Fix cancelling of loading taking too much time

Author: awulkiew

solution/GraphicalDebugging/ExpressionLoader.cs

@@ -365,7 +365,7 @@ public static void Load(string name,
                                      exprs[0].Name, exprs[0].Type,
                                      delegate ()
                                      {
-                                        return timeGuard.Update();
+                                        timeGuard.ThrowOnCancel();
                                      });
             }
             else //if (exprs.Length > 1)
@@ -380,7 +380,7 @@ public static void Load(string name,
                                      exprs,
                                      delegate ()
                                      {
-                                        return timeGuard.Update();
+                                        timeGuard.ThrowOnCancel();
                                      });
             }
 
@@ -596,7 +596,7 @@ abstract class DrawableLoader : Loader
             /// <summary>
             /// Callback function allowing to break loading of variable.
             /// </summary>
-            public delegate bool LoadCallback();
+            public delegate void LoadCallback();
 
             /// <summary>
             /// Returns geometrical information of a Drawable.
@@ -819,7 +819,8 @@ protected ResultType LoadParsed(MemoryReader mreader, // should this be passed?
                     }
                     result.Add(p);
 
-                    return callback();
+                    callback();
+                    return true;
                 });
                 return result;
             }
@@ -844,7 +845,10 @@ protected ResultType LoadMemory(MemoryReader mreader,
                         delegate (double[] values)
                         {
                             if (dimension == 0 || values.Length % dimension != 0)
+                            {
+                                result = null;
                                 return false;
+                            }
                             int size = dimension > 0
                                         ? values.Length / dimension
                                         : 0;
@@ -856,7 +860,8 @@ protected ResultType LoadMemory(MemoryReader mreader,
                                 result.Add(p);
                             }
 
-                            return callback();
+                            callback();
+                            return true;
                         }))
                 {
                     return result;
@@ -969,7 +974,8 @@ private ExpressionDrawer.DrawablesContainer LoadMemory(MemoryReader mreader, Deb
                                 result.Add(d);
                             }
 
-                            return callback();
+                            callback();
+                            return true;
                         }))
                 {
                     return result;
@@ -1218,7 +1224,8 @@ private void LoadMemory(MemoryReader mreader, Debugger debugger,
                     {
                         foreach (double v in values)
                             list.Add(v);
-                        return callback();
+                        callback();
+                        return true;
                     });
 
                 if (ok)
@@ -1248,7 +1255,8 @@ private void LoadParsed(MemoryReader mreader, Debugger debugger,
                             return false;
                     }
                     values.Add(value);
-                    return callback();
+                    callback();
+                    return true;
                 });
 
                 if (ok)

solution/GraphicalDebugging/ExpressionLoader_Boost.cs

@@ -1294,7 +1294,8 @@ private bool LoadMemoryRecursive(MemoryReader mreader, Debugger debugger,
                 else
                     return false;
 
-                return callback();
+                callback();
+                return true;
             }
 
             private bool LoadParsedRecursive(MemoryReader mreader, Debugger debugger,
@@ -1338,7 +1339,8 @@ private bool LoadParsedRecursive(MemoryReader mreader, Debugger debugger,
                             return false;
                     }
 
-                    return callback();
+                    callback();
+                    return true;
                 });
 
                 return ok;
@@ -1641,7 +1643,8 @@ public override ExpressionDrawer.IDrawable Load(MemoryReader mreader, Debugger d
                     if (turn == null)
                         return false;
                     turns.Add(turn);
-                    return callback();
+                    callback();
+                    return true;
                 });
                 return ok
                      ? new ExpressionDrawer.TurnsContainer(turns)

solution/GraphicalDebugging/ExpressionLoader_BoostGil.cs

@@ -148,8 +148,7 @@ public override ExpressionDrawer.IDrawable Load(MemoryReader mreader, Debugger d
 
                         // TODO: Checked per pixel. Too often?
                         //   But it's the same for geometries (ForEachMemoryBlock).
-                        if (! callback())
-                            return null;
+                        callback();
                     }
                 }
 

solution/GraphicalDebugging/ExpressionLoader_Util.cs

@@ -27,7 +27,7 @@ public LoadTimeGuard(string variableName, long timeThreshold)
                 stopWatch.Start();
             }
 
-            public bool Update()
+            public void ThrowOnCancel()
             {
                 if (stopWatch.ElapsedMilliseconds > timeThreshold)
                 {
@@ -85,13 +85,10 @@ public bool Update()
                             // This also means that the thread already finished
                             // or will do it in the near future because window
                             // closing shuts down the dispatcher.
+                            throw new Exception("Cancelled");
                         }
-
-                        return result;
                     }
                 }
-
-                return true;
             }
 
             public void Reset()