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-rw-r--r--vendor/golang.org/x/net/http2/write.go365
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
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+++ b/vendor/golang.org/x/net/http2/write.go
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+// 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)
+ }
+ }
+}