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view tests/test-import-context.t @ 27430:e240e914d226 stable
revlog: seek to end of file before writing (issue4943)
Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.
Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.
The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.
Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.
This patch appears to have little to no impact on performance on my
Linux machine.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | f2719b387380 |
children | 75be14993fda |
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Test applying context diffs $ cat > writepatterns.py <<EOF > import sys > > path = sys.argv[1] > lasteol = sys.argv[2] == '1' > patterns = sys.argv[3:] > > fp = file(path, 'wb') > for i, pattern in enumerate(patterns): > count = int(pattern[0:-1]) > char = pattern[-1] + '\n' > if not lasteol and i == len(patterns) - 1: > fp.write((char*count)[:-1]) > else: > fp.write(char*count) > fp.close() > EOF $ cat > cat.py <<EOF > import sys > sys.stdout.write(repr(file(sys.argv[1], 'rb').read()) + '\n') > EOF Initialize the test repository $ hg init repo $ cd repo $ python ../writepatterns.py a 0 5A 1B 5C 1D $ python ../writepatterns.py b 1 1A 1B $ python ../writepatterns.py c 1 5A $ python ../writepatterns.py d 1 5A 1B $ hg add adding a adding b adding c adding d $ hg ci -m addfiles Add file, missing a last end of line $ hg import --no-commit - <<EOF > *** /dev/null 2010-10-16 18:05:49.000000000 +0200 > --- b/newnoeol 2010-10-16 18:23:26.000000000 +0200 > *************** > *** 0 **** > --- 1,2 ---- > + a > + b > \ No newline at end of file > *** a/a Sat Oct 16 16:35:51 2010 > --- b/a Sat Oct 16 16:35:51 2010 > *************** > *** 3,12 **** > A > A > A > ! B > C > C > C > C > C > ! D > \ No newline at end of file > --- 3,13 ---- > A > A > A > ! E > C > C > C > C > C > ! F > ! F > > *** a/b 2010-10-16 18:40:38.000000000 +0200 > --- /dev/null 2010-10-16 18:05:49.000000000 +0200 > *************** > *** 1,2 **** > - A > - B > --- 0 ---- > *** a/c Sat Oct 16 21:34:26 2010 > --- b/c Sat Oct 16 21:34:27 2010 > *************** > *** 3,5 **** > --- 3,7 ---- > A > A > A > + B > + B > *** a/d Sat Oct 16 21:47:20 2010 > --- b/d Sat Oct 16 21:47:22 2010 > *************** > *** 2,6 **** > A > A > A > - A > - B > --- 2,4 ---- > EOF applying patch from stdin $ hg st M a M c M d A newnoeol R b What's in a $ python ../cat.py a 'A\nA\nA\nA\nA\nE\nC\nC\nC\nC\nC\nF\nF\n' $ python ../cat.py newnoeol 'a\nb' $ python ../cat.py c 'A\nA\nA\nA\nA\nB\nB\n' $ python ../cat.py d 'A\nA\nA\nA\n' $ cd ..