Re: QGit: Shrink used memory with custom git log format

Hi,

On Tue, 27 Nov 2007, Jan Hudec wrote:

quoted

On Tue, Nov 27, 2007 at 10:48:00 +0000, Johannes Schindelin wrote:

quoted

On Mon, 26 Nov 2007, Shawn O. Pearce wrote:

quoted

[...]
Otherwise I think what you really want here is a libgit that you can
link into your process and that can efficiently inflate an object
on demand for you.  Like the work Luiz was working on this past
summer for GSOC.  Lots of downsides to that current tree though...
like die() kills the GUI...

But then, die() calls die_routine, which you can override.  And C++

has

quoted

this funny exception mechanism which just begs to be used here.  The

only

quoted

thing you need to add is a way to flush all singletons like the object
array.

Unfortunately, exceptions won't really work. Why? Because to use
exceptions, you need to have an exception-safe code. That is the code
needs to free any allocated resources when it's aborted by exception.
And git code is not exceptions safe. Given the lack of destructors in C,
it means registering all resource allocation in some kind of pool, so
they can be freed en masse in case of failure. Than you can also use
longjmp for die (for C they really behave the same).

Sorry, I just assumed that you can read my mind (or alternatively remember
what I suggested a few months ago, namely to "override" xmalloc(),
xcalloc(), xrealloc() and xfree() (probably you need to create the
latter)).

That sounds like the easiest (but not necessarily easy) direction towards
the goal. Thread-local or global (I don't think git is currently reentrant
anyway) would do. Also filehanles would have to be taken care of and
everything checked for using malloc, calloc, strdup and other libc
functions directly.

Than die could longjmp out to a specified buffer and could be safely
overriden to throw exception for C++ apps.

--
                                         - Jan Hudec [off-list ref]