intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 74 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Lib/multiprocessing/popen_forkserver.py b/contrib/tools/python3/src/Lib/multiprocessing/popen_forkserver.py
new file mode 100644
index 00000000000..a56eb9bf110
--- /dev/null
+++ b/contrib/tools/python3/src/Lib/multiprocessing/popen_forkserver.py
@@ -0,0 +1,74 @@
+import io
+import os
+
+from .context import reduction, set_spawning_popen
+if not reduction.HAVE_SEND_HANDLE:
+    raise ImportError('No support for sending fds between processes')
+from . import forkserver
+from . import popen_fork
+from . import spawn
+from . import util
+
+
+__all__ = ['Popen']
+
+#
+# Wrapper for an fd used while launching a process
+#
+
+class _DupFd(object):
+    def __init__(self, ind):
+        self.ind = ind
+    def detach(self):
+        return forkserver.get_inherited_fds()[self.ind]
+
+#
+# Start child process using a server process
+#
+
+class Popen(popen_fork.Popen):
+    method = 'forkserver'
+    DupFd = _DupFd
+
+    def __init__(self, process_obj):
+        self._fds = []
+        super().__init__(process_obj)
+
+    def duplicate_for_child(self, fd):
+        self._fds.append(fd)
+        return len(self._fds) - 1
+
+    def _launch(self, process_obj):
+        prep_data = spawn.get_preparation_data(process_obj._name)
+        buf = io.BytesIO()
+        set_spawning_popen(self)
+        try:
+            reduction.dump(prep_data, buf)
+            reduction.dump(process_obj, buf)
+        finally:
+            set_spawning_popen(None)
+
+        self.sentinel, w = forkserver.connect_to_new_process(self._fds)
+        # Keep a duplicate of the data pipe's write end as a sentinel of the
+        # parent process used by the child process.
+        _parent_w = os.dup(w)
+        self.finalizer = util.Finalize(self, util.close_fds,
+                                       (_parent_w, self.sentinel))
+        with open(w, 'wb', closefd=True) as f:
+            f.write(buf.getbuffer())
+        self.pid = forkserver.read_signed(self.sentinel)
+
+    def poll(self, flag=os.WNOHANG):
+        if self.returncode is None:
+            from multiprocessing.connection import wait
+            timeout = 0 if flag == os.WNOHANG else None
+            if not wait([self.sentinel], timeout):
+                return None
+            try:
+                self.returncode = forkserver.read_signed(self.sentinel)
+            except (OSError, EOFError):
+                # This should not happen usually, but perhaps the forkserver
+                # process itself got killed
+                self.returncode = 255
+
+        return self.returncode