[NaCl SDK] Support non blocking TCP/UDP

native_client_sdk/src/libraries/nacl_io/event_emitter_packet.h

+// 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.
+
+#ifndef LIBRARIES_NACL_IO_EVENT_EMITTER_PACKET_H_
+#define LIBRARIES_NACL_IO_EVENT_EMITTER_PACKET_H_
+
+#include <poll.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "nacl_io/event_emitter.h"
+#include "nacl_io/fifo_packet.h"
+
+#include "sdk_util/auto_lock.h"
+
+namespace nacl_io {
+
+class EventEmitterPacket;
+typedef sdk_util::ScopedRef<EventEmitterPacket> ScopedEmitterPacket;
+
+class EventEmitterPacket : public EventEmitter {
+ public:
+  EventEmitterPacket(size_t rsize, size_t wsize)
+      : rfifo_(NULL),
+        wfifo_(NULL),
+        event_status_(0) {
+
+    rsize = std::max<size_t>(1, rsize);
+    fifo_ = new FIFOPacket(rsize);
+
+    wsize = std::max<size_t>(1, wsize);
+    fifo_ = new FIFOPacket(wsize);
+
+    UpdateStatusLocked();
+  }
+
+  ~EventEmitterPipe() {
+    delete rfifo_;
+    delete wfifo_;
+  }
+
+  virtual uint32_t GetEventStatus() {
+    return event_status_;
+  }
+
+  Packet* ReadTXPacket_Locked() {

[binji, 2013/09/12 01:47:57]

why TXPacket? ReadPacket is easier to read...

[noelallen1, 2013/09/12 23:19:03]

There are two FIFOs, an incoming and and outgoing.
You Write to the TX Fifo to Q for transmit.  You read from it on the MountStream
thread.
You Write to the RX Fifo from the MountStream thread to Q data, then read from
it on the actual thread calling Recv.

+    Packet* packet = rfifo_->Read();
+
+    UpdateStatusLocked();

[binji, 2013/09/12 01:47:57]

_Locked?

[noelallen1, 2013/09/12 23:19:03]

Done.

+    return packet;
+  }
+
+  uint32_t WriteTXPacket_Locked(Packet* packet) {
+    uint32_t result = rfifo_->Write(packet);
+
+    UpdateStatusLocked();
+    return result;
+  }
+
+ protected:
+  void UpdateStatus_Locked() {
+    uint32_t old_status = event_status_;
+
+    if (!rfifo_->IsEmpty()) {
+      event_status_ |= POLLIN;
+    } else {
+      event_status_ &= ~POLLIN;
+    }
+
+    if (!wfifo_->IsFull()) {
+      event_status_ |= POLLOUT;
+    } else {
+      event_status_ &= ~POLLOUT;
+    }
+
+    uint32_t raise_status = event_status_ & ~old_status;
+    if (raise_status)
+      RaiseEvents_Locked(raise_status);
+  }
+
+  FIFOPacket* rfifo_;
+  FIFOPacket* wfifo_;
+  uint32_t event_status_;
+};
+
+}  // namespace nacl_io
+
+#endif  // LIBRARIES_NACL_IO_EVENT_EMITTER_PIPE_H_
+