From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 04 Apr 2007 22:31:21 GMT
Subject: Re: [PATCH 1/2] Added use of xmalloc() on diff-delta.c
Message-ID: <Pine.LNX.4.64.0704041525220.6730@woody.linux-foundation.org>
In-Reply-To: <7vejn02bcv.fsf@assigned-by-dhcp.cox.net>



On Wed, 4 Apr 2007, Junio C Hamano wrote:
> 
> These patches take that nice property away, making libification
> more difficult, which is the downside.  Is there an upside?

Well, we could just make the libification rule very simple:

 - the library does *not* include "xmalloc()", and you have to handle 
   out-of-memory situations yourself inside the xmalloc() that *you* as a 
   libification user provide!.

Then, we just make our xmalloc() be non-inlined (which we should do 
*anyway* - it's long since grown so big that it shouldn't be inlined in 
the first place), and we make it part of a non-library git object file.

Other libgit uses might end up doing something like

		..
		if (sigsetjump(buffer, 1)) {
			show_oom_message();
		..

	void *xmalloc(size_t size)
	{
		void *ret = malloc(size ? size : 1);
		if (!ret)
			siglongjmp(buffer);
		return ret;
	}

or, if they use C++ exception handling, they'd just make their own 
xmalloc() raise an exception, and have the callers catch it.

The point being that this is what you'd need to do *anyway*, and trying to 
make all the library routines return NULL or some other error case is just 
worse programming practice than just having a xmalloc() that dies by 
default but that can be overridden.

		Linus