ceph/src/boost/libs/fiber/src/recursive_mutex.cpp

   1
   2 //          Copyright Oliver Kowalke 2013.
   3 // Distributed under the Boost Software License, Version 1.0.
   4 //    (See accompanying file LICENSE_1_0.txt or copy at
   5 //          http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #include "boost/fiber/recursive_mutex.hpp"
   8
   9 #include <algorithm>
  10 #include <functional>
  11
  12 #include "boost/fiber/exceptions.hpp"
  13 #include "boost/fiber/scheduler.hpp"
  14
  15 #ifdef BOOST_HAS_ABI_HEADERS
  16 #  include BOOST_ABI_PREFIX
  17 #endif
  18
  19 namespace boost {
  20 namespace fibers {
  21
  22 void
  23 recursive_mutex::lock() {
  24     context * ctx = context::active();
  25     // store this fiber in order to be notified later
  26     detail::spinlock_lock lk( wait_queue_splk_);
  27     if ( ctx == owner_) {
  28         ++count_;
  29         return;
  30     } else if ( nullptr == owner_) {
  31         owner_ = ctx;
  32         count_ = 1;
  33         return;
  34     }
  35     BOOST_ASSERT( ! ctx->wait_is_linked() );
  36     ctx->wait_link( wait_queue_);
  37     // suspend this fiber
  38     ctx->suspend( lk);
  39     BOOST_ASSERT( ! ctx->wait_is_linked() );
  40 }
  41
  42 bool
  43 recursive_mutex::try_lock() noexcept {
  44     context * ctx = context::active();
  45     detail::spinlock_lock lk( wait_queue_splk_);
  46     if ( nullptr == owner_) {
  47         owner_ = ctx;
  48         count_ = 1;
  49     } else if ( ctx == owner_) {
  50         ++count_;
  51     }
  52     lk.unlock();
  53     // let other fiber release the lock
  54     context::active()->yield();
  55     return ctx == owner_;
  56 }
  57
  58 void
  59 recursive_mutex::unlock() {
  60     context * ctx = context::active();
  61     detail::spinlock_lock lk( wait_queue_splk_);
  62     if ( ctx != owner_) {
  63         throw lock_error(
  64                 std::make_error_code( std::errc::operation_not_permitted),
  65                 "boost fiber: no  privilege to perform the operation");
  66     }
  67     if ( 0 == --count_) {
  68         if ( ! wait_queue_.empty() ) {
  69             context * ctx = & wait_queue_.front();
  70             wait_queue_.pop_front();
  71             owner_ = ctx;
  72             count_ = 1;
  73             context::active()->set_ready( ctx);
  74         } else {
  75             owner_ = nullptr;
  76             return;
  77         }
  78     }
  79 }
  80
  81 }}
  82
  83 #ifdef BOOST_HAS_ABI_HEADERS
  84 #  include BOOST_ABI_SUFFIX
  85 #endif