Changeset 17

Timestamp:

Apr 2, 2016, 8:57:38 PM (9 years ago)

Author:

chronos

Message:

• Added: Handling exceptions raised inside background thread.

Location:

trunk

Files:

• Form/UFormMain.pas (modified) (1 diff)
• UDriveScan.pas (modified) (6 diffs)

trunk/Form/UFormMain.pas

@@ -225 +225 @@
 begin
   with Core.Project do
-  if DriveInfo.Path <> TDriveInfo(ComboBoxDrive.Items.Objects[ComboBoxDrive.ItemIndex]).Path then begin
+  if (ComboBoxDrive.ItemIndex <> -1) and (DriveInfo.Path <> TDriveInfo(ComboBoxDrive.Items.Objects[ComboBoxDrive.ItemIndex]).Path) then begin
     DriveInfo.Assign(TDriveInfo(ComboBoxDrive.Items.Objects[ComboBoxDrive.ItemIndex]));
     Modified := True;

trunk/UDriveScan.pas

@@ -6 +6 @@
 
 uses
-  Classes, SysUtils, Syncobjs, UBlockMap, Forms, UConfig, DOM, XMLRead, XMLWrite,
+  Classes, SysUtils, Syncobjs, UBlockMap, Forms, DOM,
   UXMLUtils, Contnrs;
 
@@ -13 +13 @@
 
   TRunMode = (rmRead, rmWrite);
+  TExceptionEvent = procedure (Sender: TObject; E: Exception) of object;
 
   { TScanThread }
 
   TScanThread = class(TThread)
+  private
+    FOnException: TExceptionEvent;
+  public
     Scan: TDriveScan;
+    ExceptionText: string;
     procedure Execute; override;
+    property OnException: TExceptionEvent read FOnException write FOnException;
   end;
 
@@ -30 +36 @@
     FSectorCurrent: Integer;
     ScanThread: TScanThread;
+    LastExceptionMessage: string;
+    procedure DoOnExceptionSync;
+    procedure DoOnException(Sender: TObject; E: Exception);
     procedure DoChange;
     procedure DoTerminate;
@@ -111 +120 @@
 procedure TScanThread.Execute;
 begin
-  Scan.Run;
+  ExceptionText := '';
+  try
+    Scan.Run;
+  except
+    on E: Exception do
+      if Assigned(FOnException) then FOnException(Self, E);
+  end;
 end;
 
 { TDriveScan }
+
+procedure TDriveScan.DoOnExceptionSync;
+begin
+  raise Exception.Create(LastExceptionMessage);
+end;
+
+procedure TDriveScan.DoOnException(Sender: TObject; E: Exception);
+begin
+  LastExceptionMessage := E.Message;
+  TThread(Sender).Synchronize(TThread(Sender), DoOnExceptionSync);
+end;
 
 procedure TDriveScan.DoChange;
@@ -151 +177 @@
     Terminated := False;
     ScanThread := TScanThread.Create(True);
+    ScanThread.OnException := DoOnException;
     ScanThread.Scan := Self;
     ScanThread.Start;
@@ -163 +190 @@
 begin
   try
-  Lock.Acquire;
-  Terminated := False;
-  if Mode = rmRead then F := TFileStream.Create(DriveName, fmOpenRead)
-    else if Mode = rmWrite then F := TFileStream.Create(DriveName, fmOpenReadWrite);
-  try
-  SetLength(Buffer, SectorSize);
-  if Mode = rmWrite then
-    FillChar(Buffer[0], Length(Buffer), WritePattern);
-  while FSectorCurrent < SectorEnd do begin
+    Lock.Acquire;
+    Terminated := False;
+    if Mode = rmRead then F := TFileStream.Create(DriveName, fmOpenRead)
+      else if Mode = rmWrite then F := TFileStream.Create(DriveName, fmOpenReadWrite);
     try
-      Lock.Release;
-      DoChange;
-      F.Position := FSectorCurrent * SectorSize;
-      if Mode = rmRead then RealSize := F.Read(Buffer[0], SectorSize)
-        else if Mode = rmWrite then RealSize := F.Write(Buffer[0], SectorSize)
-        else raise Exception.Create(SUnknownRunMode);
+      SetLength(Buffer, SectorSize);
+      if Mode = rmWrite then
+        FillChar(Buffer[0], Length(Buffer), WritePattern);
+      while FSectorCurrent < SectorEnd do begin
+        try
+          Lock.Release;
+          DoChange;
+          F.Position := FSectorCurrent * SectorSize;
+          if Mode = rmRead then RealSize := F.Read(Buffer[0], SectorSize)
+            else if Mode = rmWrite then RealSize := F.Write(Buffer[0], SectorSize)
+            else raise Exception.Create(SUnknownRunMode);
+        finally
+          Lock.Acquire;
+        end;
+        if RealSize <> SectorSize then begin
+          BlockMap.Sectors[FSectorCurrent] := bsDamaged;
+          Inc(DamagedBlockCount);
+        end else BlockMap.Sectors[FSectorCurrent] := bsOk;
+        Inc(FSectorCurrent);
+        if Terminated then Break;
+      end;
     finally
-      Lock.Acquire;
+      F.Free;
     end;
-    if RealSize <> SectorSize then begin
-      BlockMap.Sectors[FSectorCurrent] := bsDamaged;
-      Inc(DamagedBlockCount);
-    end else BlockMap.Sectors[FSectorCurrent] := bsOk;
-    Inc(FSectorCurrent);
-    if Terminated then Break;
-  end;
-  finally
-    F.Free;
-  end;
   finally
     Lock.Release;