1 // Boost.Signals library 2 3 // Copyright Douglas Gregor 2001-2004. Use, modification and 4 // distribution is subject to the Boost Software License, Version 5 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at 6 // http://www.boost.org/LICENSE_1_0.txt) 7 8 // For more information, see http://www.boost.org 9 10 #define BOOST_SIGNALS_SOURCE 11 12 #include <boost/signals/detail/signal_base.hpp> 13 #include <cassert> 14 15 namespace boost { 16 namespace BOOST_SIGNALS_NAMESPACE { 17 namespace detail { signal_base_impl(const compare_type & comp,const any & combiner)18 signal_base_impl::signal_base_impl(const compare_type& comp, 19 const any& combiner) 20 : call_depth(0), 21 slots_(comp), 22 combiner_(combiner) 23 { 24 flags.delayed_disconnect = false; 25 flags.clearing = false; 26 } 27 ~signal_base_impl()28 signal_base_impl::~signal_base_impl() 29 { 30 // Set the "clearing" flag to ignore extraneous disconnect requests, 31 // because all slots will be disconnected on destruction anyway. 32 flags.clearing = true; 33 } 34 disconnect_all_slots()35 void signal_base_impl::disconnect_all_slots() 36 { 37 // Do nothing if we're already clearing the slot list 38 if (flags.clearing) 39 return; 40 41 if (call_depth == 0) { 42 // Clearing the slot list will disconnect all slots automatically 43 temporarily_set_clearing set_clearing(this); 44 slots_.clear(); 45 } 46 else { 47 // We can't actually remove elements from the slot list because there 48 // are still iterators into the slot list that must not be 49 // invalidated by this operation. So just disconnect each slot 50 // without removing it from the slot list. When the call depth does 51 // reach zero, the call list will be cleared. 52 flags.delayed_disconnect = true; 53 temporarily_set_clearing set_clearing(this); 54 for (iterator i = slots_.begin(); i != slots_.end(); ++i) { 55 i->first.disconnect(); 56 } 57 } 58 } 59 60 connection 61 signal_base_impl:: connect_slot(const any & slot_,const stored_group & name,shared_ptr<slot_base::data_t> data,connect_position at)62 connect_slot(const any& slot_, 63 const stored_group& name, 64 shared_ptr<slot_base::data_t> data, 65 connect_position at) 66 { 67 // Transfer the burden of ownership to a local, scoped 68 // connection. 69 data->watch_bound_objects.set_controlling(false); 70 scoped_connection safe_connection(data->watch_bound_objects); 71 72 // Allocate storage for an iterator that will hold the point of 73 // insertion of the slot into the list. This is used to later remove 74 // the slot when it is disconnected. 75 std::auto_ptr<iterator> saved_iter(new iterator); 76 77 // Add the slot to the list. 78 iterator pos = 79 slots_.insert(name, data->watch_bound_objects, slot_, at); 80 81 // The assignment operation here absolutely must not throw, which 82 // intuitively makes sense (because any container's insert method 83 // becomes impossible to use in an exception-safe manner without this 84 // assumption), but doesn't appear to be mentioned in the standard. 85 *saved_iter = pos; 86 87 // Fill out the connection object appropriately. None of these 88 // operations can throw 89 data->watch_bound_objects.get_connection()->signal = this; 90 data->watch_bound_objects.get_connection()->signal_data = 91 saved_iter.release(); 92 data->watch_bound_objects.get_connection()->signal_disconnect = 93 &signal_base_impl::slot_disconnected; 94 95 // Make the copy of the connection in the list disconnect when it is 96 // destroyed. The local, scoped connection is then released 97 // because ownership has been transferred. 98 pos->first.set_controlling(); 99 return safe_connection.release(); 100 } 101 empty() const102 bool signal_base_impl::empty() const 103 { 104 // Disconnected slots may still be in the list of slots if 105 // a) this is called while slots are being invoked (call_depth > 0) 106 // b) an exception was thrown in remove_disconnected_slots 107 for (iterator i = slots_.begin(); i != slots_.end(); ++i) { 108 if (i->first.connected()) 109 return false; 110 } 111 112 return true; 113 } 114 num_slots() const115 std::size_t signal_base_impl::num_slots() const 116 { 117 // Disconnected slots may still be in the list of slots if 118 // a) this is called while slots are being invoked (call_depth > 0) 119 // b) an exception was thrown in remove_disconnected_slots 120 std::size_t count = 0; 121 for (iterator i = slots_.begin(); i != slots_.end(); ++i) { 122 if (i->first.connected()) 123 ++count; 124 } 125 return count; 126 } 127 disconnect(const stored_group & group)128 void signal_base_impl::disconnect(const stored_group& group) 129 { slots_.disconnect(group); } 130 slot_disconnected(void * obj,void * data)131 void signal_base_impl::slot_disconnected(void* obj, void* data) 132 { 133 signal_base_impl* self = reinterpret_cast<signal_base_impl*>(obj); 134 135 // We won't need the slot iterator after this 136 std::auto_ptr<iterator> slot(reinterpret_cast<iterator*>(data)); 137 138 // If we're flags.clearing, we don't bother updating the list of slots 139 if (!self->flags.clearing) { 140 // If we're in a call, note the fact that a slot has been deleted so 141 // we can come back later to remove the iterator 142 if (self->call_depth > 0) { 143 self->flags.delayed_disconnect = true; 144 } 145 else { 146 // Just remove the slot now, it's safe 147 self->slots_.erase(*slot); 148 } 149 } 150 } 151 remove_disconnected_slots() const152 void signal_base_impl::remove_disconnected_slots() const 153 { slots_.remove_disconnected_slots(); } 154 155 call_notification:: call_notification(const shared_ptr<signal_base_impl> & b)156 call_notification(const shared_ptr<signal_base_impl>& b) : 157 impl(b) 158 { 159 // A call will be made, so increment the call depth as a notification 160 impl->call_depth++; 161 } 162 ~call_notification()163 call_notification::~call_notification() 164 { 165 impl->call_depth--; 166 167 // If the call depth is zero and we have some slots that have been 168 // disconnected during the calls, remove those slots from the list 169 if (impl->call_depth == 0 && 170 impl->flags.delayed_disconnect) { 171 impl->remove_disconnected_slots(); 172 impl->flags.delayed_disconnect = false; 173 } 174 } 175 signal_base(const compare_type & comp,const any & combiner)176 signal_base::signal_base(const compare_type& comp, const any& combiner) 177 : impl() 178 { 179 impl.reset(new signal_base_impl(comp, combiner)); 180 } 181 ~signal_base()182 signal_base::~signal_base() 183 { 184 } 185 186 } // namespace detail 187 } // namespace BOOST_SIGNALS_NAMESPACE 188 } // namespace boost 189 190