Fix GCS

Signed-off-by: Olivier Gambier <olivier@docker.com>

vendor/google.golang.org/api/gensupport/media.go

@@ -0,0 +1,200 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gensupport
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"mime/multipart"
+	"net/http"
+	"net/textproto"
+
+	"google.golang.org/api/googleapi"
+)
+
+const sniffBuffSize = 512
+
+func newContentSniffer(r io.Reader) *contentSniffer {
+	return &contentSniffer{r: r}
+}
+
+// contentSniffer wraps a Reader, and reports the content type determined by sniffing up to 512 bytes from the Reader.
+type contentSniffer struct {
+	r     io.Reader
+	start []byte // buffer for the sniffed bytes.
+	err   error  // set to any error encountered while reading bytes to be sniffed.
+
+	ctype   string // set on first sniff.
+	sniffed bool   // set to true on first sniff.
+}
+
+func (cs *contentSniffer) Read(p []byte) (n int, err error) {
+	// Ensure that the content type is sniffed before any data is consumed from Reader.
+	_, _ = cs.ContentType()
+
+	if len(cs.start) > 0 {
+		n := copy(p, cs.start)
+		cs.start = cs.start[n:]
+		return n, nil
+	}
+
+	// We may have read some bytes into start while sniffing, even if the read ended in an error.
+	// We should first return those bytes, then the error.
+	if cs.err != nil {
+		return 0, cs.err
+	}
+
+	// Now we have handled all bytes that were buffered while sniffing.  Now just delegate to the underlying reader.
+	return cs.r.Read(p)
+}
+
+// ContentType returns the sniffed content type, and whether the content type was succesfully sniffed.
+func (cs *contentSniffer) ContentType() (string, bool) {
+	if cs.sniffed {
+		return cs.ctype, cs.ctype != ""
+	}
+	cs.sniffed = true
+	// If ReadAll hits EOF, it returns err==nil.
+	cs.start, cs.err = ioutil.ReadAll(io.LimitReader(cs.r, sniffBuffSize))
+
+	// Don't try to detect the content type based on possibly incomplete data.
+	if cs.err != nil {
+		return "", false
+	}
+
+	cs.ctype = http.DetectContentType(cs.start)
+	return cs.ctype, true
+}
+
+// DetermineContentType determines the content type of the supplied reader.
+// If the content type is already known, it can be specified via ctype.
+// Otherwise, the content of media will be sniffed to determine the content type.
+// If media implements googleapi.ContentTyper (deprecated), this will be used
+// instead of sniffing the content.
+// After calling DetectContentType the caller must not perform further reads on
+// media, but rather read from the Reader that is returned.
+func DetermineContentType(media io.Reader, ctype string) (io.Reader, string) {
+	// Note: callers could avoid calling DetectContentType if ctype != "",
+	// but doing the check inside this function reduces the amount of
+	// generated code.
+	if ctype != "" {
+		return media, ctype
+	}
+
+	// For backwards compatability, allow clients to set content
+	// type by providing a ContentTyper for media.
+	if typer, ok := media.(googleapi.ContentTyper); ok {
+		return media, typer.ContentType()
+	}
+
+	sniffer := newContentSniffer(media)
+	if ctype, ok := sniffer.ContentType(); ok {
+		return sniffer, ctype
+	}
+	// If content type could not be sniffed, reads from sniffer will eventually fail with an error.
+	return sniffer, ""
+}
+
+type typeReader struct {
+	io.Reader
+	typ string
+}
+
+// multipartReader combines the contents of multiple readers to creat a multipart/related HTTP body.
+// Close must be called if reads from the multipartReader are abandoned before reaching EOF.
+type multipartReader struct {
+	pr       *io.PipeReader
+	pipeOpen bool
+	ctype    string
+}
+
+func newMultipartReader(parts []typeReader) *multipartReader {
+	mp := &multipartReader{pipeOpen: true}
+	var pw *io.PipeWriter
+	mp.pr, pw = io.Pipe()
+	mpw := multipart.NewWriter(pw)
+	mp.ctype = "multipart/related; boundary=" + mpw.Boundary()
+	go func() {
+		for _, part := range parts {
+			w, err := mpw.CreatePart(typeHeader(part.typ))
+			if err != nil {
+				mpw.Close()
+				pw.CloseWithError(fmt.Errorf("googleapi: CreatePart failed: %v", err))
+				return
+			}
+			_, err = io.Copy(w, part.Reader)
+			if err != nil {
+				mpw.Close()
+				pw.CloseWithError(fmt.Errorf("googleapi: Copy failed: %v", err))
+				return
+			}
+		}
+
+		mpw.Close()
+		pw.Close()
+	}()
+	return mp
+}
+
+func (mp *multipartReader) Read(data []byte) (n int, err error) {
+	return mp.pr.Read(data)
+}
+
+func (mp *multipartReader) Close() error {
+	if !mp.pipeOpen {
+		return nil
+	}
+	mp.pipeOpen = false
+	return mp.pr.Close()
+}
+
+// CombineBodyMedia combines a json body with media content to create a multipart/related HTTP body.
+// It returns a ReadCloser containing the combined body, and the overall "multipart/related" content type, with random boundary.
+//
+// The caller must call Close on the returned ReadCloser if reads are abandoned before reaching EOF.
+func CombineBodyMedia(body io.Reader, bodyContentType string, media io.Reader, mediaContentType string) (io.ReadCloser, string) {
+	mp := newMultipartReader([]typeReader{
+		{body, bodyContentType},
+		{media, mediaContentType},
+	})
+	return mp, mp.ctype
+}
+
+func typeHeader(contentType string) textproto.MIMEHeader {
+	h := make(textproto.MIMEHeader)
+	if contentType != "" {
+		h.Set("Content-Type", contentType)
+	}
+	return h
+}
+
+// PrepareUpload determines whether the data in the supplied reader should be
+// uploaded in a single request, or in sequential chunks.
+// chunkSize is the size of the chunk that media should be split into.
+// If chunkSize is non-zero and the contents of media do not fit in a single
+// chunk (or there is an error reading media), then media will be returned as a
+// ResumableBuffer.  Otherwise, media will be returned as a Reader.
+//
+// After PrepareUpload has been called, media should no longer be used: the
+// media content should be accessed via one of the return values.
+func PrepareUpload(media io.Reader, chunkSize int) (io.Reader,
+	*ResumableBuffer) {
+	if chunkSize == 0 { // do not chunk
+		return media, nil
+	}
+
+	rb := NewResumableBuffer(media, chunkSize)
+	rdr, _, _, err := rb.Chunk()
+
+	if err == io.EOF { // we can upload this in a single request
+		return rdr, nil
+	}
+	// err might be a non-EOF error. If it is, the next call to rb.Chunk will
+	// return the same error. Returning a ResumableBuffer ensures that this error
+	// will be handled at some point.
+
+	return nil, rb
+}