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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/k8s.io/apimachinery/pkg/util/framer | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
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.go | 167 |
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() +} |