xref: /aosp_15_r20/external/pigweed/pw_chrono/public/pw_chrono/virtual_clock.h (revision 61c4878ac05f98d0ceed94b57d316916de578985)
1 // Copyright 2024 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14 #pragma once
15 
16 namespace pw::chrono {
17 
18 /// An abstract interface representing a Clock.
19 ///
20 /// This interface allows decoupling code that uses time from the code that
21 /// creates a point in time. You can use this to your advantage by injecting
22 /// Clocks into interfaces rather than having implementations call
23 /// `SystemClock::now()` directly. However, this comes at a cost of a vtable per
24 /// implementation and more importantly passing and maintaining references to
25 /// the VirtualClock for all of the users.
26 ///
27 /// This interface is thread and IRQ safe.
28 template <typename Clock>
29 class VirtualClock {
30  public:
31   virtual ~VirtualClock() = default;
32 
33   /// Returns the current time.
34   virtual typename Clock::time_point now() = 0;
35 };
36 
37 }  // namespace pw::chrono
38