view tests/test-debugbuilddag.t @ 48671:f1ed5c304f45

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

plain

  $ hg init
  $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' \
  > --config extensions.progress= --config progress.assume-tty=1 \
  > --config progress.delay=0 --config progress.refresh=0 \
  > --config progress.format=topic,bar,number \
  > --config progress.width=60
  \r (no-eol) (esc)
  building [                                          ]  0/12\r (no-eol) (esc)
  building [                                          ]  0/12\r (no-eol) (esc)
  building [==>                                       ]  1/12\r (no-eol) (esc)
  building [==>                                       ]  1/12\r (no-eol) (esc)
  building [======>                                   ]  2/12\r (no-eol) (esc)
  building [=========>                                ]  3/12\r (no-eol) (esc)
  building [=============>                            ]  4/12\r (no-eol) (esc)
  building [=============>                            ]  4/12\r (no-eol) (esc)
  building [=============>                            ]  4/12\r (no-eol) (esc)
  building [================>                         ]  5/12\r (no-eol) (esc)
  building [====================>                     ]  6/12\r (no-eol) (esc)
  building [=======================>                  ]  7/12\r (no-eol) (esc)
  building [===========================>              ]  8/12\r (no-eol) (esc)
  building [===========================>              ]  8/12\r (no-eol) (esc)
  building [==============================>           ]  9/12\r (no-eol) (esc)
  building [==================================>       ] 10/12\r (no-eol) (esc)
  building [=====================================>    ] 11/12\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

tags
  $ cat .hg/localtags
  66f7d451a68b85ed82ff5fcc254daf50c74144bd f
  bebd167eb94d257ace0e814aeb98e6972ed2970d p2
dag
  $ hg debugdag -t -b
  +2:f
  +3:p2
  @temp*f+3
  @default*/p2+2:tip
tip
  $ hg id
  000000000000
glog
  $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n'
  o  11: r11 [] @ 11.00
  |
  o  10: r10 [] @ 10.00
  |
  o    9: r9 [] @ 9.00
  |\
  | o  8: r8 [temp] @ 8.00
  | |
  | o  7: r7 [temp] @ 7.00
  | |
  | o  6: r6 [temp] @ 6.00
  | |
  | o  5: r5 [temp] @ 5.00
  | |
  o |  4: r4 [] @ 4.00
  | |
  o |  3: r3 [] @ 3.00
  | |
  o |  2: r2 [] @ 2.00
  |/
  o  1: r1 [] @ 1.00
  |
  o  0: r0 [] @ 0.00
  

overwritten files, starting on a non-default branch

  $ rm -r .hg
  $ hg init
  $ hg debugbuilddag '@start.@default.:f +3:p2 @temp <f+4 @default /p2 +2' -q -o
tags
  $ cat .hg/localtags
  f778700ebd50fcf282b23a4446bd155da6453eb6 f
  bbccf169769006e2490efd2a02f11c3d38d462bd p2
dag
  $ hg debugdag -t -b
  @start+1
  @default+1:f
  +3:p2
  @temp*f+3
  @default*/p2+2:tip
tip
  $ hg id
  000000000000
glog
  $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n'
  o  11: r11 [] @ 11.00
  |
  o  10: r10 [] @ 10.00
  |
  o    9: r9 [] @ 9.00
  |\
  | o  8: r8 [temp] @ 8.00
  | |
  | o  7: r7 [temp] @ 7.00
  | |
  | o  6: r6 [temp] @ 6.00
  | |
  | o  5: r5 [temp] @ 5.00
  | |
  o |  4: r4 [] @ 4.00
  | |
  o |  3: r3 [] @ 3.00
  | |
  o |  2: r2 [] @ 2.00
  |/
  o  1: r1 [] @ 1.00
  |
  o  0: r0 [start] @ 0.00
  
glog of
  $ hg log -G --template '{rev}: {desc} [{branches}]\n' of
  o  11: r11 []
  |
  o  10: r10 []
  |
  o    9: r9 []
  |\
  | o  8: r8 [temp]
  | |
  | o  7: r7 [temp]
  | |
  | o  6: r6 [temp]
  | |
  | o  5: r5 [temp]
  | |
  o |  4: r4 []
  | |
  o |  3: r3 []
  | |
  o |  2: r2 []
  |/
  o  1: r1 []
  |
  o  0: r0 [start]
  
tags
  $ hg tags -v
  tip                               11:9ffe238a67a2
  p2                                 4:bbccf1697690 local
  f                                  1:f778700ebd50 local
cat of
  $ hg cat of --rev tip
  r11


new and mergeable files

  $ rm -r .hg
  $ hg init
  $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' -q -mn
dag
  $ hg debugdag -t -b
  +2:f
  +3:p2
  @temp*f+3
  @default*/p2+2:tip
tip
  $ hg id
  000000000000
glog
  $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n'
  o  11: r11 [] @ 11.00
  |
  o  10: r10 [] @ 10.00
  |
  o    9: r9 [] @ 9.00
  |\
  | o  8: r8 [temp] @ 8.00
  | |
  | o  7: r7 [temp] @ 7.00
  | |
  | o  6: r6 [temp] @ 6.00
  | |
  | o  5: r5 [temp] @ 5.00
  | |
  o |  4: r4 [] @ 4.00
  | |
  o |  3: r3 [] @ 3.00
  | |
  o |  2: r2 [] @ 2.00
  |/
  o  1: r1 [] @ 1.00
  |
  o  0: r0 [] @ 0.00
  
glog mf
  $ hg log -G --template '{rev}: {desc} [{branches}]\n' mf
  o  11: r11 []
  |
  o  10: r10 []
  |
  o    9: r9 []
  |\
  | o  8: r8 [temp]
  | |
  | o  7: r7 [temp]
  | |
  | o  6: r6 [temp]
  | |
  | o  5: r5 [temp]
  | |
  o |  4: r4 []
  | |
  o |  3: r3 []
  | |
  o |  2: r2 []
  |/
  o  1: r1 []
  |
  o  0: r0 []
  

man r4
  $ hg manifest -r4
  mf
  nf0
  nf1
  nf2
  nf3
  nf4
cat r4 mf
  $ hg cat -r4 mf
  0 r0
  1
  2 r1
  3
  4 r2
  5
  6 r3
  7
  8 r4
  9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
man r8
  $ hg manifest -r8
  mf
  nf0
  nf1
  nf5
  nf6
  nf7
  nf8
cat r8 mf
  $ hg cat -r8 mf
  0 r0
  1
  2 r1
  3
  4
  5
  6
  7
  8
  9
  10 r5
  11
  12 r6
  13
  14 r7
  15
  16 r8
  17
  18
  19
  20
  21
  22
  23
man
  $ hg manifest --rev tip
  mf
  nf0
  nf1
  nf10
  nf11
  nf2
  nf3
  nf4
  nf5
  nf6
  nf7
  nf8
  nf9
cat mf
  $ hg cat mf --rev tip
  0 r0
  1
  2 r1
  3
  4 r2
  5
  6 r3
  7
  8 r4
  9
  10 r5
  11
  12 r6
  13
  14 r7
  15
  16 r8
  17
  18 r9
  19
  20 r10
  21
  22 r11
  23