revlog: add a `_get_decompressor` method
This logic is non-trivial and we will need to reuse it.
Differential Revision: https://phab.mercurial-scm.org/D10651
$ hg init
$ echo 0 > a
$ echo 0 > b
$ hg ci -A -m m
adding a
adding b
$ hg rm a
$ hg cat a
0
$ hg cat --decode a # more tests in test-encode
0
$ echo 1 > b
$ hg ci -m m
$ echo 2 > b
$ hg cat -r 0 a
0
$ hg cat -r 0 b
0
$ hg cat -r 1 a
a: no such file in rev 7040230c159c
[1]
$ hg cat -r 1 b
1
Test multiple files
$ echo 3 > c
$ hg ci -Am addmore c
$ hg cat b c
1
3
$ hg cat .
1
3
$ hg cat . c
1
3
Test fileset
$ hg cat 'set:not(b) or a'
3
$ hg cat 'set:c or b'
1
3
$ mkdir tmp
$ hg cat --output tmp/HH_%H c
$ hg cat --output tmp/RR_%R c
$ hg cat --output tmp/h_%h c
$ hg cat --output tmp/r_%r c
$ hg cat --output tmp/%s_s c
$ hg cat --output tmp/%d%%_d c
$ hg cat --output tmp/%p_p c
$ hg log -r . --template "{rev}: {node|short}\n"
2: 45116003780e
$ find tmp -type f | sort
tmp/.%_d
tmp/HH_45116003780e3678b333fb2c99fa7d559c8457e9
tmp/RR_2
tmp/c_p
tmp/c_s
tmp/h_45116003780e
tmp/r_2
Test template output
$ hg --cwd tmp cat ../b ../c -T '== {path|relpath} ({path}) r{rev} ==\n{data}'
== ../b (b) r2 ==
1
== ../c (c) r2 ==
3
$ hg cat b c -Tjson --output -
[
{
"data": "1\n",
"path": "b"
},
{
"data": "3\n",
"path": "c"
}
]
$ hg cat b c -Tjson --output 'tmp/%p.json'
$ cat tmp/b.json
[
{
"data": "1\n",
"path": "b"
}
]
$ cat tmp/c.json
[
{
"data": "3\n",
"path": "c"
}
]
Test working directory
$ echo b-wdir > b
$ hg cat -r 'wdir()' b
b-wdir
Environment variables are not visible by default
$ PATTERN='t4' hg log -r '.' -T "{ifcontains('PATTERN', envvars, 'yes', 'no')}\n"
no
Environment variable visibility can be explicit
$ PATTERN='t4' hg log -r '.' -T "{envvars % '{key} -> {value}\n'}" \
> --config "experimental.exportableenviron=PATTERN"
PATTERN -> t4
Test behavior of output when directory structure does not already exist
$ mkdir foo
$ echo a > foo/a
$ hg add foo/a
$ hg commit -qm "add foo/a"
$ hg cat --output "output/%p" foo/a
$ cat output/foo/a
a