[PATCH v2] dropping manual malloc calculations

[Jeff King <peff@peff.net>]

On Thu, Jun 19, 2014 at 09:49:41AM -0700, Junio C Hamano wrote:

> If we twist the logic behind the 'mkpathdup' name a little bit,
> perhaps we can call it sprintf_dup or something.  That is, "sprintf
> wants a fixed preallocated piece of memory to print into, and we
> relieve the callers of having to do so", perhaps?

Right, that is the "dup" I was thinking of. Anyway, I think René's
"xstrfmt" is my favorite of the suggestions, and you seemed to like it,
too. Here is a re-roll using that name.

The first two patches are the same except for the name change. The rest
are more applications of it (and other techniques) found by grepping for
"malloc.*strlen". The diffstat is very encouraging, and I think the
results are much more readable (in addition to being more obviously
correct). The last two also fix real "bugs", but I doubt either is a
problem in practice.

    builtin/apply.c         |  4 +--
    builtin/fetch.c         |  9 ++----
    builtin/fmt-merge-msg.c |  7 ++---
    builtin/name-rev.c      |  5 +---
    builtin/receive-pack.c  |  5 +---
    builtin/show-branch.c   | 10 +++----
    environment.c           | 12 +++-----
    http-push.c             | 24 +++++-----------
    http-walker.c           |  6 ++--
    match-trees.c           |  9 ++----
    merge-recursive.c       | 53 ++++++++++++++++++++---------------
    merge.c                 | 42 +++++++++------------------
    remote.c                |  6 +---
    sequencer.c             |  9 ++----
    sha1_name.c             |  5 +---
    shell.c                 |  6 +---
    strbuf.c                | 19 +++++++++++++
    strbuf.h                |  9 ++++++
    unpack-trees.c          | 17 ++++-------
    walker.c                | 18 ++++++------
    20 files changed, 117 insertions(+), 158 deletions(-)

  [01/10]: strbuf: add xstrfmt helper
  [02/10]: use xstrfmt in favor of manual size calculations
  [03/10]: use xstrdup instead of xmalloc + strcpy
  [04/10]: use xstrfmt to replace xmalloc + sprintf
  [05/10]: use xstrfmt to replace xmalloc + strcpy/strcat
  [06/10]: setup_git_env: use git_pathdup instead of xmalloc + sprintf
  [07/10]: sequencer: use argv_array_pushf
  [08/10]: merge: use argv_array when spawning merge strategy
  [09/10]: walker_fetch: fix minor memory leak
  [10/10]: unique_path: fix unlikely heap overflow