Changeset 298 for Common/UResetableThread.pas

Timestamp:

Nov 16, 2011, 10:07:51 AM (13 years ago)

Author:

george

Message:

• Added: Exception handling in TThreadPool. If exception occurs in one of pool threads this will raise exception in main thread from RunInThread method is executed. This require special handling on the side of main thread.

File:

• Common/UResetableThread.pas (modified) (5 diffs)

Common/UResetableThread.pas

@@ -23 +23 @@
   private
     FLock: TCriticalSection;
+    FOnException: TExceptionEvent;
     FOnFinished: TNotifyEvent;
     FStartEvent: TEvent;
@@ -42 +43 @@
     property StopPending: Boolean read FStopPending;
     property Running: Boolean read GetRunning;
+    property OnException: TExceptionEvent read FOnException
+      write FOnException;
   end;
 
@@ -48 +51 @@
   TThreadPool = class(TThreadedPool)
   private
+    FOnException: TExceptionEvent;
     procedure MethodFinish(Sender: TObject);
+    procedure ThreadException(Sender: TObject; E: Exception);
   protected
     function NewItemObject: TObject; override;
   public
+    LastExceptionClass: TClass;
+    LastExceptionMessage: string;
+    procedure CheckException;
     procedure WaitForEmpty;
+    procedure Clear;
     procedure RunInThread(AMethod: TMethodCall);
     constructor Create; override;
     destructor Destroy; override;
+    property OnException: TExceptionEvent read FOnException
+      write FOnException;
   end;
 
@@ -193 +204 @@
           try
             FLock.Release;
-            Method;
-            if Assigned(FOnFinished) then
-              FOnFinished(Parent);
+            try
+              try
+                Method;
+              finally
+                if Assigned(FOnFinished) then
+                  FOnFinished(Parent);
+              end;
+            except
+              on E: Exception do
+                if Assigned(FOnException) then
+                  FOnException(Self, E);
+            end;
           finally
             FLock.Acquire;
@@ -219 +239 @@
 end;
 
+procedure TThreadPool.ThreadException(Sender: TObject; E: Exception);
+begin
+  LastExceptionClass := E.ClassType;
+  LastExceptionMessage := E.Message;
+end;
+
+procedure TThreadPool.CheckException;
+begin
+  if Assigned(LastExceptionClass) then
+    raise Exception.Create(LastExceptionMessage);
+end;
+
 function TThreadPool.NewItemObject: TObject;
 begin
   Result := TResetableThread.Create;
+  TResetableThread(Result).OnException := ThreadException;
 end;
 
 procedure TThreadPool.WaitForEmpty;
 begin
-  while UsedCount > 0 do
+  while UsedCount > 0 do begin
     Sleep(1);
+  end;
+end;
+
+procedure TThreadPool.Clear;
+begin
+  TotalCount := 0;
+  LastExceptionClass := nil;
+  LastExceptionMessage := '';
 end;
 
 procedure TThreadPool.RunInThread(AMethod: TMethodCall);
 begin
+  CheckException;
   with TResetableThread(Acquire) do begin
     Method := AMethod;