xref: /aosp_15_r20/external/webrtc/third_party/abseil-cpp/absl/log/log_sink.h (revision d9f758449e529ab9291ac668be2861e7a55c2422)
1 // Copyright 2022 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of 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,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 //
15 // -----------------------------------------------------------------------------
16 // File: log/log_sink.h
17 // -----------------------------------------------------------------------------
18 //
19 // This header declares the interface class `absl::LogSink`.
20 
21 #ifndef ABSL_LOG_LOG_SINK_H_
22 #define ABSL_LOG_LOG_SINK_H_
23 
24 #include "absl/base/config.h"
25 #include "absl/log/log_entry.h"
26 
27 namespace absl {
28 ABSL_NAMESPACE_BEGIN
29 
30 // absl::LogSink
31 //
32 // `absl::LogSink` is an interface which can be extended to intercept and
33 // process particular messages (with `LOG.ToSinkOnly()` or
34 // `LOG.ToSinkAlso()`) or all messages (if registered with
35 // `absl::AddLogSink`).  Implementations must be thread-safe, and should take
36 // care not to take any locks that might be held by the `LOG` caller.
37 class LogSink {
38  public:
39   virtual ~LogSink() = default;
40 
41   // LogSink::Send()
42   //
43   // `Send` is called synchronously during the log statement.
44   //
45   // It is safe to use `LOG` within an implementation of `Send`.  `ToSinkOnly`
46   // and `ToSinkAlso` are safe in general but can be used to create an infinite
47   // loop if you try.
48   virtual void Send(const absl::LogEntry& entry) = 0;
49 
50   // LogSink::Flush()
51   //
52   // Sinks that buffer messages should override this method to flush the buffer
53   // and return.
Flush()54   virtual void Flush() {}
55 
56  private:
57   // https://lld.llvm.org/missingkeyfunction.html#missing-key-function
58   virtual void KeyFunction() const final;  // NOLINT(readability/inheritance)
59 };
60 
61 ABSL_NAMESPACE_END
62 }  // namespace absl
63 
64 #endif  // ABSL_LOG_LOG_SINK_H_
65