Thread: Cancel Button not working

I finally got around to finishing the set of functions I was writing for displaying a progress window while CopyFileEx() runs. The only problem is that the cancel button on the window won't work. Well, actually it will work if I display a message box right before I create the window, which I haven't been able to explain yet... Anyway, here is the full code for it, less the headers:

Code:

//Include files////////////////////////////////////////////////////////////////////////////

#include "global_definitions.h"

#include <windows.h>
#include <commctrl.h>
#include "debug.h"
#include "memory.h"
#include "stringio.h"
#include "window_classes.h"

///////////////////////////////////////////////////////////////////////////////////////////



//Function prototypes//////////////////////////////////////////////////////////////////////

void InitProgressWindowClass(void);

int CopyFileProgressEx(LPCTSTR lpExistingFileName, LPCTSTR lpNewFileName, DWORD dwCopyFlags, HWND hWndParent, char * title, char * message, BOOL popup, DWORD parentUpdate);

DWORD WINAPI ProgressWindowThread(LPVOID lParam);

INT_PTR CALLBACK ProgressWindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

LRESULT ProgressWindow_OnCreate(HWND hWnd, WPARAM wParam, LPARAM lParam);

DWORD CALLBACK CopyProgressRoutine(LARGE_INTEGER TotalFileSize, LARGE_INTEGER TotalBytesTransferred, LARGE_INTEGER StreamSize, LARGE_INTEGER StreamBytesTransferred, DWORD dwStreamNumber, DWORD dwCallbackReason, HANDLE hSourceFile, HANDLE hDestinationFile, LPVOID lpData);

///////////////////////////////////////////////////////////////////////////////////////////



//Function definitions/////////////////////////////////////////////////////////////////////

void InitProgressWindowClass(void)
{

    WNDCLASSEX wc = {0};

	//Register the progress window class
    wc.cbSize         = sizeof(wc);
    wc.lpszClassName  = "Progress Window";
    wc.hInstance      = GetModuleHandle(NULL);
    wc.lpfnWndProc    = ProgressWindowProc;
    wc.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground  = (HBRUSH)GetSysColorBrush(COLOR_BTNFACE);
    wc.cbWndExtra     = sizeof(PROGRESSINFO *);

	RegisterClassEx(&wc);

}

int CopyFileProgressEx(LPCTSTR lpExistingFileName, LPCTSTR lpNewFileName, DWORD dwCopyFlags, HWND hWndParent, char * title, char * message, BOOL popup, DWORD parentUpdate)
{

	PROGRESSINFO * pip = ClearMemAlloc(sizeof(PROGRESSINFO));
	BOOL error;
	BOOL cancel = 0;
	DWORD threadId;

	if(!title)
		title = "";

	if(!message)
		message = "";

	pip->title = title;
	pip->message = message;

	pip->popup = popup;

	pip->cancel = &cancel;

	pip->hWndParent = hWndParent;

	pip->parentUpdate = parentUpdate;

	pip->lastParentUpdate = GetTickCount();

	SetFocus(hWndParent);

	CreateThread(NULL, 0, ProgressWindowThread, pip, 0, &threadId);

	while(!pip->hWndProgress)
		Sleep(0);

	error = CopyFileEx(lpExistingFileName, lpNewFileName, CopyProgressRoutine, pip, NULL, dwCopyFlags);

	if(!error)
		return 1;
	else if(cancel)
		return 2;

	return 0;

}

DWORD WINAPI ProgressWindowThread(LPVOID lParam)
{

	MSG msg;
	DWORD exitCode = 0;
	PROGRESSINFO * pip = (PROGRESSINFO *) lParam;
	DWORD dwStyle = (pip->hWndParent != NULL ? WS_CHILD : 0) | WS_VISIBLE;
	RECT progressCords;

	if(pip->popup)
	{
		progressCords.left = GetSystemMetrics(SM_CXSCREEN) / 2 - PROGRESSWINDOW_WIDTH / 2;
		progressCords.top = GetSystemMetrics(SM_CYSCREEN) / 2 - PROGRESSWINDOW_HEIGHT / 2;

		dwStyle |= WS_POPUPWINDOW;
	}
	else
	{
		dwStyle |= WS_DLGFRAME;

		GetClientRect(pip->hWndParent, &progressCords);

		progressCords.left = (progressCords.right - progressCords.left) / 2 - PROGRESSWINDOW_WIDTH / 2;
		progressCords.top = (progressCords.bottom - progressCords.top) / 2 - PROGRESSWINDOW_HEIGHT / 2;
	}

	pip->hWndProgress = CreateWindowEx(
		0,
		"Progress Window",
		pip->title,
		dwStyle,
		progressCords.left,
		progressCords.top,
		PROGRESSWINDOW_WIDTH,
		PROGRESSWINDOW_HEIGHT,
		pip->hWndParent,
		NULL,
		GetModuleHandle(NULL),
		pip);

	while(GetMessage(&msg, NULL, 0, 0))
	{ 
		TranslateMessage(&msg); 
		DispatchMessage(&msg); 
	} 

	GetExitCodeThread(GetCurrentThread(), &exitCode);

	ExitThread(exitCode);

	ErrorMessage("Abnormal thread termination", NULL, NULL, MB_ICONEXCLAMATION, 1);

	return FALSE;

}

INT_PTR CALLBACK ProgressWindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{

	switch(uMsg)
	{

	case WM_CREATE:
		return ProgressWindow_OnCreate(hWnd, wParam, lParam);
		break;

	case WM_COMMAND:
		switch(LOWORD(wParam))
		{

		case BN_CLICKED:
			*(((PROGRESSINFO *)(GetWindowLongPtr(hWnd, GWL_USERDATA)))->cancel) = 1;
			break;

		}
		break;

	case WM_CLOSE:
		DestroyWindow(hWnd);
		break;

	case WM_DESTROY:
		free((void *) GetWindowLongPtr(hWnd, GWL_USERDATA));
		break;

	}

    return DefWindowProc(hWnd, uMsg, wParam, lParam);

}

LRESULT ProgressWindow_OnCreate(HWND hWnd, WPARAM wParam, LPARAM lParam)
{

	PROGRESSINFO * pip = *(PROGRESSINFO **) lParam;
	RECT rect;

	SetWindowLongPtr(hWnd, GWL_USERDATA, (LONG) pip);

	GetClientRect(hWnd, &rect);

	pip->progressBar = CreateWindowEx(
		WS_EX_CLIENTEDGE,
		PROGRESS_CLASS,
		NULL,
		WS_CHILD | WS_VISIBLE | PBS_SMOOTH,
		rect.left + 2,
		PROGRESSWINDOW_HEIGHT / 2 - GetSystemMetrics(SM_CYVSCROLL),
		rect.right - 5,
		GetSystemMetrics(SM_CYVSCROLL),
		hWnd,
		0,
		GetModuleHandle(NULL),
		NULL);

	pip->hWndStatic = CreateWindowEx(
		0,
		"Static",
		NULL,
		WS_CHILD | WS_VISIBLE | SS_CENTER,
		rect.left + 2,
		rect.top + 10,
		rect.right - 5,
		rect.top + 20,
		hWnd,
		0,
		GetModuleHandle(NULL),
		NULL);

	SetWindowText(pip->hWndStatic, pip->message);

	pip->hWndCancel = CreateWindowEx(
		0,
		"Button",
		NULL,
		WS_CHILD | WS_VISIBLE | BS_TEXT | BS_PUSHBUTTON,
		((rect.right - rect.left) / 2) + rect.left - 30,
		rect.bottom  - 30,
		60,
		24,
		hWnd,
		0,
		GetModuleHandle(NULL),
		NULL);

	SetWindowText(pip->hWndCancel, "Cancel");

	pip->hWndProgress = hWnd;

	SetFocus(pip->hWndCancel);

	return FALSE;

}

DWORD CALLBACK CopyProgressRoutine(LARGE_INTEGER TotalFileSize, LARGE_INTEGER TotalBytesTransferred, LARGE_INTEGER StreamSize, LARGE_INTEGER StreamBytesTransferred, DWORD dwStreamNumber, DWORD dwCallbackReason, HANDLE hSourceFile, HANDLE hDestinationFile, LPVOID lpData)
{

	int i;
	unsigned __int64 biasBit = 0x8000000000000000;
	int progressRange;
	int progressAchieved;
	PROGRESSINFO * pip = lpData;

	if(!pip->progressBias)
	{
		if(!(TotalFileSize.QuadPart & 0xFFFFFFFF80000000))
			pip->progressBias = 0;

		else  //Untested...
		{
			for(i = 33; i; i--)
			{
				if(biasBit & TotalFileSize.QuadPart)
					break;

				biasBit = biasBit>>1;
			}

			pip->progressBias = 32 - i;
		}
	}

	progressRange = (int) (TotalFileSize.QuadPart>>(pip->progressBias + 1));

	progressAchieved = (int) (TotalBytesTransferred.QuadPart>>(pip->progressBias + 1));

	SendMessage(pip->progressBar, (UINT) PBM_SETRANGE32, (WPARAM) 0, (LPARAM) progressRange);

	SendMessage(pip->progressBar, (UINT) PBM_SETPOS, (WPARAM) progressAchieved, (LPARAM) 0);

	if(pip->parentUpdate && pip->lastParentUpdate + pip->parentUpdate < GetTickCount())
	{
		UpdateWindow(pip->hWndParent);
		pip->lastParentUpdate = GetTickCount();
	}

	if(TotalFileSize.QuadPart == TotalBytesTransferred.QuadPart)  //Not sure if this is gurenteed to always be true the last time and only the last time this funtion is called. If it isn't it could be a bit proboblematic
	{
		PostMessage(pip->hWndProgress, WM_CLOSE, 0, 0);
		return PROGRESS_CONTINUE;
	}

	if(*pip->cancel)
	{
		PostMessage(pip->hWndProgress, WM_CLOSE, 0, 0);
		return PROGRESS_CANCEL;
	}
	else
		return PROGRESS_CONTINUE;

}

///////////////////////////////////////////////////////////////////////////////////////////

Ok, I finally figured it out. Since the CopyFileEx funtion completely hijacks the same thread that is used for message processing of the parent window I set for the function to use, that causes some problems. Well that's easy enough to fix, but I'd still like to know why calling a message box fixes the issue... Heh, isn't multithreading fun .

When you call MessageBox, your thread will enter a message loop until the user dismisses the message box.

gg

In my case though, the message box is destroyed before CopyFileProgressEx() is called...