container: Rename Optional to Option

container/option.go

@@ -0,0 +1,31 @@
+package ucontainer
+
+// Option can either hold a value, or nothing.
+type Option[T any] struct {
+	value T
+	exists bool
+}
+
+// O creates a new option with the specified value.
+func O[T any] (value T) Option[T] {
+	return Option[T] {
+		value: value,
+		exists: true,
+	}
+}
+
+// Void returns an option with no value.
+func Void[T any] () Option[T] {
+	return Option[T] { }
+}
+
+// Exists returns if the value is currently set.
+func (option Option[T]) Exists () bool {
+	return option.exists
+}
+
+// Value returns the value and true if the value exists. If not, it returns the
+// zero value and false.
+func (option Option[T]) Value () (T, bool) {
+	return option.value, option.exists
+}

container/optional.go

@@ -1,31 +0,0 @@
-package ucontainer
-
-// Optional can either hold a value, or nothing.
-type Optional[T any] struct {
-	value T
-	exists bool
-}
-
-// O creates a new optional with the specified value.
-func O[T any] (value T) Optional[T] {
-	return Optional[T] {
-		value: value,
-		exists: true,
-	}
-}
-
-// Void returns an optional with no value.
-func Void[T any] () Optional[T] {
-	return Optional[T] { }
-}
-
-// Exists returns if the value is currently set.
-func (optional Optional[T]) Exists () bool {
-	return optional.exists
-}
-
-// Value returns the value and true if the value exists. If not, it returns the
-// zero value and false.
-func (optional Optional[T]) Value () (T, bool) {
-	return optional.value, optional.exists
-}

sync/atomic/generic.go

@@ -0,0 +1,38 @@
+package uatomic
+
+import "sync/atomic"
+
+// Atom is a generic wrapper for atomic.Value.
+type Atom[T comparable] struct {
+	value atomic.Value
+}
+
+type atomWrapper[T comparable] struct { value T }
+
+// CompareAndSwap executes the compare-and-swap operation for the Atom.
+func (atom *Atom[T]) CompareAndSwap(old, neww T) (swapped bool) {
+	return atom.value.CompareAndSwap(
+		atomWrapper[T] { value: old },
+		atomWrapper[T] { value: neww })
+}
+
+func (atom *Atom[T]) Load() T {
+	return castSafe[T](atom.value.Load())
+}
+
+func (atom *Atom[T]) Store(val T) {
+	atom.value.Store(val)
+}
+
+func (atom *Atom[T]) Swap(neww T) T {
+	return castSafe[T](atom.value.Swap(neww))
+}
+
+func castSafe[T comparable](value any) T {
+	var zero T
+	if value == nil {
+		return zero
+	} else {
+		return value.(T)
+	}
+}

sync/gate.go

@@ -1,6 +1,6 @@
 package usync
 
-import "sync"
+import "sync/atomic"
 
 // Error defines errors that this package can produce
 type Error string; const (
@@ -12,83 +12,74 @@ func (err Error) Error () string {
 	return string(err)
 }
 
+// if you know of a better way, i'd like to hear of it. otherwise, STFU!!!!
+
 // Gate wraps a channel and allows the receiver to abruptly stop receiving
 // messages without causing the sender to lock up.
 type Gate[T any] struct {
-	channel    chan T
+	channel    atomic.Value
-	lock       sync.RWMutex
-	open       bool
 	bufferSize int
 }
 
 // NewGate creates a new gate with no buffer.
 func NewGate[T any] () Gate[T] {
-	return Gate[T] {
+	return NewBufferedGate[T](0)
-		channel: make(chan T),
-		open:    true,
-	}
 }
 
 // NewBufferedGate creates a new gate with a buffer.
 func NewBufferedGate[T any] (buffer int) Gate[T] {
-	return Gate[T] {
+	gate := Gate[T] {
-		channel:    make(chan T, buffer),
-		open:       true,
 		bufferSize: buffer,
 	}
+	gate.channel.Store(make(chan T, buffer))
+	return gate
 }
 
 // Send sends and item to the channel, returning whether the item was sent.
-func (this *Gate[T]) Send (item T) bool {
+func (this *Gate[T]) Send (item T) (ok bool) {
-	this.lock.RLock()
+	channel := this.load()
-	defer this.lock.RUnlock()
+	if channel == nil { return false }
-	if !this.open { return false }
+	// if the channel send panics, "return true" never gets run so it just
-	this.channel <- item
+	// returns false after recovering
+	defer func() { recover() }()
+	channel <- item
 	return true
 }
 
 // Receive returns a receive-only channel that can be used to receive items.
 func (this *Gate[T]) Receive () <- chan T {
-	this.lock.RLock()
+	return this.load()
-	defer this.lock.RUnlock()
-	return this.channel
 }
 
-// Close closes the gate, drains all remaining messages, and closes the channel.
+// Close closes the gate, unblocking any send or receive operations.
 func (this *Gate[T]) Close () error {
-	this.lock.Lock()
+	channel := this.channel.Swap((chan T)(nil)).(chan T)
-	if !this.open { return ErrAlreadyClosed }
+	if channel == nil { return ErrAlreadyClosed }
-	this.open = false
+	close(channel)
-	this.lock.Unlock()
-	for len(this.channel) > 0 { <- this.channel }
-	close(this.channel)
 	return nil
 }
 
 // Reset re-opens the gate if it is closed, and creates a new channel.
 func (this *Gate[T]) Reset () error {
-	this.lock.Lock()
+	this.channel.Store(make(chan T, this.bufferSize))
-	defer this.lock.Unlock()
-	this.open = true
-	if this.channel != nil { close(this.channel) }
-	this.channel = make(chan T, this.bufferSize)
 	return nil
 }
 
 // Open returns whether the gate is open.
 func (this *Gate[T]) Open () bool {
-	this.lock.RLock()
+	return this.load() != nil
-	defer this.lock.RUnlock()
-	return this.open
 }
 
 // Len returns the amount of items in the channel.
 func (this *Gate[T]) Len () int {
-	return len(this.channel)
+	return len(this.load())
 }
 
 // Cap returns the amount of items the channel can hold.
 func (this *Gate[T]) Cap () int {
-	return cap(this.channel)
+	return cap(this.load())
 }
 
+func (this *Gate[T]) load() chan T {
+	return this.channel.Load().(chan T)
+}

sync/gate_test.go

@@ -0,0 +1,63 @@
+package usync
+
+import "time"
+import "errors"
+import "testing"
+
+func TestGate(test *testing.T) {
+	gate := NewGate[int]()
+	go func() {
+		for number := range 21 {
+			test.Log("send", number)
+			gate.Send(number)
+		}
+		test.Log("send done")
+	}()
+	for correct := range 21 {
+		got := <- gate.Receive()
+		test.Log("RECV", correct, got)
+		if correct != got {
+			test.Fatal("RECV not equal")
+		}
+	}
+	test.Log("RECV done")
+}
+
+func TestGateCloseEarly(test *testing.T) {
+	gate := NewGate[int]()
+	sendDone := make(chan struct { })
+	go func() {
+		for number := range 21 {
+			test.Log("send", number)
+			gate.Send(number)
+		}
+		test.Log("send done")
+		close(sendDone)
+	}()
+	for correct := range 15 {
+		got := <- gate.Receive()
+		test.Log("RECV", correct, got)
+		if correct != got {
+			test.Fatal("RECV not equal")
+		}
+	}
+	test.Log("RECV done, closing gate... DOOR STUCK!! PLS I BEG OF YOU!!")
+	gate.Close()
+	test.Log("RECV closed gate yay :)))")
+	timeout := time.NewTimer(time.Second * 4)
+	select {
+	case <- sendDone:
+	case <- timeout.C:
+		test.Fatal("timed out waiting for sender goroutine to stop")
+	}
+}
+
+func TestGateCloseIdempotent(test *testing.T) {
+	gate := NewGate[int]()
+	err := gate.Close()
+	if err != nil { test.Fatal(err) }
+	err = gate.Close()
+	if !errors.Is(err, ErrAlreadyClosed) {
+		test.Fatal("wrong error: ", err)
+	}
+}

sync/monitor.go

@@ -39,12 +39,12 @@ func (this *Monitor[T]) Borrow () (T, func ()) {
 // updated value. The intended use of this function is like this:
 //
 //   value, done := monitor.BorrowReturn()
-//   defer done(value)
+//   defer done(&value)
-func (this *Monitor[T]) BorrowReturn () (T, func (T)) {
+func (this *Monitor[T]) BorrowReturn () (T, func (*T)) {
 	this.mutex.Lock()
-	return this.value, func (value T) {
+	return this.value, func (value *T) {
 		defer this.mutex.Unlock()
-		this.value = value
+		this.value = *value
 	}
 }
 
@@ -86,12 +86,12 @@ func (this *RWMonitor[T]) Borrow () (T, func ()) {
 // updated value. The intended use of this function is like this:
 //
 //   value, done := monitor.BorrowReturn()
-//   defer done(value)
+//   defer done(&value)
-func (this *RWMonitor[T]) BorrowReturn () (T, func (T)) {
+func (this *RWMonitor[T]) BorrowReturn () (T, func (*T)) {
 	this.mutex.Lock()
-	return this.value, func (value T) {
+	return this.value, func (value *T) {
 		defer this.mutex.Unlock()
-		this.value = value
+		this.value = *value
 	}
 }
 

sync/monitor_test.go

@@ -13,8 +13,8 @@ func TestMonitor (test *testing.T) {
 	} ()
 	func () {
 		value, done := mon.BorrowReturn()
+		defer done(&value)
 		value += 3
-		defer done(value)
 	} ()
 	func () {
 		value, done := mon.Borrow()
@@ -56,8 +56,8 @@ func TestRWMonitor (test *testing.T) {
 	} ()
 	func () {
 		value, done := mon.BorrowReturn()
+		defer done(&value)
 		value += 3
-		defer done(value)
 	} ()
 	func () {
 		value, done := mon.RBorrow()