package log

import (
	"io"

	"github.com/go-kit/log"
)

// SwapLogger wraps another logger that may be safely replaced while other
// goroutines use the SwapLogger concurrently. The zero value for a SwapLogger
// will discard all log events without error.
//
// SwapLogger serves well as a package global logger that can be changed by
// importers.
type SwapLogger = log.SwapLogger

// NewSyncWriter returns a new writer that is safe for concurrent use by
// multiple goroutines. Writes to the returned writer are passed on to w. If
// another write is already in progress, the calling goroutine blocks until
// the writer is available.
//
// If w implements the following interface, so does the returned writer.
//
//    interface {
//        Fd() uintptr
//    }
func NewSyncWriter(w io.Writer) io.Writer {
	return log.NewSyncWriter(w)
}

// NewSyncLogger returns a logger that synchronizes concurrent use of the
// wrapped logger. When multiple goroutines use the SyncLogger concurrently
// only one goroutine will be allowed to log to the wrapped logger at a time.
// The other goroutines will block until the logger is available.
func NewSyncLogger(logger Logger) Logger {
	return log.NewSyncLogger(logger)
}