[NaCl SDK] Support non blocking TCP/UDP

native_client_sdk/src/libraries/nacl_io/event_emitter_pipe.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_PIPE_H_
+#define LIBRARIES_NACL_IO_EVENT_EMITTER_PIPE_H_
+
+#include <poll.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "nacl_io/event_emitter.h"
+#include "nacl_io/fifo_char.h"
+
+#include "sdk_util/auto_lock.h"
+
+namespace nacl_io {
+
+class EventEmitterPipe;
+typedef sdk_util::ScopedRef<EventEmitterPipe> ScopedEmitterPipe;
+
+class EventEmitterPipe : public EventEmitter {
+ public:
+  EventEmitterPipe(size_t size)
+      : fifo_(NULL),
+        event_status_(0) {
+    size = std::max<size_t>(1, size);
+    fifo_ = new FIFOChar(size);
+
+    UpdateStatus_Locked();
+  }
+
+  ~EventEmitterPipe() {
+    delete fifo_;
+  }
+
+  virtual uint32_t GetEventStatus() {
+    return event_status_;
+  }
+
+  size_t Read_Locked(char* data, size_t len) {
+    size_t out_len = fifo_->Read(data, len);
+
+    UpdateStatus_Locked();
+    return out_len;
+  }
+
+  size_t Write_Locked(const char* data, size_t len) {
+    size_t out_len = fifo_->Write(data, len);
+
+    UpdateStatus_Locked();
+    return out_len;
+  }
+
+ protected:
+  void UpdateStatus_Locked() {
+    uint32_t old_status = event_status_;
+
+    if (!fifo_->IsEmpty()) {
+      event_status_ |= POLLIN;
+    } else {
+      event_status_ &= ~POLLIN;
+    }
+
+    if (!fifo_->IsFull()) {
+      event_status_ |= POLLOUT;
+    } else {
+      event_status_ &= ~POLLOUT;
+    }
+
+    uint32_t raise_status = event_status_ & ~old_status;
+    if (raise_status)
+      RaiseEvents_Locked(raise_status);
+  }
+
+  FIFOChar* fifo_;
+  uint32_t event_status_;
+};
+
+}  // namespace nacl_io
+
+#endif  // LIBRARIES_NACL_IO_EVENT_EMITTER_PIPE_H_
+