--- a/mercurial/appendfile.py
+++ b/mercurial/appendfile.py
@@ -6,7 +6,7 @@
# of the GNU General Public License, incorporated herein by reference.
from demandload import *
-demandload(globals(), "cStringIO changelog manifest os tempfile")
+demandload(globals(), "cStringIO changelog errno manifest os tempfile")
# writes to metadata files are ordered. reads: changelog, manifest,
# normal files. writes: normal files, manifest, changelog.
@@ -33,18 +33,32 @@ class appendfile(object):
file and temp file. readers cannot see appended data until
writedata called.'''
- def __init__(self, fp):
- fd, self.tmpname = tempfile.mkstemp()
- self.tmpfp = os.fdopen(fd, 'ab+')
+ def __init__(self, fp, tmpname):
+ if tmpname:
+ self.tmpname = tmpname
+ self.tmpfp = open(self.tmpname, 'ab+')
+ else:
+ fd, self.tmpname = tempfile.mkstemp()
+ self.tmpfp = os.fdopen(fd, 'ab+')
self.realfp = fp
self.offset = fp.tell()
# real file is not written by anyone else. cache its size so
# seek and read can be fast.
- self.fpsize = os.fstat(fp.fileno()).st_size
+ self.realsize = os.fstat(fp.fileno()).st_size
def end(self):
self.tmpfp.flush() # make sure the stat is correct
- return self.fpsize + os.fstat(self.tmpfp.fileno()).st_size
+ return self.realsize + os.fstat(self.tmpfp.fileno()).st_size
+
+ def tell(self):
+ return self.offset
+
+ def flush(self):
+ self.tmpfp.flush()
+
+ def close(self):
+ self.realfp.close()
+ self.tmpfp.close()
def seek(self, offset, whence=0):
'''virtual file offset spans real file and temp file.'''
@@ -55,16 +69,16 @@ class appendfile(object):
elif whence == 2:
self.offset = self.end() + offset
- if self.offset < self.fpsize:
+ if self.offset < self.realsize:
self.realfp.seek(self.offset)
else:
- self.tmpfp.seek(self.offset - self.fpsize)
+ self.tmpfp.seek(self.offset - self.realsize)
def read(self, count=-1):
'''only trick here is reads that span real file and temp file.'''
fp = cStringIO.StringIO()
old_offset = self.offset
- if self.offset < self.fpsize:
+ if self.offset < self.realsize:
s = self.realfp.read(count)
fp.write(s)
self.offset += len(s)
@@ -72,7 +86,7 @@ class appendfile(object):
count -= len(s)
if count != 0:
if old_offset != self.offset:
- self.tmpfp.seek(self.offset - self.fpsize)
+ self.tmpfp.seek(self.offset - self.realsize)
s = self.tmpfp.read(count)
fp.write(s)
self.offset += len(s)
@@ -83,98 +97,47 @@ class appendfile(object):
self.tmpfp.seek(0, 2)
self.tmpfp.write(s)
# all writes are appends, so offset must go to end of file.
- self.offset = self.fpsize + self.tmpfp.tell()
-
- def writedata(self):
- '''copy data from temp file to real file.'''
- self.tmpfp.seek(0)
- s = self.tmpfp.read()
- self.tmpfp.close()
- self.realfp.seek(0, 2)
- # small race here. we write all new data in one call, but
- # reader can see partial update due to python or os. file
- # locking no help: slow, not portable, not reliable over nfs.
- # only safe thing is write to temp file every time and rename,
- # but performance bad when manifest or changelog gets big.
- self.realfp.write(s)
- self.realfp.close()
-
- def __del__(self):
- '''delete temp file even if exception raised.'''
- try: os.unlink(self.tmpname)
- except: pass
-
-class sharedfile(object):
- '''let file objects share a single appendfile safely. each
- sharedfile has own offset, syncs up with appendfile offset before
- read and after read and write.'''
-
- def __init__(self, fp):
- self.fp = fp
- self.offset = 0
-
- def tell(self):
- return self.offset
-
- def seek(self, offset, whence=0):
- if whence == 0:
- self.offset = offset
- elif whence == 1:
- self.offset += offset
- elif whence == 2:
- self.offset = self.fp.end() + offset
-
- def read(self, count=-1):
- try:
- if self.offset != self.fp.offset:
- self.fp.seek(self.offset)
- return self.fp.read(count)
- finally:
- self.offset = self.fp.offset
-
- def write(self, s):
- try:
- return self.fp.write(s)
- finally:
- self.offset = self.fp.offset
-
- def close(self):
- # revlog wants this.
- pass
-
- def flush(self):
- # revlog wants this.
- pass
-
- def writedata(self):
- self.fp.writedata()
+ self.offset = self.realsize + self.tmpfp.tell()
class appendopener(object):
'''special opener for files that only read or append.'''
def __init__(self, opener):
self.realopener = opener
- # key: file name, value: appendfile object
- self.fps = {}
+ # key: file name, value: appendfile name
+ self.tmpnames = {}
def __call__(self, name, mode='r'):
- '''open file. return same cached appendfile object for every
- later call.'''
+ '''open file.'''
assert mode in 'ra+'
- fp = self.fps.get(name)
- if fp is None:
- fp = appendfile(self.realopener(name, 'a+'))
- self.fps[name] = fp
- return sharedfile(fp)
+ try:
+ realfp = self.realopener(name, 'r')
+ except IOError, err:
+ if err.errno != errno.ENOENT: raise
+ realfp = self.realopener(name, 'w+')
+ tmpname = self.tmpnames.get(name)
+ fp = appendfile(realfp, tmpname)
+ if tmpname is None:
+ self.tmpnames[name] = fp.tmpname
+ return fp
def writedata(self):
'''copy data from temp files to real files.'''
# write .d file before .i file.
- fps = self.fps.items()
- fps.sort()
- for name, fp in fps:
- fp.writedata()
+ tmpnames = self.tmpnames.items()
+ tmpnames.sort()
+ for name, tmpname in tmpnames:
+ fp = open(tmpname, 'rb')
+ s = fp.read()
+ fp.close()
+ fp = self.realopener(name, 'a')
+ fp.write(s)
+ fp.close()
+
+ def __del__(self):
+ for tmpname in self.tmpnames.itervalues():
+ os.unlink(tmpname)
# files for changelog and manifest are in different appendopeners, so
# not mixed up together.