[NaCl SDK] Support non blocking TCP/UDP

native_client_sdk/src/libraries/nacl_io/mount_stream.cc

+// Copyright (c) 2013 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.
+
+#include "nacl_io/ossocket.h"
+#ifdef PROVIDES_SOCKET_API
+
+#include <errno.h>
+
+#include "nacl_io/mount_node_socket.h"
+#include "nacl_io/mount_stream.h"
+
+namespace nacl_io {
+
+
+void DispatchStart(void* work_ptr, int32_t val) {
+  MountStreamWork* work = static_cast<MountStreamWork*>(work_ptr);
+
+  // Delete if it fails to Start, Run will never get called.
+  if (!work->Start(val))
+    delete work;
+}
+
+void DispatchRun(void* work_ptr, int32_t val) {
+  MountStreamWork* work = static_cast<MountStreamWork*>(work_ptr);
+
+  work->Run(val);
+  delete work;
+}
+
+void* MountStream::StreamThreadThunk(void* mount_ptr) {
+  MountStream* mount = static_cast<MountStream*>(mount_ptr);
+  mount->StreamThread();
+  return NULL;
+}
+
+// All work is done via completions callbacks from posted work.
+void MountStream::StreamThread() {
+  {
+    AUTO_LOCK(message_lock_)
+    message_loop_ =
+        ppapi_->GetMessageLoopInterface()->Create(ppapi()->GetInstance());
+    ppapi_->GetMessageLoopInterface()->AttachToCurrentThread(message_loop_);
+    pthread_cond_broadcast(&message_cond_);
+  }
+
+  while(1)

[binji, 2013/09/15 22:18:58]

no way to exit the loop?

[noelallen1, 2013/09/17 21:21:54]

Done.

+    ppapi_->GetMessageLoopInterface()->Run(message_loop_);
+}
+
+PP_CompletionCallback MountStream::GetStartCompletion(MountStreamWork* work) {
+  return PP_MakeCompletionCallback(DispatchStart, work);
+}
+
+PP_CompletionCallback MountStream::GetRunCompletion(MountStreamWork* work) {
+  return PP_MakeCompletionCallback(DispatchRun, work);
+}
+
+// Place enqueue onto the socket thread.
+void MountStream::EnqueueWork(MountStreamWork* work) {
+  if (message_loop_ == 0) {

[binji, 2013/09/15 22:18:58]

looks racy. What happens if two threads enqueue work? Both will enter the if,
then one will create a thread, then the other.

[noelallen1, 2013/09/17 21:21:54]

Done.

[binji, 2013/09/19 00:48:54]

Probably should use pthread_once_t instead of double-checked locking here
instead:
http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_once.html

[noelallen1, 2013/09/19 21:29:27]

The once init routine doesn't take a parameter, so I don't have a clean way to
call a member init function.   I can't make it static because I may have more
than one mount, for example testing...

+    AUTO_LOCK(message_lock_);
+    pthread_t thread;
+    pthread_create(&thread, NULL, StreamThreadThunk, this);
+
+    while (message_loop_ == 0)
+      pthread_cond_wait(&message_cond_, message_lock_.mutex());
+  }
+
+  PP_CompletionCallback cb = PP_MakeCompletionCallback(DispatchStart, work);
+  ppapi_->GetMessageLoopInterface()->PostWork(message_loop_, cb, 0);
+}
+
+
+MountStream::MountStream()
+    : message_loop_(0) {
+}
+
+Error MountStream::Access(const Path& path, int a_mode) { return EACCES; }
+Error MountStream::Open(const Path& path,
+                        int o_flags,
+                        ScopedMountNode* out_node) { return EACCES; }
+
+Error MountStream::Unlink(const Path& path) { return EACCES; }
+Error MountStream::Mkdir(const Path& path, int permissions) { return EACCES; }
+Error MountStream::Rmdir(const Path& path) { return EACCES; }
+Error MountStream::Remove(const Path& path) { return EACCES; }
+
+}  // namespace nacl_io
+#endif  // PROVIDES_SOCKET_API