Mercurial > hg
view tests/test-diff-hashes.t @ 50400:95acba2c29f6
encoding: avoid quadratic time complexity when json-encoding non-UTF8 strings
Apparently the code uses "+=" with a bytes object, which is linear-time, so the
whole encoding is quadratic-time. This patch makes us use a bytearray object,
instead, which has a(n amortized-)constant-time append operation.
The encoding is still not particularly fast, but at least a 10MB file
takes tens of seconds, not many hours to encode.
| author | Arseniy Alekseyev <aalekseyev@janestreet.com> |
|---|---|
| date | Mon, 06 Mar 2023 11:27:57 +0000 |
| parents | 251332dbf33d |
| children |
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$ hg init a $ cd a $ hg diff inexistent1 inexistent2 inexistent1: * (glob) inexistent2: * (glob) $ echo bar > foo $ hg add foo $ hg ci -m 'add foo' $ echo foobar > foo $ hg ci -m 'change foo' $ hg --quiet diff -r 0 -r 1 diff -r a99fb63adac3 -r 9b8568d3af2f foo --- a/foo Thu Jan 01 00:00:00 1970 +0000 +++ b/foo Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,1 @@ -bar +foobar $ hg diff -r 0 -r 1 diff -r a99fb63adac3 -r 9b8568d3af2f foo --- a/foo Thu Jan 01 00:00:00 1970 +0000 +++ b/foo Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,1 @@ -bar +foobar $ hg --verbose diff -r 0 -r 1 diff -r a99fb63adac3 -r 9b8568d3af2f foo --- a/foo Thu Jan 01 00:00:00 1970 +0000 +++ b/foo Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,1 @@ -bar +foobar $ hg --debug diff -r 0 -r 1 diff -r a99fb63adac3f31816a22f665bc3b7a7655b30f4 -r 9b8568d3af2f1749445eef03aede868a6f39f210 foo --- a/foo Thu Jan 01 00:00:00 1970 +0000 +++ b/foo Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +1,1 @@ -bar +foobar $ cd ..