Rewrite using class, to make waiting for processes possible;

by default children are waited for automatically.

diff --git a/Lib/popen2.py b/Lib/popen2.py
index d2867c616b73a370dc0c8937f5445b131e951025..ae89f949340f57d72db595a45ab746c64e53bca6 100644 (file)
--- a/Lib/popen2.py
+++ b/Lib/popen2.py
@@ -2,49 +2,97 @@ import os
 import sys
 import string
 
-MAXFD = 100    # Max number of file descriptors (os.getdtablesize()???)
+MAXFD = 256    # Max number of file descriptors (os.getdtablesize()???)
 
-def _popen2(cmd, capturestderr=0):
+_active = []
+
+def _cleanup():
+    for inst in _active[:]:
+       inst.poll()
+
+class Popen3:
+    def __init__(self, cmd, capturestderr=0):
        cmd = ['/bin/sh', '-c', cmd]
        p2cread, p2cwrite = os.pipe()
        c2pread, c2pwrite = os.pipe()
        if capturestderr:
-               errout, errin = os.pipe()
-       pid = os.fork()
-       if pid == 0:
-               # Child
-               os.close(0)
-               os.close(1)
-               if os.dup(p2cread) <> 0:
-                       sys.stderr.write('popen2: bad read dup\n')
-               if os.dup(c2pwrite) <> 1:
-                       sys.stderr.write('popen2: bad write dup\n')
-               if capturestderr:
-                       os.close(2)
-                       if os.dup(errin) <> 2: pass
-               for i in range(3, MAXFD):
-                       try:
-                               os.close(i)
-                       except: pass
+           errout, errin = os.pipe()
+       self.pid = os.fork()
+       if self.pid == 0:
+           # Child
+           os.close(0)
+           os.close(1)
+           if os.dup(p2cread) <> 0:
+               sys.stderr.write('popen2: bad read dup\n')
+           if os.dup(c2pwrite) <> 1:
+               sys.stderr.write('popen2: bad write dup\n')
+           if capturestderr:
+               os.close(2)
+               if os.dup(errin) <> 2: pass
+           for i in range(3, MAXFD):
                try:
-                       os.execv(cmd[0], cmd)
-               finally:
-                       os._exit(1)
-               # Shouldn't come here, I guess
+                   os.close(i)
+               except: pass
+           try:
+               os.execv(cmd[0], cmd)
+           finally:
                os._exit(1)
+           # Shouldn't come here, I guess
+           os._exit(1)
        os.close(p2cread)
-       tochild = os.fdopen(p2cwrite, 'w')
+       self.tochild = os.fdopen(p2cwrite, 'w')
        os.close(c2pwrite)
-       fromchild = os.fdopen(c2pread, 'r')
+       self.fromchild = os.fdopen(c2pread, 'r')
        if capturestderr:
-               os.close(errin)
-               childerr = os.fdopen(errout, 'r')
-               return fromchild, tochild, childerr
+           os.close(errin)
+           self.childerr = os.fdopen(errout, 'r')
        else:
-               return fromchild, tochild, None
+           self.childerr = None
+       self.sts = -1 # Child not completed yet
+       _active.append(self)
+    def poll(self):
+       if self.sts < 0:
+           try:
+               pid, sts = os.waitpid(self.pid, os.WNOHANG)
+               if pid == self.pid:
+                   self.sts = sts
+                   _active.remove(self)
+           except os.error:
+               pass
+       return self.sts
+    def wait(self):
+       pid, sts = os.waitpid(self.pid, 0)
+       if pid == self.pid:
+           self.sts = sts
+           _active.remove(self)
+       return self.sts
 
 def popen2(cmd):
-       return _popen2(cmd, 0)[:2]
+    _cleanup()
+    inst = Popen3(cmd, 0)
+    return inst.fromchild, inst.tochild
 
 def popen3(cmd):
-       return _popen2(cmd, 1)
+    _cleanup()
+    inst = Popen3(cmd, 1)
+    return inst.fromchild, inst.tochild, inst.childerr
+
+def _test():
+    teststr = "abc\n"
+    print "testing popen2..."
+    r, w = popen2('cat')
+    w.write(teststr)
+    w.close()
+    assert r.read() == teststr
+    print "testing popen3..."
+    r, w, e = popen3('cat')
+    w.write(teststr)
+    w.close()
+    assert r.read() == teststr
+    assert e.read() == ""
+    _cleanup()
+    assert not _active
+    print "All OK"
+
+if __name__ == '__main__':
+    _test()