findrenames: Optimise "addremove -s100" by matching files by their SHA1 hashes.
We speed up 'findrenames' for the usecase when a user specifies they
want a similarity of 100% by matching files by their exact SHA1 hash
value. This reduces the number of comparisons required to find exact
matches from O(n^2) to O(n).
While it would be nice if we could just use mercurial's pre-calculated
SHA1 hash for existing files, this hash includes the file's ancestor
information making it unsuitable for our purposes. Instead, we calculate
the hash of old content from scratch.
The following benchmarks were taken on the current head of crew:
addremove 100% similarity:
rm -rf *; hg up -C; mv tests tests.new
hg --time addremove -s100 --dry-run
before: real 176.350 secs (user 128.890+0.000 sys 47.430+0.000)
after: real 2.130 secs (user 1.890+0.000 sys 0.240+0.000)
addremove 75% similarity:
rm -rf *; hg up -C; mv tests tests.new; \
for i in tests.new/*; do echo x >> $i; done
hg --time addremove -s75 --dry-run
before: real 264.560 secs (user 215.130+0.000 sys 49.410+0.000)
after: real 218.710 secs (user 172.790+0.000 sys 45.870+0.000)
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
pulling from ../test1
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
(run 'hg update' to get a working copy)
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
% the changelog should mention file a:
a
pulling from ../test2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
changeset: 2:37dccb76c058
tag: tip
parent: 0:4536b1c2ca69
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: chmod +x a
changeset: 1:a187cb361a5a
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: a updated
changeset: 2:37dccb76c058
tag: tip
parent: 0:4536b1c2ca69
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: chmod +x a
changeset: 1:a187cb361a5a
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: a updated
changeset: 0:4536b1c2ca69
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: added a b
resolving manifests
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
pulling from ../test2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
changeset: 2:37dccb76c058
tag: tip
parent: 0:4536b1c2ca69
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: chmod +x a
changeset: 1:d54568174d8e
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: b updated
changeset: 2:37dccb76c058
tag: tip
parent: 0:4536b1c2ca69
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: chmod +x a
changeset: 1:d54568174d8e
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: b updated
changeset: 0:4536b1c2ca69
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: added a b
resolving manifests
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
-rwxr-x---
-rwxr-x---
-rwxr-x---
rev offset length base linkrev nodeid p1 p2
0 0 0 0 0 b80de5d13875 000000000000 000000000000
rev offset length base linkrev nodeid p1 p2
0 0 0 0 0 b80de5d13875 000000000000 000000000000
rev offset length base linkrev nodeid p1 p2
0 0 0 0 0 b80de5d13875 000000000000 000000000000
1 0 5 1 1 7fe919cc0336 b80de5d13875 000000000000