message: relocate from container

This package is quite useful. This change allows it to be imported without importing container.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 0 insertions, 77 deletions

diff --git a/container/output.go b/container/output.go
deleted file mode 100644
index 4d799eb4..00000000
--- a/container/output.go
+++ /dev/null
@@ -1,77 +0,0 @@
-package container
-
-import (
-	"bytes"
-	"io"
-	"sync"
-	"sync/atomic"
-	"syscall"
-)
-
-const (
-	suspendBufInitial = 1 << 12
-	suspendBufMax     = 1 << 24
-)
-
-// Suspendable proxies writes to a downstream [io.Writer] but optionally withholds writes
-// between calls to Suspend and Resume.
-type Suspendable struct {
-	Downstream io.Writer
-
-	s atomic.Bool
-
-	buf bytes.Buffer
-	// for growing buf
-	bufOnce sync.Once
-	// for synchronising all other buf operations
-	bufMu sync.Mutex
-
-	dropped int
-}
-
-func (s *Suspendable) Write(p []byte) (n int, err error) {
-	if !s.s.Load() {
-		return s.Downstream.Write(p)
-	}
-	s.bufOnce.Do(func() { s.buf.Grow(suspendBufInitial) })
-
-	s.bufMu.Lock()
-	defer s.bufMu.Unlock()
-
-	if free := suspendBufMax - s.buf.Len(); free < len(p) {
-		// fast path
-		if free <= 0 {
-			s.dropped += len(p)
-			return 0, syscall.ENOMEM
-		}
-
-		n, _ = s.buf.Write(p[:free])
-		err = syscall.ENOMEM
-		s.dropped += len(p) - n
-		return
-	}
-
-	return s.buf.Write(p)
-}
-
-// IsSuspended returns whether [Suspendable] is currently between a call to Suspend and Resume.
-func (s *Suspendable) IsSuspended() bool { return s.s.Load() }
-
-// Suspend causes [Suspendable] to start withholding output in its buffer.
-func (s *Suspendable) Suspend() bool { return s.s.CompareAndSwap(false, true) }
-
-// Resume undoes the effect of Suspend and dumps the buffered into the downstream [io.Writer].
-func (s *Suspendable) Resume() (resumed bool, dropped uintptr, n int64, err error) {
-	if s.s.CompareAndSwap(true, false) {
-		s.bufMu.Lock()
-		defer s.bufMu.Unlock()
-
-		resumed = true
-		dropped = uintptr(s.dropped)
-
-		s.dropped = 0
-		n, err = io.Copy(s.Downstream, &s.buf)
-		s.buf.Reset()
-	}
-	return
-}