1 //===----------------------------------------------------------------------===//
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 #include <__assert>
10 #include <__thread/id.h>
11 #include <__utility/exception_guard.h>
12 #include <limits>
13 #include <mutex>
14 
15 #include "include/atomic_support.h"
16 
17 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
18 #  pragma comment(lib, "pthread")
19 #endif
20 
21 _LIBCPP_PUSH_MACROS
22 #include <__undef_macros>
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 // ~mutex is defined elsewhere
27 
28 void mutex::lock() {
29   int ec = __libcpp_mutex_lock(&__m_);
30   if (ec)
31     __throw_system_error(ec, "mutex lock failed");
32 }
33 
34 bool mutex::try_lock() noexcept { return __libcpp_mutex_trylock(&__m_); }
35 
36 void mutex::unlock() noexcept {
37   int ec = __libcpp_mutex_unlock(&__m_);
38   (void)ec;
39   _LIBCPP_ASSERT_VALID_EXTERNAL_API_CALL(
40       ec == 0, "call to mutex::unlock failed. A possible reason is that the mutex wasn't locked");
41 }
42 
43 // recursive_mutex
44 
45 recursive_mutex::recursive_mutex() {
46   int ec = __libcpp_recursive_mutex_init(&__m_);
47   if (ec)
48     __throw_system_error(ec, "recursive_mutex constructor failed");
49 }
50 
51 recursive_mutex::~recursive_mutex() {
52   int e = __libcpp_recursive_mutex_destroy(&__m_);
53   (void)e;
54   _LIBCPP_ASSERT_VALID_EXTERNAL_API_CALL(e == 0, "call to ~recursive_mutex() failed");
55 }
56 
57 void recursive_mutex::lock() {
58   int ec = __libcpp_recursive_mutex_lock(&__m_);
59   if (ec)
60     __throw_system_error(ec, "recursive_mutex lock failed");
61 }
62 
63 void recursive_mutex::unlock() noexcept {
64   int e = __libcpp_recursive_mutex_unlock(&__m_);
65   (void)e;
66   _LIBCPP_ASSERT_VALID_EXTERNAL_API_CALL(
67       e == 0, "call to recursive_mutex::unlock() failed. A possible reason is that the mutex wasn't locked");
68 }
69 
70 bool recursive_mutex::try_lock() noexcept { return __libcpp_recursive_mutex_trylock(&__m_); }
71 
72 // timed_mutex
73 
74 timed_mutex::timed_mutex() : __locked_(false) {}
75 
76 timed_mutex::~timed_mutex() { lock_guard<mutex> _(__m_); }
77 
78 void timed_mutex::lock() {
79   unique_lock<mutex> lk(__m_);
80   while (__locked_)
81     __cv_.wait(lk);
82   __locked_ = true;
83 }
84 
85 bool timed_mutex::try_lock() noexcept {
86   unique_lock<mutex> lk(__m_, try_to_lock);
87   if (lk.owns_lock() && !__locked_) {
88     __locked_ = true;
89     return true;
90   }
91   return false;
92 }
93 
94 void timed_mutex::unlock() noexcept {
95   lock_guard<mutex> _(__m_);
96   __locked_ = false;
97   __cv_.notify_one();
98 }
99 
100 // recursive_timed_mutex
101 
102 recursive_timed_mutex::recursive_timed_mutex() : __count_(0), __id_{} {}
103 
104 recursive_timed_mutex::~recursive_timed_mutex() { lock_guard<mutex> _(__m_); }
105 
106 void recursive_timed_mutex::lock() {
107   __thread_id id = this_thread::get_id();
108   unique_lock<mutex> lk(__m_);
109   if (id == __id_) {
110     if (__count_ == numeric_limits<size_t>::max())
111       __throw_system_error(EAGAIN, "recursive_timed_mutex lock limit reached");
112     ++__count_;
113     return;
114   }
115   while (__count_ != 0)
116     __cv_.wait(lk);
117   __count_ = 1;
118   __id_    = id;
119 }
120 
121 bool recursive_timed_mutex::try_lock() noexcept {
122   __thread_id id = this_thread::get_id();
123   unique_lock<mutex> lk(__m_, try_to_lock);
124   if (lk.owns_lock() && (__count_ == 0 || id == __id_)) {
125     if (__count_ == numeric_limits<size_t>::max())
126       return false;
127     ++__count_;
128     __id_ = id;
129     return true;
130   }
131   return false;
132 }
133 
134 void recursive_timed_mutex::unlock() noexcept {
135   unique_lock<mutex> lk(__m_);
136   if (--__count_ == 0) {
137     __id_.__reset();
138     lk.unlock();
139     __cv_.notify_one();
140   }
141 }
142 
143 _LIBCPP_END_NAMESPACE_STD
144 
145 _LIBCPP_POP_MACROS
146