zig/std/event/loop.zig

913 lines
38 KiB
Zig

const std = @import("../std.zig");
const builtin = @import("builtin");
const assert = std.debug.assert;
const testing = std.testing;
const mem = std.mem;
const AtomicRmwOp = builtin.AtomicRmwOp;
const AtomicOrder = builtin.AtomicOrder;
const fs = std.event.fs;
const os = std.os;
const posix = os.posix;
const windows = os.windows;
const maxInt = std.math.maxInt;
pub const Loop = struct {
allocator: *mem.Allocator,
next_tick_queue: std.atomic.Queue(promise),
os_data: OsData,
final_resume_node: ResumeNode,
pending_event_count: usize,
extra_threads: []*os.Thread,
// pre-allocated eventfds. all permanently active.
// this is how we send promises to be resumed on other threads.
available_eventfd_resume_nodes: std.atomic.Stack(ResumeNode.EventFd),
eventfd_resume_nodes: []std.atomic.Stack(ResumeNode.EventFd).Node,
pub const NextTickNode = std.atomic.Queue(promise).Node;
pub const ResumeNode = struct {
id: Id,
handle: promise,
overlapped: Overlapped,
pub const overlapped_init = switch (builtin.os) {
builtin.Os.windows => windows.OVERLAPPED{
.Internal = 0,
.InternalHigh = 0,
.Offset = 0,
.OffsetHigh = 0,
.hEvent = null,
},
else => {},
};
pub const Overlapped = @typeOf(overlapped_init);
pub const Id = enum {
Basic,
Stop,
EventFd,
};
pub const EventFd = switch (builtin.os) {
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => KEventFd,
builtin.Os.linux => struct {
base: ResumeNode,
epoll_op: u32,
eventfd: i32,
},
builtin.Os.windows => struct {
base: ResumeNode,
completion_key: usize,
},
else => @compileError("unsupported OS"),
};
const KEventFd = struct {
base: ResumeNode,
kevent: posix.Kevent,
};
pub const Basic = switch (builtin.os) {
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => KEventBasic,
builtin.Os.linux => struct {
base: ResumeNode,
},
builtin.Os.windows => struct {
base: ResumeNode,
},
else => @compileError("unsupported OS"),
};
const KEventBasic = struct {
base: ResumeNode,
kev: posix.Kevent,
};
};
/// After initialization, call run().
/// TODO copy elision / named return values so that the threads referencing *Loop
/// have the correct pointer value.
pub fn initSingleThreaded(self: *Loop, allocator: *mem.Allocator) !void {
return self.initInternal(allocator, 1);
}
/// The allocator must be thread-safe because we use it for multiplexing
/// coroutines onto kernel threads.
/// After initialization, call run().
/// TODO copy elision / named return values so that the threads referencing *Loop
/// have the correct pointer value.
pub fn initMultiThreaded(self: *Loop, allocator: *mem.Allocator) !void {
if (builtin.single_threaded) @compileError("initMultiThreaded unavailable when building in single-threaded mode");
const core_count = try os.cpuCount(allocator);
return self.initInternal(allocator, core_count);
}
/// Thread count is the total thread count. The thread pool size will be
/// max(thread_count - 1, 0)
fn initInternal(self: *Loop, allocator: *mem.Allocator, thread_count: usize) !void {
self.* = Loop{
.pending_event_count = 1,
.allocator = allocator,
.os_data = undefined,
.next_tick_queue = std.atomic.Queue(promise).init(),
.extra_threads = undefined,
.available_eventfd_resume_nodes = std.atomic.Stack(ResumeNode.EventFd).init(),
.eventfd_resume_nodes = undefined,
.final_resume_node = ResumeNode{
.id = ResumeNode.Id.Stop,
.handle = undefined,
.overlapped = ResumeNode.overlapped_init,
},
};
const extra_thread_count = thread_count - 1;
self.eventfd_resume_nodes = try self.allocator.alloc(
std.atomic.Stack(ResumeNode.EventFd).Node,
extra_thread_count,
);
errdefer self.allocator.free(self.eventfd_resume_nodes);
self.extra_threads = try self.allocator.alloc(*os.Thread, extra_thread_count);
errdefer self.allocator.free(self.extra_threads);
try self.initOsData(extra_thread_count);
errdefer self.deinitOsData();
}
pub fn deinit(self: *Loop) void {
self.deinitOsData();
self.allocator.free(self.extra_threads);
}
const InitOsDataError = os.LinuxEpollCreateError || mem.Allocator.Error || os.LinuxEventFdError ||
os.SpawnThreadError || os.LinuxEpollCtlError || os.BsdKEventError ||
os.WindowsCreateIoCompletionPortError;
const wakeup_bytes = []u8{0x1} ** 8;
fn initOsData(self: *Loop, extra_thread_count: usize) InitOsDataError!void {
switch (builtin.os) {
builtin.Os.linux => {
self.os_data.fs_queue = std.atomic.Queue(fs.Request).init();
self.os_data.fs_queue_item = 0;
// we need another thread for the file system because Linux does not have an async
// file system I/O API.
self.os_data.fs_end_request = fs.RequestNode{
.prev = undefined,
.next = undefined,
.data = fs.Request{
.msg = fs.Request.Msg.End,
.finish = fs.Request.Finish.NoAction,
},
};
errdefer {
while (self.available_eventfd_resume_nodes.pop()) |node| os.close(node.data.eventfd);
}
for (self.eventfd_resume_nodes) |*eventfd_node| {
eventfd_node.* = std.atomic.Stack(ResumeNode.EventFd).Node{
.data = ResumeNode.EventFd{
.base = ResumeNode{
.id = ResumeNode.Id.EventFd,
.handle = undefined,
.overlapped = ResumeNode.overlapped_init,
},
.eventfd = try os.linuxEventFd(1, posix.EFD_CLOEXEC | posix.EFD_NONBLOCK),
.epoll_op = posix.EPOLL_CTL_ADD,
},
.next = undefined,
};
self.available_eventfd_resume_nodes.push(eventfd_node);
}
self.os_data.epollfd = try os.linuxEpollCreate(posix.EPOLL_CLOEXEC);
errdefer os.close(self.os_data.epollfd);
self.os_data.final_eventfd = try os.linuxEventFd(0, posix.EFD_CLOEXEC | posix.EFD_NONBLOCK);
errdefer os.close(self.os_data.final_eventfd);
self.os_data.final_eventfd_event = posix.epoll_event{
.events = posix.EPOLLIN,
.data = posix.epoll_data{ .ptr = @ptrToInt(&self.final_resume_node) },
};
try os.linuxEpollCtl(
self.os_data.epollfd,
posix.EPOLL_CTL_ADD,
self.os_data.final_eventfd,
&self.os_data.final_eventfd_event,
);
self.os_data.fs_thread = try os.spawnThread(self, posixFsRun);
errdefer {
self.posixFsRequest(&self.os_data.fs_end_request);
self.os_data.fs_thread.wait();
}
if (builtin.single_threaded) {
assert(extra_thread_count == 0);
return;
}
var extra_thread_index: usize = 0;
errdefer {
// writing 8 bytes to an eventfd cannot fail
os.posixWrite(self.os_data.final_eventfd, wakeup_bytes) catch unreachable;
while (extra_thread_index != 0) {
extra_thread_index -= 1;
self.extra_threads[extra_thread_index].wait();
}
}
while (extra_thread_index < extra_thread_count) : (extra_thread_index += 1) {
self.extra_threads[extra_thread_index] = try os.spawnThread(self, workerRun);
}
},
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
self.os_data.kqfd = try os.bsdKQueue();
errdefer os.close(self.os_data.kqfd);
self.os_data.fs_kqfd = try os.bsdKQueue();
errdefer os.close(self.os_data.fs_kqfd);
self.os_data.fs_queue = std.atomic.Queue(fs.Request).init();
// we need another thread for the file system because Darwin does not have an async
// file system I/O API.
self.os_data.fs_end_request = fs.RequestNode{
.prev = undefined,
.next = undefined,
.data = fs.Request{
.msg = fs.Request.Msg.End,
.finish = fs.Request.Finish.NoAction,
},
};
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
for (self.eventfd_resume_nodes) |*eventfd_node, i| {
eventfd_node.* = std.atomic.Stack(ResumeNode.EventFd).Node{
.data = ResumeNode.EventFd{
.base = ResumeNode{
.id = ResumeNode.Id.EventFd,
.handle = undefined,
.overlapped = ResumeNode.overlapped_init,
},
// this one is for sending events
.kevent = posix.Kevent{
.ident = i,
.filter = posix.EVFILT_USER,
.flags = posix.EV_CLEAR | posix.EV_ADD | posix.EV_DISABLE,
.fflags = 0,
.data = 0,
.udata = @ptrToInt(&eventfd_node.data.base),
},
},
.next = undefined,
};
self.available_eventfd_resume_nodes.push(eventfd_node);
const kevent_array = (*const [1]posix.Kevent)(&eventfd_node.data.kevent);
_ = try os.bsdKEvent(self.os_data.kqfd, kevent_array, empty_kevs, null);
eventfd_node.data.kevent.flags = posix.EV_CLEAR | posix.EV_ENABLE;
eventfd_node.data.kevent.fflags = posix.NOTE_TRIGGER;
}
// Pre-add so that we cannot get error.SystemResources
// later when we try to activate it.
self.os_data.final_kevent = posix.Kevent{
.ident = extra_thread_count,
.filter = posix.EVFILT_USER,
.flags = posix.EV_ADD | posix.EV_DISABLE,
.fflags = 0,
.data = 0,
.udata = @ptrToInt(&self.final_resume_node),
};
const final_kev_arr = (*const [1]posix.Kevent)(&self.os_data.final_kevent);
_ = try os.bsdKEvent(self.os_data.kqfd, final_kev_arr, empty_kevs, null);
self.os_data.final_kevent.flags = posix.EV_ENABLE;
self.os_data.final_kevent.fflags = posix.NOTE_TRIGGER;
self.os_data.fs_kevent_wake = posix.Kevent{
.ident = 0,
.filter = posix.EVFILT_USER,
.flags = posix.EV_ADD | posix.EV_ENABLE,
.fflags = posix.NOTE_TRIGGER,
.data = 0,
.udata = undefined,
};
self.os_data.fs_kevent_wait = posix.Kevent{
.ident = 0,
.filter = posix.EVFILT_USER,
.flags = posix.EV_ADD | posix.EV_CLEAR,
.fflags = 0,
.data = 0,
.udata = undefined,
};
self.os_data.fs_thread = try os.spawnThread(self, posixFsRun);
errdefer {
self.posixFsRequest(&self.os_data.fs_end_request);
self.os_data.fs_thread.wait();
}
if (builtin.single_threaded) {
assert(extra_thread_count == 0);
return;
}
var extra_thread_index: usize = 0;
errdefer {
_ = os.bsdKEvent(self.os_data.kqfd, final_kev_arr, empty_kevs, null) catch unreachable;
while (extra_thread_index != 0) {
extra_thread_index -= 1;
self.extra_threads[extra_thread_index].wait();
}
}
while (extra_thread_index < extra_thread_count) : (extra_thread_index += 1) {
self.extra_threads[extra_thread_index] = try os.spawnThread(self, workerRun);
}
},
builtin.Os.windows => {
self.os_data.io_port = try os.windowsCreateIoCompletionPort(
windows.INVALID_HANDLE_VALUE,
null,
undefined,
maxInt(windows.DWORD),
);
errdefer os.close(self.os_data.io_port);
for (self.eventfd_resume_nodes) |*eventfd_node, i| {
eventfd_node.* = std.atomic.Stack(ResumeNode.EventFd).Node{
.data = ResumeNode.EventFd{
.base = ResumeNode{
.id = ResumeNode.Id.EventFd,
.handle = undefined,
.overlapped = ResumeNode.overlapped_init,
},
// this one is for sending events
.completion_key = @ptrToInt(&eventfd_node.data.base),
},
.next = undefined,
};
self.available_eventfd_resume_nodes.push(eventfd_node);
}
if (builtin.single_threaded) {
assert(extra_thread_count == 0);
return;
}
var extra_thread_index: usize = 0;
errdefer {
var i: usize = 0;
while (i < extra_thread_index) : (i += 1) {
while (true) {
const overlapped = &self.final_resume_node.overlapped;
os.windowsPostQueuedCompletionStatus(self.os_data.io_port, undefined, undefined, overlapped) catch continue;
break;
}
}
while (extra_thread_index != 0) {
extra_thread_index -= 1;
self.extra_threads[extra_thread_index].wait();
}
}
while (extra_thread_index < extra_thread_count) : (extra_thread_index += 1) {
self.extra_threads[extra_thread_index] = try os.spawnThread(self, workerRun);
}
},
else => {},
}
}
fn deinitOsData(self: *Loop) void {
switch (builtin.os) {
builtin.Os.linux => {
os.close(self.os_data.final_eventfd);
while (self.available_eventfd_resume_nodes.pop()) |node| os.close(node.data.eventfd);
os.close(self.os_data.epollfd);
self.allocator.free(self.eventfd_resume_nodes);
},
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
os.close(self.os_data.kqfd);
os.close(self.os_data.fs_kqfd);
},
builtin.Os.windows => {
os.close(self.os_data.io_port);
},
else => {},
}
}
/// resume_node must live longer than the promise that it holds a reference to.
/// flags must contain EPOLLET
pub fn linuxAddFd(self: *Loop, fd: i32, resume_node: *ResumeNode, flags: u32) !void {
assert(flags & posix.EPOLLET == posix.EPOLLET);
self.beginOneEvent();
errdefer self.finishOneEvent();
try self.linuxModFd(
fd,
posix.EPOLL_CTL_ADD,
flags,
resume_node,
);
}
pub fn linuxModFd(self: *Loop, fd: i32, op: u32, flags: u32, resume_node: *ResumeNode) !void {
assert(flags & posix.EPOLLET == posix.EPOLLET);
var ev = os.linux.epoll_event{
.events = flags,
.data = os.linux.epoll_data{ .ptr = @ptrToInt(resume_node) },
};
try os.linuxEpollCtl(self.os_data.epollfd, op, fd, &ev);
}
pub fn linuxRemoveFd(self: *Loop, fd: i32) void {
os.linuxEpollCtl(self.os_data.epollfd, os.linux.EPOLL_CTL_DEL, fd, undefined) catch {};
self.finishOneEvent();
}
pub async fn linuxWaitFd(self: *Loop, fd: i32, flags: u32) !void {
defer self.linuxRemoveFd(fd);
suspend {
// TODO explicitly put this memory in the coroutine frame #1194
var resume_node = ResumeNode.Basic{
.base = ResumeNode{
.id = ResumeNode.Id.Basic,
.handle = @handle(),
.overlapped = ResumeNode.overlapped_init,
},
};
try self.linuxAddFd(fd, &resume_node.base, flags);
}
}
pub async fn bsdWaitKev(self: *Loop, ident: usize, filter: i16, fflags: u32) !posix.Kevent {
// TODO #1194
suspend {
resume @handle();
}
var resume_node = ResumeNode.Basic{
.base = ResumeNode{
.id = ResumeNode.Id.Basic,
.handle = @handle(),
.overlapped = ResumeNode.overlapped_init,
},
.kev = undefined,
};
defer self.bsdRemoveKev(ident, filter);
suspend {
try self.bsdAddKev(&resume_node, ident, filter, fflags);
}
return resume_node.kev;
}
/// resume_node must live longer than the promise that it holds a reference to.
pub fn bsdAddKev(self: *Loop, resume_node: *ResumeNode.Basic, ident: usize, filter: i16, fflags: u32) !void {
self.beginOneEvent();
errdefer self.finishOneEvent();
var kev = posix.Kevent{
.ident = ident,
.filter = filter,
.flags = posix.EV_ADD | posix.EV_ENABLE | posix.EV_CLEAR,
.fflags = fflags,
.data = 0,
.udata = @ptrToInt(&resume_node.base),
};
const kevent_array = (*const [1]posix.Kevent)(&kev);
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
_ = try os.bsdKEvent(self.os_data.kqfd, kevent_array, empty_kevs, null);
}
pub fn bsdRemoveKev(self: *Loop, ident: usize, filter: i16) void {
var kev = posix.Kevent{
.ident = ident,
.filter = filter,
.flags = posix.EV_DELETE,
.fflags = 0,
.data = 0,
.udata = 0,
};
const kevent_array = (*const [1]posix.Kevent)(&kev);
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
_ = os.bsdKEvent(self.os_data.kqfd, kevent_array, empty_kevs, null) catch undefined;
self.finishOneEvent();
}
fn dispatch(self: *Loop) void {
while (self.available_eventfd_resume_nodes.pop()) |resume_stack_node| {
const next_tick_node = self.next_tick_queue.get() orelse {
self.available_eventfd_resume_nodes.push(resume_stack_node);
return;
};
const eventfd_node = &resume_stack_node.data;
eventfd_node.base.handle = next_tick_node.data;
switch (builtin.os) {
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
const kevent_array = (*const [1]posix.Kevent)(&eventfd_node.kevent);
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
_ = os.bsdKEvent(self.os_data.kqfd, kevent_array, empty_kevs, null) catch {
self.next_tick_queue.unget(next_tick_node);
self.available_eventfd_resume_nodes.push(resume_stack_node);
return;
};
},
builtin.Os.linux => {
// the pending count is already accounted for
const epoll_events = posix.EPOLLONESHOT | os.linux.EPOLLIN | os.linux.EPOLLOUT |
os.linux.EPOLLET;
self.linuxModFd(
eventfd_node.eventfd,
eventfd_node.epoll_op,
epoll_events,
&eventfd_node.base,
) catch {
self.next_tick_queue.unget(next_tick_node);
self.available_eventfd_resume_nodes.push(resume_stack_node);
return;
};
},
builtin.Os.windows => {
os.windowsPostQueuedCompletionStatus(
self.os_data.io_port,
undefined,
undefined,
&eventfd_node.base.overlapped,
) catch {
self.next_tick_queue.unget(next_tick_node);
self.available_eventfd_resume_nodes.push(resume_stack_node);
return;
};
},
else => @compileError("unsupported OS"),
}
}
}
/// Bring your own linked list node. This means it can't fail.
pub fn onNextTick(self: *Loop, node: *NextTickNode) void {
self.beginOneEvent(); // finished in dispatch()
self.next_tick_queue.put(node);
self.dispatch();
}
pub fn cancelOnNextTick(self: *Loop, node: *NextTickNode) void {
if (self.next_tick_queue.remove(node)) {
self.finishOneEvent();
}
}
pub fn run(self: *Loop) void {
self.finishOneEvent(); // the reference we start with
self.workerRun();
switch (builtin.os) {
builtin.Os.linux,
builtin.Os.macosx,
builtin.Os.freebsd,
builtin.Os.netbsd,
=> self.os_data.fs_thread.wait(),
else => {},
}
for (self.extra_threads) |extra_thread| {
extra_thread.wait();
}
}
/// This is equivalent to an async call, except instead of beginning execution of the async function,
/// it immediately returns to the caller, and the async function is queued in the event loop. It still
/// returns a promise to be awaited.
pub fn call(self: *Loop, comptime func: var, args: ...) !(promise->@typeOf(func).ReturnType) {
const S = struct {
async fn asyncFunc(loop: *Loop, handle: *promise->@typeOf(func).ReturnType, args2: ...) @typeOf(func).ReturnType {
suspend {
handle.* = @handle();
var my_tick_node = Loop.NextTickNode{
.prev = undefined,
.next = undefined,
.data = @handle(),
};
loop.onNextTick(&my_tick_node);
}
// TODO guaranteed allocation elision for await in same func as async
return await (async func(args2) catch unreachable);
}
};
var handle: promise->@typeOf(func).ReturnType = undefined;
return async<self.allocator> S.asyncFunc(self, &handle, args);
}
/// Awaiting a yield lets the event loop run, starting any unstarted async operations.
/// Note that async operations automatically start when a function yields for any other reason,
/// for example, when async I/O is performed. This function is intended to be used only when
/// CPU bound tasks would be waiting in the event loop but never get started because no async I/O
/// is performed.
pub async fn yield(self: *Loop) void {
suspend {
var my_tick_node = Loop.NextTickNode{
.prev = undefined,
.next = undefined,
.data = @handle(),
};
self.onNextTick(&my_tick_node);
}
}
/// call finishOneEvent when done
pub fn beginOneEvent(self: *Loop) void {
_ = @atomicRmw(usize, &self.pending_event_count, AtomicRmwOp.Add, 1, AtomicOrder.SeqCst);
}
pub fn finishOneEvent(self: *Loop) void {
const prev = @atomicRmw(usize, &self.pending_event_count, AtomicRmwOp.Sub, 1, AtomicOrder.SeqCst);
if (prev == 1) {
// cause all the threads to stop
switch (builtin.os) {
builtin.Os.linux => {
self.posixFsRequest(&self.os_data.fs_end_request);
// writing 8 bytes to an eventfd cannot fail
os.posixWrite(self.os_data.final_eventfd, wakeup_bytes) catch unreachable;
return;
},
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
self.posixFsRequest(&self.os_data.fs_end_request);
const final_kevent = (*const [1]posix.Kevent)(&self.os_data.final_kevent);
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
// cannot fail because we already added it and this just enables it
_ = os.bsdKEvent(self.os_data.kqfd, final_kevent, empty_kevs, null) catch unreachable;
return;
},
builtin.Os.windows => {
var i: usize = 0;
while (i < self.extra_threads.len + 1) : (i += 1) {
while (true) {
const overlapped = &self.final_resume_node.overlapped;
os.windowsPostQueuedCompletionStatus(self.os_data.io_port, undefined, undefined, overlapped) catch continue;
break;
}
}
return;
},
else => @compileError("unsupported OS"),
}
}
}
fn workerRun(self: *Loop) void {
while (true) {
while (true) {
const next_tick_node = self.next_tick_queue.get() orelse break;
self.dispatch();
resume next_tick_node.data;
self.finishOneEvent();
}
switch (builtin.os) {
builtin.Os.linux => {
// only process 1 event so we don't steal from other threads
var events: [1]os.linux.epoll_event = undefined;
const count = os.linuxEpollWait(self.os_data.epollfd, events[0..], -1);
for (events[0..count]) |ev| {
const resume_node = @intToPtr(*ResumeNode, ev.data.ptr);
const handle = resume_node.handle;
const resume_node_id = resume_node.id;
switch (resume_node_id) {
ResumeNode.Id.Basic => {},
ResumeNode.Id.Stop => return,
ResumeNode.Id.EventFd => {
const event_fd_node = @fieldParentPtr(ResumeNode.EventFd, "base", resume_node);
event_fd_node.epoll_op = posix.EPOLL_CTL_MOD;
const stack_node = @fieldParentPtr(std.atomic.Stack(ResumeNode.EventFd).Node, "data", event_fd_node);
self.available_eventfd_resume_nodes.push(stack_node);
},
}
resume handle;
if (resume_node_id == ResumeNode.Id.EventFd) {
self.finishOneEvent();
}
}
},
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
var eventlist: [1]posix.Kevent = undefined;
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
const count = os.bsdKEvent(self.os_data.kqfd, empty_kevs, eventlist[0..], null) catch unreachable;
for (eventlist[0..count]) |ev| {
const resume_node = @intToPtr(*ResumeNode, ev.udata);
const handle = resume_node.handle;
const resume_node_id = resume_node.id;
switch (resume_node_id) {
ResumeNode.Id.Basic => {
const basic_node = @fieldParentPtr(ResumeNode.Basic, "base", resume_node);
basic_node.kev = ev;
},
ResumeNode.Id.Stop => return,
ResumeNode.Id.EventFd => {
const event_fd_node = @fieldParentPtr(ResumeNode.EventFd, "base", resume_node);
const stack_node = @fieldParentPtr(std.atomic.Stack(ResumeNode.EventFd).Node, "data", event_fd_node);
self.available_eventfd_resume_nodes.push(stack_node);
},
}
resume handle;
if (resume_node_id == ResumeNode.Id.EventFd) {
self.finishOneEvent();
}
}
},
builtin.Os.windows => {
var completion_key: usize = undefined;
const overlapped = while (true) {
var nbytes: windows.DWORD = undefined;
var overlapped: ?*windows.OVERLAPPED = undefined;
switch (os.windowsGetQueuedCompletionStatus(self.os_data.io_port, &nbytes, &completion_key, &overlapped, windows.INFINITE)) {
os.WindowsWaitResult.Aborted => return,
os.WindowsWaitResult.Normal => {},
os.WindowsWaitResult.EOF => {},
os.WindowsWaitResult.Cancelled => continue,
}
if (overlapped) |o| break o;
} else unreachable; // TODO else unreachable should not be necessary
const resume_node = @fieldParentPtr(ResumeNode, "overlapped", overlapped);
const handle = resume_node.handle;
const resume_node_id = resume_node.id;
switch (resume_node_id) {
ResumeNode.Id.Basic => {},
ResumeNode.Id.Stop => return,
ResumeNode.Id.EventFd => {
const event_fd_node = @fieldParentPtr(ResumeNode.EventFd, "base", resume_node);
const stack_node = @fieldParentPtr(std.atomic.Stack(ResumeNode.EventFd).Node, "data", event_fd_node);
self.available_eventfd_resume_nodes.push(stack_node);
},
}
resume handle;
self.finishOneEvent();
},
else => @compileError("unsupported OS"),
}
}
}
fn posixFsRequest(self: *Loop, request_node: *fs.RequestNode) void {
self.beginOneEvent(); // finished in posixFsRun after processing the msg
self.os_data.fs_queue.put(request_node);
switch (builtin.os) {
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
const fs_kevs = (*const [1]posix.Kevent)(&self.os_data.fs_kevent_wake);
const empty_kevs = ([*]posix.Kevent)(undefined)[0..0];
_ = os.bsdKEvent(self.os_data.fs_kqfd, fs_kevs, empty_kevs, null) catch unreachable;
},
builtin.Os.linux => {
_ = @atomicRmw(i32, &self.os_data.fs_queue_item, AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst);
const rc = os.linux.futex_wake(&self.os_data.fs_queue_item, os.linux.FUTEX_WAKE, 1);
switch (os.linux.getErrno(rc)) {
0 => {},
posix.EINVAL => unreachable,
else => unreachable,
}
},
else => @compileError("Unsupported OS"),
}
}
fn posixFsCancel(self: *Loop, request_node: *fs.RequestNode) void {
if (self.os_data.fs_queue.remove(request_node)) {
self.finishOneEvent();
}
}
fn posixFsRun(self: *Loop) void {
while (true) {
if (builtin.os == builtin.Os.linux) {
_ = @atomicRmw(i32, &self.os_data.fs_queue_item, AtomicRmwOp.Xchg, 0, AtomicOrder.SeqCst);
}
while (self.os_data.fs_queue.get()) |node| {
switch (node.data.msg) {
@TagType(fs.Request.Msg).End => return,
@TagType(fs.Request.Msg).PWriteV => |*msg| {
msg.result = os.posix_pwritev(msg.fd, msg.iov.ptr, msg.iov.len, msg.offset);
},
@TagType(fs.Request.Msg).PReadV => |*msg| {
msg.result = os.posix_preadv(msg.fd, msg.iov.ptr, msg.iov.len, msg.offset);
},
@TagType(fs.Request.Msg).Open => |*msg| {
msg.result = os.posixOpenC(msg.path.ptr, msg.flags, msg.mode);
},
@TagType(fs.Request.Msg).Close => |*msg| os.close(msg.fd),
@TagType(fs.Request.Msg).WriteFile => |*msg| blk: {
const flags = posix.O_LARGEFILE | posix.O_WRONLY | posix.O_CREAT |
posix.O_CLOEXEC | posix.O_TRUNC;
const fd = os.posixOpenC(msg.path.ptr, flags, msg.mode) catch |err| {
msg.result = err;
break :blk;
};
defer os.close(fd);
msg.result = os.posixWrite(fd, msg.contents);
},
}
switch (node.data.finish) {
@TagType(fs.Request.Finish).TickNode => |*tick_node| self.onNextTick(tick_node),
@TagType(fs.Request.Finish).DeallocCloseOperation => |close_op| {
self.allocator.destroy(close_op);
},
@TagType(fs.Request.Finish).NoAction => {},
}
self.finishOneEvent();
}
switch (builtin.os) {
builtin.Os.linux => {
const rc = os.linux.futex_wait(&self.os_data.fs_queue_item, os.linux.FUTEX_WAIT, 0, null);
switch (os.linux.getErrno(rc)) {
0, posix.EINTR, posix.EAGAIN => continue,
else => unreachable,
}
},
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
const fs_kevs = (*const [1]posix.Kevent)(&self.os_data.fs_kevent_wait);
var out_kevs: [1]posix.Kevent = undefined;
_ = os.bsdKEvent(self.os_data.fs_kqfd, fs_kevs, out_kevs[0..], null) catch unreachable;
},
else => @compileError("Unsupported OS"),
}
}
}
const OsData = switch (builtin.os) {
builtin.Os.linux => LinuxOsData,
builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => KEventData,
builtin.Os.windows => struct {
io_port: windows.HANDLE,
extra_thread_count: usize,
},
else => struct {},
};
const KEventData = struct {
kqfd: i32,
final_kevent: posix.Kevent,
fs_kevent_wake: posix.Kevent,
fs_kevent_wait: posix.Kevent,
fs_thread: *os.Thread,
fs_kqfd: i32,
fs_queue: std.atomic.Queue(fs.Request),
fs_end_request: fs.RequestNode,
};
const LinuxOsData = struct {
epollfd: i32,
final_eventfd: i32,
final_eventfd_event: os.linux.epoll_event,
fs_thread: *os.Thread,
fs_queue_item: i32,
fs_queue: std.atomic.Queue(fs.Request),
fs_end_request: fs.RequestNode,
};
};
test "std.event.Loop - basic" {
// https://github.com/ziglang/zig/issues/1908
if (builtin.single_threaded or builtin.os != builtin.Os.linux) return error.SkipZigTest;
var da = std.heap.DirectAllocator.init();
defer da.deinit();
const allocator = &da.allocator;
var loop: Loop = undefined;
try loop.initMultiThreaded(allocator);
defer loop.deinit();
loop.run();
}
test "std.event.Loop - call" {
// https://github.com/ziglang/zig/issues/1908
if (builtin.single_threaded or builtin.os != builtin.Os.linux) return error.SkipZigTest;
var da = std.heap.DirectAllocator.init();
defer da.deinit();
const allocator = &da.allocator;
var loop: Loop = undefined;
try loop.initMultiThreaded(allocator);
defer loop.deinit();
var did_it = false;
const handle = try loop.call(testEventLoop);
const handle2 = try loop.call(testEventLoop2, handle, &did_it);
defer cancel handle2;
loop.run();
testing.expect(did_it);
}
async fn testEventLoop() i32 {
return 1234;
}
async fn testEventLoop2(h: promise->i32, did_it: *bool) void {
const value = await h;
testing.expect(value == 1234);
did_it.* = true;
}