[Vortex] Windows issues and memory tracking in debug builds

[Yourch, Chris]

1. The source code downloaded from Sourceforge does not include the
libaxl.def. Also, the libaxl.vcproj file does not include the .DEF file
either.

2. Oh, I was thinking this was a private API call. At least in debug
builds, using the memory tracking suggestions below, a free on an object
already freed would be caught.

As for the memory tracking changes, I can make them here and send you
the updated modules?

Chris


-----Original Message-----
From: Francis Brosnan Blazquez [mailto:francis at aspl.es] 
Sent: Thursday, November 08, 2007 12:41 AM
To: Yourch, Chris
Cc: Vortex
Subject: Re: Windows issues and memory tracking in debug builds

Hi Chris,

> Here's a bunch of issues and suggestions related to the Windows/Visual
> Studio environment:
> 
> 
> 1. The libaxl project is missing a .DEF file so it only compiles as a
> static library for now.

The windows installer includes the libaxl.def file and the libaxl.lib at
the lib/ directory, and the source code includes the libaxl.def inside
the src/ directory. Let me know if there is something missing.

> 2. Suggestion: Instead of  "vortex_frame_unref(VortexFrame * frame)"
how
> about "vortex_frame_unref(VortexFrame ** frame)" so that when the ref
> count goes to 0 and the frame is freed you can set the frame pointer
to
> NULL.

This looks good, but looks as a hard API change. What about adding
something like vortex_frame_unref_nullify (VortexFrame ** frame), which
would coexists with vortex_frame_unref?

> 3. Tracking memory allocations: For debug builds, define
> _CRTDBG_MAP_ALLOC in the libvortex and libaxl Visual Studio projects
> under the Properties -> C/C++ ->  preprocessor section.
> 
> 
> 4. Turning on more aggressive allocation/free checking: At line 44 of
> vortex_win32.c add the following:
> 
> #ifdef _DEBUG
> #include <crtdbg.h>
> #endif
> 
> And, in the same module, add this to the first line of DllMain():
> #ifdef _DEBUG
>    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF|_CRTDBG_CHECK_ALWAYS_DF|
>                     _CRTDBG_CHECK_CRT_DF|_CRTDBG_DELAY_FREE_MEM_DF|
>                     _CRTDBG_LEAK_CHECK_DF);
> #endif
> 
> 
> 5. Further memory tracking: To track allocations and frees for Vortex
> specific objects during _DEBUG builds have axl_new() call
_calloc_dbg()
> and axl_free() call _free_dbg(). The debug versions of these functions
> have additional parameters. They take a blocktype value (an int), the
> filename and the linenumber. The blocktype is an important field. For
> each specific Vortex "type" define a sub-blocktype number that is
OR'ed
> with the blocktype. 
> 
> // Define the memory block sub-type for Vortex types:
> enum MicrosoftMemoryBlockTypes
> {
> 	BLKTYPE_VortexChannelData = 1,  // VortexChannelData:
> 	BLKTYPE_char,                   // char:
> 	BLKTYPE_VortexChannel           // VortexChannel
> 
> 	// and so on...
> };
> 
> // Update the signature of axl_new():
> #ifdef _DEBUG
>   #define axl_new(type, count, blksubtype)  \
>       (type *) _calloc_dbg(count, sizeof(type), \
>                            (_CLIENT_BLOCK | ((blksubtype) << 16)), \
>                            __FILE__, __LINE__)
> #else
>   #define axl_new(type, count)    (type *) calloc (count, sizeof
(type))
> #endif
> 
> // Update the signature of axl_free():
> #ifdef _DEBUG
>   #define axl_free(ptr, blksubtype)  \
>       _free_dbg(ptr, (_CLIENT_BLOCK | ((blksubtype) << 16))
> #else
>   #define axl_free(ptr)    free(ptr)
> #endif
> 
> 
> Finally, when leaks are detected or the memory needs to be dumped, the
> Vortex specific dump function will be called. This is defined as
> follows:
> 
> #ifdef _DEBUG
> void __cdecl DumpVortexObjectFunction(void *pUserData, size_t nBytes)
> {
>   int blktype = _CrtReportBlockType(pUserData);
>   int blksubtype = ((blktype >> 16) & 0xFFFF);
> 
>   if (blksubtype == BLKTYPE_VortexChannelData)
>   {
>     VortexChannelData *channelData = (VortexChannelData *)pUserData;
> 
>     _RPT2(_CRT_WARN, "VortexChannelData: host=%s, channel_num = %d\n",

>                vortex_connection_get_host(channelData->connection),
>                channelData->channel_num);
> 
>     _ASSERTE(channelData->connection != NULL);
>   }
>   else if (blksubtype == BLKTYPE_VortexChannel)
>   {
>     VortexChannel *channel = (VortexChannel *)pUserData;
> 
>     _RPT3(_CRT_WARN, "VortexChannel: host=%s, port=%s, channel_num =
> %d\n", 
>                vortex_connection_get_host(channel->connection),
>                vortex_connection_get_port(channel->connection),
>                channelData->channel_num);
> 
>     _ASSERTE(channel->connection != NULL);
>     _ASSERTE(channel->profile != NULL);  
>   }
> 
>   // And so on....
> 
> }
> #endif
> 
> To install the dump function call this method as follows:
> #ifdef _DEBUG
>   _CrtSetDumpClient(DumpVortexObjectFunction);
> #endif
> This call would be placed as the 2nd line of DllMain().
> 
> 
> 
> 
> Making the above changes will really help to ensure a solid Windows
> version of the Vortex library.
> 
> Thanks for listening!

Thanks for the suggestions Chris,
Cheers!

> Best Regards,
> 
> Chris Yourch
> 
> 
> 
> 

-- 
Francis Brosnan Blazquez <francis at aspl.es>
Advanced Software Production Line, S.L.