vendor files

vendor/k8s.io/apimachinery/pkg/util/framer/framer.go

@@ -0,0 +1,167 @@
+/*
+Copyright 2015 The Kubernetes 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 framer implements simple frame decoding techniques for an io.ReadCloser
+package framer
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"io"
+)
+
+type lengthDelimitedFrameWriter struct {
+	w io.Writer
+	h [4]byte
+}
+
+func NewLengthDelimitedFrameWriter(w io.Writer) io.Writer {
+	return &lengthDelimitedFrameWriter{w: w}
+}
+
+// Write writes a single frame to the nested writer, prepending it with the length in
+// in bytes of data (as a 4 byte, bigendian uint32).
+func (w *lengthDelimitedFrameWriter) Write(data []byte) (int, error) {
+	binary.BigEndian.PutUint32(w.h[:], uint32(len(data)))
+	n, err := w.w.Write(w.h[:])
+	if err != nil {
+		return 0, err
+	}
+	if n != len(w.h) {
+		return 0, io.ErrShortWrite
+	}
+	return w.w.Write(data)
+}
+
+type lengthDelimitedFrameReader struct {
+	r         io.ReadCloser
+	remaining int
+}
+
+// NewLengthDelimitedFrameReader returns an io.Reader that will decode length-prefixed
+// frames off of a stream.
+//
+// The protocol is:
+//
+//   stream: message ...
+//   message: prefix body
+//   prefix: 4 byte uint32 in BigEndian order, denotes length of body
+//   body: bytes (0..prefix)
+//
+// If the buffer passed to Read is not long enough to contain an entire frame, io.ErrShortRead
+// will be returned along with the number of bytes read.
+func NewLengthDelimitedFrameReader(r io.ReadCloser) io.ReadCloser {
+	return &lengthDelimitedFrameReader{r: r}
+}
+
+// Read attempts to read an entire frame into data. If that is not possible, io.ErrShortBuffer
+// is returned and subsequent calls will attempt to read the last frame. A frame is complete when
+// err is nil.
+func (r *lengthDelimitedFrameReader) Read(data []byte) (int, error) {
+	if r.remaining <= 0 {
+		header := [4]byte{}
+		n, err := io.ReadAtLeast(r.r, header[:4], 4)
+		if err != nil {
+			return 0, err
+		}
+		if n != 4 {
+			return 0, io.ErrUnexpectedEOF
+		}
+		frameLength := int(binary.BigEndian.Uint32(header[:]))
+		r.remaining = frameLength
+	}
+
+	expect := r.remaining
+	max := expect
+	if max > len(data) {
+		max = len(data)
+	}
+	n, err := io.ReadAtLeast(r.r, data[:max], int(max))
+	r.remaining -= n
+	if err == io.ErrShortBuffer || r.remaining > 0 {
+		return n, io.ErrShortBuffer
+	}
+	if err != nil {
+		return n, err
+	}
+	if n != expect {
+		return n, io.ErrUnexpectedEOF
+	}
+
+	return n, nil
+}
+
+func (r *lengthDelimitedFrameReader) Close() error {
+	return r.r.Close()
+}
+
+type jsonFrameReader struct {
+	r         io.ReadCloser
+	decoder   *json.Decoder
+	remaining []byte
+}
+
+// NewJSONFramedReader returns an io.Reader that will decode individual JSON objects off
+// of a wire.
+//
+// The boundaries between each frame are valid JSON objects. A JSON parsing error will terminate
+// the read.
+func NewJSONFramedReader(r io.ReadCloser) io.ReadCloser {
+	return &jsonFrameReader{
+		r:       r,
+		decoder: json.NewDecoder(r),
+	}
+}
+
+// ReadFrame decodes the next JSON object in the stream, or returns an error. The returned
+// byte slice will be modified the next time ReadFrame is invoked and should not be altered.
+func (r *jsonFrameReader) Read(data []byte) (int, error) {
+	// Return whatever remaining data exists from an in progress frame
+	if n := len(r.remaining); n > 0 {
+		if n <= len(data) {
+			data = append(data[0:0], r.remaining...)
+			r.remaining = nil
+			return n, nil
+		}
+
+		n = len(data)
+		data = append(data[0:0], r.remaining[:n]...)
+		r.remaining = r.remaining[n:]
+		return n, io.ErrShortBuffer
+	}
+
+	// RawMessage#Unmarshal appends to data - we reset the slice down to 0 and will either see
+	// data written to data, or be larger than data and a different array.
+	n := len(data)
+	m := json.RawMessage(data[:0])
+	if err := r.decoder.Decode(&m); err != nil {
+		return 0, err
+	}
+
+	// If capacity of data is less than length of the message, decoder will allocate a new slice
+	// and set m to it, which means we need to copy the partial result back into data and preserve
+	// the remaining result for subsequent reads.
+	if len(m) > n {
+		data = append(data[0:0], m[:n]...)
+		r.remaining = m[n:]
+		return n, io.ErrShortBuffer
+	}
+	return len(m), nil
+}
+
+func (r *jsonFrameReader) Close() error {
+	return r.r.Close()
+}