[NaCl SDK] Support non blocking TCP/UDP

native_client_sdk/src/libraries/nacl_io/fifo_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_FIFO_PACKET_H_
+#define LIBRARIES_NACL_IO_FIFO_PACKET_H_
+
+#include <string.h>
+
+#include <list>
+#include <vector>
+
+#include "nacl_io/fifo_interface.h"
+#include "ppapi/c/pp_resource.h"
+
+#include "sdk_util/macros.h"
+
+namespace nacl_io {
+
+struct Packet {
+  Packet(const void *buffer, size_t len, PP_Resource addr)
+      : addr_(addr),
+        buffer_(len) {
+    memcpy(buffer_.data(), buffer, len);
+  }
+
+  PP_Resource addr_;
+  std::vector<char> buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(Packet);
+};
+
+
+// FIFOPacket
+//
+// A FIFOPackiet is linked list of packets.  Data is stored and returned
+// in packet size increments.  FIFOPacket signals EMPTY where there are
+// no packets, and FULL when the total bytes of all packets meets or
+// exceeds the max size hint.
+class  FIFOPacket : public FIFOInterface {
+ public:
+  explicit FIFOPacket(size_t size);
+  virtual ~FIFOPacket();
+
+  virtual bool IsEmpty();
+  virtual bool IsFull();
+  virtual bool Resize(size_t len);
+
+  size_t ReadAvailable();
+  size_t WriteAvailable();
+
+  // Return a pointer to the top packet without releasing ownership.
+  Packet* PeekPacket();
+
+  // Relinquish top packet, and remove it from the FIFO.
+  Packet* ReadPacket();
+
+  // Take ownership of packet and place it in the FIFO.
+  void WritePacket(Packet* packet);
+
+ private:
+  std::list<Packet*> packets_;
+  uint32_t max_bytes_;
+  uint32_t cur_bytes_;
+
+  DISALLOW_COPY_AND_ASSIGN(FIFOPacket);
+};
+
+}  // namespace nacl_io
+
+#endif  // LIBRARIES_NACL_IO_FIFO_PACKET_H_