From e1e8d058a33f7566f9c565d04b0d8b56f9645c35 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Wed, 25 Apr 2018 09:28:54 +0200 Subject: add vendor --- vendor/golang.org/x/net/http2/writesched.go | 242 ++++++++++++++++++++++++++++ 1 file changed, 242 insertions(+) create mode 100644 vendor/golang.org/x/net/http2/writesched.go (limited to 'vendor/golang.org/x/net/http2/writesched.go') diff --git a/vendor/golang.org/x/net/http2/writesched.go b/vendor/golang.org/x/net/http2/writesched.go new file mode 100644 index 0000000..4fe3073 --- /dev/null +++ b/vendor/golang.org/x/net/http2/writesched.go @@ -0,0 +1,242 @@ +// 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 "fmt" + +// WriteScheduler is the interface implemented by HTTP/2 write schedulers. +// Methods are never called concurrently. +type WriteScheduler interface { + // OpenStream opens a new stream in the write scheduler. + // It is illegal to call this with streamID=0 or with a streamID that is + // already open -- the call may panic. + OpenStream(streamID uint32, options OpenStreamOptions) + + // CloseStream closes a stream in the write scheduler. Any frames queued on + // this stream should be discarded. It is illegal to call this on a stream + // that is not open -- the call may panic. + CloseStream(streamID uint32) + + // AdjustStream adjusts the priority of the given stream. This may be called + // on a stream that has not yet been opened or has been closed. Note that + // RFC 7540 allows PRIORITY frames to be sent on streams in any state. See: + // https://tools.ietf.org/html/rfc7540#section-5.1 + AdjustStream(streamID uint32, priority PriorityParam) + + // Push queues a frame in the scheduler. In most cases, this will not be + // called with wr.StreamID()!=0 unless that stream is currently open. The one + // exception is RST_STREAM frames, which may be sent on idle or closed streams. + Push(wr FrameWriteRequest) + + // Pop dequeues the next frame to write. Returns false if no frames can + // be written. Frames with a given wr.StreamID() are Pop'd in the same + // order they are Push'd. + Pop() (wr FrameWriteRequest, ok bool) +} + +// OpenStreamOptions specifies extra options for WriteScheduler.OpenStream. +type OpenStreamOptions struct { + // PusherID is zero if the stream was initiated by the client. Otherwise, + // PusherID names the stream that pushed the newly opened stream. + PusherID uint32 +} + +// FrameWriteRequest is a request to write a frame. +type FrameWriteRequest struct { + // write is the interface value that does the writing, once the + // WriteScheduler has selected this frame to write. The write + // functions are all defined in write.go. + write writeFramer + + // stream is the stream on which this frame will be written. + // nil for non-stream frames like PING and SETTINGS. + stream *stream + + // done, if non-nil, must be a buffered channel with space for + // 1 message and is sent the return value from write (or an + // earlier error) when the frame has been written. + done chan error +} + +// StreamID returns the id of the stream this frame will be written to. +// 0 is used for non-stream frames such as PING and SETTINGS. +func (wr FrameWriteRequest) StreamID() uint32 { + if wr.stream == nil { + if se, ok := wr.write.(StreamError); ok { + // (*serverConn).resetStream doesn't set + // stream because it doesn't necessarily have + // one. So special case this type of write + // message. + return se.StreamID + } + return 0 + } + return wr.stream.id +} + +// DataSize returns the number of flow control bytes that must be consumed +// to write this entire frame. This is 0 for non-DATA frames. +func (wr FrameWriteRequest) DataSize() int { + if wd, ok := wr.write.(*writeData); ok { + return len(wd.p) + } + return 0 +} + +// Consume consumes min(n, available) bytes from this frame, where available +// is the number of flow control bytes available on the stream. Consume returns +// 0, 1, or 2 frames, where the integer return value gives the number of frames +// returned. +// +// If flow control prevents consuming any bytes, this returns (_, _, 0). If +// the entire frame was consumed, this returns (wr, _, 1). Otherwise, this +// returns (consumed, rest, 2), where 'consumed' contains the consumed bytes and +// 'rest' contains the remaining bytes. The consumed bytes are deducted from the +// underlying stream's flow control budget. +func (wr FrameWriteRequest) Consume(n int32) (FrameWriteRequest, FrameWriteRequest, int) { + var empty FrameWriteRequest + + // Non-DATA frames are always consumed whole. + wd, ok := wr.write.(*writeData) + if !ok || len(wd.p) == 0 { + return wr, empty, 1 + } + + // Might need to split after applying limits. + allowed := wr.stream.flow.available() + if n < allowed { + allowed = n + } + if wr.stream.sc.maxFrameSize < allowed { + allowed = wr.stream.sc.maxFrameSize + } + if allowed <= 0 { + return empty, empty, 0 + } + if len(wd.p) > int(allowed) { + wr.stream.flow.take(allowed) + consumed := FrameWriteRequest{ + stream: wr.stream, + write: &writeData{ + streamID: wd.streamID, + p: wd.p[:allowed], + // Even if the original had endStream set, there + // are bytes remaining because len(wd.p) > allowed, + // so we know endStream is false. + endStream: false, + }, + // Our caller is blocking on the final DATA frame, not + // this intermediate frame, so no need to wait. + done: nil, + } + rest := FrameWriteRequest{ + stream: wr.stream, + write: &writeData{ + streamID: wd.streamID, + p: wd.p[allowed:], + endStream: wd.endStream, + }, + done: wr.done, + } + return consumed, rest, 2 + } + + // The frame is consumed whole. + // NB: This cast cannot overflow because allowed is <= math.MaxInt32. + wr.stream.flow.take(int32(len(wd.p))) + return wr, empty, 1 +} + +// String is for debugging only. +func (wr FrameWriteRequest) String() string { + var des string + if s, ok := wr.write.(fmt.Stringer); ok { + des = s.String() + } else { + des = fmt.Sprintf("%T", wr.write) + } + return fmt.Sprintf("[FrameWriteRequest stream=%d, ch=%v, writer=%v]", wr.StreamID(), wr.done != nil, des) +} + +// replyToWriter sends err to wr.done and panics if the send must block +// This does nothing if wr.done is nil. +func (wr *FrameWriteRequest) replyToWriter(err error) { + if wr.done == nil { + return + } + select { + case wr.done <- err: + default: + panic(fmt.Sprintf("unbuffered done channel passed in for type %T", wr.write)) + } + wr.write = nil // prevent use (assume it's tainted after wr.done send) +} + +// writeQueue is used by implementations of WriteScheduler. +type writeQueue struct { + s []FrameWriteRequest +} + +func (q *writeQueue) empty() bool { return len(q.s) == 0 } + +func (q *writeQueue) push(wr FrameWriteRequest) { + q.s = append(q.s, wr) +} + +func (q *writeQueue) shift() FrameWriteRequest { + if len(q.s) == 0 { + panic("invalid use of queue") + } + wr := q.s[0] + // TODO: less copy-happy queue. + copy(q.s, q.s[1:]) + q.s[len(q.s)-1] = FrameWriteRequest{} + q.s = q.s[:len(q.s)-1] + return wr +} + +// consume consumes up to n bytes from q.s[0]. If the frame is +// entirely consumed, it is removed from the queue. If the frame +// is partially consumed, the frame is kept with the consumed +// bytes removed. Returns true iff any bytes were consumed. +func (q *writeQueue) consume(n int32) (FrameWriteRequest, bool) { + if len(q.s) == 0 { + return FrameWriteRequest{}, false + } + consumed, rest, numresult := q.s[0].Consume(n) + switch numresult { + case 0: + return FrameWriteRequest{}, false + case 1: + q.shift() + case 2: + q.s[0] = rest + } + return consumed, true +} + +type writeQueuePool []*writeQueue + +// put inserts an unused writeQueue into the pool. +func (p *writeQueuePool) put(q *writeQueue) { + for i := range q.s { + q.s[i] = FrameWriteRequest{} + } + q.s = q.s[:0] + *p = append(*p, q) +} + +// get returns an empty writeQueue. +func (p *writeQueuePool) get() *writeQueue { + ln := len(*p) + if ln == 0 { + return new(writeQueue) + } + x := ln - 1 + q := (*p)[x] + (*p)[x] = nil + *p = (*p)[:x] + return q +} -- cgit v1.2.3