Crash if force close Data Source when acquire image

[kmbui]

Hi,

I write a dll that handle image acquire from imaging software data source.
There is a strange case that cost me days without any solution:
1. Use PortView (an Twain data source from Port View imaging software).
2. Open PortView to acquire image.
3. In PortView, import an image, then close (press X button on UI).
4. Close data source programmatically:
(*g_pDSM_Entry) (&g_AppID, 0, DG_CONTROL, DAT_IDENTITY, MSG_CLOSEDS, &srcID)
Then my dll crash.

In step #3, in does not crash if:
3a. Close PortView without importing an image (has no image).
3b. Click Send button on UI to send the image to the dll.

I try do find any different between the crash case and 3b to do something specially, but there’s nothing:
– Both case has: event.TWMessage == MSG_XFERREADY (In 3a event.TWMessage == MSG_CLOSEDSREQ).
– Both case has image transferred back to the dll.

Any hint would be much appreciated.
Thanks,

[kmbui]

More info:
In step #4, i call 3 commands:

4.1. (*g_pDSM_Entry) (&g_AppID, &srcID, DG_CONTROL, DAT_USERINTERFACE, MSG_DISABLEDS, &ui)
4.2. (*g_pDSM_Entry) (&g_AppID, 0, DG_CONTROL, DAT_IDENTITY, MSG_CLOSEDS, &srcID)
4.3 (*g_pDSM_Entry) (&g_AppID, 0, DG_CONTROL, DAT_PARENT, MSG_CLOSEDSM, (TW_MEMREF)&hwnd)

and it crash at #4.2.
if i comment out #4.1, it crash at 4.3.

[kmbui]

Here is my whole function:

static int acquireByName(JNIEnv *env, BOOL showUI, BOOL modal, const char* sourceName, int maxImages, jobjectArray images)

{

TW_UINT16 rc;



// Create a static window whose handle is passed to DSM_Entry() when we

// open the data source manager.

HWND hwnd = CreateWindow("STATIC",

sourceName,

WS_POPUPWINDOW,

CW_USEDEFAULT,

CW_USEDEFAULT,

CW_USEDEFAULT,

CW_USEDEFAULT,

HWND_DESKTOP,

0,

g_hinstDLL,

0);



// If window could not be created, throw exception. Because the exception

// is not actually thrown until execution returns to Java, we must return

// a value -- (jobject) 0 was chosen to represent Image null. This value

// will not be seen in the Java code because of the exception.

if (hwnd == 0)

{

return TWRC_FAILURE;

}



// Ensure that the default data source's dialog box does not disappear

// behind other windows, which can be very disconcerting to the user. We do

// that by making the hwnd -- created above and passed to DSM_Entry() below

// -- the handle of the topmost window.

SetWindowPos(hwnd, HWND_TOP, 0, 0, 0, 0, SWP_SHOWWINDOW);



// Open Data Source Manager

BLOCK_BEGIN(1)



// Open the data source manager.

rc = (*g_pDSM_Entry) (&g_AppID,

0,

DG_CONTROL,

DAT_PARENT,

MSG_OPENDSM,

(TW_MEMREF)&hwnd);



// If data source manager could not be opened, throw exception. Because the

// exception is not actually thrown until execution returns to Java, we

// first exit current block to destroy previously-created window and return

// a value (which isn't seen in the Java code).

if (rc != TWRC_SUCCESS)

{

EXIT_CURRENT_BLOCK

}



// Open Data Source

BLOCK_BEGIN(2)



// Find the data source match the name

TW_IDENTITY srcID;

memset(&srcID, 0, sizeof(srcID));

BOOL found = FALSE;



// Check with first DataSource

rc = (*g_pDSM_Entry) (&g_AppID,

0,

DG_CONTROL,

DAT_IDENTITY,

MSG_GETFIRST,

(TW_MEMREF)&srcID);

if (rc == TWRC_SUCCESS)

{

// found

if (_stricmp(srcID.ProductName, sourceName) == 0)

{

found = TRUE;

}

else

{

do

{

rc = (*g_pDSM_Entry) (&g_AppID,

0,

DG_CONTROL,

DAT_IDENTITY,

MSG_GETNEXT,

(TW_MEMREF)&srcID);

if (rc == TWRC_SUCCESS)

{

// found

if (_stricmp(srcID.ProductName, sourceName) == 0)

{

found = TRUE;

break;

}

}

} while (rc == TWRC_SUCCESS);

}



if (found != TRUE)

{

EXIT_CURRENT_BLOCK

}

}

else

{

EXIT_CURRENT_BLOCK

}



// Open the selected data source.

rc = (*g_pDSM_Entry) (&g_AppID,

0,

DG_CONTROL,

DAT_IDENTITY,

MSG_OPENDS,

&srcID);



// If default data source could not be opened, throw exception. Because the

// exception is not actually thrown until execution returns to Java, we

// first exit current block to close data source manager and destroy the

// previously-created window.

if (rc != TWRC_SUCCESS)

{

EXIT_CURRENT_BLOCK

}



// Does capturing

BLOCK_BEGIN(3)



// Prepare to enable the default data source. Make sure to show the data

// source's own user interface (dialog box).

TW_USERINTERFACE ui;

ui.ShowUI = showUI;

ui.ModalUI = modal;

ui.hParent = hwnd;



// Enable the default data source.

rc = (*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_USERINTERFACE,

MSG_ENABLEDS,

&ui);



// If default data source could not be enabled, throw exception. Because

// the exception is not actually thrown until execution returns to Java, we

// first exit current block to close data source, close data source

// manager and destroy the previously-created window.

if (rc != TWRC_SUCCESS)

{

EXIT_CURRENT_BLOCK

}



// Begin the event-handling loop. Data transfer takes place in this loop.

MSG msg;

TW_EVENT event;

TW_PENDINGXFERS pxfers;

memset(&pxfers, 0, sizeof(TW_PENDINGXFERS));



while (GetMessage((LPMSG)&msg, 0, 0, 0))

{

// Each window message must be forwarded to the data source.

event.pEvent = (TW_MEMREF)&msg;

event.TWMessage = MSG_NULL;



rc = (*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_EVENT,

MSG_PROCESSEVENT,

(TW_MEMREF)&event);



// If the message does not correspond to a data source event, we must

// dispatch it to the appropriate Windows window.

if (rc == TWRC_NOTDSEVENT)

{

TranslateMessage((LPMSG)&msg);

DispatchMessage((LPMSG)&msg);

continue;

}



// If the default data source is requesting that the data source's

// dialog box be closed (user pressed Cancel), we must break out of the

// message loop.

if (event.TWMessage == MSG_CLOSEDSREQ)

break;



// If the default data source is requesting that it is ready to begin

// the data transfer, we must perform that transfer.

if (event.TWMessage == MSG_XFERREADY)

{

int acquiredImages = 0;

do

{

// Obtain information about the first image to be transferred.

TW_IMAGEINFO ii;

rc = (*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_IMAGE,

DAT_IMAGEINFO,

MSG_GET,

(TW_MEMREF)&ii);



// If unable to obtain image information ...

if (rc != TWRC_SUCCESS)

{

// Cancel all transfers.

(*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_PENDINGXFERS,

MSG_RESET,

(TW_MEMREF)&pxfers);



// break out of event loop.

break;

}



// If image is compressed or is not 8-bit color and not 24-bit color ...

if (ii.Compression != TWCP_NONE || ii.BitsPerPixel != 8 && ii.BitsPerPixel != 24)

{

// Cancel all transfers.

(*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_PENDINGXFERS,

MSG_RESET,

(TW_MEMREF)&pxfers);



// break out of event loop.

break;

}



// Perform the transfer.

TW_UINT32 handle;



rc = (*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_IMAGE,

DAT_IMAGENATIVEXFER,

MSG_GET,

(TW_MEMREF)&handle);



// If image not successfully transferred ...

if (rc != TWRC_XFERDONE)

{

// Cancel all remaining transfers.

(*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_PENDINGXFERS,

MSG_RESET,

(TW_MEMREF)&pxfers);



// break out of event loop.

break;

}



rc = (*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_PENDINGXFERS,

MSG_ENDXFER,

(TW_MEMREF)&pxfers);



// Transfer Windows-based DIB to a Java-based Image (via a MemoryImageSource).

LPBITMAPINFOHEADER lpbmih;

lpbmih = (LPBITMAPINFOHEADER)GlobalLock((HANDLE)handle);



jobject image;

/*if (ii.BitsPerPixel == 8)

{

image = xferDIB8toImage(lpbmih, env);

}

else

{

image = xferDIB24toImage(lpbmih, env);

}

env->SetObjectArrayElement(images, acquiredImages, image);*/



GlobalUnlock((HANDLE)handle);

GlobalFree((HANDLE)handle);



acquiredImages++;

if (acquiredImages >= maxImages)

{

// Cancel all remaining transfers.

(*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_PENDINGXFERS,

MSG_RESET,

(TW_MEMREF)&pxfers);



// break out of acquire loop.

break;

}

} while (pxfers.Count != 0);



// break out of event loop.

break;

}

}



// Disable the data source.

(*g_pDSM_Entry) (&g_AppID,

&srcID,

DG_CONTROL,

DAT_USERINTERFACE,

MSG_DISABLEDS,

&ui);



BLOCK_END(3)



// Close the data source.

(*g_pDSM_Entry) (&g_AppID,

0,

DG_CONTROL,

DAT_IDENTITY,

MSG_CLOSEDS,

&srcID);



BLOCK_END(2)



// Close the data source manager.

(*g_pDSM_Entry) (&g_AppID,

0,

DG_CONTROL,

DAT_PARENT,

MSG_CLOSEDSM,

(TW_MEMREF)&hwnd);



BLOCK_END(1)



DestroyWindow(hwnd);



return TWRC_SUCCESS;

}

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