78 lines
2.0 KiB
Go
78 lines
2.0 KiB
Go
package usync
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import "sync"
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// Monitor guards access to a value. It must not be copied after first use.
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type Monitor[T any] struct {
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value T
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mutex sync.Mutex
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}
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// NewMonitor creates a new Monitor with the specified value.
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func NewMonitor[T any] (value T) Monitor[T] {
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return Monitor[T] {
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value: value,
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}
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}
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// Set sets the value of the Monitor.
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func (this *Monitor[T]) Set (value T) {
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this.mutex.Lock()
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defer this.mutex.Unlock()
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this.value = value
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}
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// Borrow borrows the value from the Monitor, and returns a function that must
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// immediately be deferred, like this:
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//
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// value, done := Monitor.Borrow()
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// defer done()
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//
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// From the time Borrow is called to the time the done function is called, it is
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// safe to access the locked object from within the current goroutine.
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func (this *Monitor[T]) Borrow () (T, func ()) {
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this.mutex.Lock()
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return this.value, this.mutex.Unlock
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}
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// RWMonitor guards separate read/write access to a value.
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type RWMonitor[T any] struct {
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value T
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mutex sync.RWMutex
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}
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// NewRWMonitor creates a new Monitor with the specified value. It must not be
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// copied after first use.
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func NewRWMonitor[T any] (value T) RWMonitor[T] {
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return RWMonitor[T] {
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value: value,
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}
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}
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// Set sets the value of the Monitor.
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func (this *RWMonitor[T]) Set (value T) {
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this.mutex.Lock()
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defer this.mutex.Unlock()
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this.value = value
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}
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// Borrow borrows the value from the Monitor for write access, and returns a
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// function that must immediately be deferred, like this:
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//
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// value, done := Monitor.Borrow()
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// defer done()
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//
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// From the time Borrow is called to the time the done function is called, it is
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// safe to access the locked object from within the current goroutine.
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func (this *RWMonitor[T]) Borrow () (T, func ()) {
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this.mutex.Lock()
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return this.value, this.mutex.Unlock
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}
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// RBorrow is like Borrow, but returns the item for read access only. Do not
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// under any circumstances modify anything returned by this method.
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func (this *RWMonitor[T]) RBorrow () (T, func ()) {
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this.mutex.Lock()
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return this.value, this.mutex.Unlock
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}
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