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restic/internal/ui/progress/counter.go
greatroar 2dafda9164 ui/progress: Load both values in a single Lock/Unlock
We always need both values, except in a test, so we don't need to lock
twice and risk scheduling in between.

Also, removed the resetting in Done. This copied a mutex, which isn't
allowed. Static analyzers tend to trip over that.
2022-10-25 07:55:24 +02:00

123 lines
2.5 KiB
Go

package progress
import (
"sync"
"time"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/ui/signals"
)
// A Func is a callback for a Counter.
//
// The final argument is true if Counter.Done has been called,
// which means that the current call will be the last.
type Func func(value uint64, total uint64, runtime time.Duration, final bool)
// A Counter tracks a running count and controls a goroutine that passes its
// value periodically to a Func.
//
// The Func is also called when SIGUSR1 (or SIGINFO, on BSD) is received.
type Counter struct {
report Func
start time.Time
stopped chan struct{} // Closed by run.
stop chan struct{} // Close to stop run.
tick *time.Ticker
valueMutex sync.Mutex
value uint64
max uint64
}
// New starts a new Counter.
func New(interval time.Duration, total uint64, report Func) *Counter {
c := &Counter{
report: report,
start: time.Now(),
stopped: make(chan struct{}),
stop: make(chan struct{}),
max: total,
}
if interval > 0 {
c.tick = time.NewTicker(interval)
}
go c.run()
return c
}
// Add v to the Counter. This method is concurrency-safe.
func (c *Counter) Add(v uint64) {
if c == nil {
return
}
c.valueMutex.Lock()
c.value += v
c.valueMutex.Unlock()
}
// SetMax sets the maximum expected counter value. This method is concurrency-safe.
func (c *Counter) SetMax(max uint64) {
if c == nil {
return
}
c.valueMutex.Lock()
c.max = max
c.valueMutex.Unlock()
}
// Done tells a Counter to stop and waits for it to report its final value.
func (c *Counter) Done() {
if c == nil {
return
}
if c.tick != nil {
c.tick.Stop()
}
close(c.stop)
<-c.stopped // Wait for last progress report.
}
// Get returns the current value and the maximum of c.
// This method is concurrency-safe.
func (c *Counter) Get() (v, max uint64) {
c.valueMutex.Lock()
v, max = c.value, c.max
c.valueMutex.Unlock()
return v, max
}
func (c *Counter) run() {
defer close(c.stopped)
defer func() {
// Must be a func so that time.Since isn't called at defer time.
v, max := c.Get()
c.report(v, max, time.Since(c.start), true)
}()
var tick <-chan time.Time
if c.tick != nil {
tick = c.tick.C
}
signalsCh := signals.GetProgressChannel()
for {
var now time.Time
select {
case now = <-tick:
case sig := <-signalsCh:
debug.Log("Signal received: %v\n", sig)
now = time.Now()
case <-c.stop:
return
}
v, max := c.Get()
c.report(v, max, now.Sub(c.start), false)
}
}