[Debugger] Make DebuggingService dictionaries thread safe.

The sessions dictionary and the nextStatementLocations dictionary
were accessed from multiple threads. Changed these dictionaries to
be ConcurrentDictionary so their use is thread safe.

1 files changed, 13 insertions, 15 deletions

diff --git a/main/src/addins/MonoDevelop.Debugger/MonoDevelop.Debugger/DebuggingService.cs b/main/src/addins/MonoDevelop.Debugger/MonoDevelop.Debugger/DebuggingService.cs
index 60d5fa309f..25c19d22ad 100644
--- a/main/src/addins/MonoDevelop.Debugger/MonoDevelop.Debugger/DebuggingService.cs
+++ b/main/src/addins/MonoDevelop.Debugger/MonoDevelop.Debugger/DebuggingService.cs
@@ -67,8 +67,8 @@ namespace MonoDevelop.Debugger
 		static readonly BreakpointStore breakpoints = new BreakpointStore ();
 		static readonly DebugExecutionHandlerFactory executionHandlerFactory;
 
-		static Dictionary<long, SourceLocation> nextStatementLocations = new Dictionary<long, SourceLocation> ();
-		static Dictionary<DebuggerSession, SessionManager> sessions = new Dictionary<DebuggerSession, SessionManager> ();
+		static ConcurrentDictionary<long, SourceLocation> nextStatementLocations = new ConcurrentDictionary<long, SourceLocation> ();
+		static ConcurrentDictionary<DebuggerSession, SessionManager> sessions = new ConcurrentDictionary<DebuggerSession, SessionManager> ();
 		static Backtrace currentBacktrace;
 		static SessionManager currentSession;
 		static int currentFrame;
@@ -151,7 +151,7 @@ namespace MonoDevelop.Debugger
 
 		public static DebuggerSession GetSession (IRunTarget runTarget)
 		{
-			foreach (KeyValuePair<DebuggerSession, SessionManager> item in sessions.ToArray ()) {
+			foreach (KeyValuePair<DebuggerSession, SessionManager> item in sessions) {
 				if (item.Value.RunTarget == runTarget) {
 					return item.Key;
 				}
@@ -161,10 +161,8 @@ namespace MonoDevelop.Debugger
 
 		public static IRunTarget GetRunTarget (DebuggerSession session)
 		{
-			foreach (KeyValuePair<DebuggerSession, SessionManager> item in sessions.ToArray ()) {
-				if (item.Key == session) {
-					return item.Value.RunTarget;
-				}
+			if (sessions.TryGetValue (session, out SessionManager sessionManager)) {
+				return sessionManager.RunTarget;
 			}
 			return null;
 		}
@@ -177,8 +175,8 @@ namespace MonoDevelop.Debugger
 		public static BreakEventStatus GetBreakpointStatus (Breakpoint bp)
 		{
 			var result = BreakEventStatus.Disconnected;
-			foreach (var sesion in sessions.Keys.ToArray ()) {
-				var status = bp.GetStatus (sesion);
+			foreach (var session in sessions.Keys) {
+				var status = bp.GetStatus (session);
 				if (status == BreakEventStatus.Bound)
 					return BreakEventStatus.Bound;
 				else
@@ -418,7 +416,7 @@ namespace MonoDevelop.Debugger
 
 		static void SetupSession (SessionManager sessionManager)
 		{
-			sessions.Add (sessionManager.Session, sessionManager);
+			sessions [sessionManager.Session] = sessionManager;
 			isBusy = false;
 			var session = sessionManager.Session;
 			session.Breakpoints = breakpoints;
@@ -463,7 +461,7 @@ namespace MonoDevelop.Debugger
 					currentBacktrace = null;
 				}
 				busyStatusIcon = null;
-				sessions.Remove (sessionManager.Session);
+				sessions.TryRemove (sessionManager.Session, out _);
 				pinnedWatches.InvalidateAll ();
 			}
 
@@ -549,7 +547,7 @@ namespace MonoDevelop.Debugger
 
 		public static void Pause ()
 		{
-			foreach (var session in sessions.Keys.ToArray ()) {
+			foreach (var session in sessions.Keys) {
 				if (session.IsRunning)
 					session.Stop ();
 			}
@@ -577,7 +575,7 @@ namespace MonoDevelop.Debugger
 			if (HandleStopQueue ())
 				return;
 
-			foreach (var session in sessions.Keys.ToArray ()) {
+			foreach (var session in sessions.Keys) {
 				if (!session.IsRunning)
 					session.Continue ();
 			}
@@ -695,7 +693,7 @@ namespace MonoDevelop.Debugger
 			PropertyService.Set ("Monodevelop.StackTrace.ShowLineNumber", options.EvaluationOptions.StackFrameFormat.Line);
 			PropertyService.Set ("Monodevelop.StackTrace.ShowExternalCode", options.EvaluationOptions.StackFrameFormat.ExternalCode);
 
-			foreach (var session in sessions.Keys.ToArray ()) {
+			foreach (var session in sessions.Keys) {
 				session.Options.EvaluationOptions = GetUserOptions ().EvaluationOptions;
 			}
 			if (EvaluationOptionsChanged != null)
@@ -1133,7 +1131,7 @@ namespace MonoDevelop.Debugger
 			if (!IsDebugging)
 				return;
 
-			foreach (var pair in sessions.ToArray ()) {
+			foreach (var pair in sessions) {
 				pair.Key.Exit ();
 				Cleanup (pair.Value);
 			}