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)
adding a
adding b
adding c
adding a
adding d
adding e
% test invalid splicemap
abort: syntax error in splicemap(1): key/value pair expected
% splice repo2 on repo1
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
scanning source...
sorting...
converting...
2 addaandd
spliced in ['6d4c2037ddc2cb2627ac3a244ecce35283268f8e'] as parents of 527cdedf31fbd5ea708aa14eeecf53d4676f38db
1 changed
spliced in ['e55c719b85b60e5102fac26110ba626e7cb6b7dc', '527cdedf31fbd5ea708aa14eeecf53d4676f38db'] as parents of e4ea00df91897da3079a10fab658c1eddba6617b
0 adde
o 5 "adde" files: e
|
o 4 "changed" files: d
|\
| o 3 "addaandd" files: a d
| |
@ | 2 "addc" files: c
|/
o 1 "addb" files: a b
|
o 0 "adda" files: a