delta/git.git/builtin/cat-file.c, branch v2.37.6

Merge branch 'jc/cat-file-batch-default-format-optim'

2022-03-23T21:09:31+00:00

Optimize away strbuf_expand() call with a hardcoded formatting logic
specific for the default format in the --batch and --batch-check
options of "git cat-file".

* jc/cat-file-batch-default-format-optim:
  cat-file: skip expanding default format

Merge branch 'ab/object-file-api-updates'

2022-03-17T00:53:08+00:00

Object-file API shuffling.

* ab/object-file-api-updates:
  object-file API: pass an enum to read_object_with_reference()
  object-file.c: add a literal version of write_object_file_prepare()
  object-file API: have hash_object_file() take "enum object_type"
  object API: rename hash_object_file_literally() to write_*()
  object-file API: split up and simplify check_object_signature()
  object API users + docs: check <0, not !0 with check_object_signature()
  object API docs: move check_object_signature() docs to cache.h
  object API: correct "buf" v.s. "map" mismatch in *.c and *.h
  object-file API: have write_object_file() take "enum object_type"
  object-file API: add a format_object_header() function
  object-file API: return "void", not "int" from hash_object_file()
  object-file.c: split up declaration of unrelated variables

cat-file: skip expanding default format

2022-03-15T17:15:32+00:00

When format is passed into --batch, --batch-check, --batch-command,
the format gets expanded. When nothing is passed in, the default format
is set and the expand_format() gets called.

We can save on these cycles by hardcoding how to print the
information when nothing is passed as the format, or when the default
format is passed. There is no need for the fully expanded format with
the default. Since batch_object_write() happens on every object provided
in batch mode, we get a nice performance improvement.

git rev-list --all > /tmp/all-obj.txt

git cat-file --batch-check 
Signed-off-by: John Cai 
Signed-off-by: Junio C Hamano

object-file API: pass an enum to read_object_with_reference()

2022-02-26T01:16:32+00:00

Change the read_object_with_reference() function to take an "enum
object_type". It was not prepared to handle an arbitrary "const
char *type", as it was itself calling type_from_string().

Let's change the only caller that passes in user data to use
type_from_string(), and convert the rest to use e.g. "OBJ_TREE"
instead of "tree_type".

The "cat-file" caller is not on the codepath that
handles"--allow-unknown", so the type_from_string() there is safe. Its
use of type_from_string() doesn't functionally differ from that of the
pre-image.

Signed-off-by: Ævar Arnfjörð Bjarmason 
Signed-off-by: Junio C Hamano

cat-file: add --batch-command mode

2022-02-18T19:21:46+00:00

Add a new flag --batch-command that accepts commands and arguments
from stdin, similar to git-update-ref --stdin.

At GitLab, we use a pair of long running cat-file processes when
accessing object content. One for iterating over object metadata with
--batch-check, and the other to grab object contents with --batch.

However, if we had --batch-command, we wouldn't need to keep both
processes around, and instead just have one --batch-command process
where we can flip between getting object info, and getting object
contents. Since we have a pair of cat-file processes per repository,
this means we can get rid of roughly half of long lived git cat-file
processes. Given there are many repositories being accessed at any given
time, this can lead to huge savings.

git cat-file --batch-command

will enter an interactive command mode whereby the user can enter in
commands and their arguments that get queued in memory:

 [arg1] [arg2] LF
 [arg1] [arg2] LF

When --buffer mode is used, commands will be queued in memory until a
flush command is issued that execute them:

flush LF

The reason for a flush command is that when a consumer process (A)
talks to a git cat-file process (B) and interactively writes to and
reads from it in --buffer mode, (A) needs to be able to control when
the buffer is flushed to stdout.

Currently, from (A)'s perspective, the only way is to either

1. kill (B)'s process
2. send an invalid object to stdin.

1. is not ideal from a performance perspective as it will require
spawning a new cat-file process each time, and 2. is hacky and not a
good long term solution.

With this mechanism of queueing up commands and letting (A) issue a
flush command, process (A) can control when the buffer is flushed and
can guarantee it will receive all of the output when in --buffer mode.
--batch-command also will not allow (B) to flush to stdout until a flush
is received.

This patch adds the basic structure for adding command which can be
extended in the future to add more commands. It also adds the following
two commands (on top of the flush command):

contents  LF
info  LF

The contents command takes an  argument and prints out the object
contents.

The info command takes an  argument and prints out the object
metadata.

These can be used in the following way with --buffer:

info  LF
contents  LF
contents  LF
info  LF
flush LF
info  LF
flush LF

When used without --buffer:

info  LF
contents  LF
contents  LF
info  LF
info  LF

Helped-by: Ævar Arnfjörð Bjarmason 
Signed-off-by: John Cai 
Signed-off-by: Junio C Hamano

cat-file: introduce batch_mode enum to replace print_contents

2022-02-18T19:21:46+00:00

A future patch introduces a new --batch-command flag. Including --batch
and --batch-check, we will have a total of three batch modes. print_contents
is the only boolean on the batch_options sturct used to distinguish
between the different modes. This makes the code harder to read.

To reduce potential confusion, replace print_contents with an enum to
help readability and clarity.

Helped-by: Junio C Hamano 
Signed-off-by: John Cai 
Signed-off-by: Junio C Hamano

cat-file: rename cmdmode to transform_mode

2022-02-18T19:21:46+00:00

In the next patch, we will add an enum on the batch_options struct that
indicates which type of batch operation will be used: --batch,
--batch-check and the soon to be  --batch-command that will read
commands from stdin. --batch-command mode might get confused with
the cmdmode flag.

There is value in renaming cmdmode in any case. cmdmode refers to how
the result output of the blob will be transformed, either according to
--filter or --textconv. So transform_mode is a more descriptive name
for the flag.

Rename cmdmode to transform_mode in cat-file.c

Signed-off-by: John Cai 
Signed-off-by: Junio C Hamano

cat-file: s/_/-/ in typo'd usage_msg_optf() message

2022-01-12T18:12:39+00:00

Fix a typo in my recent 03dc51fe849 (cat-file: fix remaining usage
bugs, 2021-10-09).

Signed-off-by: Ævar Arnfjörð Bjarmason 
Acked-by: Taylor Blau 
Signed-off-by: Junio C Hamano

cat-file: don't whitespace-pad "(...)" in SYNOPSIS and usage output

2022-01-12T18:12:20+00:00

Fix up whitespace issues around "(... | ...)" in the SYNOPSIS and
usage. These were introduced in ab/cat-file series. See
e145efa6059 (Merge branch 'ab/cat-file' into next, 2022-01-05). In
particular 57d6a1cf96, 5a40417876 and 97fe7250753 in that series.

We'll now correctly emit this usage output:

    $ git cat-file -h
    usage: git cat-file  
       or: git cat-file (-e | -p) 
       or: git cat-file (-t | -s) [--allow-unknown-type] 
    [...]

Before this the last line of that would be inconsistent with the
preceding "(-e | -p)":

   or: git cat-file ( -t | -s ) [--allow-unknown-type] 

Reported-by: Jiang Xin 
Signed-off-by: Ævar Arnfjörð Bjarmason 
Acked-by: Taylor Blau 
Signed-off-by: Junio C Hamano

i18n: turn even more messages into "cannot be used together" ones

2022-01-05T21:31:00+00:00

Even if some of these messages are not subject to gettext i18n, this
helps bring a single style of message for a given error type.

Signed-off-by: Jean-Noël Avila 
Reviewed-by: Johannes Sixt 
Signed-off-by: Junio C Hamano