Add a diff_free() function to free anything we may have allocated in
the "diff_options" struct, and the ability to make calling it a noop
by setting "no_free" in "diff_options".
This is required because when e.g. "git diff" is run we'll allocate
things in that struct, use the diff machinery once, and then exit.
But if we run e.g. "git log -p" we're going to re-use what we
allocated across multiple diff_flush() calls, and only want to free
things at the end.
We've thus ended up with features like the recently added "diff -I"[1]
where we'll leak memory. As it turns out it could have simply used the
pattern established in 6ea57703f6 (log: prepare log/log-tree to reuse
the diffopt.close_file attribute, 2016-06-22).
Manually adding more such flags to things log_tree_commit() every time
we need to allocate something would be tedious. Let's instead move
that fclose() code it to a new diff_free(), in anticipation of freeing
more things in that function in follow-up commits.
Some functions such as log_tree_commit() need an idiom of optionally
retaining a previous "no_free", as they may either free the memory
themselves, or their caller may do so. I'm keeping that idiom in
log_show_early() for good measure, even though I don't think it's
currently called in this manner. It also gets passed an existing
"struct rev_info", so future callers may want to set the "no_free"
flag.
This change is a bit hard to read because while the freeing pattern
we're introducing isn't unusual, the "file" member is a special
snowflake. We usually don't want to fclose() it. This is because
"file" is usually stdout, in which case we don't want to fclose()
it. We only want to opt-in to closing it when we e.g. open a file on
the filesystem. Thus the opt-in "close_file" flag.
So the API in general just needs a "no_free" flag to defer freeing,
but the "file" member still needs its "close_file" flag. This is made
more confusing because while refactoring this code we could replace
some "close_file=0" with "no_free=1", whereas others need to set both
flags.
This is because there were some cases where an existing "close_file=0"
meant "let's defer deallocation", and others where it meant "we don't
want to close this file handle at all".
1. 296d4a94e7 (diff: add -I<regex> that ignores matching changes,
2020-10-20)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public
License version 2 (some parts of it are under different licenses,
compatible with the GPLv2). It was originally written by Linus
Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/
including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
Issues which are security relevant should be disclosed privately to
the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that
list the current status of various development topics to the mailing
list. The discussion following them give a good reference for
project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very
first version. He described the tool as "the stupid content tracker"
and the name as (depending on your mood):
random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
"global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
"goddamn idiotic truckload of sh*t": when it breaks
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