Changeset beeff61e for libcfa/src/concurrency/future.hfa
- Timestamp:
- May 1, 2023, 4:00:06 PM (15 months ago)
- Branches:
- ADT, ast-experimental, master
- Children:
- 73bf7ddc
- Parents:
- bb7422a
- File:
-
- 1 edited
Legend:
- Unmodified
- Added
- Removed
-
libcfa/src/concurrency/future.hfa
rbb7422a rbeeff61e 19 19 #include "monitor.hfa" 20 20 #include "select.hfa" 21 #include "locks.hfa" 21 22 22 23 //---------------------------------------------------------------------------- … … 26 27 // future_t is lockfree and uses atomics which aren't needed given we use locks here 27 28 forall( T ) { 28 // enum (int){ FUTURE_EMPTY = 0, FUTURE_FULFILLED = 1 }; // Enums seem to be broken so feel free to add this back afterwards29 // enum { FUTURE_EMPTY = 0, FUTURE_FULFILLED = 1 }; // Enums seem to be broken so feel free to add this back afterwards 29 30 30 31 // temporary enum replacement … … 44 45 }; 45 46 46 // C_TODO: perhaps allow exceptions to be inserted like uC++?47 48 47 static inline { 49 48 … … 82 81 void _internal_flush( future(T) & this ) with(this) { 83 82 while( ! waiters`isEmpty ) { 83 if ( !__handle_waituntil_OR( waiters ) ) // handle special waituntil OR case 84 break; // if handle_OR returns false then waiters is empty so break 84 85 select_node &s = try_pop_front( waiters ); 85 86 86 if ( s. race_flag== 0p )87 if ( s.clause_status == 0p ) 87 88 // poke in result so that woken threads do not need to reacquire any locks 88 // *(((future_node(T) &)s).my_result) = result;89 89 copy_T( result, *(((future_node(T) &)s).my_result) ); 90 else if ( ! install_select_winner( s, &this ) ) continue;90 else if ( !__make_select_node_available( s ) ) continue; 91 91 92 92 // only unpark if future is not selected … … 97 97 98 98 // Fulfil the future, returns whether or not someone was unblocked 99 bool fulfil( future(T) & this, T &val ) with(this) {99 bool fulfil( future(T) & this, T val ) with(this) { 100 100 lock( lock ); 101 101 if( state != FUTURE_EMPTY ) … … 153 153 } 154 154 155 void * register_select( future(T) & this, select_node & s ) with(this) { 156 lock( lock ); 157 158 // future not ready -> insert select node and return 0p 155 bool register_select( future(T) & this, select_node & s ) with(this) { 156 lock( lock ); 157 158 // check if we can complete operation. If so race to establish winner in special OR case 159 if ( !s.park_counter && state != FUTURE_EMPTY ) { 160 if ( !__make_select_node_available( s ) ) { // we didn't win the race so give up on registering 161 unlock( lock ); 162 return false; 163 } 164 } 165 166 // future not ready -> insert select node and return 159 167 if( state == FUTURE_EMPTY ) { 160 168 insert_last( waiters, s ); 161 169 unlock( lock ); 162 return 0p; 163 } 164 165 // future ready and we won race to install it as the select winner return 1p 166 if ( install_select_winner( s, &this ) ) { 167 unlock( lock ); 168 return 1p; 169 } 170 171 unlock( lock ); 172 // future ready and we lost race to install it as the select winner 173 return 2p; 174 } 175 176 void unregister_select( future(T) & this, select_node & s ) with(this) { 170 return false; 171 } 172 173 __make_select_node_available( s ); 174 unlock( lock ); 175 return true; 176 } 177 178 bool unregister_select( future(T) & this, select_node & s ) with(this) { 179 if ( ! s`isListed ) return false; 177 180 lock( lock ); 178 181 if ( s`isListed ) remove( s ); 179 182 unlock( lock ); 183 return false; 180 184 } 181 185 186 bool on_selected( future(T) & this, select_node & node ) { return true; } 182 187 } 183 188 } … … 186 191 // These futures below do not support select statements so they may not be as useful as 'future' 187 192 // however the 'single_future' is cheap and cheerful and is most likely more performant than 'future' 188 // since it uses raw atomics and no locks afaik193 // since it uses raw atomics and no locks 189 194 // 190 195 // As far as 'multi_future' goes I can't see many use cases as it will be less performant than 'future'
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