4coder/platform_all/4ed_coroutine.cpp

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/*
* Mr. 4th Dimention - Allen Webster
*
* 19.07.2017
*
* Coroutine implementation from thread+mutex+cv
*
*/
// TOP
typedef u32 Coroutine_State;
enum{
CoroutineState_Dead,
CoroutineState_Active,
CoroutineState_Inactive,
CoroutineState_Waiting,
};
typedef u32 Coroutine_Type;
enum{
CoroutineType_Uninitialized,
CoroutineType_Root,
CoroutineType_Sub,
};
struct Coroutine{
Coroutine_Head head;
Thread thread;
Condition_Variable cv;
struct Coroutine_System *sys;
Coroutine_Function *function;
Coroutine *yield_ctx;
Coroutine_State state;
Coroutine_Type type;
};
struct Coroutine_System{
Mutex lock;
Condition_Variable init_cv;
b32 did_init;
Coroutine *active;
};
#define COROUTINE_INT_SKIP_SLEEP false
internal void
coroutine_internal_pass_control(Coroutine *me, Coroutine *other, Coroutine_State my_new_state, b32 do_sleep_loop = true){
Assert(me->state == CoroutineState_Active);
Assert(me->sys == other->sys);
me->state = my_new_state;
other->state = CoroutineState_Active;
me->sys->active = other;
system_signal_cv(&other->cv, &me->sys->lock);
if (do_sleep_loop){
for (;me->state != CoroutineState_Active;){
system_wait_cv(&me->cv, &me->sys->lock);
}
}
}
internal
PLAT_THREAD_SIG(coroutine_main){
Coroutine *me = (Coroutine*)ptr;
// NOTE(allen): Init handshake
Assert(me->state == CoroutineState_Dead);
system_acquire_lock(&me->sys->lock);
me->sys->did_init = true;
system_signal_cv(&me->sys->init_cv, &me->sys->lock);
for (;;){
// NOTE(allen): Wait until someone wakes us up, then go into our procedure.
for (;me->state != CoroutineState_Active;){
system_wait_cv(&me->cv, &me->sys->lock);
}
Assert(me->type != CoroutineType_Root);
Assert(me->yield_ctx != 0);
Assert(me->function != 0);
me->function(&me->head);
// NOTE(allen): Wake up the caller and set this coroutine back to being dead.
Coroutine *other = me->yield_ctx;
Assert(other != 0);
Assert(other->state == CoroutineState_Waiting);
coroutine_internal_pass_control(me, other, CoroutineState_Dead, COROUTINE_INT_SKIP_SLEEP);
me->function = 0;
}
}
internal void
init_coroutine_system(Coroutine *root, Coroutine_System *sys){
system_init_lock(&sys->lock);
system_init_cv(&sys->init_cv);
sys->active = root;
memset(root, 0, sizeof(*root));
root->sys = sys;
root->state = CoroutineState_Active;
root->type = CoroutineType_Root;
system_init_cv(&root->cv);
2018-05-07 02:47:22 +00:00
system_acquire_lock(&sys->lock);
}
internal void
init_coroutine_sub(Coroutine *co, Coroutine_System *sys){
memset(co, 0, sizeof(*co));
co->sys = sys;
co->state = CoroutineState_Dead;
co->type = CoroutineType_Sub;
system_init_cv(&co->cv);
sys->did_init = false;
system_init_and_launch_thread(&co->thread, coroutine_main, co);
for (;!sys->did_init;){
system_wait_cv(&sys->init_cv, &sys->lock);
}
}
// HACK(allen): I want to bundle this with launch!
internal void
coroutine_set_function(Coroutine *me, Coroutine_Function *function){
Assert(me->state == CoroutineState_Dead);
me->function = function;
}
internal void
coroutine_launch(Coroutine *me, Coroutine *other){
Assert(me->sys == other->sys);
Assert(other->state == CoroutineState_Dead);
Assert(other->function != 0);
other->yield_ctx = me;
coroutine_internal_pass_control(me, other, CoroutineState_Waiting);
}
internal void
coroutine_yield(Coroutine *me){
Coroutine *other = me->yield_ctx;
Assert(other != 0);
Assert(me->sys == other->sys);
Assert(other->state == CoroutineState_Waiting);
coroutine_internal_pass_control(me, other, CoroutineState_Inactive);
}
internal void
coroutine_resume(Coroutine *me, Coroutine *other){
Assert(me->sys == other->sys);
Assert(other->state == CoroutineState_Inactive);
other->yield_ctx = me;
coroutine_internal_pass_control(me, other, CoroutineState_Waiting);
}
////////////////////////////////
struct Coroutine_Alloc_Block{
Coroutine coroutine;
Coroutine_Alloc_Block *next;
};
#define COROUTINE_SLOT_SIZE sizeof(Coroutine_Alloc_Block)
struct Coroutine_System_Auto_Alloc{
Coroutine_System sys;
Coroutine root;
Coroutine_Alloc_Block *head_free_uninit;
Coroutine_Alloc_Block *head_free_inited;
};
internal void
init_coroutine_system(Coroutine_System_Auto_Alloc *sys){
init_coroutine_system(&sys->root, &sys->sys);
sys->head_free_uninit = 0;
sys->head_free_inited = 0;
}
internal void
coroutine_system_provide_memory(Coroutine_System_Auto_Alloc *sys, void *memory, umem size){
memset(memory, 0, size);
Coroutine_Alloc_Block *blocks = (Coroutine_Alloc_Block*)memory;
umem count = (size / sizeof(*blocks));
Coroutine_Alloc_Block *old_head = sys->head_free_uninit;
sys->head_free_uninit = &blocks[0];
Coroutine_Alloc_Block *block = blocks;
for (u32 i = 1; i < count; ++i, ++block){
block->next = block + 1;
}
block->next = old_head;
}
internal Coroutine_Alloc_Block*
coroutine_system_pop(Coroutine_Alloc_Block **head){
Coroutine_Alloc_Block *result = *head;
if (result != 0){
*head = result->next;
}
result->next = 0;
return(result);
}
internal void
coroutine_system_push(Coroutine_Alloc_Block **head, Coroutine_Alloc_Block *block){
block->next = *head;
*head = block;
}
internal void
coroutine_system_force_init(Coroutine_System_Auto_Alloc *sys, u32 count){
for (u32 i = 0; i < count; ++i){
Coroutine_Alloc_Block *block = coroutine_system_pop(&sys->head_free_uninit);
if (block == 0){
break;
}
init_coroutine_sub(&block->coroutine, &sys->sys);
coroutine_system_push(&sys->head_free_inited, block);
}
}
internal Coroutine*
coroutine_system_alloc(Coroutine_System_Auto_Alloc *sys){
Coroutine_Alloc_Block *block = coroutine_system_pop(&sys->head_free_inited);
if (block == 0){
coroutine_system_force_init(sys, 1);
block = coroutine_system_pop(&sys->head_free_inited);
}
Coroutine *result = 0;
if (block != 0){
result = &block->coroutine;
}
return(result);
}
internal void
coroutine_system_free(Coroutine_System_Auto_Alloc *sys, Coroutine *co){
Coroutine_Alloc_Block *block = (Coroutine_Alloc_Block*)co;
coroutine_system_push(&sys->head_free_inited, block);
}
// BOTTOM