Botan::RWLock Class Reference

#include <rwlock.h>

Public Member Functions
void	lock ()
void	lock_shared ()
	RWLock ()
void	unlock ()
void	unlock_shared ()

Detailed Description

A read-write lock. Writers are favored.

Definition at line 19 of file rwlock.h.

Constructor & Destructor Documentation

RWLock()

Botan::RWLock::RWLock

(

)

Definition at line 11 of file rwlock.cpp.

: m_state(0) {}

Member Function Documentation

lock()

void Botan::RWLock::lock

(

)

Definition at line 13 of file rwlock.cpp.

                  {
   std::unique_lock<std::mutex> lock(m_mutex);
   while(m_state & is_writing) {
      m_gate1.wait(lock);
   }
   m_state |= is_writing;
   while(m_state & readers_mask) {
      m_gate2.wait(lock);
   }
}

References lock().

Referenced by lock(), lock_shared(), unlock(), and unlock_shared().

lock_shared()

void Botan::RWLock::lock_shared

(

)

Definition at line 30 of file rwlock.cpp.

                         {
   std::unique_lock<std::mutex> lock(m_mutex);
   while((m_state & is_writing) || (m_state & readers_mask) == readers_mask) {
      m_gate1.wait(lock);
   }
   const uint32_t num_readers = (m_state & readers_mask) + 1;
   m_state &= ~readers_mask;
   m_state |= num_readers;
}

References lock().

unlock()

void Botan::RWLock::unlock

(

)

Definition at line 24 of file rwlock.cpp.

                    {
   std::unique_lock<std::mutex> lock(m_mutex);
   m_state = 0;
   m_gate1.notify_all();
}

References lock().

unlock_shared()

void Botan::RWLock::unlock_shared

(

)

Definition at line 40 of file rwlock.cpp.

                           {
   std::unique_lock<std::mutex> lock(m_mutex);
   const uint32_t num_readers = (m_state & readers_mask) - 1;
   m_state &= ~readers_mask;
   m_state |= num_readers;
   if(m_state & is_writing) {
      if(num_readers == 0) {
         m_gate2.notify_one();
      }
   } else {
      if(num_readers == readers_mask - 1) {
         m_gate1.notify_one();
      }
   }
}

References lock().

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The documentation for this class was generated from the following files:

• src/lib/utils/thread_utils/rwlock.h
• src/lib/utils/thread_utils/rwlock.cpp