Use 'stat' module instead of hardcoding information from <sys/stat.h>.

Lib/cmpcache.py

@@ -8,10 +8,9 @@
 #	- 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
-#
-# XXX There is a dependency on constants in <sys/stat.h> here.
 
 import posix
+import stat
 import statcache
 
 
@@ -27,7 +26,7 @@ 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 s1[0] <> 8 or s2[0] <> 8: # XXX 8 is S_IFREG in <sys/stat.h>
+	if not stat.S_ISREG(s1[0]) or not stat.S_ISREG(s2[0]):
 		# Either is a not a plain file -- always report as different
 		return 0
 	if s1 = s2:
@@ -53,12 +52,7 @@ def cmp(f1, f2):
 # Return signature (i.e., type, size, mtime) from raw stat data.
 #
 def sig(st):
-	# 0-5: st_mode, st_ino, st_dev, st_nlink, st_uid, st_gid
-	# 6-9: st_size, st_atime, st_mtime, st_ctime
-	type = st[0] / 4096 # XXX dependent on S_IFMT in <sys/stat.h>
-	size = st[6]
-	mtime = st[8]
-	return type, size, mtime
+	return stat.S_IFMT(st[ST_MODE]), st[stat.ST_SIZE], st[stat.ST_MTIME]
 
 # Compare two files, really.
 #

Lib/dircmp.py

@@ -9,17 +9,7 @@ import path
 import dircache
 import cmpcache
 import statcache
-
-
-# File type constants from <sys/stat.h>.
-#
-S_IFDIR = 4
-S_IFREG = 8
-
-# Extract the file type from a stat buffer.
-#
-def S_IFMT(st): return st[0] / 4096
-
+from stat import *
 
 # Directory comparison class.
 #
@@ -79,13 +69,13 @@ class dircmp():
 				ok = 0
 			#
 			if ok:
-				a_type = S_IFMT(a_stat)
-				b_type = S_IFMT(b_stat)
+				a_type = S_IFMT(a_stat[ST_MODE])
+				b_type = S_IFMT(b_stat[ST_MODE])
 				if a_type <> b_type:
 					dd.common_funny.append(x)
-				elif a_type = S_IFDIR:
+				elif S_ISDIR(a_type):
 					dd.common_dirs.append(x)
-				elif a_type = S_IFREG:
+				elif S_ISREG(a_type):
 					dd.common_files.append(x)
 				else:
 					dd.common_funny.append(x)

Lib/posixpath.py

 # Module 'path' -- common operations on POSIX pathnames
 
 import posix
+import stat
 
 
 # Intelligent pathname concatenation.
@@ -63,7 +64,7 @@ def isdir(path):
 		st = posix.stat(path)
 	except posix.error:
 		return 0
-	return st[0] / 4096 = 4 # S_IFDIR
+	return stat.S_ISDIR(st[stat.ST_MODE])
 
 
 # Is a path a symbolic link?
@@ -74,7 +75,7 @@ def islink(path):
 		st = posix.lstat(path)
 	except (posix.error, NameError):
 		return 0
-	return st[0] / 4096 = 10 # S_IFLNK
+	return stat.S_ISLNK(st[stat.ST_MODE])
 
 
 _mounts = []

Lib/statcache.py

@@ -4,7 +4,7 @@
 # There are functions to reset the cache or to selectively remove items.
 
 import posix
-
+from stat import *
 
 # The cache.
 # Keys are pathnames, values are `posix.stat' outcomes.
@@ -15,10 +15,8 @@ cache = {}
 # Stat a file, possibly out of the cache.
 #
 def stat(path):
-	try:
+	if cache.has_key(path):
 		return cache[path]
-	except RuntimeError:
-		pass
 	cache[path] = ret = posix.stat(path)
 	return ret
 
@@ -37,10 +35,8 @@ def reset():
 # Remove a given item from the cache, if it exists.
 #
 def forget(path):
-	try:
+	if cache.has_key(path):
 		del cache[path]
-	except RuntimeError:
-		pass
 
 
 # Remove all pathnames with a given prefix.
@@ -84,7 +80,7 @@ def forget_except_prefix(prefix):
 #
 def isdir(path):
 	try:
-		# mode is st[0]; type is mode/4096; S_IFDIR is 4
-		return stat(path)[0] / 4096 = 4
-	except RuntimeError:
+		st = stat(path)
+	except posix.error:
 		return 0
+	return S_ISDIR(st[ST_MODE])