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)
% init
% commit
adding base
% qnew mqbase
% qrefresh
% qdiff
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@
-base
+patched
% qdiff dirname
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@
-base
+patched
% qdiff filename
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@
-base
+patched
% revert
% qpop
popping mqbase
patch queue now empty
% qdelete mqbase
% commit 2
adding lines
% qnew 2
% qdiff -U 1
diff -r 35fb829491c1 lines
--- a/lines
+++ b/lines
@@ -1,1 +1,3 @@
+
+
1
@@ -4,4 +6,4 @@
4
-hello world
-goodbye world
+hello world
+ goodbye world
7
% qdiff -b
diff -r 35fb829491c1 lines
--- a/lines
+++ b/lines
@@ -1,9 +1,11 @@
+
+
1
2
3
4
hello world
-goodbye world
+ goodbye world
7
8
9
% qdiff -U 1 -B
diff -r 35fb829491c1 lines
--- a/lines
+++ b/lines
@@ -4,4 +6,4 @@
4
-hello world
-goodbye world
+hello world
+ goodbye world
7
% qdiff -w
diff -r 35fb829491c1 lines
--- a/lines
+++ b/lines
@@ -1,3 +1,5 @@
+
+
1
2
3
% qdiff --reverse
diff -r 35fb829491c1 lines
--- a/lines
+++ b/lines
@@ -1,11 +1,9 @@
-
-
1
2
3
4
-hello world
- goodbye world
+hello world
+goodbye world
7
8
9
% qdiff preserve existing git flag
diff --git a/lines b/lines
--- a/lines
+++ b/lines
@@ -1,9 +1,12 @@
+
+
1
2
3
4
-hello world
-goodbye world
+hello world
+ goodbye world
7
8
9
+a
% qdiff --stat
lines | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)