Re: Libification project (SoC)

From: Shawn O. Pearce <spearce@spearce.org>
Date: Mar 18, 2007, 05:23 UTC
Message-ID: <20070318052332.GC15885@spearce.org>
In-Reply-To: <20070317195832.2af87c06@home.brethil>

"Luiz Fernando N. Capitulino" <lcapitulino@mandriva.com.br> wrote:

Show 28 quoted lines

> On Fri, 16 Mar 2007 19:16:46 -0400
> "Shawn O. Pearce" <spearce@spearce.org> wrote:
> | And then make their callers (if they are above the public API layer)
> | die instead.  In some cases this might imply an undesirable change
> | in the error message produced, as necessary details that are included
> | today would be unavailable in the caller.
> 
>  I've found a possible solution, though.
> 
>  Take a look at Rusty's solution for the same problem in
> module-init-tools:
> 
> """
> /* We use error numbers in a loose translation... */
> static const char *insert_moderror(int err)
> {
> 	switch (err) {
> 	case ENOEXEC:
> 		return "Invalid module format";
> 	case ENOENT:
> 		return "Unknown symbol in module, or unknown parameter (see dmesg)";
> 	case ENOSYS:
> 		return "Kernel does not have module support";
> 	default:
> 		return strerror(err);
> 	}
> }
> """

Take a look at sha1_file.c, open_packed_git_1:

...
    if (!pack_version_ok(hdr.hdr_version))
        return error("packfile %s is version %u and not supported"
            " (try upgrading GIT to a newer version)",
            p->pack_name, ntohl(hdr.hdr_version));
...

Here we are supplying a lot more than just a simple error code that can be mapped to a static string.

Of course that code is currently feeding it to the error function, which today calls the error_routine (see usage.c). We could buffer the strings sent to error()/warn() and let the caller obtain all strings that occurred during the last API call.

-- 
Shawn.