terraform-provider-google/vendor/google.golang.org/api/gensupport/buffer.go
Paddy 961c878e0d Switch to using Go modules. (#2679)
Switch to using Go modules.

This migrates our vendor.json to use Go 1.11's modules system, and
replaces the vendor folder with the output of go mod vendor.

The vendored code should remain basically the same; I believe some
tree shaking of packages and support scripts/licenses/READMEs/etc.
happened.

This also fixes Travis and our Makefile to no longer use govendor.
2018-12-20 17:22:22 -08:00

80 lines
2.4 KiB
Go

// 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 (
"bytes"
"io"
"google.golang.org/api/googleapi"
)
// MediaBuffer buffers data from an io.Reader to support uploading media in
// retryable chunks. It should be created with NewMediaBuffer.
type MediaBuffer struct {
media io.Reader
chunk []byte // The current chunk which is pending upload. The capacity is the chunk size.
err error // Any error generated when populating chunk by reading media.
// The absolute position of chunk in the underlying media.
off int64
}
// NewMediaBuffer initializes a MediaBuffer.
func NewMediaBuffer(media io.Reader, chunkSize int) *MediaBuffer {
return &MediaBuffer{media: media, chunk: make([]byte, 0, chunkSize)}
}
// Chunk returns the current buffered chunk, the offset in the underlying media
// from which the chunk is drawn, and the size of the chunk.
// Successive calls to Chunk return the same chunk between calls to Next.
func (mb *MediaBuffer) Chunk() (chunk io.Reader, off int64, size int, err error) {
// There may already be data in chunk if Next has not been called since the previous call to Chunk.
if mb.err == nil && len(mb.chunk) == 0 {
mb.err = mb.loadChunk()
}
return bytes.NewReader(mb.chunk), mb.off, len(mb.chunk), mb.err
}
// loadChunk will read from media into chunk, up to the capacity of chunk.
func (mb *MediaBuffer) loadChunk() error {
bufSize := cap(mb.chunk)
mb.chunk = mb.chunk[:bufSize]
read := 0
var err error
for err == nil && read < bufSize {
var n int
n, err = mb.media.Read(mb.chunk[read:])
read += n
}
mb.chunk = mb.chunk[:read]
return err
}
// Next advances to the next chunk, which will be returned by the next call to Chunk.
// Calls to Next without a corresponding prior call to Chunk will have no effect.
func (mb *MediaBuffer) Next() {
mb.off += int64(len(mb.chunk))
mb.chunk = mb.chunk[0:0]
}
type readerTyper struct {
io.Reader
googleapi.ContentTyper
}
// ReaderAtToReader adapts a ReaderAt to be used as a Reader.
// If ra implements googleapi.ContentTyper, then the returned reader
// will also implement googleapi.ContentTyper, delegating to ra.
func ReaderAtToReader(ra io.ReaderAt, size int64) io.Reader {
r := io.NewSectionReader(ra, 0, size)
if typer, ok := ra.(googleapi.ContentTyper); ok {
return readerTyper{r, typer}
}
return r
}