diff options
Diffstat (limited to 'vendor/google.golang.org/api/gensupport/buffer.go')
| -rw-r--r-- | vendor/google.golang.org/api/gensupport/buffer.go | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/vendor/google.golang.org/api/gensupport/buffer.go b/vendor/google.golang.org/api/gensupport/buffer.go new file mode 100644 index 0000000..4b8ec14 --- /dev/null +++ b/vendor/google.golang.org/api/gensupport/buffer.go @@ -0,0 +1,77 @@ +// 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" +) + +// ResumableBuffer buffers data from an io.Reader to support uploading media in retryable chunks. +type ResumableBuffer 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 +} + +func NewResumableBuffer(media io.Reader, chunkSize int) *ResumableBuffer { + return &ResumableBuffer{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 (rb *ResumableBuffer) 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 rb.err == nil && len(rb.chunk) == 0 { + rb.err = rb.loadChunk() + } + return bytes.NewReader(rb.chunk), rb.off, len(rb.chunk), rb.err +} + +// loadChunk will read from media into chunk, up to the capacity of chunk. +func (rb *ResumableBuffer) loadChunk() error { + bufSize := cap(rb.chunk) + rb.chunk = rb.chunk[:bufSize] + + read := 0 + var err error + for err == nil && read < bufSize { + var n int + n, err = rb.media.Read(rb.chunk[read:]) + read += n + } + rb.chunk = rb.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 (rb *ResumableBuffer) Next() { + rb.off += int64(len(rb.chunk)) + rb.chunk = rb.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 +} |
