Commit e3ae2cfb52
Changed files (13)
std/debug/index.zig
@@ -23,7 +23,10 @@ pub const runtime_safety = switch (builtin.mode) {
var stderr_file: os.File = undefined;
var stderr_file_out_stream: io.FileOutStream = undefined;
var stderr_stream: ?*io.OutStream(io.FileOutStream.Error) = null;
+var stderr_mutex = std.Mutex.init();
pub fn warn(comptime fmt: []const u8, args: ...) void {
+ const held = stderr_mutex.acquire();
+ defer held.release();
const stderr = getStderrStream() catch return;
stderr.print(fmt, args) catch return;
}
std/event/channel.zig
@@ -116,6 +116,10 @@ pub fn Channel(comptime T: type) type {
return result;
}
+ fn getOrNull(self: *SelfChannel) ?T {
+ TODO();
+ }
+
fn dispatch(self: *SelfChannel) void {
// set the "need dispatch" flag
_ = @atomicRmw(u8, &self.need_dispatch, AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst);
std/event/fs.zig
@@ -253,7 +253,9 @@ pub async fn openReadWrite(
}
/// This abstraction helps to close file handles in defer expressions
-/// without suspending. Start a CloseOperation before opening a file.
+/// without the possibility of failure and without the use of suspend points.
+/// Start a `CloseOperation` before opening a file, so that you can defer
+/// `CloseOperation.deinit`.
pub const CloseOperation = struct {
loop: *event.Loop,
have_fd: bool,
std/event/group.zig
@@ -29,6 +29,17 @@ pub fn Group(comptime ReturnType: type) type {
};
}
+ /// Cancel all the outstanding promises. Can be called even if wait was already called.
+ pub fn deinit(self: *Self) void {
+ while (self.coro_stack.pop()) |node| {
+ cancel node.data;
+ }
+ while (self.alloc_stack.pop()) |node| {
+ cancel node.data;
+ self.lock.loop.allocator.destroy(node);
+ }
+ }
+
/// Add a promise to the group. Thread-safe.
pub fn add(self: *Self, handle: promise->ReturnType) (error{OutOfMemory}!void) {
const node = try self.lock.loop.allocator.create(Stack.Node{
@@ -88,7 +99,7 @@ pub fn Group(comptime ReturnType: type) type {
await node.data;
} else {
(await node.data) catch |err| {
- self.cancelAll();
+ self.deinit();
return err;
};
}
@@ -100,25 +111,12 @@ pub fn Group(comptime ReturnType: type) type {
await handle;
} else {
(await handle) catch |err| {
- self.cancelAll();
+ self.deinit();
return err;
};
}
}
}
-
- /// Cancel all the outstanding promises. May only be called if wait was never called.
- /// TODO These should be `cancelasync` not `cancel`.
- /// See https://github.com/ziglang/zig/issues/1261
- pub fn cancelAll(self: *Self) void {
- while (self.coro_stack.pop()) |node| {
- cancel node.data;
- }
- while (self.alloc_stack.pop()) |node| {
- cancel node.data;
- self.lock.loop.allocator.destroy(node);
- }
- }
};
}
std/event/lock.zig
@@ -9,6 +9,7 @@ const Loop = std.event.Loop;
/// Thread-safe async/await lock.
/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
/// are resumed when the lock is released, in order.
+/// Allows only one actor to hold the lock.
pub const Lock = struct {
loop: *Loop,
shared_bit: u8, // TODO make this a bool
std/event/rwlock.zig
@@ -0,0 +1,292 @@
+const std = @import("../index.zig");
+const builtin = @import("builtin");
+const assert = std.debug.assert;
+const mem = std.mem;
+const AtomicRmwOp = builtin.AtomicRmwOp;
+const AtomicOrder = builtin.AtomicOrder;
+const Loop = std.event.Loop;
+
+/// Thread-safe async/await lock.
+/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
+/// are resumed when the lock is released, in order.
+/// Many readers can hold the lock at the same time; however locking for writing is exclusive.
+pub const RwLock = struct {
+ loop: *Loop,
+ shared_state: u8, // TODO make this an enum
+ writer_queue: Queue,
+ reader_queue: Queue,
+ writer_queue_empty_bit: u8, // TODO make this a bool
+ reader_queue_empty_bit: u8, // TODO make this a bool
+ reader_lock_count: usize,
+
+ const State = struct {
+ const Unlocked = 0;
+ const WriteLock = 1;
+ const ReadLock = 2;
+ };
+
+ const Queue = std.atomic.Queue(promise);
+
+ pub const HeldRead = struct {
+ lock: *RwLock,
+
+ pub fn release(self: HeldRead) void {
+ // If other readers still hold the lock, we're done.
+ if (@atomicRmw(usize, &self.lock.reader_lock_count, AtomicRmwOp.Sub, 1, AtomicOrder.SeqCst) != 1) {
+ return;
+ }
+
+ _ = @atomicRmw(u8, &self.lock.reader_queue_empty_bit, AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst);
+ if (@cmpxchgStrong(u8, &self.lock.shared_state, State.ReadLock, State.Unlocked, AtomicOrder.SeqCst, AtomicOrder.SeqCst) != null) {
+ // Didn't unlock. Someone else's problem.
+ return;
+ }
+
+ self.lock.commonPostUnlock();
+ }
+ };
+
+ pub const HeldWrite = struct {
+ lock: *RwLock,
+
+ pub fn release(self: HeldWrite) void {
+ // See if we can leave it locked for writing, and pass the lock to the next writer
+ // in the queue to grab the lock.
+ if (self.lock.writer_queue.get()) |node| {
+ self.lock.loop.onNextTick(node);
+ return;
+ }
+
+ // We need to release the write lock. Check if any readers are waiting to grab the lock.
+ if (@atomicLoad(u8, &self.lock.reader_queue_empty_bit, AtomicOrder.SeqCst) == 0) {
+ // Switch to a read lock.
+ _ = @atomicRmw(u8, &self.lock.shared_state, AtomicRmwOp.Xchg, State.ReadLock, AtomicOrder.SeqCst);
+ while (self.lock.reader_queue.get()) |node| {
+ self.lock.loop.onNextTick(node);
+ }
+ return;
+ }
+
+ _ = @atomicRmw(u8, &self.lock.writer_queue_empty_bit, AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst);
+ _ = @atomicRmw(u8, &self.lock.shared_state, AtomicRmwOp.Xchg, State.Unlocked, AtomicOrder.SeqCst);
+
+ self.lock.commonPostUnlock();
+ }
+ };
+
+ pub fn init(loop: *Loop) RwLock {
+ return RwLock{
+ .loop = loop,
+ .shared_state = State.Unlocked,
+ .writer_queue = Queue.init(),
+ .writer_queue_empty_bit = 1,
+ .reader_queue = Queue.init(),
+ .reader_queue_empty_bit = 1,
+ .reader_lock_count = 0,
+ };
+ }
+
+ /// Must be called when not locked. Not thread safe.
+ /// All calls to acquire() and release() must complete before calling deinit().
+ pub fn deinit(self: *RwLock) void {
+ assert(self.shared_state == State.Unlocked);
+ while (self.writer_queue.get()) |node| cancel node.data;
+ while (self.reader_queue.get()) |node| cancel node.data;
+ }
+
+ pub async fn acquireRead(self: *RwLock) HeldRead {
+ _ = @atomicRmw(usize, &self.reader_lock_count, AtomicRmwOp.Add, 1, AtomicOrder.SeqCst);
+
+ suspend |handle| {
+ // TODO explicitly put this memory in the coroutine frame #1194
+ var my_tick_node = Loop.NextTickNode{
+ .data = handle,
+ .next = undefined,
+ };
+
+ self.reader_queue.put(&my_tick_node);
+
+ // At this point, we are in the reader_queue, so we might have already been resumed and this coroutine
+ // frame might be destroyed. For the rest of the suspend block we cannot access the coroutine frame.
+
+ // We set this bit so that later we can rely on the fact, that if reader_queue_empty_bit is 1,
+ // some actor will attempt to grab the lock.
+ _ = @atomicRmw(u8, &self.reader_queue_empty_bit, AtomicRmwOp.Xchg, 0, AtomicOrder.SeqCst);
+
+ // Here we don't care if we are the one to do the locking or if it was already locked for reading.
+ const have_read_lock = if (@cmpxchgStrong(u8, &self.shared_state, State.Unlocked, State.ReadLock, AtomicOrder.SeqCst, AtomicOrder.SeqCst)) |old_state| old_state == State.ReadLock else true;
+ if (have_read_lock) {
+ // Give out all the read locks.
+ if (self.reader_queue.get()) |first_node| {
+ while (self.reader_queue.get()) |node| {
+ self.loop.onNextTick(node);
+ }
+ resume first_node.data;
+ }
+ }
+ }
+ return HeldRead{ .lock = self };
+ }
+
+ pub async fn acquireWrite(self: *RwLock) HeldWrite {
+ suspend |handle| {
+ // TODO explicitly put this memory in the coroutine frame #1194
+ var my_tick_node = Loop.NextTickNode{
+ .data = handle,
+ .next = undefined,
+ };
+
+ self.writer_queue.put(&my_tick_node);
+
+ // At this point, we are in the writer_queue, so we might have already been resumed and this coroutine
+ // frame might be destroyed. For the rest of the suspend block we cannot access the coroutine frame.
+
+ // We set this bit so that later we can rely on the fact, that if writer_queue_empty_bit is 1,
+ // some actor will attempt to grab the lock.
+ _ = @atomicRmw(u8, &self.writer_queue_empty_bit, AtomicRmwOp.Xchg, 0, AtomicOrder.SeqCst);
+
+ // Here we must be the one to acquire the write lock. It cannot already be locked.
+ if (@cmpxchgStrong(u8, &self.shared_state, State.Unlocked, State.WriteLock, AtomicOrder.SeqCst, AtomicOrder.SeqCst) == null) {
+ // We now have a write lock.
+ if (self.writer_queue.get()) |node| {
+ // Whether this node is us or someone else, we tail resume it.
+ resume node.data;
+ }
+ }
+ }
+ return HeldWrite{ .lock = self };
+ }
+
+ fn commonPostUnlock(self: *RwLock) void {
+ while (true) {
+ // There might be a writer_queue item or a reader_queue item
+ // If we check and both are empty, we can be done, because the other actors will try to
+ // obtain the lock.
+ // But if there's a writer_queue item or a reader_queue item,
+ // we are the actor which must loop and attempt to grab the lock again.
+ if (@atomicLoad(u8, &self.writer_queue_empty_bit, AtomicOrder.SeqCst) == 0) {
+ if (@cmpxchgStrong(u8, &self.shared_state, State.Unlocked, State.WriteLock, AtomicOrder.SeqCst, AtomicOrder.SeqCst) != null) {
+ // We did not obtain the lock. Great, the queues are someone else's problem.
+ return;
+ }
+ // If there's an item in the writer queue, give them the lock, and we're done.
+ if (self.writer_queue.get()) |node| {
+ self.loop.onNextTick(node);
+ return;
+ }
+ // Release the lock again.
+ _ = @atomicRmw(u8, &self.writer_queue_empty_bit, AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst);
+ _ = @atomicRmw(u8, &self.shared_state, AtomicRmwOp.Xchg, State.Unlocked, AtomicOrder.SeqCst);
+ continue;
+ }
+
+ if (@atomicLoad(u8, &self.reader_queue_empty_bit, AtomicOrder.SeqCst) == 0) {
+ if (@cmpxchgStrong(u8, &self.shared_state, State.Unlocked, State.ReadLock, AtomicOrder.SeqCst, AtomicOrder.SeqCst) != null) {
+ // We did not obtain the lock. Great, the queues are someone else's problem.
+ return;
+ }
+ // If there are any items in the reader queue, give out all the reader locks, and we're done.
+ if (self.reader_queue.get()) |first_node| {
+ self.loop.onNextTick(first_node);
+ while (self.reader_queue.get()) |node| {
+ self.loop.onNextTick(node);
+ }
+ return;
+ }
+ // Release the lock again.
+ _ = @atomicRmw(u8, &self.reader_queue_empty_bit, AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst);
+ if (@cmpxchgStrong(u8, &self.shared_state, State.ReadLock, State.Unlocked, AtomicOrder.SeqCst, AtomicOrder.SeqCst) != null) {
+ // Didn't unlock. Someone else's problem.
+ return;
+ }
+ continue;
+ }
+ return;
+ }
+ }
+};
+
+test "std.event.RwLock" {
+ 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 lock = RwLock.init(&loop);
+ defer lock.deinit();
+
+ const handle = try async<allocator> testLock(&loop, &lock);
+ defer cancel handle;
+ loop.run();
+
+ const expected_result = [1]i32{shared_it_count * @intCast(i32, shared_test_data.len)} ** shared_test_data.len;
+ assert(mem.eql(i32, shared_test_data, expected_result));
+}
+
+async fn testLock(loop: *Loop, lock: *RwLock) void {
+ // TODO explicitly put next tick node memory in the coroutine frame #1194
+ suspend |p| {
+ resume p;
+ }
+
+ var read_nodes: [100]Loop.NextTickNode = undefined;
+ for (read_nodes) |*read_node| {
+ read_node.data = async readRunner(lock) catch @panic("out of memory");
+ loop.onNextTick(read_node);
+ }
+
+ var write_nodes: [shared_it_count]Loop.NextTickNode = undefined;
+ for (write_nodes) |*write_node| {
+ write_node.data = async writeRunner(lock) catch @panic("out of memory");
+ loop.onNextTick(write_node);
+ }
+
+ for (write_nodes) |*write_node| {
+ await @ptrCast(promise->void, write_node.data);
+ }
+ for (read_nodes) |*read_node| {
+ await @ptrCast(promise->void, read_node.data);
+ }
+}
+
+const shared_it_count = 10;
+var shared_test_data = [1]i32{0} ** 10;
+var shared_test_index: usize = 0;
+var shared_count: usize = 0;
+
+async fn writeRunner(lock: *RwLock) void {
+ suspend; // resumed by onNextTick
+
+ var i: usize = 0;
+ while (i < shared_test_data.len) : (i += 1) {
+ std.os.time.sleep(0, 100000);
+ const lock_promise = async lock.acquireWrite() catch @panic("out of memory");
+ const handle = await lock_promise;
+ defer handle.release();
+
+ shared_count += 1;
+ while (shared_test_index < shared_test_data.len) : (shared_test_index += 1) {
+ shared_test_data[shared_test_index] = shared_test_data[shared_test_index] + 1;
+ }
+ shared_test_index = 0;
+ }
+}
+
+async fn readRunner(lock: *RwLock) void {
+ suspend; // resumed by onNextTick
+ std.os.time.sleep(0, 1);
+
+ var i: usize = 0;
+ while (i < shared_test_data.len) : (i += 1) {
+ const lock_promise = async lock.acquireRead() catch @panic("out of memory");
+ const handle = await lock_promise;
+ defer handle.release();
+
+ assert(shared_test_index == 0);
+ assert(shared_test_data[i] == @intCast(i32, shared_count));
+ }
+}
std/event/rwlocked.zig
@@ -0,0 +1,58 @@
+const std = @import("../index.zig");
+const RwLock = std.event.RwLock;
+const Loop = std.event.Loop;
+
+/// Thread-safe async/await RW lock that protects one piece of data.
+/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
+/// are resumed when the lock is released, in order.
+pub fn RwLocked(comptime T: type) type {
+ return struct {
+ lock: RwLock,
+ locked_data: T,
+
+ const Self = this;
+
+ pub const HeldReadLock = struct {
+ value: *const T,
+ held: RwLock.HeldRead,
+
+ pub fn release(self: HeldReadLock) void {
+ self.held.release();
+ }
+ };
+
+ pub const HeldWriteLock = struct {
+ value: *T,
+ held: RwLock.HeldWrite,
+
+ pub fn release(self: HeldWriteLock) void {
+ self.held.release();
+ }
+ };
+
+ pub fn init(loop: *Loop, data: T) Self {
+ return Self{
+ .lock = RwLock.init(loop),
+ .locked_data = data,
+ };
+ }
+
+ pub fn deinit(self: *Self) void {
+ self.lock.deinit();
+ }
+
+ pub async fn acquireRead(self: *Self) HeldReadLock {
+ return HeldReadLock{
+ .held = await (async self.lock.acquireRead() catch unreachable),
+ .value = &self.locked_data,
+ };
+ }
+
+ pub async fn acquireWrite(self: *Self) HeldWriteLock {
+ return HeldWriteLock{
+ .held = await (async self.lock.acquireWrite() catch unreachable),
+ .value = &self.locked_data,
+ };
+ }
+ };
+}
std/event/tcp.zig
@@ -61,7 +61,7 @@ pub const Server = struct {
/// Stop listening
pub fn close(self: *Server) void {
- self.loop.removeFd(self.sockfd.?);
+ self.loop.linuxRemoveFd(self.sockfd.?);
std.os.close(self.sockfd.?);
}
@@ -116,7 +116,7 @@ pub async fn connect(loop: *Loop, _address: *const std.net.Address) !std.os.File
errdefer std.os.close(sockfd);
try std.os.posixConnectAsync(sockfd, &address.os_addr);
- try await try async loop.linuxWaitFd(sockfd, posix.EPOLLIN | posix.EPOLLOUT);
+ try await try async loop.linuxWaitFd(sockfd, posix.EPOLLIN | posix.EPOLLOUT | posix.EPOLLET);
try std.os.posixGetSockOptConnectError(sockfd);
return std.os.File.openHandle(sockfd);
std/event.zig
@@ -3,6 +3,8 @@ pub const Future = @import("event/future.zig").Future;
pub const Group = @import("event/group.zig").Group;
pub const Lock = @import("event/lock.zig").Lock;
pub const Locked = @import("event/locked.zig").Locked;
+pub const RwLock = @import("event/rwlock.zig").Lock;
+pub const RwLocked = @import("event/rwlocked.zig").RwLocked;
pub const Loop = @import("event/loop.zig").Loop;
pub const fs = @import("event/fs.zig");
pub const tcp = @import("event/tcp.zig");
@@ -14,6 +16,8 @@ test "import event tests" {
_ = @import("event/group.zig");
_ = @import("event/lock.zig");
_ = @import("event/locked.zig");
+ _ = @import("event/rwlock.zig");
+ _ = @import("event/rwlocked.zig");
_ = @import("event/loop.zig");
_ = @import("event/tcp.zig");
}
std/hash_map.zig
@@ -163,6 +163,16 @@ pub fn HashMap(comptime K: type, comptime V: type, comptime hash: fn (key: K) u3
};
}
+ pub fn clone(self: Self) !Self {
+ var other = Self.init(self.allocator);
+ try other.initCapacity(self.entries.len);
+ var it = self.iterator();
+ while (it.next()) |entry| {
+ try other.put(entry.key, entry.value);
+ }
+ return other;
+ }
+
fn initCapacity(hm: *Self, capacity: usize) !void {
hm.entries = try hm.allocator.alloc(Entry, capacity);
hm.size = 0;
std/index.zig
@@ -9,6 +9,7 @@ pub const LinkedList = @import("linked_list.zig").LinkedList;
pub const IntrusiveLinkedList = @import("linked_list.zig").IntrusiveLinkedList;
pub const SegmentedList = @import("segmented_list.zig").SegmentedList;
pub const DynLib = @import("dynamic_library.zig").DynLib;
+pub const Mutex = @import("mutex.zig").Mutex;
pub const atomic = @import("atomic/index.zig");
pub const base64 = @import("base64.zig");
@@ -48,6 +49,7 @@ test "std" {
_ = @import("hash_map.zig");
_ = @import("linked_list.zig");
_ = @import("segmented_list.zig");
+ _ = @import("mutex.zig");
_ = @import("base64.zig");
_ = @import("build.zig");
std/mutex.zig
@@ -0,0 +1,27 @@
+const std = @import("index.zig");
+const builtin = @import("builtin");
+const AtomicOrder = builtin.AtomicOrder;
+const AtomicRmwOp = builtin.AtomicRmwOp;
+const assert = std.debug.assert;
+
+/// TODO use syscalls instead of a spinlock
+pub const Mutex = struct {
+ lock: u8, // TODO use a bool
+
+ pub const Held = struct {
+ mutex: *Mutex,
+
+ pub fn release(self: Held) void {
+ assert(@atomicRmw(u8, &self.mutex.lock, builtin.AtomicRmwOp.Xchg, 0, AtomicOrder.SeqCst) == 1);
+ }
+ };
+
+ pub fn init() Mutex {
+ return Mutex{ .lock = 0 };
+ }
+
+ pub fn acquire(self: *Mutex) Held {
+ while (@atomicRmw(u8, &self.lock, builtin.AtomicRmwOp.Xchg, 1, AtomicOrder.SeqCst) != 0) {}
+ return Held{ .mutex = self };
+ }
+};
CMakeLists.txt
@@ -466,6 +466,8 @@ set(ZIG_STD_FILES
"event/lock.zig"
"event/locked.zig"
"event/loop.zig"
+ "event/rwlock.zig"
+ "event/rwlocked.zig"
"event/tcp.zig"
"fmt/errol/enum3.zig"
"fmt/errol/index.zig"
@@ -554,6 +556,7 @@ set(ZIG_STD_FILES
"math/tanh.zig"
"math/trunc.zig"
"mem.zig"
+ "mutex.zig"
"net.zig"
"os/child_process.zig"
"os/darwin.zig"