From c2587c76f1b416cdbecb979e54941933246bf856 Mon Sep 17 00:00:00 2001
From: Skip Montanaro <skip.montanaro@gmail.com>
Date: Tue, 16 Feb 2021 20:14:16 -0600
Subject: starting over

---
 lib/cmpcache.py | 80 ++++++++++++++++++++++++++++-----------------------------
 1 file changed, 40 insertions(+), 40 deletions(-)

(limited to 'lib/cmpcache.py')

diff --git a/lib/cmpcache.py b/lib/cmpcache.py
index 4aea356..e846f58 100644
--- a/lib/cmpcache.py
+++ b/lib/cmpcache.py
@@ -3,11 +3,11 @@
 # 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
+#	- 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 posix
 from stat import *
@@ -23,46 +23,46 @@ cache = {}
 # May raise posix.error if a stat or open of either fails.
 #
 def cmp(f1, f2):
- # 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 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 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 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 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 = 8096 # Could be tuned
- fp1 = open(f1, 'r')
- fp2 = open(f2, 'r')
- while 1:
- b1 = fp1.read(bufsize)
- b2 = fp2.read(bufsize)
- if b1 <> b2: return 0
- if not b1: return 1
+	#print '    cmp', f1, f2 # XXX remove when debugged
+	bufsize = 8096 # Could be tuned
+	fp1 = open(f1, 'r')
+	fp2 = open(f2, 'r')
+	while 1:
+		b1 = fp1.read(bufsize)
+		b2 = fp2.read(bufsize)
+		if b1 <> b2: return 0
+		if not b1: return 1
-- 
cgit v1.2.3