simplify and unify FDCapture API and usage:

* FDCapture now takes care through the 'patchsys' option to
  also set sys.stdin/out/err - setfiles/unsetfiles methods removed -
  i doubt anybody uses this outside of py.test's own old usage.
* stdin also goes through FDCapture now.

--HG--
branch : trunk

py/_io/capture.py

@@ -26,23 +26,26 @@ except ImportError:
                 raise TypeError("not a byte value: %r" %(data,))
             StringIO.write(self, data)
 
+patchsysdict = {0: 'stdin', 1: 'stdout', 2: 'stderr'}
+
 class FDCapture: 
     """ Capture IO to/from a given os-level filedescriptor. """
     
-    def __init__(self, targetfd, tmpfile=None, now=True):
+    def __init__(self, targetfd, tmpfile=None, now=True, patchsys=False):
         """ save targetfd descriptor, and open a new 
             temporary file there.  If no tmpfile is 
             specified a tempfile.Tempfile() will be opened
             in text mode. 
         """
         self.targetfd = targetfd
-        self._patched = []
         if tmpfile is None: 
             f = tempfile.TemporaryFile('wb+')
             tmpfile = dupfile(f, encoding="UTF-8") 
             f.close()
         self.tmpfile = tmpfile 
         self._savefd = os.dup(self.targetfd)
+        if patchsys:
+            self._oldsys = getattr(sys, patchsysdict[targetfd])
         if now:
             self.start()
 
@@ -53,20 +56,8 @@ class FDCapture:
             raise ValueError("saved filedescriptor not valid, "
                 "did you call start() twice?")
         os.dup2(self.tmpfile.fileno(), self.targetfd) 
-
-    def setasfile(self, name, module=sys): 
-        """ patch <module>.<name> to self.tmpfile
-        """
-        key = (module, name)
-        self._patched.append((key, getattr(module, name)))
-        setattr(module, name, self.tmpfile) 
-
-    def unsetfiles(self): 
-        """ unpatch all patched items
-        """
-        while self._patched: 
-            (module, name), value = self._patched.pop()
-            setattr(module, name, value) 
+        if hasattr(self, '_oldsys'):
+            setattr(sys, patchsysdict[self.targetfd], self.tmpfile)
 
     def done(self): 
         """ unpatch and clean up, returns the self.tmpfile (file object)
@@ -74,7 +65,8 @@ class FDCapture:
         os.dup2(self._savefd, self.targetfd) 
         os.close(self._savefd) 
         self.tmpfile.seek(0)
-        self.unsetfiles() 
+        if hasattr(self, '_oldsys'):
+            setattr(sys, patchsysdict[self.targetfd], self._oldsys)
         return self.tmpfile 
 
     def writeorg(self, data):
@@ -182,7 +174,6 @@ class StdCaptureFD(Capture):
         in_=True, patchsys=True, now=True):
         self._options = locals()
         self._save()
-        self.patchsys = patchsys
         if now:
             self.startall()
 
@@ -191,10 +182,17 @@ class StdCaptureFD(Capture):
         out = self._options['out']
         err = self._options['err']
         mixed = self._options['mixed']
-        self.in_ = in_
+        patchsys = self._options['patchsys']
         if in_:
+            if hasattr(in_, 'read'):
+                tmpfile = in_
+            else:
+                fd = os.open(devnullpath, os.O_RDONLY)
+                tmpfile = os.fdopen(fd)
             try:
-                self._oldin = (sys.stdin, os.dup(0))
+                self.in_ = FDCapture(0, tmpfile=tmpfile, now=False,
+                    patchsys=patchsys)
+                self._options['in_'] = self.in_.tmpfile
             except OSError:
                 pass 
         if out:
@@ -202,7 +200,8 @@ class StdCaptureFD(Capture):
             if hasattr(out, 'write'):
                 tmpfile = out
             try:
-                self.out = FDCapture(1, tmpfile=tmpfile, now=False)
+                self.out = FDCapture(1, tmpfile=tmpfile, 
+                           now=False, patchsys=patchsys)
                 self._options['out'] = self.out.tmpfile
             except OSError:
                 pass 
@@ -214,28 +213,23 @@ class StdCaptureFD(Capture):
             else:
                 tmpfile = None
             try:
-                self.err = FDCapture(2, tmpfile=tmpfile, now=False) 
+                self.err = FDCapture(2, tmpfile=tmpfile, 
+                           now=False, patchsys=patchsys) 
                 self._options['err'] = self.err.tmpfile
             except OSError:
                 pass 
 
     def startall(self):
-        if self.in_:
+        if hasattr(self, 'in_'):
+            self.in_.start()
             sys.stdin  = DontReadFromInput()
-            fd = os.open(devnullpath, os.O_RDONLY)
-            os.dup2(fd, 0)
-            os.close(fd)
        
         out = getattr(self, 'out', None) 
         if out:
             out.start()
-            if self.patchsys:
-                out.setasfile('stdout')
         err = getattr(self, 'err', None)
         if err:
             err.start()
-            if self.patchsys:
-                err.setasfile('stderr')
 
     def resume(self):
         """ resume capturing with original temp files. """
@@ -248,11 +242,8 @@ class StdCaptureFD(Capture):
             outfile = self.out.done() 
         if hasattr(self, 'err') and not self.err.tmpfile.closed:
             errfile = self.err.done() 
-        if hasattr(self, '_oldin'):
-            oldsys, oldfd = self._oldin 
-            os.dup2(oldfd, 0)
-            os.close(oldfd)
-            sys.stdin = oldsys 
+        if hasattr(self, 'in_'):
+            tmpfile = self.in_.done()
         self._save()
         return outfile, errfile 
 

testing/io_/test_capture.py

@@ -144,8 +144,7 @@ class TestFDCapture:
         f.close()
 
     def test_stderr(self): 
-        cap = py.io.FDCapture(2)
-        cap.setasfile('stderr')
+        cap = py.io.FDCapture(2, patchsys=True)
         print_("hello", file=sys.stderr)
         f = cap.done()
         s = f.read()