From: Eric Sunshine <sunshine@sunshineco.com>
Date: Tue, 10 Jun 2014 08:00:34 GMT
Subject: Re: [PATCH 08/15] provide helpers to access the commit buffer
Message-ID: <CAPig+cTkwFVDEj7L6qriNP9-Qsu=B-wJsv0z1b++u57dir8XOw@mail.gmail.com>
In-Reply-To: <20140609181158.GH20315@sigill.intra.peff.net>

On Monday, June 9, 2014, Jeff King <peff@peff.net> wrote:
> Many sites look at commit->buffer to get more detailed
> information than what is in the parsed commit struct.
> However, we sometimes drop commit->buffer to save memory,
> in which case the caller would need to read the object
> afresh. Some callers do this (leading to duplicated code),
> and others do not (which opens the possibility of a segfault
> if somebody else frees the buffer).
>
> Let's provide a pair of helpers, "get" and "unuse", that let
> callers easily get the buffer. They will use the cached
> buffer when possible, and otherwise load from disk using
> read_sha1_file.
>
> Note that we also need to add a "get_cached" variant which
> returns NULL when we do not have a cached buffer. At first
> glance this seems to defeat the purpose of "get", which is
> to always provide a return value. However, some log code
> paths actually use the NULL-ness of commit->buffer as a
> boolean flag to decide whether to try to printing the

s/printing/print/ ... or some other variation of the phrase.

> commit. At least for now, we want to continue supporting
> that use.
>
> Signed-off-by: Jeff King <peff@peff.net>