1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef NET_QUIC_PLATFORM_IMPL_QUIC_EPOLL_CLOCK_H_
6 #define NET_QUIC_PLATFORM_IMPL_QUIC_EPOLL_CLOCK_H_
7 
8 #include "base/compiler_specific.h"
9 #include "base/macros.h"
10 #include "net/third_party/quiche/src/quic/core/quic_clock.h"
11 #include "net/third_party/quiche/src/quic/core/quic_time.h"
12 
13 namespace epoll_server {
14 
15 class SimpleEpollServer;
16 
17 }  // namespace epoll_server
18 
19 namespace quic {
20 
21 // Clock to efficiently retrieve an approximately accurate time from an
22 // net::EpollServer.
23 class QuicEpollClock : public QuicClock {
24  public:
25   explicit QuicEpollClock(epoll_server::SimpleEpollServer* epoll_server);
26   ~QuicEpollClock() override;
27 
28   // Returns the approximate current time as a QuicTime object.
29   QuicTime ApproximateNow() const override;
30 
31   // Returns the current time as a QuicTime object.
32   // Note: this uses significant resources, please use only if needed.
33   QuicTime Now() const override;
34 
35   // Returns the current time as a QuicWallTime object.
36   // Note: this uses significant resources, please use only if needed.
37   QuicWallTime WallNow() const override;
38 
39   // Override to do less work in this implementation.  The epoll clock is
40   // already based on system (unix epoch) time, no conversion required.
41   QuicTime ConvertWallTimeToQuicTime(
42       const QuicWallTime& walltime) const override;
43 
44  protected:
45   epoll_server::SimpleEpollServer* epoll_server_;
46   // Largest time returned from Now() so far.
47   mutable QuicTime largest_time_;
48 
49  private:
50   DISALLOW_COPY_AND_ASSIGN(QuicEpollClock);
51 };
52 
53 }  // namespace quic
54 
55 #endif  // NET_QUIC_PLATFORM_IMPL_QUIC_EPOLL_CLOCK_H_
56