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janet/src/core/ev.c
Calvin Rose 553b4d9428 Add timeouts to net functions.
Further debugging of the general timeout system, as well
as having a single fiber wait on multiple state machines (select).
2020-07-19 19:41:12 -05:00

564 lines
18 KiB
C

/*
* Copyright (c) 2020 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef JANET_AMALG
#include "features.h"
#include <janet.h>
#include "util.h"
#include "gc.h"
#include "state.h"
#include "vector.h"
#include "fiber.h"
#endif
#ifdef JANET_EV
/* Includes */
#include <limits.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/epoll.h>
#include <fcntl.h>
#include <sys/timerfd.h>
/* New fibers to spawn or resume */
typedef struct JanetTask JanetTask;
struct JanetTask {
JanetFiber *fiber;
Janet value;
};
/* Min priority queue of timestamps for timeouts. */
typedef uint64_t JanetTimestamp;
typedef struct JanetTimeout JanetTimeout;
struct JanetTimeout {
JanetTimestamp when;
JanetFiber *fiber;
};
/* Forward declaration */
static void janet_unlisten(JanetListenerState *state);
/* Global data */
JANET_THREAD_LOCAL size_t janet_vm_active_listeners = 0;
JANET_THREAD_LOCAL size_t janet_vm_spawn_capacity = 0;
JANET_THREAD_LOCAL size_t janet_vm_spawn_count = 0;
JANET_THREAD_LOCAL size_t janet_vm_tq_count = 0;
JANET_THREAD_LOCAL size_t janet_vm_tq_capacity = 0;
JANET_THREAD_LOCAL JanetTask *janet_vm_spawn = NULL;
JANET_THREAD_LOCAL JanetTimeout *janet_vm_tq = NULL;
/* Get current timestamp (millisecond precision) */
static JanetTimestamp ts_now(void);
/* Get current timestamp + an interval (millisecond precision) */
static JanetTimestamp ts_delta(JanetTimestamp ts, double delta) {
ts += (int64_t)round(delta * 1000);
return ts;
}
/* Look at the next timeout value without
* removing it. */
static int peek_timeout(JanetTimeout *out) {
if (janet_vm_tq_count == 0) return 0;
*out = janet_vm_tq[0];
return 1;
}
/* Remove the next timeout from the priority queue */
static void pop_timeout(size_t index) {
if (janet_vm_tq_count <= index) return;
janet_vm_tq[index].fiber->timeout_index = -1;
janet_vm_tq[index] = janet_vm_tq[--janet_vm_tq_count];
janet_vm_tq[index].fiber->timeout_index = index;
for (;;) {
size_t left = (index << 1) + 1;
size_t right = left + 1;
size_t smallest = index;
if (left < janet_vm_tq_count &&
(janet_vm_tq[left].when < janet_vm_tq[smallest].when))
smallest = left;
if (right < janet_vm_tq_count &&
(janet_vm_tq[right].when < janet_vm_tq[smallest].when))
smallest = right;
if (smallest == index) return;
JanetTimeout temp = janet_vm_tq[index];
janet_vm_tq[index] = janet_vm_tq[smallest];
janet_vm_tq[smallest] = temp;
janet_vm_tq[index].fiber->timeout_index = index;
janet_vm_tq[smallest].fiber->timeout_index = smallest;
index = smallest;
}
}
/* Add a timeout to the timeout min heap */
static void add_timeout(JanetTimeout to) {
size_t oldcount = janet_vm_tq_count;
size_t newcount = oldcount + 1;
if (newcount > janet_vm_tq_capacity) {
size_t newcap = 2 * newcount;
JanetTimeout *tq = realloc(janet_vm_tq, newcap * sizeof(JanetTimeout));
if (NULL == tq) {
JANET_OUT_OF_MEMORY;
}
janet_vm_tq = tq;
janet_vm_tq_capacity = newcap;
}
/* Append */
janet_vm_tq_count = newcount;
janet_vm_tq[oldcount] = to;
/* Heapify */
size_t index = oldcount;
if (to.fiber->timeout_index >= 0) {
pop_timeout(to.fiber->timeout_index);
}
to.fiber->timeout_index = index;
while (index > 0) {
size_t parent = (index - 1) >> 1;
if (janet_vm_tq[parent].when <= janet_vm_tq[index].when) break;
/* Swap */
JanetTimeout tmp = janet_vm_tq[index];
janet_vm_tq[index] = janet_vm_tq[parent];
janet_vm_tq[parent] = tmp;
/* Next */
index = parent;
}
}
/* Create a new event listener */
static JanetListenerState *janet_listen_impl(JanetPollable *pollable, JanetListener behavior, int mask, size_t size) {
if (pollable->_mask & mask) {
janet_panic("cannot listen for duplicate event on pollable");
}
if (size < sizeof(JanetListenerState))
size = sizeof(JanetListenerState);
JanetListenerState *state = malloc(size);
if (NULL == state) {
JANET_OUT_OF_MEMORY;
}
state->machine = behavior;
if (mask & JANET_ASYNC_LISTEN_SPAWNER) {
state->fiber = NULL;
} else {
state->fiber = janet_vm_root_fiber;
janet_v_push(janet_vm_root_fiber->waiting, state);
}
mask |= JANET_ASYNC_LISTEN_SPAWNER;
state->pollable = pollable;
state->_mask = mask;
pollable->_mask |= mask;
janet_vm_active_listeners++;
/* Prepend to linked list */
state->_next = pollable->state;
pollable->state = state;
/* Emit INIT event for convenience */
state->machine(state, JANET_ASYNC_EVENT_INIT);
return state;
}
/* Indicate we are no longer listening for an event. This
* frees the memory of the state machine as well. */
static void janet_unlisten_impl(JanetListenerState *state) {
state->machine(state, JANET_ASYNC_EVENT_DEINIT);
/* Remove state machine from poll list */
JanetListenerState **iter = &(state->pollable->state);
while (*iter && *iter != state)
iter = &((*iter)->_next);
janet_assert(*iter, "failed to remove listener");
*iter = state->_next;
janet_vm_active_listeners--;
/* Remove mask */
state->pollable->_mask &= ~(state->_mask);
/* Ensure fiber does not reference this state */
JanetFiber *fiber = state->fiber;
if (NULL != fiber) {
int32_t count = janet_v_count(fiber->waiting);
for (int32_t i = 0; i < count; i++) {
if (fiber->waiting[i] == state) {
fiber->waiting[i] = janet_v_last(fiber->waiting);
janet_v_pop(fiber->waiting);
break;
}
}
}
free(state);
}
/* Call after creating a pollable */
void janet_pollable_init(JanetPollable *pollable, JanetPollType handle) {
pollable->handle = handle;
pollable->flags = 0;
pollable->state = NULL;
pollable->_mask = 0;
}
/* Mark a pollable for GC */
void janet_pollable_mark(JanetPollable *pollable) {
JanetListenerState *state = pollable->state;
while (NULL != state) {
if (NULL != state->fiber) {
janet_mark(janet_wrap_fiber(state->fiber));
}
(state->machine)(state, JANET_ASYNC_EVENT_MARK);
state = state->_next;
}
}
/* Must be called to close all pollables - does NOT call `close` for you.
* Also does not free memory of the pollable, so can be used on close. */
void janet_pollable_deinit(JanetPollable *pollable) {
pollable->flags |= JANET_POLL_FLAG_CLOSED;
JanetListenerState *state = pollable->state;
while (NULL != state) {
state->machine(state, JANET_ASYNC_EVENT_CLOSE);
JanetListenerState *next_state = state->_next;
janet_unlisten_impl(state);
state = next_state;
}
pollable->state = NULL;
}
/* Cancel any state machines waiting on this fiber. */
void janet_cancel(JanetFiber *fiber) {
int32_t lcount = janet_v_count(fiber->waiting);
janet_v_empty(fiber->waiting);
for (int32_t index = 0; index < lcount; index++) {
janet_unlisten(fiber->waiting[index]);
}
/* Clear timeout on the current fiber */
if (fiber->timeout_index >= 0) {
pop_timeout(fiber->timeout_index);
fiber->timeout_index = -1;
}
}
/* Register a fiber to resume with value */
void janet_schedule(JanetFiber *fiber, Janet value) {
if (fiber->flags & JANET_FIBER_FLAG_SCHEDULED) return;
fiber->flags |= JANET_FIBER_FLAG_SCHEDULED;
size_t oldcount = janet_vm_spawn_count;
size_t newcount = oldcount + 1;
if (newcount > janet_vm_spawn_capacity) {
size_t newcap = 2 * newcount;
JanetTask *tasks = realloc(janet_vm_spawn, newcap * sizeof(JanetTask));
if (NULL == tasks) {
JANET_OUT_OF_MEMORY;
}
janet_vm_spawn = tasks;
janet_vm_spawn_capacity = newcap;
}
janet_vm_spawn_count = newcount;
janet_vm_spawn[oldcount].fiber = fiber;
janet_vm_spawn[oldcount].value = value;
}
/* Mark all pending tasks */
void janet_ev_mark(void) {
for (size_t i = 0; i < janet_vm_spawn_count; i++) {
janet_mark(janet_wrap_fiber(janet_vm_spawn[i].fiber));
janet_mark(janet_vm_spawn[i].value);
}
for (size_t i = 0; i < janet_vm_tq_count; i++) {
janet_mark(janet_wrap_fiber(janet_vm_tq[i].fiber));
}
}
/* Run a top level task */
static void run_one(JanetFiber *fiber, Janet value) {
fiber->flags &= ~JANET_FIBER_FLAG_SCHEDULED;
Janet res;
JanetSignal sig = janet_continue(fiber, value, &res);
if (sig != JANET_SIGNAL_OK && sig != JANET_SIGNAL_EVENT) {
janet_stacktrace(fiber, res);
}
}
/* Common init code */
void janet_ev_init_common(void) {
janet_vm_spawn_capacity = 0;
janet_vm_spawn_count = 0;
janet_vm_spawn = NULL;
janet_vm_active_listeners = 0;
janet_vm_tq = NULL;
janet_vm_tq_count = 0;
janet_vm_tq_capacity = 0;
}
/* Common deinit code */
void janet_ev_deinit_common(void) {
free(janet_vm_spawn);
}
/* Short hand to yield to event loop */
void janet_await(void) {
janet_signalv(JANET_SIGNAL_EVENT, janet_wrap_nil());
}
/* Set timeout for the current root fiber */
void janet_addtimeout(double sec) {
JanetFiber *fiber = janet_vm_root_fiber;
JanetTimeout to;
to.when = ts_delta(ts_now(), sec);
to.fiber = fiber;
add_timeout(to);
}
/* Main event loop */
void janet_loop1_impl(void);
void janet_loop(void) {
while (janet_vm_active_listeners || janet_vm_spawn_count || janet_vm_tq_count) {
/* Run expired timers */
JanetTimeout to;
while (peek_timeout(&to) && to.when <= ts_now()) {
pop_timeout(0);
janet_schedule(to.fiber, janet_wrap_nil());
}
/* Run scheduled fibers */
size_t index = 0;
while (index < janet_vm_spawn_count) {
JanetTask task = janet_vm_spawn[index];
run_one(task.fiber, task.value);
index++;
}
janet_vm_spawn_count = 0;
/* Poll for events */
if (janet_vm_active_listeners || janet_vm_tq_count) {
janet_loop1_impl();
}
}
}
#ifdef JANET_LINUX
/*
* Start linux/epoll implementation
*/
static JanetTimestamp ts_now(void) {
struct timespec now;
janet_assert(-1 != clock_gettime(CLOCK_MONOTONIC, &now), "failed to get time");
uint64_t res = 1000 * now.tv_sec;
res += now.tv_nsec / 1000000;
return res;
}
/* Epoll global data */
JANET_THREAD_LOCAL int janet_vm_epoll = 0;
JANET_THREAD_LOCAL int janet_vm_timerfd = 0;
JANET_THREAD_LOCAL int janet_vm_timer_enabled = 0;
static int make_epoll_events(int mask) {
int events = EPOLLET;
if (mask & JANET_ASYNC_LISTEN_READ)
events |= EPOLLIN;
if (mask & JANET_ASYNC_LISTEN_WRITE)
events |= EPOLLOUT;
return events;
}
/* Wait for the next event */
JanetListenerState *janet_listen(JanetPollable *pollable, JanetListener behavior, int mask, size_t size) {
int is_first = !(pollable->state);
int op = is_first ? EPOLL_CTL_ADD : EPOLL_CTL_MOD;
JanetListenerState *state = janet_listen_impl(pollable, behavior, mask, size);
struct epoll_event ev;
ev.events = make_epoll_events(state->pollable->_mask);
ev.data.ptr = pollable;
int status;
do {
status = epoll_ctl(janet_vm_epoll, op, pollable->handle, &ev);
} while (status == -1 && errno == EINTR);
if (status == -1) {
janet_unlisten_impl(state);
janet_panicf("failed to schedule event: %s", strerror(errno));
}
return state;
}
/* Tell system we are done listening for a certain event */
static void janet_unlisten(JanetListenerState *state) {
JanetPollable *pollable = state->pollable;
int is_last = (state->_next == NULL && pollable->state == state);
int op = is_last ? EPOLL_CTL_DEL : EPOLL_CTL_MOD;
struct epoll_event ev;
ev.events = make_epoll_events(pollable->_mask & ~state->_mask);
ev.data.ptr = pollable;
int status;
do {
status = epoll_ctl(janet_vm_epoll, op, pollable->handle, &ev);
} while (status == -1 && errno == EINTR);
if (status == -1) {
janet_panicf("failed to unschedule event: %s", strerror(errno));
}
/* Destroy state machine and free memory */
janet_unlisten_impl(state);
}
/* Replace janet_loop with this */
#define JANET_EPOLL_MAX_EVENTS 64
void janet_loop1_impl(void) {
/* Set timer */
JanetTimeout to;
struct itimerspec its;
memset(&to, 0, sizeof(to));
int has_timeout = peek_timeout(&to);
if (janet_vm_timer_enabled || has_timeout) {
memset(&its, 0, sizeof(its));
if (has_timeout) {
its.it_value.tv_sec = to.when / 1000;
its.it_value.tv_nsec = (to.when % 1000) * 1000000;
}
timerfd_settime(janet_vm_timerfd, TFD_TIMER_ABSTIME, &its, NULL);
}
janet_vm_timer_enabled = has_timeout;
/* Poll for events */
struct epoll_event events[JANET_EPOLL_MAX_EVENTS];
int ready;
do {
ready = epoll_wait(janet_vm_epoll, events, JANET_EPOLL_MAX_EVENTS, -1);
} while (ready == -1 && errno == EINTR);
if (ready == -1) {
JANET_EXIT("failed to poll events");
}
/* Step state machines */
for (int i = 0; i < ready; i++) {
JanetPollable *pollable = events[i].data.ptr;
if (NULL == pollable) {
/* Timer event */
pop_timeout(0);
/* Cancel waiters for this fiber */
janet_schedule(to.fiber, janet_wrap_nil());
} else {
/* Normal event */
int mask = events[i].events;
JanetListenerState *state = pollable->state;
while (NULL != state) {
JanetListenerState *next_state = state->_next;
JanetAsyncStatus status1 = JANET_ASYNC_STATUS_NOT_DONE;
JanetAsyncStatus status2 = JANET_ASYNC_STATUS_NOT_DONE;
if (mask & EPOLLOUT)
status1 = state->machine(state, JANET_ASYNC_EVENT_WRITE);
if (mask & EPOLLIN)
status2 = state->machine(state, JANET_ASYNC_EVENT_READ);
if (status1 == JANET_ASYNC_STATUS_DONE || status2 == JANET_ASYNC_STATUS_DONE)
janet_unlisten(state);
state = next_state;
}
}
}
}
void janet_ev_init(void) {
janet_ev_init_common();
janet_vm_epoll = epoll_create1(EPOLL_CLOEXEC);
janet_vm_timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | TFD_NONBLOCK);
janet_vm_timer_enabled = 0;
if (janet_vm_epoll == -1 || janet_vm_timerfd == -1) goto error;
struct epoll_event ev;
ev.events = EPOLLIN | EPOLLET;
ev.data.ptr = NULL;
if (-1 == epoll_ctl(janet_vm_epoll, EPOLL_CTL_ADD, janet_vm_timerfd, &ev)) goto error;
return;
error:
JANET_EXIT("failed to initialize event loop");
}
void janet_ev_deinit(void) {
janet_ev_deinit_common();
close(janet_vm_epoll);
close(janet_vm_timerfd);
janet_vm_epoll = 0;
}
/*
* End epoll implementation
*/
#else
#endif
/* C functions */
static Janet cfun_ev_go(int32_t argc, Janet *argv) {
janet_arity(argc, 1, 2);
JanetFiber *fiber = janet_getfiber(argv, 0);
Janet value = argc == 2 ? argv[1] : janet_wrap_nil();
janet_schedule(fiber, value);
return argv[0];
}
static Janet cfun_ev_call(int32_t argc, Janet *argv) {
janet_arity(argc, 1, -1);
JanetFunction *fn = janet_getfunction(argv, 0);
JanetFiber *fiber = janet_fiber(fn, 64, argc - 1, argv + 1);
janet_schedule(fiber, janet_wrap_nil());
return janet_wrap_fiber(fiber);
}
static Janet cfun_ev_sleep(int32_t argc, Janet *argv) {
janet_fixarity(argc, 1);
double sec = janet_getnumber(argv, 0);
JanetTimeout to;
to.when = ts_delta(ts_now(), sec);
to.fiber = janet_vm_root_fiber;
add_timeout(to);
janet_await();
}
static const JanetReg ev_cfuns[] = {
{
"ev/call", cfun_ev_call,
JDOC("(ev/call fn & args)\n\n"
"Call a function asynchronously. Returns a fiber that is scheduled to "
"run the function.")
},
{
"ev/go", cfun_ev_go,
JDOC("(ev/go fiber &opt value)\n\n"
"Put a fiber on the event loop to be resumed later. Optionally pass "
"a value to resume with, otherwise resumes with nil.")
},
{
"ev/sleep", cfun_ev_sleep,
JDOC("(ev/sleep sec)\n\n"
"Suspend the current fiber for sec seconds without blocking the event loop.")
},
{NULL, NULL, NULL}
};
void janet_lib_ev(JanetTable *env) {
janet_core_cfuns(env, NULL, ev_cfuns);
}
#endif