diff options
Diffstat (limited to 'vendor/go.uber.org/zap/zapcore/write_syncer.go')
-rw-r--r-- | vendor/go.uber.org/zap/zapcore/write_syncer.go | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/vendor/go.uber.org/zap/zapcore/write_syncer.go b/vendor/go.uber.org/zap/zapcore/write_syncer.go new file mode 100644 index 000000000..209e25fe2 --- /dev/null +++ b/vendor/go.uber.org/zap/zapcore/write_syncer.go @@ -0,0 +1,123 @@ +// Copyright (c) 2016 Uber Technologies, Inc. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package zapcore + +import ( + "io" + "sync" + + "go.uber.org/multierr" +) + +// A WriteSyncer is an io.Writer that can also flush any buffered data. Note +// that *os.File (and thus, os.Stderr and os.Stdout) implement WriteSyncer. +type WriteSyncer interface { + io.Writer + Sync() error +} + +// AddSync converts an io.Writer to a WriteSyncer. It attempts to be +// intelligent: if the concrete type of the io.Writer implements WriteSyncer, +// we'll use the existing Sync method. If it doesn't, we'll add a no-op Sync. +func AddSync(w io.Writer) WriteSyncer { + switch w := w.(type) { + case WriteSyncer: + return w + default: + return writerWrapper{w} + } +} + +type lockedWriteSyncer struct { + sync.Mutex + ws WriteSyncer +} + +// Lock wraps a WriteSyncer in a mutex to make it safe for concurrent use. In +// particular, *os.Files must be locked before use. +func Lock(ws WriteSyncer) WriteSyncer { + if _, ok := ws.(*lockedWriteSyncer); ok { + // no need to layer on another lock + return ws + } + return &lockedWriteSyncer{ws: ws} +} + +func (s *lockedWriteSyncer) Write(bs []byte) (int, error) { + s.Lock() + n, err := s.ws.Write(bs) + s.Unlock() + return n, err +} + +func (s *lockedWriteSyncer) Sync() error { + s.Lock() + err := s.ws.Sync() + s.Unlock() + return err +} + +type writerWrapper struct { + io.Writer +} + +func (w writerWrapper) Sync() error { + return nil +} + +type multiWriteSyncer []WriteSyncer + +// NewMultiWriteSyncer creates a WriteSyncer that duplicates its writes +// and sync calls, much like io.MultiWriter. +func NewMultiWriteSyncer(ws ...WriteSyncer) WriteSyncer { + if len(ws) == 1 { + return ws[0] + } + // Copy to protect against https://github.com/golang/go/issues/7809 + return multiWriteSyncer(append([]WriteSyncer(nil), ws...)) +} + +// See https://golang.org/src/io/multi.go +// When not all underlying syncers write the same number of bytes, +// the smallest number is returned even though Write() is called on +// all of them. +func (ws multiWriteSyncer) Write(p []byte) (int, error) { + var writeErr error + nWritten := 0 + for _, w := range ws { + n, err := w.Write(p) + writeErr = multierr.Append(writeErr, err) + if nWritten == 0 && n != 0 { + nWritten = n + } else if n < nWritten { + nWritten = n + } + } + return nWritten, writeErr +} + +func (ws multiWriteSyncer) Sync() error { + var err error + for _, w := range ws { + err = multierr.Append(err, w.Sync()) + } + return err +} |