Merge pull request #113 from andfoy/env_var_reading_mode

PR: Add PYWINPTY_BLOCK envirnoment variable to disable ptyprocess read block

winpty/ptyprocess.py

@@ -31,6 +31,7 @@ def __init__(self, pty):
         assert isinstance(pty, PTY)
         self.pty = pty
         self.pid = pty.pid
+        self.read_blocking = bool(os.environ.get('PYWINPTY_BLOCK', 1))
         self.closed = False
         self.flag_eof = False
 
@@ -51,7 +52,7 @@ def __init__(self, pty):
 
         # Read from the pty in a thread.
         self._thread = threading.Thread(target=_read_in_thread,
-            args=(address, self.pty))
+            args=(address, self.pty, self.read_blocking))
         self._thread.setDaemon(True)
         self._thread.start()
 
@@ -321,18 +322,18 @@ def setwinsize(self, rows, cols):
         self.pty.set_size(cols, rows)
 
 
-def _read_in_thread(address, pty):
+def _read_in_thread(address, pty, blocking):
     """Read data from the pty in a thread.
     """
     client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     client.connect(address)
 
     while 1:
-        data = pty.read(4096, blocking=True)
+        data = pty.read(4096, blocking=blocking)
 
         if not data and not pty.isalive():
             while not data and not pty.iseof():
-                data += pty.read(4096, blocking=True)
+                data += pty.read(4096, blocking=blocking)
 
             if not data:
                 try: