static bool RemoveThread(int threadID)
         {
             lock (m_threads)
@@ -165,9 +194,14 @@ namespace OpenSim.Framework
             try
             {
                 if (m_threads.TryGetValue(threadID, out threadInfo))
+                {
                     threadInfo.LastTick = Environment.TickCount & Int32.MaxValue;
+                    threadInfo.IsTimedOut = false;
+                }
                 else
-                    AddThread(new ThreadWatchdogInfo(Thread.CurrentThread));
+                {
+                    m_log.WarnFormat("[WATCHDOG]: Asked to update thread {0} which is not being monitored", threadID);
+                }
             }
             catch { }
         }
@@ -196,10 +230,16 @@ namespace OpenSim.Framework
 
                     foreach (ThreadWatchdogInfo threadInfo in m_threads.Values)
                     {
-                        if (threadInfo.Thread.ThreadState == ThreadState.Stopped || now - threadInfo.LastTick >= WATCHDOG_TIMEOUT_MS)
+                        if (threadInfo.Thread.ThreadState == ThreadState.Stopped)
                         {
                             timedOut = threadInfo;
-                            m_threads.Remove(threadInfo.Thread.ManagedThreadId);
+                            RemoveThread(threadInfo.Thread.ManagedThreadId);
+                            break;
+                        }
+                        else if (!threadInfo.IsTimedOut && now - threadInfo.LastTick >= threadInfo.Timeout)
+                        {
+                            threadInfo.IsTimedOut = true;
+                            timedOut = threadInfo;
                             break;
                         }
                     }
@@ -212,4 +252,4 @@ namespace OpenSim.Framework
             m_watchdogTimer.Start();
         }
     }
-}
+}
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