1//===-- ProcessRunLock.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_PROCESSRUNLOCK_H
10#define LLDB_HOST_PROCESSRUNLOCK_H
11
12#include <cstdint>
13#include <ctime>
14
15#include "lldb/lldb-defines.h"
16
17/// Enumerations for broadcasting.
18namespace lldb_private {
19
20/// \class ProcessRunLock ProcessRunLock.h "lldb/Host/ProcessRunLock.h"
21/// A class used to prevent the process from starting while other
22/// threads are accessing its data, and prevent access to its data while it is
23/// running.
24
25class ProcessRunLock {
26public:
27  ProcessRunLock();
28  ~ProcessRunLock();
29
30  bool ReadTryLock();
31  bool ReadUnlock();
32  bool SetRunning();
33  bool TrySetRunning();
34  bool SetStopped();
35
36  class ProcessRunLocker {
37  public:
38    ProcessRunLocker() = default;
39
40    ~ProcessRunLocker() { Unlock(); }
41
42    // Try to lock the read lock, but only do so if there are no writers.
43    bool TryLock(ProcessRunLock *lock) {
44      if (m_lock) {
45        if (m_lock == lock)
46          return true; // We already have this lock locked
47        else
48          Unlock();
49      }
50      if (lock) {
51        if (lock->ReadTryLock()) {
52          m_lock = lock;
53          return true;
54        }
55      }
56      return false;
57    }
58
59  protected:
60    void Unlock() {
61      if (m_lock) {
62        m_lock->ReadUnlock();
63        m_lock = nullptr;
64      }
65    }
66
67    ProcessRunLock *m_lock = nullptr;
68
69  private:
70    ProcessRunLocker(const ProcessRunLocker &) = delete;
71    const ProcessRunLocker &operator=(const ProcessRunLocker &) = delete;
72  };
73
74protected:
75  lldb::rwlock_t m_rwlock;
76  bool m_running = false;
77
78private:
79  ProcessRunLock(const ProcessRunLock &) = delete;
80  const ProcessRunLock &operator=(const ProcessRunLock &) = delete;
81};
82
83} // namespace lldb_private
84
85#endif // LLDB_HOST_PROCESSRUNLOCK_H
86