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author | JoramWilander <jwawilander@gmail.com> | 2018-07-10 15:01:43 -0400 |
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committer | JoramWilander <jwawilander@gmail.com> | 2018-07-10 15:01:43 -0400 |
commit | 6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005 (patch) | |
tree | 5564a47257bf6e85aaef711980c5b0fcb4d07dcc /vendor/golang.org/x/net/http2/write.go | |
parent | c042ffa460296587579aff54b157a5109e022f7e (diff) | |
parent | 1e1a5e5e85240f25c4faddcb24c5a29a915fe6e4 (diff) | |
download | chat-6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005.tar.gz chat-6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005.tar.bz2 chat-6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005.zip |
Merge branch 'plugins-2'
Diffstat (limited to 'vendor/golang.org/x/net/http2/write.go')
-rw-r--r-- | vendor/golang.org/x/net/http2/write.go | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/vendor/golang.org/x/net/http2/write.go b/vendor/golang.org/x/net/http2/write.go new file mode 100644 index 000000000..8a9711f6e --- /dev/null +++ b/vendor/golang.org/x/net/http2/write.go @@ -0,0 +1,365 @@ +// 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 ( + "bytes" + "fmt" + "log" + "net/http" + "net/url" + + "golang.org/x/net/http/httpguts" + "golang.org/x/net/http2/hpack" +) + +// writeFramer is implemented by any type that is used to write frames. +type writeFramer interface { + writeFrame(writeContext) error + + // staysWithinBuffer reports whether this writer promises that + // it will only write less than or equal to size bytes, and it + // won't Flush the write context. + staysWithinBuffer(size int) bool +} + +// writeContext is the interface needed by the various frame writer +// types below. All the writeFrame methods below are scheduled via the +// frame writing scheduler (see writeScheduler in writesched.go). +// +// This interface is implemented by *serverConn. +// +// TODO: decide whether to a) use this in the client code (which didn't +// end up using this yet, because it has a simpler design, not +// currently implementing priorities), or b) delete this and +// make the server code a bit more concrete. +type writeContext interface { + Framer() *Framer + Flush() error + CloseConn() error + // HeaderEncoder returns an HPACK encoder that writes to the + // returned buffer. + HeaderEncoder() (*hpack.Encoder, *bytes.Buffer) +} + +// writeEndsStream reports whether w writes a frame that will transition +// the stream to a half-closed local state. This returns false for RST_STREAM, +// which closes the entire stream (not just the local half). +func writeEndsStream(w writeFramer) bool { + switch v := w.(type) { + case *writeData: + return v.endStream + case *writeResHeaders: + return v.endStream + case nil: + // This can only happen if the caller reuses w after it's + // been intentionally nil'ed out to prevent use. Keep this + // here to catch future refactoring breaking it. + panic("writeEndsStream called on nil writeFramer") + } + return false +} + +type flushFrameWriter struct{} + +func (flushFrameWriter) writeFrame(ctx writeContext) error { + return ctx.Flush() +} + +func (flushFrameWriter) staysWithinBuffer(max int) bool { return false } + +type writeSettings []Setting + +func (s writeSettings) staysWithinBuffer(max int) bool { + const settingSize = 6 // uint16 + uint32 + return frameHeaderLen+settingSize*len(s) <= max + +} + +func (s writeSettings) writeFrame(ctx writeContext) error { + return ctx.Framer().WriteSettings([]Setting(s)...) +} + +type writeGoAway struct { + maxStreamID uint32 + code ErrCode +} + +func (p *writeGoAway) writeFrame(ctx writeContext) error { + err := ctx.Framer().WriteGoAway(p.maxStreamID, p.code, nil) + ctx.Flush() // ignore error: we're hanging up on them anyway + return err +} + +func (*writeGoAway) staysWithinBuffer(max int) bool { return false } // flushes + +type writeData struct { + streamID uint32 + p []byte + endStream bool +} + +func (w *writeData) String() string { + return fmt.Sprintf("writeData(stream=%d, p=%d, endStream=%v)", w.streamID, len(w.p), w.endStream) +} + +func (w *writeData) writeFrame(ctx writeContext) error { + return ctx.Framer().WriteData(w.streamID, w.endStream, w.p) +} + +func (w *writeData) staysWithinBuffer(max int) bool { + return frameHeaderLen+len(w.p) <= max +} + +// handlerPanicRST is the message sent from handler goroutines when +// the handler panics. +type handlerPanicRST struct { + StreamID uint32 +} + +func (hp handlerPanicRST) writeFrame(ctx writeContext) error { + return ctx.Framer().WriteRSTStream(hp.StreamID, ErrCodeInternal) +} + +func (hp handlerPanicRST) staysWithinBuffer(max int) bool { return frameHeaderLen+4 <= max } + +func (se StreamError) writeFrame(ctx writeContext) error { + return ctx.Framer().WriteRSTStream(se.StreamID, se.Code) +} + +func (se StreamError) staysWithinBuffer(max int) bool { return frameHeaderLen+4 <= max } + +type writePingAck struct{ pf *PingFrame } + +func (w writePingAck) writeFrame(ctx writeContext) error { + return ctx.Framer().WritePing(true, w.pf.Data) +} + +func (w writePingAck) staysWithinBuffer(max int) bool { return frameHeaderLen+len(w.pf.Data) <= max } + +type writeSettingsAck struct{} + +func (writeSettingsAck) writeFrame(ctx writeContext) error { + return ctx.Framer().WriteSettingsAck() +} + +func (writeSettingsAck) staysWithinBuffer(max int) bool { return frameHeaderLen <= max } + +// splitHeaderBlock splits headerBlock into fragments so that each fragment fits +// in a single frame, then calls fn for each fragment. firstFrag/lastFrag are true +// for the first/last fragment, respectively. +func splitHeaderBlock(ctx writeContext, headerBlock []byte, fn func(ctx writeContext, frag []byte, firstFrag, lastFrag bool) error) error { + // For now we're lazy and just pick the minimum MAX_FRAME_SIZE + // that all peers must support (16KB). Later we could care + // more and send larger frames if the peer advertised it, but + // there's little point. Most headers are small anyway (so we + // generally won't have CONTINUATION frames), and extra frames + // only waste 9 bytes anyway. + const maxFrameSize = 16384 + + first := true + for len(headerBlock) > 0 { + frag := headerBlock + if len(frag) > maxFrameSize { + frag = frag[:maxFrameSize] + } + headerBlock = headerBlock[len(frag):] + if err := fn(ctx, frag, first, len(headerBlock) == 0); err != nil { + return err + } + first = false + } + return nil +} + +// writeResHeaders is a request to write a HEADERS and 0+ CONTINUATION frames +// for HTTP response headers or trailers from a server handler. +type writeResHeaders struct { + streamID uint32 + httpResCode int // 0 means no ":status" line + h http.Header // may be nil + trailers []string // if non-nil, which keys of h to write. nil means all. + endStream bool + + date string + contentType string + contentLength string +} + +func encKV(enc *hpack.Encoder, k, v string) { + if VerboseLogs { + log.Printf("http2: server encoding header %q = %q", k, v) + } + enc.WriteField(hpack.HeaderField{Name: k, Value: v}) +} + +func (w *writeResHeaders) staysWithinBuffer(max int) bool { + // TODO: this is a common one. It'd be nice to return true + // here and get into the fast path if we could be clever and + // calculate the size fast enough, or at least a conservative + // uppper bound that usually fires. (Maybe if w.h and + // w.trailers are nil, so we don't need to enumerate it.) + // Otherwise I'm afraid that just calculating the length to + // answer this question would be slower than the ~2µs benefit. + return false +} + +func (w *writeResHeaders) writeFrame(ctx writeContext) error { + enc, buf := ctx.HeaderEncoder() + buf.Reset() + + if w.httpResCode != 0 { + encKV(enc, ":status", httpCodeString(w.httpResCode)) + } + + encodeHeaders(enc, w.h, w.trailers) + + if w.contentType != "" { + encKV(enc, "content-type", w.contentType) + } + if w.contentLength != "" { + encKV(enc, "content-length", w.contentLength) + } + if w.date != "" { + encKV(enc, "date", w.date) + } + + headerBlock := buf.Bytes() + if len(headerBlock) == 0 && w.trailers == nil { + panic("unexpected empty hpack") + } + + return splitHeaderBlock(ctx, headerBlock, w.writeHeaderBlock) +} + +func (w *writeResHeaders) writeHeaderBlock(ctx writeContext, frag []byte, firstFrag, lastFrag bool) error { + if firstFrag { + return ctx.Framer().WriteHeaders(HeadersFrameParam{ + StreamID: w.streamID, + BlockFragment: frag, + EndStream: w.endStream, + EndHeaders: lastFrag, + }) + } else { + return ctx.Framer().WriteContinuation(w.streamID, lastFrag, frag) + } +} + +// writePushPromise is a request to write a PUSH_PROMISE and 0+ CONTINUATION frames. +type writePushPromise struct { + streamID uint32 // pusher stream + method string // for :method + url *url.URL // for :scheme, :authority, :path + h http.Header + + // Creates an ID for a pushed stream. This runs on serveG just before + // the frame is written. The returned ID is copied to promisedID. + allocatePromisedID func() (uint32, error) + promisedID uint32 +} + +func (w *writePushPromise) staysWithinBuffer(max int) bool { + // TODO: see writeResHeaders.staysWithinBuffer + return false +} + +func (w *writePushPromise) writeFrame(ctx writeContext) error { + enc, buf := ctx.HeaderEncoder() + buf.Reset() + + encKV(enc, ":method", w.method) + encKV(enc, ":scheme", w.url.Scheme) + encKV(enc, ":authority", w.url.Host) + encKV(enc, ":path", w.url.RequestURI()) + encodeHeaders(enc, w.h, nil) + + headerBlock := buf.Bytes() + if len(headerBlock) == 0 { + panic("unexpected empty hpack") + } + + return splitHeaderBlock(ctx, headerBlock, w.writeHeaderBlock) +} + +func (w *writePushPromise) writeHeaderBlock(ctx writeContext, frag []byte, firstFrag, lastFrag bool) error { + if firstFrag { + return ctx.Framer().WritePushPromise(PushPromiseParam{ + StreamID: w.streamID, + PromiseID: w.promisedID, + BlockFragment: frag, + EndHeaders: lastFrag, + }) + } else { + return ctx.Framer().WriteContinuation(w.streamID, lastFrag, frag) + } +} + +type write100ContinueHeadersFrame struct { + streamID uint32 +} + +func (w write100ContinueHeadersFrame) writeFrame(ctx writeContext) error { + enc, buf := ctx.HeaderEncoder() + buf.Reset() + encKV(enc, ":status", "100") + return ctx.Framer().WriteHeaders(HeadersFrameParam{ + StreamID: w.streamID, + BlockFragment: buf.Bytes(), + EndStream: false, + EndHeaders: true, + }) +} + +func (w write100ContinueHeadersFrame) staysWithinBuffer(max int) bool { + // Sloppy but conservative: + return 9+2*(len(":status")+len("100")) <= max +} + +type writeWindowUpdate struct { + streamID uint32 // or 0 for conn-level + n uint32 +} + +func (wu writeWindowUpdate) staysWithinBuffer(max int) bool { return frameHeaderLen+4 <= max } + +func (wu writeWindowUpdate) writeFrame(ctx writeContext) error { + return ctx.Framer().WriteWindowUpdate(wu.streamID, wu.n) +} + +// encodeHeaders encodes an http.Header. If keys is not nil, then (k, h[k]) +// is encoded only only if k is in keys. +func encodeHeaders(enc *hpack.Encoder, h http.Header, keys []string) { + if keys == nil { + sorter := sorterPool.Get().(*sorter) + // Using defer here, since the returned keys from the + // sorter.Keys method is only valid until the sorter + // is returned: + defer sorterPool.Put(sorter) + keys = sorter.Keys(h) + } + for _, k := range keys { + vv := h[k] + k = lowerHeader(k) + if !validWireHeaderFieldName(k) { + // Skip it as backup paranoia. Per + // golang.org/issue/14048, these should + // already be rejected at a higher level. + continue + } + isTE := k == "transfer-encoding" + for _, v := range vv { + if !httpguts.ValidHeaderFieldValue(v) { + // TODO: return an error? golang.org/issue/14048 + // For now just omit it. + continue + } + // TODO: more of "8.1.2.2 Connection-Specific Header Fields" + if isTE && v != "trailers" { + continue + } + encKV(enc, k, v) + } + } +} |