Mass patch by Ka-Ping Yee:
1. Comments at the beginning of the module, before
functions, and before classes have been turned
into docstrings.
2. Tabs are normalized to four spaces.
Also, removed the "remove" function from dircmp.py, which reimplements
list.remove() (it must have been very old).
diff --git a/Lib/cmpcache.py b/Lib/cmpcache.py
index 5446e66..93332b7 100644
--- a/Lib/cmpcache.py
+++ b/Lib/cmpcache.py
@@ -1,13 +1,12 @@
-# Module 'cmpcache'
-#
-# Efficiently compare files, boolean outcome only (equal / not equal).
-#
-# Tricks (used in this order):
-# - Use the statcache module to avoid statting files more than once
-# - Files with identical type, size & mtime are assumed to be clones
-# - Files with different type or size cannot be identical
-# - We keep a cache of outcomes of earlier comparisons
-# - We don't fork a process to run 'cmp' but read the files ourselves
+"""Efficiently compare files, boolean outcome only (equal / not equal).
+
+Tricks (used in this order):
+ - Use the statcache module to avoid statting files more than once
+ - Files with identical type, size & mtime are assumed to be clones
+ - Files with different type or size cannot be identical
+ - We keep a cache of outcomes of earlier comparisons
+ - We don't fork a process to run 'cmp' but read the files ourselves
+"""
import os
from stat import *
@@ -19,50 +18,47 @@
cache = {}
-# Compare two files, use the cache if possible.
-# May raise os.error if a stat or open of either fails.
-#
def cmp(f1, f2, shallow=1):
- # Return 1 for identical files, 0 for different.
- # Raise exceptions if either file could not be statted, read, etc.
- s1, s2 = sig(statcache.stat(f1)), sig(statcache.stat(f2))
- if not S_ISREG(s1[0]) or not S_ISREG(s2[0]):
- # Either is a not a plain file -- always report as different
- return 0
- if shallow and s1 == s2:
- # type, size & mtime match -- report same
- return 1
- if s1[:2] <> s2[:2]: # Types or sizes differ, don't bother
- # types or sizes differ -- report different
- return 0
- # same type and size -- look in the cache
- key = f1 + ' ' + f2
- if cache.has_key(key):
- cs1, cs2, outcome = cache[key]
- # cache hit
- if s1 == cs1 and s2 == cs2:
- # cached signatures match
- return outcome
- # stale cached signature(s)
- # really compare
- outcome = do_cmp(f1, f2)
- cache[key] = s1, s2, outcome
- return outcome
+ """Compare two files, use the cache if possible.
+ May raise os.error if a stat or open of either fails.
+ Return 1 for identical files, 0 for different.
+ Raise exceptions if either file could not be statted, read, etc."""
+ s1, s2 = sig(statcache.stat(f1)), sig(statcache.stat(f2))
+ if not S_ISREG(s1[0]) or not S_ISREG(s2[0]):
+ # Either is a not a plain file -- always report as different
+ return 0
+ if shallow and s1 == s2:
+ # type, size & mtime match -- report same
+ return 1
+ if s1[:2] <> s2[:2]: # Types or sizes differ, don't bother
+ # types or sizes differ -- report different
+ return 0
+ # same type and size -- look in the cache
+ key = f1 + ' ' + f2
+ if cache.has_key(key):
+ cs1, cs2, outcome = cache[key]
+ # cache hit
+ if s1 == cs1 and s2 == cs2:
+ # cached signatures match
+ return outcome
+ # stale cached signature(s)
+ # really compare
+ outcome = do_cmp(f1, f2)
+ cache[key] = s1, s2, outcome
+ return outcome
-# Return signature (i.e., type, size, mtime) from raw stat data.
-#
def sig(st):
- return S_IFMT(st[ST_MODE]), st[ST_SIZE], st[ST_MTIME]
+ """Return signature (i.e., type, size, mtime) from raw stat data."""
+ return S_IFMT(st[ST_MODE]), st[ST_SIZE], st[ST_MTIME]
-# Compare two files, really.
-#
def do_cmp(f1, f2):
- #print ' cmp', f1, f2 # XXX remove when debugged
- bufsize = 8*1024 # Could be tuned
- fp1 = open(f1, 'rb')
- fp2 = open(f2, 'rb')
- while 1:
- b1 = fp1.read(bufsize)
- b2 = fp2.read(bufsize)
- if b1 <> b2: return 0
- if not b1: return 1
+ """Compare two files, really."""
+ #print ' cmp', f1, f2 # XXX remove when debugged
+ bufsize = 8*1024 # Could be tuned
+ fp1 = open(f1, 'rb')
+ fp2 = open(f2, 'rb')
+ while 1:
+ b1 = fp1.read(bufsize)
+ b2 = fp2.read(bufsize)
+ if b1 <> b2: return 0
+ if not b1: return 1