GRPC Core  18.0.0
work_serializer.h
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1 /*
2  *
3  * Copyright 2019 gRPC authors.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
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14  * See the License for the specific language governing permissions and
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17  */
18 
20 
21 #include <functional>
22 
23 #include "absl/synchronization/mutex.h"
24 
32 
33 #ifndef GRPC_CORE_LIB_IOMGR_WORK_SERIALIZER_H
34 #define GRPC_CORE_LIB_IOMGR_WORK_SERIALIZER_H
35 
36 namespace grpc_core {
37 
38 // WorkSerializer is a mechanism to schedule callbacks in a synchronized manner.
39 // All callbacks scheduled on a WorkSerializer instance will be executed
40 // serially in a borrowed thread. The API provides a FIFO guarantee to the
41 // execution of callbacks scheduled on the thread.
42 // When a thread calls Run() with a callback, the thread is considered borrowed.
43 // The callback might run inline, or it might run asynchronously in a different
44 // thread that is already inside of Run(). If the callback runs directly inline,
45 // other callbacks from other threads might also be executed before Run()
46 // returns. Since an arbitrary set of callbacks might be executed when Run() is
47 // called, generally no locks should be held while calling Run().
48 class ABSL_LOCKABLE WorkSerializer {
49  public:
51 
52  ~WorkSerializer();
53 
54  // Runs a given callback.
55  //
56  // If you want to use clang thread annotation to make sure that callback is
57  // called by WorkSerializer only, you need to add the annotation to both the
58  // lambda function given to Run and the actual callback function like;
59  //
60  // void run_callback() {
61  // work_serializer.Run(
62  // []() ABSL_EXCLUSIVE_LOCKS_REQUIRED(work_serializer) {
63  // callback();
64  // }, DEBUG_LOCATION);
65  // }
66  // void callback() ABSL_EXCLUSIVE_LOCKS_REQUIRED(work_serializer) { ... }
67  //
68  // TODO(yashkt): Replace grpc_core::DebugLocation with absl::SourceLocation
69  // once we can start using it directly.
70  void Run(std::function<void()> callback,
71  const grpc_core::DebugLocation& location);
72 
73  private:
74  class WorkSerializerImpl;
75 
77 };
78 
79 } /* namespace grpc_core */
80 
81 #endif /* GRPC_CORE_LIB_IOMGR_WORK_SERIALIZER_H */
Definition: debug_location.h:31
Definition: work_serializer.cc:36
Definition: work_serializer.h:48
Round Robin Policy.
Definition: backend_metric.cc:26
std::unique_ptr< T, Deleter > OrphanablePtr
Definition: orphanable.h:67