Crash in built-in debugger after restoring from minimised

[tomcw]

Using a debug build from HEAD of master (so ahead of 1.29.13.0(rel)).

Repro:

• Run SST, doing a drive speed check on drive-2 (blankwoz.woz)
• Minimize AppleWin
• (wait 1 minute?)
• Restore AppleWin (black screen, no buttons, no toolbar)
• F7 (in an attempt to force a redraw)
• Crash...

>	AppleWin.exe!FillBackground(long left=0x00000000, long top=0x00000000, long right=0x00000161, long bottom=0x00000008)  Line 909 + 0x12 bytes	C++
 	AppleWin.exe!PrintText(const char * pText=0x0018f4a4, tagRECT & rRect={...})  Line 885 + 0x20 bytes	C++
 	AppleWin.exe!PrintTextCursorX(const char * pText=0x0018f4a4, tagRECT & rRect={...})  Line 934 + 0xd bytes	C++
 	AppleWin.exe!DrawDisassemblyLine(int iLine=0x00000000, const unsigned short nBaseAddress=0xb90f)  Line 2115 + 0x13 bytes	C++
 	AppleWin.exe!DrawSubWindow_Code(int iWindow=0x00000002)  Line 4278 + 0xe bytes	C++
 	AppleWin.exe!DrawWindow_Code(int bUpdate=0xffffffff)  Line 4057 + 0xb bytes	C++
 	AppleWin.exe!UpdateDisplay(int bUpdate=0xffffffff)  Line 4201 + 0x9 bytes	C++
 	AppleWin.exe!DebugBegin()  Line 8632 + 0x7 bytes	C++
 	AppleWin.exe!ProcessButtonClick(int button=0x00000006, bool bFromButtonUI=true)  Line 2134	C++
 	AppleWin.exe!FrameWndProc(HWND__ * window=0x000104ae, unsigned int message=0x00000101, unsigned int wparam=0x00000076, long lparam=0xc0410001)  Line 1505 + 0xe bytes	C++
 	user32.dll!7728630a() 	
 	[Frames below may be incorrect and/or missing, no symbols loaded for user32.dll]	
 	user32.dll!77286d4a() 	
 	user32.dll!77286cf9() 	
 	user32.dll!772877d7() 	
 	user32.dll!77287bda() 	
 	AppleWin.exe!EnterMessageLoop()  Line 515 + 0xa bytes	C++
 	AppleWin.exe!WinMain(HINSTANCE__ * passinstance=0x00400000, HINSTANCE__ * __formal=0x00000000, char * lpCmdLine=0x002c684d, HINSTANCE__ * __formal=0x00000000)  Line 1400	C++
 	AppleWin.exe!__tmainCRTStartup()  Line 263 + 0x2c bytes	C
 	AppleWin.exe!WinMainCRTStartup()  Line 182	C
 	kernel32.dll!7512343d() 	
 	ntdll.dll!77989812() 	
 	ntdll.dll!779897e5() 	

Crash reason:
g_pDebuggerMemFramebits == NULL

Probably crash introduced at "Improved debugger video performance (#800)": af9568c

---

Reproduced the black screen with 1.29.13.0(rel), but no crash with F7.

• couldn't get the buttons / screen to redraw though.

[tomcw]

NB. Tried to repro (but failed) by doing...

• Boot to AppleSoft, set full-speed, and minimise (waited 1 min)
• Boot to AppleSoft, read C0E9 (motor on), and minimise (waited 2 mins)

[tomcw]

At the point of the crash, AppleWin's GDI Objects = 10,000 (from Task Manager).

Normally, just booting a disk, and F7, then GDI Objects = 66 (and repeatedly pressing F7 to enter/exit debugger, doesn't increase/leak GDI Objects).

But when running SST's Check Drive Speed, and minimising, then Task Manager shows GDI Objects increasing by ~1000/second! Unminimising (eg. when GDI Objects = 4775) doesn't release these GDI objects.

As a check, restarting AppleWin, then boot to AppleSoft + read C0E9 (or running at full-speed) + minimising doesn't cause GDI Objects to increase.

[tomcw]

A binary-chop shows this leak was introduced in 1.25.0.0 (it doesn't occur in 1.24.0.0).
GDIView.exe shows that it's DC objects that are leaking.

[tomcw]

The DC leak was occurring in this function: FrameDrawDiskStatus(), specifically on this line:

	HDC  dc     = (passdc ? passdc : GetDC(g_hFrameWindow));

I don't understand why it leaks handles only when the app window is minimised.
On this MS doc page for GetDC, it says:

After painting with a common DC, the ReleaseDC function must be called to release the DC. Class and private DCs do not have to be released.

So maybe when minimised, the DC is common; but when not minimised it's a class/private DC?

Anyway, this is fixed, so closing.