configure: Modernize Python in configure.py.

file is a Python built-in (https://docs.python.org/2/library/functions.html?highlight=file#file) so it should be avoided as a variable name.
Use "with open" syntax to automate file close where possible.
os.getenv() will return None if the key is not in os.environ.
Use ternary if to simplify conditional assignment where it improves, not hinders, readability.

Closes #500.

1 files changed, 35 insertions, 50 deletions

diff --git a/make/configure.py b/make/configure.py
index 3209b7989..b6e0be58c 100644
--- a/make/configure.py
+++ b/make/configure.py
@@ -150,14 +150,14 @@ class Configure( object ):
             return
         self._record = False
         self.verbose = Configure.OUT_QUIET
-        file = self.open( 'log/config.info.txt', 'w' )
+        log_info_file = self.open( 'log/config.info.txt', 'w' )
         for line in self._log_info:
-            file.write( line )
-        file.close()
-        file = self.open( 'log/config.verbose.txt', 'w' )
+            log_info_file.write( line )
+        log_info_file.close()
+        log_verbose_file = self.open( 'log/config.verbose.txt', 'w' )
         for line in self._log_verbose:
-            file.write( line )
-        file.close()
+            log_verbose_file.write( line )
+        log_verbose_file.close()
 
     ## Find executable by searching path.
     ## On success, returns full pathname of executable.
@@ -168,11 +168,7 @@ class Configure( object ):
                 return name
             return None
 
-        if not os.environ.has_key( 'PATH' ) or os.environ[ 'PATH' ] == '':
-            path = os.defpath
-        else:
-            path = os.environ['PATH']
-
+        path = os.getenv( 'PATH' ) or os.defpath
         for dir in path.split( os.pathsep ):
             f = os.path.join( dir, name )
             if os.access( f, os.X_OK ):
@@ -340,9 +336,8 @@ class CCProbe( Action ):
 
     def _action( self ):
         ## write program file
-        file = open( 'conftest.c', 'w' )
-        file.write( self.test_file )
-        file.close()
+        with open( 'conftest.c', 'w' ) as out_file:
+            out_file.write( self.test_file )
         ## pipe and redirect stderr to stdout; effects communicate result
         pipe = subprocess.Popen( '%s -c -o conftest.o conftest.c' % self.command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT )
 
@@ -382,9 +377,8 @@ class LDProbe( Action ):
 
     def _action( self ):
         ## write program file
-        file = open( 'conftest.c', 'w' )
-        file.write( self.test_file )
-        file.close()
+        with open( 'conftest.c', 'w' ) as out_file:
+            out_file.write( self.test_file )
         ## pipe and redirect stderr to stdout; effects communicate result
         pipe = subprocess.Popen( '%s -o conftest conftest.c %s' % (self.command, self.lib), shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT )
 
@@ -429,10 +423,7 @@ class HostTupleProbe( ShellProbe, list ):
         super( HostTupleProbe, self ).__init__( 'host tuple', '%s/config.guess' % (cfg.dir), abort=True, head=True )
 
     def _parseSession( self ):
-        if len(self.session):
-            self.spec = self.session[0]
-        else:
-            self.spec = ''
+        self.spec = self.session[0] if self.session else ''
 
         ## grok GNU host tuples
         m = re.match( HostTupleProbe.GNU_TUPLE_RE, self.spec )
@@ -780,9 +771,8 @@ class RepoProbe( ShellProbe ):
         try:
             hvp = os.path.join( cfg.src_dir, 'version.txt' )
             if os.path.isfile( hvp ) and os.path.getsize( hvp ) > 0:
-                file = open( hvp, 'r' )
-                self.session = file.readlines()
-                file.close()
+                with open( hvp, 'r' ) as in_file:
+                    self.session = in_file.readlines()
                 if self.session:
                     self._parseSession()
             if self.rev != 0:
@@ -974,12 +964,7 @@ class VersionProbe( Action ):
         ## read data into memory buffers
         data = pipe.communicate()
         self.fail = pipe.returncode != 0
-
-        if data[0]:
-            self.session = data[0].splitlines()
-        else:
-            self.session = []
-
+        self.session = data[0].splitlines() if data[0] else []
         self.svers = '0.0.0'
         self.ivers = [0,0,0]
 
@@ -1096,22 +1081,22 @@ class ConfigDocument:
     def __init__( self ):
         self._elements = []
 
-    def _outputMake( self, file, namelen, name, value, append ):
+    def _outputMake( self, out_file, namelen, name, value, append ):
         if append:
             if value == None or len(str(value)) == 0:
-                file.write( '%-*s +=\n' % (namelen, name) )
+                out_file.write( '%-*s +=\n' % (namelen, name) )
             else:
-                file.write( '%-*s += %s\n' % (namelen, name, value) )
+                out_file.write( '%-*s += %s\n' % (namelen, name, value) )
         else:
             if value == None or len(str(value)) == 0:
-                file.write( '%-*s  =\n' % (namelen, name) )
+                out_file.write( '%-*s  =\n' % (namelen, name) )
             else:
-                file.write( '%-*s  = %s\n' % (namelen, name, value) )
+                out_file.write( '%-*s  = %s\n' % (namelen, name, value) )
 
-    def _outputM4( self, file, namelen, name, value ):
+    def _outputM4( self, out_file, namelen, name, value ):
         namelen += 7
         name = '<<__%s>>,' % name.replace( '.', '_' )
-        file.write( 'define(%-*s  <<%s>>)dnl\n' % (namelen, name, value ))
+        out_file.write( 'define(%-*s  <<%s>>)dnl\n' % (namelen, name, value ))
 
     def add( self, name, value, append=False ):
         self._elements.append( [name,value,append] )
@@ -1129,7 +1114,7 @@ class ConfigDocument:
     def addM4( self, line ):
         self._elements.append( ('?m4',line) )
 
-    def output( self, file, type ):
+    def output( self, out_file, type ):
         namelen = 0
         for item in self._elements:
             if item == None or item[0].find( '?' ) == 0:
@@ -1139,19 +1124,19 @@ class ConfigDocument:
         for item in self._elements:
             if item == None:
                 if type == 'm4':
-                    file.write( 'dnl\n' )
+                    out_file.write( 'dnl\n' )
                 else:
-                    file.write( '\n' )
+                    out_file.write( '\n' )
                 continue
             if item[0].find( '?' ) == 0:
                 if item[0].find( type, 1 ) == 1:
-                    file.write( '%s\n' % (item[1]) )
+                    out_file.write( '%s\n' % (item[1]) )
                 continue
 
             if type == 'm4':
-                self._outputM4( file, namelen, item[0], item[1] )
+                self._outputM4( out_file, namelen, item[0], item[1] )
             else:
-                self._outputMake( file, namelen, item[0], item[1], item[2] )
+                self._outputMake( out_file, namelen, item[0], item[1], item[2] )
 
     def update( self, name, value ):
         for item in self._elements:
@@ -1173,11 +1158,11 @@ class ConfigDocument:
         ftmp = cfg.mktmpname(fname)
         try:
             try:
-                file = cfg.open( ftmp, 'w' )
-                self.output( file, type )
+                out_file = cfg.open( ftmp, 'w' )
+                self.output( out_file, type )
             finally:
                 try:
-                    file.close()
+                    out_file.close()
                 except:
                     pass
         except Exception, x:
@@ -1207,12 +1192,12 @@ def encodeDistfileConfig():
     }
     try:
         try:
-            file = cfg.open( ftmp, 'w' )
-            json.dump(data, file)
-            file.write('\n')
+            out_file = cfg.open( ftmp, 'w' )
+            json.dump(data, out_file)
+            out_file.write('\n')
         finally:
             try:
-                file.close()
+                out_file.close()
             except:
                 pass
     except Exception, x: