mojo: Add RunLoop::Current() and refactor unit tests.

mojo/public/python/mojo/system.pyx

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # distutils language = c++
 
 cimport c_core
 cimport c_environment
 
 
 from cpython.buffer cimport PyBUF_CONTIG
 from cpython.buffer cimport PyBUF_CONTIG_RO
 from cpython.buffer cimport Py_buffer
 from cpython.buffer cimport PyBuffer_FillInfo
 from cpython.buffer cimport PyBuffer_Release
 from cpython.buffer cimport PyObject_GetBuffer
 from cpython.mem cimport PyMem_Malloc, PyMem_Free
 from libc.stdint cimport int32_t, int64_t, uint32_t, uint64_t, uintptr_t
 
+import ctypes
+import threading
+
 def SetSystemThunks(system_thunks_as_object):
   """Bind the basic Mojo Core functions.
 
   This should only be used by the embedder.
   """
   cdef const c_core.MojoSystemThunks* system_thunks = (
       <const c_core.MojoSystemThunks*><uintptr_t>system_thunks_as_object)
   c_core.MojoSetSystemThunks(system_thunks)
 
 HANDLE_INVALID = c_core.MOJO_HANDLE_INVALID
@@ skipping 674 matching lines @@
   """Options for duplicating a shared buffer.
 
   See mojo/public/c/system/buffer.h
   """
   FLAG_NONE = c_core.MOJO_DUPLICATE_BUFFER_HANDLE_OPTIONS_FLAG_NONE
 
   def __init__(self):
     self.flags = DuplicateSharedBufferOptions.FLAG_NONE
 
 
+_RUN_LOOPS = threading.local()

[sdefresne, 2014/10/10 12:29:44]

IIUC, _RUN_LOOPS is used to keep a weak-ref to the thread instance of RunLoop,
right? Could you add a comment making this explicit?

[qsr, 2014/10/10 12:34:07]

Done.

+
+
 cdef class RunLoop(object):
   """RunLoop to use when using asynchronous operations on handles."""
 
-  cdef c_environment.CRunLoop c_run_loop
+  cdef c_environment.CRunLoop* c_run_loop
+
+  def __init__(self):
+    assert not <uintptr_t>(c_environment.CRunLoopCurrent())
+    self.c_run_loop = new c_environment.CRunLoop()
+    _RUN_LOOPS.loop = id(self)
+
+  def __dealloc__(self):
+    del _RUN_LOOPS.loop
+    del self.c_run_loop
+
+  @staticmethod
+  def Current():
+    if hasattr(_RUN_LOOPS, 'loop'):
+      return ctypes.cast(_RUN_LOOPS.loop, ctypes.py_object).value
+    return None
 
   def Run(self):
     """Run the runloop until Quit is called."""
     self.c_run_loop.Run()
 
   def RunUntilIdle(self):
     """Run the runloop until Quit is called or no operation is waiting."""
     self.c_run_loop.RunUntilIdle()
 
   def Quit(self):
     """Quit the runloop."""
     self.c_run_loop.Quit()
 
   def PostDelayedTask(self, runnable, delay=0):
     """
     Post a task on the runloop. This must be called from the thread owning the
     runloop.
     """
     cdef c_environment.CClosure closure = c_environment.BuildClosure(runnable)
     self.c_run_loop.PostDelayedTask(closure, delay)
 
 
 cdef c_environment.CEnvironment* _ENVIRONMENT = new c_environment.CEnvironment()
 cdef c_environment.PythonAsyncWaiter* _ASYNC_WAITER = new c_environment.PythonAsyncWaiter()