encoding: fix trim() to be O(n) instead of O(n^2)
`encoding.trim()` iterated over the possible lengths smaller than the
input and created a slice for each. It then calculated the column
width of the result, which is of course O(n), so the overall algorithm
was O(n). This patch rewrites it to iterate over the unicode
characters, keeping track of the length so far. Also, the old
algorithm started from the end of the string, which made it much worse
when the input is large and the limit is small (such as the typical 72
we pass to it).
You can time it by running something like this:
```
time python3 -c 'from mercurial.utils import stringutil; print(stringutil.ellipsis(b"0123456789" * 1000, 5))'
```
That drops from 4.05 s to 83 ms with this patch (and most of that is
of course startup time).
Differential Revision: https://phab.mercurial-scm.org/D12089
$ echo "[extensions]" >> $HGRCPATH
$ echo "churn=" >> $HGRCPATH
create test repository
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda -u user1 -d 6:00
adding a
$ echo b >> a
$ echo b > b
$ hg ci -m changeba -u user2 -d 9:00 a
$ hg ci -Am addb -u user2 -d 9:30
adding b
$ echo c >> a
$ echo c >> b
$ echo c > c
$ hg ci -m changeca -u user3 -d 12:00 a
$ hg ci -m changecb -u user3 -d 12:15 b
$ hg ci -Am addc -u user3 -d 12:30
adding c
$ mkdir -p d/e
$ echo abc > d/e/f1.txt
$ hg ci -Am "add d/e/f1.txt" -u user1 -d 12:45 d/e/f1.txt
$ mkdir -p d/g
$ echo def > d/g/f2.txt
$ hg ci -Am "add d/g/f2.txt" -u user1 -d 13:00 d/g/f2.txt
churn separate directories
$ cd d
$ hg churn e
user1 1 ***************************************************************
churn all
$ hg churn
user1 3 ***************************************************************
user3 3 ***************************************************************
user2 2 ******************************************
churn excluding one dir
$ hg churn -X e
user3 3 ***************************************************************
user1 2 ******************************************
user2 2 ******************************************
churn up to rev 2
$ hg churn -r :2
user2 2 ***************************************************************
user1 1 *******************************
$ cd ..
churn with aliases
$ cat > ../aliases <<EOF
> user1 alias1
> user3 alias3
> not-an-alias
> EOF
churn with .hgchurn
$ mv ../aliases .hgchurn
$ hg churn
skipping malformed alias: not-an-alias
alias1 3 **************************************************************
alias3 3 **************************************************************
user2 2 *****************************************
$ rm .hgchurn
churn with column specifier
$ COLUMNS=40 hg churn
user1 3 ***********************
user3 3 ***********************
user2 2 ***************
churn by hour
$ hg churn -f '%H' -s
06 1 ****************
09 2 *********************************
12 4 ******************************************************************
13 1 ****************
churn with separated added/removed lines
$ hg rm d/g/f2.txt
$ hg ci -Am "removed d/g/f2.txt" -u user1 -d 14:00 d/g/f2.txt
$ hg churn --diffstat
user1 +3/-1 ++++++++++++++++++++++++++++++++++++++++-------------
user3 +3/-0 ++++++++++++++++++++++++++++++++++++++++
user2 +2/-0 +++++++++++++++++++++++++++
churn --diffstat with color
$ hg --config extensions.color= churn --config color.mode=ansi \
> --diffstat --color=always
user1 +3/-1 \x1b[0;32m++++++++++++++++++++++++++++++++++++++++\x1b[0m\x1b[0;31m-------------\x1b[0m (esc)
user3 +3/-0 \x1b[0;32m++++++++++++++++++++++++++++++++++++++++\x1b[0m (esc)
user2 +2/-0 \x1b[0;32m+++++++++++++++++++++++++++\x1b[0m (esc)
changeset number churn
$ hg churn -c
user1 4 ***************************************************************
user3 3 ***********************************************
user2 2 *******************************
$ echo 'with space = no-space' >> ../aliases
$ echo a >> a
$ hg commit -m a -u 'with space' -d 15:00
churn with space in alias
$ hg churn --aliases ../aliases -r tip
no-space 1 ************************************************************
$ cd ..
Issue833: ZeroDivisionError
$ hg init issue-833
$ cd issue-833
$ touch foo
$ hg ci -Am foo
adding foo
this was failing with a ZeroDivisionError
$ hg churn
test 0
$ cd ..
Ignore trailing or leading spaces in emails
$ cd repo
$ touch bar
$ hg ci -Am'bar' -u 'user4 <user4@x.com>'
adding bar
$ touch foo
$ hg ci -Am'foo' -u 'user4 < user4@x.com >'
adding foo
$ hg log -l2 --template '[{author|email}]\n'
[ user4@x.com ]
[user4@x.com]
$ hg churn -c
user1 4 *********************************************************
user3 3 ******************************************
user2 2 ****************************
user4@x.com 2 ****************************
with space 1 **************
Test multibyte sequences in names
$ echo bar >> bar
$ hg --encoding utf-8 ci -m'changed bar' -u 'El NiƱo <nino@x.com>'
$ hg --encoding utf-8 churn -ct '{author|person}'
user1 4 **********************************************************
user3 3 *******************************************
user2 2 *****************************
user4 2 *****************************
El Ni\xc3\xb1o 1 ************** (esc)
with space 1 **************
Test --template argument, with backwards compatibility
$ hg churn -t '{author|user}'
user1 4 ***************************************************************
user3 3 ***********************************************
user2 2 *******************************
nino 1 ***************
with 1 ***************
0
user4 0
$ hg churn -T '{author|user}'
user1 4 ***************************************************************
user3 3 ***********************************************
user2 2 *******************************
nino 1 ***************
with 1 ***************
0
user4 0
$ hg churn -t 'alltogether'
alltogether 11 *********************************************************
$ hg churn -T 'alltogether'
alltogether 11 *********************************************************
$ cd ..
count lines that look like headings but are not
$ hg init not-headers
$ cd not-headers
$ cat > a <<EOF
> diff
> @@ -195,3 +195,21 @@
> -- a/tests/test-churn.t
> ++ b/tests/test-churn.t
> EOF
$ hg ci -Am adda -u user1
adding a
$ hg churn --diffstat
user1 +4/-0 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
$ hg rm a
$ hg ci -Am removea -u user1
$ hg churn --diffstat
user1 +4/-4 +++++++++++++++++++++++++++---------------------------