Index: Source/exehead/fileform.h
===================================================================
RCS file: /cvsroot/nsis/NSIS/Source/exehead/fileform.h,v
retrieving revision 1.79
diff -u -r1.79 fileform.h
--- Source/exehead/fileform.h	18 Feb 2005 13:39:42 -0000	1.79
+++ Source/exehead/fileform.h	30 May 2005 22:21:43 -0000
@@ -504,6 +507,8 @@
 
 extern HANDLE g_db_hFile;
 extern int g_quit_flag;
+extern int g_cancel_flag;
+extern int g_install_thread_running;
 
 BOOL NSISCALL ReadSelfFile(LPVOID lpBuffer, DWORD nNumberOfBytesToRead);
 DWORD NSISCALL SetSelfFilePointer(LONG lDistanceToMove);
Index: Source/exehead/Ui.c
===================================================================
RCS file: /cvsroot/nsis/NSIS/Source/exehead/Ui.c,v
retrieving revision 1.232
diff -u -r1.232 Ui.c
--- Source/exehead/Ui.c	17 May 2005 19:52:44 -0000	1.232
+++ Source/exehead/Ui.c	31 May 2005 02:49:26 -0000
@@ -42,6 +42,10 @@
 int dlg_offset;
 int ui_dlg_visible=0; // At start main window is not visible
 int g_quit_flag; // set when Quit has been called (meaning bail out ASAP)
+int g_cancel_flag; // set when Cancel button clicked during install
+int g_install_thread_running; // set when install_thread is running
+
+HANDLE install_thread_handle;
 
 #if NSIS_MAX_INST_TYPES > 32 || NSIS_MAX_INST_TYPES < 1
 #error invalid value for NSIS_MAX_INST_TYPES
@@ -630,12 +634,17 @@
       }
       else
       {
+        if (g_install_thread_running)
+            g_cancel_flag = TRUE;
+        else
+        {
 #ifdef NSIS_SUPPORT_CODECALLBACKS
-        if (!ExecuteCallbackFunction(CB_ONUSERABORT))
+          if (!ExecuteCallbackFunction(CB_ONUSERABORT))
 #endif//NSIS_SUPPORT_CODECALLBACKS
-        {
-          m_retcode=1;
-          outernotify(NOTIFY_BYE_BYE);
+          {
+            m_retcode=1;
+            outernotify(NOTIFY_BYE_BYE);
+          }
         }
       }
     }
@@ -1415,6 +1424,8 @@
   }
 #endif
 
+  g_install_thread_running = TRUE;
+
   while (m_inst_sec--)
   {
 #ifdef NSIS_CONFIG_COMPONENTPAGE
@@ -1436,12 +1447,28 @@
 #endif
     s++;
   }
-  NotifyCurWnd(WM_NOTIFY_INSTPROC_DONE);
+
+  g_install_thread_running = FALSE;
+
+  if (g_cancel_flag && !g_exec_flags.abort)
+  {
+    g_cancel_flag = FALSE;
+#ifdef NSIS_SUPPORT_CODECALLBACKS
+    if (!ExecuteCallbackFunction(CB_ONUSERABORT))
+#endif//NSIS_SUPPORT_CODECALLBACKS
+    {
+      g_quit_flag++;
+      g_exec_flags.abort++;
+    }
+  }
 
 #if defined(NSIS_SUPPORT_ACTIVEXREG) || defined(NSIS_SUPPORT_CREATESHORTCUT)
   OleUninitialize();
 #endif
 
+  if (m_curwnd)
+    PostMessage(m_curwnd, WM_NOTIFY_INSTPROC_DONE, 0, 0);
+
   return g_exec_flags.abort;
 }
 
@@ -1501,7 +1528,7 @@
   }
   if (uMsg == WM_NOTIFY_START) {
     DWORD id;
-    CloseHandle(CreateThread(NULL,0,install_thread,GetUIItem(IDC_PROGRESS),0,&id));
+    install_thread_handle = CreateThread(NULL,0,install_thread,GetUIItem(IDC_PROGRESS),0,&id);
   }
   if (uMsg == WM_COMMAND && LOWORD(wParam) == IDC_SHOWDETAILS)
   {
@@ -1511,6 +1538,12 @@
   }
   if (uMsg == WM_NOTIFY_INSTPROC_DONE)
   {
+    if (install_thread_handle != NULL)
+    {
+      WaitForSingleObject(install_thread_handle, INFINITE);
+      CloseHandle(install_thread_handle);
+      install_thread_handle = NULL;
+    }
     if (g_quit_flag)
     {
       m_retcode=2;
Index: Source/exehead/exec.c
===================================================================
RCS file: /cvsroot/nsis/NSIS/Source/exehead/exec.c,v
retrieving revision 1.158
diff -u -r1.158 exec.c
--- Source/exehead/exec.c	8 Apr 2005 15:29:52 -0000	1.158
+++ Source/exehead/exec.c	30 May 2005 19:36:25 -0000
@@ -68,6 +68,18 @@
       extern int progress_bar_pos, progress_bar_len;
       progress_bar_pos+=rv;
       SendMessage(hwndProgress,PBM_SETPOS,MulDiv(progress_bar_pos,30000,progress_bar_len+!progress_bar_len),0);
+
+      if (g_install_thread_running && g_cancel_flag)
+      {
+        g_cancel_flag = FALSE;
+#ifdef NSIS_SUPPORT_CODECALLBACKS
+        if (!ExecuteCallbackFunction(CB_ONUSERABORT))
+#endif//NSIS_SUPPORT_CODECALLBACKS
+        {
+          g_quit_flag++;
+          return(EXEC_ERROR);
+        }
+      }
     }
   }
   return 0;