From 8befc6a8fc0d898365f0a473c882ca601d1649b2 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Mon, 25 Jan 2016 22:49:32 +0100
Subject: [PATCH] protocols: add pipe_ipc (incomplete)

---
 artiq/protocols/pipe_ipc.py | 93 +++++++++++++++++++++++++++++++++++++
 artiq/test/pipe_ipc.py      | 42 +++++++++++++++++
 2 files changed, 135 insertions(+)
 create mode 100644 artiq/protocols/pipe_ipc.py
 create mode 100644 artiq/test/pipe_ipc.py

diff --git a/artiq/protocols/pipe_ipc.py b/artiq/protocols/pipe_ipc.py
new file mode 100644
index 000000000..085e0eea8
--- /dev/null
+++ b/artiq/protocols/pipe_ipc.py
@@ -0,0 +1,93 @@
+import os
+import asyncio
+
+
+class _BaseIO:
+    def write(self, data):
+        self.writer.write(data)
+
+    async def drain(self):
+        await self.writer.drain()
+
+    async def readline(self):
+        return await self.reader.readline()
+
+    async def read(self, n):
+        return await self.reader.read(n)
+
+    def close(self):
+        self.writer.close()
+
+
+if os.name != "nt":
+    class AsyncioParentComm(_BaseIO):
+        def __init__(self):
+            self.c_rfd, self.p_wfd = os.pipe()
+            self.p_rfd, self.c_wfd = os.pipe()
+
+        def get_address(self):
+            return "{},{}".format(self.c_rfd, self.c_wfd)
+
+        async def create_subprocess(self, *args, **kwargs):
+            loop = asyncio.get_event_loop()
+            self.process = await asyncio.create_subprocess_exec(
+                *args, pass_fds={self.c_rfd, self.c_wfd}, **kwargs)
+            os.close(self.c_rfd)
+            os.close(self.c_wfd)
+
+            pipe = open(self.p_rfd, "rb", 0)
+            self.reader = asyncio.StreamReader(loop=loop)
+            def factory():
+                return asyncio.StreamReaderProtocol(self.reader, loop=loop)
+            await loop.connect_read_pipe(factory, pipe)
+
+            pipe = open(self.p_wfd, "wb", 0)
+            transport, protocol = await loop.connect_write_pipe(
+                asyncio.Protocol, pipe)
+            self.writer = asyncio.StreamWriter(transport, protocol,
+                                               None, loop)
+
+    class AsyncioChildComm(_BaseIO):
+        pass
+
+    class ChildComm:
+        def __init__(self, address):
+            rfd, wfd = address.split(",", maxsplit=1)
+            self.rf = open(int(rfd), "rb", 0)
+            self.wf = open(int(wfd), "wb", 0)
+
+        def read(self, n):
+            return self.rf.read(n)
+
+        def readline(self):
+            return self.rf.readline()
+
+        def write(self, data):
+            return self.wf.write(data)
+
+        def close(self):
+            self.rf.close()
+            self.wf.close()
+
+
+else:  # windows
+    class AsyncioParentComm(_BaseIO):
+        pass
+
+    class AsyncioChildComm(_BaseIO):
+        """Requires ProactorEventLoop"""
+        def __init__(self, address):
+            self.address = address
+
+        async def connect(self):
+            loop = asyncio.get_event_loop()
+            self.reader = asyncio.StreamReader(loop=loop)
+            def factory():
+                return asyncio.StreamReaderProtocol(self.reader)
+            transport, protocol = await loop.create_pipe_connection(self.address,
+                                                                    factory)
+            self.writer = asyncio.StreamWriter(transport, protocol,
+                                               self.reader, loop)
+
+    class ChildComm:
+        pass
diff --git a/artiq/test/pipe_ipc.py b/artiq/test/pipe_ipc.py
new file mode 100644
index 000000000..901c49fa6
--- /dev/null
+++ b/artiq/test/pipe_ipc.py
@@ -0,0 +1,42 @@
+import unittest
+import sys
+import asyncio
+
+from artiq.protocols import pipe_ipc
+
+
+class IPCCase(unittest.TestCase):
+    def setUp(self):
+        self.loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(self.loop)
+
+    def tearDown(self):
+        self.loop.close()
+
+    async def _coro_test(self, child_blocking):
+        ipc = pipe_ipc.AsyncioParentComm()
+        await ipc.create_subprocess(sys.executable,
+                                    sys.modules[__name__].__file__,
+                                    ipc.get_address())
+        for i in range(10):
+            ipc.write("{}\n".format(i).encode())
+            s = (await ipc.readline()).decode()
+            self.assertEqual(int(s), i+1)
+        ipc.write(b"-1\n")
+        await ipc.process.wait()
+        ipc.close()
+
+    def test_blocking(self):
+        self.loop.run_until_complete(self._coro_test(True))
+
+
+def run_child():
+    child_comm = pipe_ipc.ChildComm(sys.argv[1])
+    while True:
+        x = int(child_comm.readline().decode())
+        if x < 0:
+            break
+        child_comm.write((str(x+1) + "\n").encode())
+
+if __name__ == "__main__":
+    run_child()