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)
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Main should be gone
a
created new head
changeset: 3:ded32b0db104
tag: tip
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: Added side2
changeset: 2:92a816cea698
parent: 0:537353581d3d
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: Added side1
changeset: 1:221226fb2bd8
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: Added main
changeset: 0:537353581d3d
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: Added a
Should have two heads, side2 and main
changeset: 3:ded32b0db104
tag: tip
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: Added side2
changeset: 1:221226fb2bd8
user: test
date: Mon Jan 12 13:46:40 1970 +0000
summary: Added main
Should show a side1 side2
a
side1
side2
resolving manifests
overwrite True partial False
ancestor ded32b0db104+ local ded32b0db104+ remote 221226fb2bd8
side2: other deleted -> r
side1: other deleted -> r
main: remote created -> g
update: side1 1/3 files (33.33%)
removing side1
update: side2 2/3 files (66.67%)
removing side2
update: main 3/3 files (100.00%)
getting main
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
Should only show a main
a
main