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authorMatthew Heon <matthew.heon@gmail.com>2017-11-01 11:24:59 -0400
committerMatthew Heon <matthew.heon@gmail.com>2017-11-01 11:24:59 -0400
commita031b83a09a8628435317a03f199cdc18b78262f (patch)
treebc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/k8s.io/apimachinery/pkg/util/framer
parent2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff)
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Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/util/framer')
-rw-r--r--vendor/k8s.io/apimachinery/pkg/util/framer/framer.go167
1 files changed, 167 insertions, 0 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/util/framer/framer.go b/vendor/k8s.io/apimachinery/pkg/util/framer/framer.go
new file mode 100644
index 000000000..066680f44
--- /dev/null
+++ b/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()
+}