initial add - go fmt on grpc
Change-Id: Ib0afadd2fe5571d1456a091f94f5644458f7d3f4
diff --git a/vendor/golang.org/x/net/http2/databuffer.go b/vendor/golang.org/x/net/http2/databuffer.go
new file mode 100644
index 0000000..a3067f8
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/databuffer.go
@@ -0,0 +1,146 @@
+// Copyright 2014 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 http2
+
+import (
+ "errors"
+ "fmt"
+ "sync"
+)
+
+// Buffer chunks are allocated from a pool to reduce pressure on GC.
+// The maximum wasted space per dataBuffer is 2x the largest size class,
+// which happens when the dataBuffer has multiple chunks and there is
+// one unread byte in both the first and last chunks. We use a few size
+// classes to minimize overheads for servers that typically receive very
+// small request bodies.
+//
+// TODO: Benchmark to determine if the pools are necessary. The GC may have
+// improved enough that we can instead allocate chunks like this:
+// make([]byte, max(16<<10, expectedBytesRemaining))
+var (
+ dataChunkSizeClasses = []int{
+ 1 << 10,
+ 2 << 10,
+ 4 << 10,
+ 8 << 10,
+ 16 << 10,
+ }
+ dataChunkPools = [...]sync.Pool{
+ {New: func() interface{} { return make([]byte, 1<<10) }},
+ {New: func() interface{} { return make([]byte, 2<<10) }},
+ {New: func() interface{} { return make([]byte, 4<<10) }},
+ {New: func() interface{} { return make([]byte, 8<<10) }},
+ {New: func() interface{} { return make([]byte, 16<<10) }},
+ }
+)
+
+func getDataBufferChunk(size int64) []byte {
+ i := 0
+ for ; i < len(dataChunkSizeClasses)-1; i++ {
+ if size <= int64(dataChunkSizeClasses[i]) {
+ break
+ }
+ }
+ return dataChunkPools[i].Get().([]byte)
+}
+
+func putDataBufferChunk(p []byte) {
+ for i, n := range dataChunkSizeClasses {
+ if len(p) == n {
+ dataChunkPools[i].Put(p)
+ return
+ }
+ }
+ panic(fmt.Sprintf("unexpected buffer len=%v", len(p)))
+}
+
+// dataBuffer is an io.ReadWriter backed by a list of data chunks.
+// Each dataBuffer is used to read DATA frames on a single stream.
+// The buffer is divided into chunks so the server can limit the
+// total memory used by a single connection without limiting the
+// request body size on any single stream.
+type dataBuffer struct {
+ chunks [][]byte
+ r int // next byte to read is chunks[0][r]
+ w int // next byte to write is chunks[len(chunks)-1][w]
+ size int // total buffered bytes
+ expected int64 // we expect at least this many bytes in future Write calls (ignored if <= 0)
+}
+
+var errReadEmpty = errors.New("read from empty dataBuffer")
+
+// Read copies bytes from the buffer into p.
+// It is an error to read when no data is available.
+func (b *dataBuffer) Read(p []byte) (int, error) {
+ if b.size == 0 {
+ return 0, errReadEmpty
+ }
+ var ntotal int
+ for len(p) > 0 && b.size > 0 {
+ readFrom := b.bytesFromFirstChunk()
+ n := copy(p, readFrom)
+ p = p[n:]
+ ntotal += n
+ b.r += n
+ b.size -= n
+ // If the first chunk has been consumed, advance to the next chunk.
+ if b.r == len(b.chunks[0]) {
+ putDataBufferChunk(b.chunks[0])
+ end := len(b.chunks) - 1
+ copy(b.chunks[:end], b.chunks[1:])
+ b.chunks[end] = nil
+ b.chunks = b.chunks[:end]
+ b.r = 0
+ }
+ }
+ return ntotal, nil
+}
+
+func (b *dataBuffer) bytesFromFirstChunk() []byte {
+ if len(b.chunks) == 1 {
+ return b.chunks[0][b.r:b.w]
+ }
+ return b.chunks[0][b.r:]
+}
+
+// Len returns the number of bytes of the unread portion of the buffer.
+func (b *dataBuffer) Len() int {
+ return b.size
+}
+
+// Write appends p to the buffer.
+func (b *dataBuffer) Write(p []byte) (int, error) {
+ ntotal := len(p)
+ for len(p) > 0 {
+ // If the last chunk is empty, allocate a new chunk. Try to allocate
+ // enough to fully copy p plus any additional bytes we expect to
+ // receive. However, this may allocate less than len(p).
+ want := int64(len(p))
+ if b.expected > want {
+ want = b.expected
+ }
+ chunk := b.lastChunkOrAlloc(want)
+ n := copy(chunk[b.w:], p)
+ p = p[n:]
+ b.w += n
+ b.size += n
+ b.expected -= int64(n)
+ }
+ return ntotal, nil
+}
+
+func (b *dataBuffer) lastChunkOrAlloc(want int64) []byte {
+ if len(b.chunks) != 0 {
+ last := b.chunks[len(b.chunks)-1]
+ if b.w < len(last) {
+ return last
+ }
+ }
+ chunk := getDataBufferChunk(want)
+ b.chunks = append(b.chunks, chunk)
+ b.w = 0
+ return chunk
+}