[Python-checkins] python/dist/src/Lib subprocess.py,1.17,1.18

[astrand at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Lib
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv3791

Modified Files:
	subprocess.py 
Log Message:
Optimization for communicate(): If only one of stdin/stdout/stderr is
redirected, using select() or threads is unnecessary.


Index: subprocess.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/subprocess.py,v
retrieving revision 1.17
retrieving revision 1.18
diff -u -d -r1.17 -r1.18
--- subprocess.py	21 Feb 2005 08:13:02 -0000	1.17
+++ subprocess.py	3 Mar 2005 20:28:59 -0000	1.18
@@ -619,6 +619,33 @@
         data = data.replace("\r", "\n")
         return data
 
+    def communicate(self, input=None):
+        """Interact with process: Send data to stdin.  Read data from
+        stdout and stderr, until end-of-file is reached.  Wait for
+        process to terminate.  The optional input argument should be a
+        string to be sent to the child process, or None, if no data
+        should be sent to the child.
+        
+        communicate() returns a tuple (stdout, stderr)."""
+
+        # Optimization: If we are only using one pipe, or no pipe at
+        # all, using select() or threads is unnecessary.
+        if [self.stdin, self.stdout, self.stderr].count(None) >= 2:
+            stdout = None 
+            stderr = None 
+            if self.stdin:
+                if input:
+                    self.stdin.write(input)
+                self.stdin.close()
+            elif self.stdout:
+                stdout = self.stdout.read()
+            elif self.stderr:
+                stderr = self.stderr.read()
+            self.wait()
+            return (stdout, stderr)
+        
+        return self._communicate(input)
+
 
     if mswindows:
         #
@@ -811,14 +838,7 @@
             buffer.append(fh.read())
 
 
-        def communicate(self, input=None):
-            """Interact with process: Send data to stdin.  Read data from
-            stdout and stderr, until end-of-file is reached.  Wait for
-            process to terminate.  The optional input argument should be a
-            string to be sent to the child process, or None, if no data
-            should be sent to the child.
-
-            communicate() returns a tuple (stdout, stderr)."""
+        def _communicate(self, input):
             stdout = None # Return
             stderr = None # Return
 
@@ -1066,14 +1086,7 @@
             return self.returncode
 
 
-        def communicate(self, input=None):
-            """Interact with process: Send data to stdin.  Read data from
-            stdout and stderr, until end-of-file is reached.  Wait for
-            process to terminate.  The optional input argument should be a
-            string to be sent to the child process, or None, if no data
-            should be sent to the child.
-
-            communicate() returns a tuple (stdout, stderr)."""
+        def _communicate(self, input):
             read_set = []
             write_set = []
             stdout = None # Return