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author | gVisor bot <gvisor-bot@google.com> | 2019-06-02 06:44:55 +0000 |
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committer | gVisor bot <gvisor-bot@google.com> | 2019-06-02 06:44:55 +0000 |
commit | ceb0d792f328d1fc0692197d8856a43c3936a571 (patch) | |
tree | 83155f302eff44a78bcc30a3a08f4efe59a79379 /pkg/linewriter | |
parent | deb7ecf1e46862d54f4b102f2d163cfbcfc37f3b (diff) | |
parent | 216da0b733dbed9aad9b2ab92ac75bcb906fd7ee (diff) |
Merge 216da0b7 (automated)
Diffstat (limited to 'pkg/linewriter')
-rw-r--r-- | pkg/linewriter/linewriter.go | 78 | ||||
-rwxr-xr-x | pkg/linewriter/linewriter_state_autogen.go | 4 |
2 files changed, 82 insertions, 0 deletions
diff --git a/pkg/linewriter/linewriter.go b/pkg/linewriter/linewriter.go new file mode 100644 index 000000000..cd6e4e2ce --- /dev/null +++ b/pkg/linewriter/linewriter.go @@ -0,0 +1,78 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package linewriter provides an io.Writer which calls an emitter on each line. +package linewriter + +import ( + "bytes" + "sync" +) + +// Writer is an io.Writer which buffers input, flushing +// individual lines through an emitter function. +type Writer struct { + // the mutex locks buf. + sync.Mutex + + // buf holds the data we haven't emitted yet. + buf bytes.Buffer + + // emit is used to flush individual lines. + emit func(p []byte) +} + +// NewWriter creates a Writer which emits using emitter. +// The emitter must not retain p. It may change after emitter returns. +func NewWriter(emitter func(p []byte)) *Writer { + return &Writer{emit: emitter} +} + +// Write implements io.Writer.Write. +// It calls emit on each line of input, not including the newline. +// Write may be called concurrently. +func (w *Writer) Write(p []byte) (int, error) { + w.Lock() + defer w.Unlock() + + total := 0 + for len(p) > 0 { + emit := true + i := bytes.IndexByte(p, '\n') + if i < 0 { + // No newline, we will buffer everything. + i = len(p) + emit = false + } + + n, err := w.buf.Write(p[:i]) + if err != nil { + return total, err + } + total += n + + p = p[i:] + + if emit { + // Skip the newline, but still count it. + p = p[1:] + total++ + + w.emit(w.buf.Bytes()) + w.buf.Reset() + } + } + + return total, nil +} diff --git a/pkg/linewriter/linewriter_state_autogen.go b/pkg/linewriter/linewriter_state_autogen.go new file mode 100755 index 000000000..194088d76 --- /dev/null +++ b/pkg/linewriter/linewriter_state_autogen.go @@ -0,0 +1,4 @@ +// automatically generated by stateify. + +package linewriter + |