Method readMetaFrame

internal/http2/frame.go:1561–1693

readMetaFrame returns 0 or more CONTINUATION frames from fr and merge them into the provided hf and returns a MetaHeadersFrame with the decoded hpack values.

(hf *HeadersFrame, dumps []*dump.Dumper)

// merge them into the provided hf and returns a MetaHeadersFrame
// with the decoded hpack values.
func (h2f *Framer) readMetaFrame(hf *HeadersFrame, dumps []*dump.Dumper) (Frame, error) {
	if h2f.AllowIllegalReads {
		return nil, errors.New("illegal use of AllowIllegalReads with ReadMetaHeaders")
	}
	mh := &MetaHeadersFrame{
		HeadersFrame: hf,
	}
	remainSize := h2f.maxHeaderListSize()
	var sawRegular bool

	var invalid error // pseudo header field errors
	hdec := h2f.ReadMetaHeaders
	hdec.SetEmitEnabled(true)
	hdec.SetMaxStringLength(h2f.maxHeaderStringLen())
	rawEmitFunc := func(hf hpack.HeaderField) {
		if VerboseLogs && h2f.logReads {
			h2f.debugReadLoggerf("http2: decoded hpack field %+v", hf)
		}
		if !httpguts.ValidHeaderFieldValue(hf.Value) {
			// Don't include the value in the error, because it may be sensitive.
			invalid = headerFieldValueError(hf.Name)
		}
		isPseudo := strings.HasPrefix(hf.Name, ":")
		if isPseudo {
			if sawRegular {
				invalid = errPseudoAfterRegular
			}
		} else {
			sawRegular = true
			if !validWireHeaderFieldName(hf.Name) {
				invalid = headerFieldNameError(hf.Name)
			}
		}

		if invalid != nil {
			hdec.SetEmitEnabled(false)
			return
		}

		size := hf.Size()
		if size > remainSize {
			hdec.SetEmitEnabled(false)
			mh.Truncated = true
			remainSize = 0
			return
		}
		remainSize -= size

		mh.Fields = append(mh.Fields, hf)
	}
	emitFunc := rawEmitFunc

	ds := dump.Dumpers(dumps)
	if ds.ShouldDump() {
		emitFunc = func(hf hpack.HeaderField) {
			ds.DumpResponseHeader([]byte(fmt.Sprintf("%s: %s\r\n", hf.Name, hf.Value)))
			rawEmitFunc(hf)
		}