Implement writing to child process

kitty/boss.py

@@ -2,18 +2,27 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
-from PyQt5.QtCore import QObject
+import os
+import io
+
+from PyQt5.QtCore import QObject, QSocketNotifier
 
 from .screen import Screen
 from .term import TerminalWidget
-from .utils import resize_pty, hangup
+from .utils import resize_pty, hangup, create_pty
 
 
 class Boss(QObject):
 
-    def __init__(self, opts, parent=None):
+    def __init__(self, opts, parent):
         QObject.__init__(self, parent)
-        self.screen = Screen(opts, parent=self)
+        self.write_buf = memoryview(b'')
+        self.read_notifier = QSocketNotifier(create_pty()[0], QSocketNotifier.Read, self)
+        self.read_notifier.activated.connect(self.read_ready)
+        self.write_notifier = QSocketNotifier(create_pty()[0], QSocketNotifier.Write, self)
+        self.write_notifier.setEnabled(False)
+        self.write_notifier.activated.connect(self.write_ready)
+        self.screen = Screen(opts, self.write_to_child, parent=self)
         self.term = TerminalWidget(opts, self.screen.linebuf, parent)
         self.term.relayout_lines.connect(self.relayout_lines)
         resize_pty(self.screen.columns, self.screen.lines)
@@ -22,6 +31,25 @@ class Boss(QObject):
         self.screen.apply_opts(opts)
         self.term.apply_opts(opts)
 
+    def read_ready(self, read_fd):
+        data = os.read(read_fd, io.DEFAULT_BUFFER_SIZE)
+        if not data:
+            # EOF
+            self.parent().child_process_died()
+            return
+
+    def write_ready(self, write_fd):
+        while self.write_buf:
+            n = os.write(write_fd, io.DEFAULT_BUFFER_SIZE)
+            if not n:
+                return
+            self.write_buf = self.write_buf[n:]
+        self.write_notifier.setEnabled(False)
+
+    def write_to_child(self, data):
+        self.write_buf = memoryview(self.write_buf.tobytes() + data)
+        self.write_notifier.setEnabled(True)
+
     def relayout_lines(self, previous, cells_per_line, previousl, lines_per_screen):
         self.screen.resize(lines_per_screen, cells_per_line)
         resize_pty(cells_per_line, lines_per_screen)

kitty/main.py

@@ -59,6 +59,9 @@ class MainWindow(QMainWindow):
             if signal.SIGINT in signals or signal.SIGTERM in signals:
                 self.shutdown()
 
+    def child_process_died(self):
+        self.shutdown()
+
     def shutdown(self):
         self.close()
         self.boss.shutdown()

kitty/screen.py

@@ -45,8 +45,9 @@ class Screen(QObject):
     line_added_to_history = pyqtSignal()
     _notify_cursor_position = True
 
-    def __init__(self, opts, columns: int=80, lines: int=24, parent=None):
+    def __init__(self, opts, write_to_child, columns: int=80, lines: int=24, parent=None):
         QObject.__init__(self, parent)
+        self.write_process_input = write_to_child
         self.savepoints = deque()
         self.columns = columns
         self.lines = lines
@@ -855,16 +856,6 @@ class Screen(QObject):
             self.write_process_input(
                 ctrl.CSI + "{0};{1}R".format(y, x).encode())
 
-    def write_process_input(self, data):
-        """Writes data to the process running inside the terminal.
-
-        By default is a noop.
-
-        :param bytes data: data to write to the process ``stdin``.
-
-        .. versionadded:: 0.5.0
-        """
-
     def debug(self, *args, **kwargs):
         """Endpoint for unrecognized escape sequences.
 

kitty/utils.py

@@ -36,6 +36,7 @@ def create_pty():
     if not hasattr(create_pty, 'master'):
         create_pty.master, create_pty.slave = os.openpty()
         fcntl.fcntl(create_pty.slave, fcntl.F_SETFD, fcntl.fcntl(create_pty.slave, fcntl.F_GETFD) & ~fcntl.FD_CLOEXEC)
+        # Note that master and slave are in blocking mode
     return create_pty.master, create_pty.slave