Initial untested stab at vcs mirroring component, with DESIGN plan

1 files changed, 81 insertions, 0 deletions

diff --git a/async_subprocess.py b/async_subprocess.py
new file mode 100644
index 0000000..53abaa1
--- /dev/null
+++ b/async_subprocess.py
@@ -0,0 +1,81 @@
+# async_subprocess.py:
+# Run a subprocess asynchronously using GLib
+#
+# Licensed under the new-BSD license (http://www.opensource.org/licenses/bsd-license.php)
+# Copyright (C) 2010 Red Hat, Inc.
+# Written by Colin Walters <walters@verbum.org>
+
+import glib
+import logging
+
+PIPE_STDOUT = 'pipe-stdout'
+
+def spawn_async_log_info(argv, cwd=None, stdout=None):
+    logging.info("Starting subprocess: %r" % (argv, ))
+    return AsyncProcess(argv, cwd=cwd, stdout=stdout)
+
+def spawn_async_output_to_file(argv, output_filepath, on_exited, cwd=None):
+    f = open(output_filepath, 'w')
+    process = AsyncProcess(argv, cwd=cwd, stdout=PIPE_STDOUT)
+    def _write_to_file(process, buf):
+        f.write(buf)
+    def _on_exited(process):
+        f.close()
+        on_exited()
+    process.set_callbacks(_write_to_file, _on_exited)
+    return process
+    
+class AsyncProcess(object):
+    def __init__(self, argv, cwd=None, stdout=None):
+        self.argv = argv
+        if stdout == PIPE_STDOUT:
+            (pid, stdin, stdout, stderr) = glib.spawn_async(argv,
+                                                            working_directory=cwd,
+                                                            flags=(glib.SPAWN_SEARCH_PATH
+                                                                   | glib.SPAWN_DO_NOT_REAP_CHILD),
+                                                            standard_output=True,
+                                                            standard_error=None)
+            assert stdout == stderr
+        else:
+            (pid, stdin, stdout, stderr) = glib.spawn_async(argv,
+                                                            working_directory=cwd,
+                                                            (glib.SPAWN_SEARCH_PATH
+                                                             | glib.SPAWN_DO_NOT_REAP_CHILD
+                                                             | glib.SPAWN_STDOUT_TO_DEV_NULL
+                                                             | glib.SPAWN_STDERR_TO_DEV_NULL))
+            assert stdout is None
+            assert stderr is None
+
+        assert stdin is None
+        self.pid = pid
+        self._child_watch_id = glib.child_watch_add(pid, self._on_child_exited)
+        self._stdout_fd = stdout
+
+    def set_callbacks(self, output_callback, exited_callback):
+        self._output_callback = output_callback
+        self._exited_callback = exited_callback
+        if (self.stdout and self._stdout_watch_id == 0):
+            glib.io_add_watch(self.stdout, glib.IO_IN | glib.IO_ERR | glib.IO_HUP,
+                              self._on_io)
+
+    def _on_child_exited(self, pid, condition):
+        logging.info("Child pid %d exited with code %r" % (pid, condition))
+        self._exited_callback(self, condition)
+
+    def _on_io(self, source, condition):
+        have_read = condition & gobject.IO_IN
+        if have_read:
+            buf = os.read(source, 8192)
+            self._output_callback(self, buf)
+        if ((condition & glib.IO_ERR) > 0
+            or (condition & glib.IO_HUP) > 0):
+            os.close(source)
+            self._stdout_watch_id = 0
+            return False
+        return have_read
+                
+            
+
+
+ 
+