1 //===-- LockFileBase.h ------------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef liblldb_Host_LockFileBase_h_
11 #define liblldb_Host_LockFileBase_h_
12 
13 #include "lldb/Utility/Status.h"
14 
15 #include <functional>
16 
17 namespace lldb_private {
18 
19 class LockFileBase {
20 public:
21   virtual ~LockFileBase() = default;
22 
23   bool IsLocked() const;
24 
25   Status WriteLock(const uint64_t start, const uint64_t len);
26   Status TryWriteLock(const uint64_t start, const uint64_t len);
27 
28   Status ReadLock(const uint64_t start, const uint64_t len);
29   Status TryReadLock(const uint64_t start, const uint64_t len);
30 
31   Status Unlock();
32 
33 protected:
34   using Locker = std::function<Status(const uint64_t, const uint64_t)>;
35 
36   LockFileBase(int fd);
37 
38   virtual bool IsValidFile() const;
39 
40   virtual Status DoWriteLock(const uint64_t start, const uint64_t len) = 0;
41   virtual Status DoTryWriteLock(const uint64_t start, const uint64_t len) = 0;
42 
43   virtual Status DoReadLock(const uint64_t start, const uint64_t len) = 0;
44   virtual Status DoTryReadLock(const uint64_t start, const uint64_t len) = 0;
45 
46   virtual Status DoUnlock() = 0;
47 
48   Status DoLock(const Locker &locker, const uint64_t start, const uint64_t len);
49 
50   int m_fd; // not owned.
51   bool m_locked;
52   uint64_t m_start;
53   uint64_t m_len;
54 };
55 }
56 
57 #endif
58