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[binutils.git] / gold / gold-threads.h
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1 // gold-threads.h -- thread support for gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 // gold can be configured to support threads. If threads are
24 // supported, the user can specify at runtime whether or not to
25 // support them. This provides an interface to manage locking
26 // accordingly.
28 // Lock
29 // A simple lock class.
31 #ifndef GOLD_THREADS_H
32 #define GOLD_THREADS_H
34 namespace gold
37 class Condvar;
39 // The interface for the implementation of a Lock.
41 class Lock_impl
43 public:
44 Lock_impl()
45 { }
47 virtual
48 ~Lock_impl()
49 { }
51 virtual void
52 acquire() = 0;
54 virtual void
55 release() = 0;
58 // A simple lock class.
60 class Lock
62 public:
63 Lock();
65 ~Lock();
67 // Acquire the lock.
68 void
69 acquire()
70 { this->lock_->acquire(); }
72 // Release the lock.
73 void
74 release()
75 { this->lock_->release(); }
77 private:
78 // This class can not be copied.
79 Lock(const Lock&);
80 Lock& operator=(const Lock&);
82 friend class Condvar;
83 Lock_impl*
84 get_impl() const
85 { return this->lock_; }
87 Lock_impl* lock_;
90 // RAII for Lock.
92 class Hold_lock
94 public:
95 Hold_lock(Lock& lock)
96 : lock_(lock)
97 { this->lock_.acquire(); }
99 ~Hold_lock()
100 { this->lock_.release(); }
102 private:
103 // This class can not be copied.
104 Hold_lock(const Hold_lock&);
105 Hold_lock& operator=(const Hold_lock&);
107 Lock& lock_;
110 // The interface for the implementation of a condition variable.
112 class Condvar_impl
114 public:
115 Condvar_impl()
118 virtual
119 ~Condvar_impl()
122 virtual void
123 wait(Lock_impl*) = 0;
125 virtual void
126 signal() = 0;
128 virtual void
129 broadcast() = 0;
132 // A simple condition variable class. It is always associated with a
133 // specific lock.
135 class Condvar
137 public:
138 Condvar(Lock& lock);
139 ~Condvar();
141 // Wait for the condition variable to be signalled. This should
142 // only be called when the lock is held.
143 void
144 wait()
145 { this->condvar_->wait(this->lock_.get_impl()); }
147 // Signal the condition variable--wake up at least one thread
148 // waiting on the condition variable. This should only be called
149 // when the lock is held.
150 void
151 signal()
152 { this->condvar_->signal(); }
154 // Broadcast the condition variable--wake up all threads waiting on
155 // the condition variable. This should only be called when the lock
156 // is held.
157 void
158 broadcast()
159 { this->condvar_->broadcast(); }
161 private:
162 // This class can not be copied.
163 Condvar(const Condvar&);
164 Condvar& operator=(const Condvar&);
166 Lock& lock_;
167 Condvar_impl* condvar_;
170 } // End namespace gold.
172 #endif // !defined(GOLD_THREADS_H)