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MainLoopBase.h
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1 //===-- MainLoopBase.h ------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef lldb_Host_posix_MainLoopBase_h_
10 #define lldb_Host_posix_MainLoopBase_h_
11 
12 #include "lldb/Utility/IOObject.h"
13 #include "lldb/Utility/Status.h"
14 #include "llvm/Support/ErrorHandling.h"
15 #include <functional>
16 
17 namespace lldb_private {
18 
19 // The purpose of this class is to enable multiplexed processing of data from
20 // different sources without resorting to multi-threading. Clients can register
21 // IOObjects, which will be monitored for readability, and when they become
22 // ready, the specified callback will be invoked. Monitoring for writability is
23 // not supported, but can be easily added if needed.
24 //
25 // The RegisterReadObject function return a handle, which controls the duration
26 // of the monitoring. When this handle is destroyed, the callback is
27 // deregistered.
28 //
29 // This class simply defines the interface common for all platforms, actual
30 // implementations are platform-specific.
31 class MainLoopBase {
32 private:
33  class ReadHandle;
34 
35 public:
37  virtual ~MainLoopBase() {}
38 
39  typedef std::unique_ptr<ReadHandle> ReadHandleUP;
40 
41  typedef std::function<void(MainLoopBase &)> Callback;
42 
43  virtual ReadHandleUP RegisterReadObject(const lldb::IOObjectSP &object_sp,
44  const Callback &callback,
45  Status &error) {
46  llvm_unreachable("Not implemented");
47  }
48 
49  // Waits for registered events and invoke the proper callbacks. Returns when
50  // all callbacks deregister themselves or when someone requests termination.
51  virtual Status Run() { llvm_unreachable("Not implemented"); }
52 
53  // Requests the exit of the Run() function.
54  virtual void RequestTermination() { llvm_unreachable("Not implemented"); }
55 
56 protected:
57  ReadHandleUP CreateReadHandle(const lldb::IOObjectSP &object_sp) {
58  return ReadHandleUP(new ReadHandle(*this, object_sp->GetWaitableHandle()));
59  }
60 
62  llvm_unreachable("Not implemented");
63  }
64 
65 private:
66  class ReadHandle {
67  public:
68  ~ReadHandle() { m_mainloop.UnregisterReadObject(m_handle); }
69 
70  private:
71  ReadHandle(MainLoopBase &mainloop, IOObject::WaitableHandle handle)
72  : m_mainloop(mainloop), m_handle(handle) {}
73 
74  MainLoopBase &m_mainloop;
75  IOObject::WaitableHandle m_handle;
76 
77  friend class MainLoopBase;
78  DISALLOW_COPY_AND_ASSIGN(ReadHandle);
79  };
80 
81 private:
82  DISALLOW_COPY_AND_ASSIGN(MainLoopBase);
83 };
84 
85 } // namespace lldb_private
86 
87 #endif // lldb_Host_posix_MainLoopBase_h_
ReadHandleUP CreateReadHandle(const lldb::IOObjectSP &object_sp)
Definition: MainLoopBase.h:57
Enumerations for broadcasting.
Definition: SBLaunchInfo.h:14
virtual void UnregisterReadObject(IOObject::WaitableHandle handle)
Definition: MainLoopBase.h:61
std::function< void(MainLoopBase &)> Callback
Definition: MainLoopBase.h:41
virtual ReadHandleUP RegisterReadObject(const lldb::IOObjectSP &object_sp, const Callback &callback, Status &error)
Definition: MainLoopBase.h:43
std::unique_ptr< ReadHandle > ReadHandleUP
Definition: MainLoopBase.h:39
virtual Status Run()
Definition: MainLoopBase.h:51
virtual void RequestTermination()
Definition: MainLoopBase.h:54
An error handling class.
Definition: Status.h:44