Initial checkin of gRPC to third_party/

third_party/grpc/tools/http2_interop/settings.go

Index: third_party/grpc/tools/http2_interop/settings.go
diff --git a/third_party/grpc/tools/http2_interop/settings.go b/third_party/grpc/tools/http2_interop/settings.go
new file mode 100644
index 0000000000000000000000000000000000000000..544cec01ee7c1d3a40ea0663a17b2607d6920612
--- /dev/null
+++ b/third_party/grpc/tools/http2_interop/settings.go
@@ -0,0 +1,112 @@
+package http2interop
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+const (
+	SETTINGS_ACK = 1
+)
+
+type SettingsFrame struct {
+	Header FrameHeader
+	Params []SettingsParameter
+}
+
+type SettingsIdentifier uint16
+
+const (
+	SettingsHeaderTableSize      SettingsIdentifier = 1
+	SettingsEnablePush           SettingsIdentifier = 2
+	SettingsMaxConcurrentStreams SettingsIdentifier = 3
+	SettingsInitialWindowSize    SettingsIdentifier = 4
+	SettingsMaxFrameSize         SettingsIdentifier = 5
+	SettingsMaxHeaderListSize    SettingsIdentifier = 6
+)
+
+const (
+	SETTINGS_FLAG_ACK byte = 0x01
+)
+
+func (si SettingsIdentifier) String() string {
+	switch si {
+	case SettingsHeaderTableSize:
+		return "SETTINGS_HEADER_TABLE_SIZE"
+	case SettingsEnablePush:
+		return "SETTINGS_ENABLE_PUSH"
+	case SettingsMaxConcurrentStreams:
+		return "SETTINGS_MAX_CONCURRENT_STREAMS"
+	case SettingsInitialWindowSize:
+		return "SETTINGS_INITIAL_WINDOW_SIZE"
+	case SettingsMaxFrameSize:
+		return "SETTINGS_MAX_FRAME_SIZE"
+	case SettingsMaxHeaderListSize:
+		return "SETTINGS_MAX_HEADER_LIST_SIZE"
+	default:
+		return fmt.Sprintf("SETTINGS_UNKNOWN(%d)", uint16(si))
+	}
+}
+
+type SettingsParameter struct {
+	Identifier SettingsIdentifier
+	Value      uint32
+}
+
+func (f *SettingsFrame) GetHeader() *FrameHeader {
+	return &f.Header
+}
+
+func (f *SettingsFrame) ParsePayload(r io.Reader) error {
+	raw := make([]byte, f.Header.Length)
+	if _, err := io.ReadFull(r, raw); err != nil {
+		return err
+	}
+	return f.UnmarshalPayload(raw)
+}
+
+func (f *SettingsFrame) UnmarshalPayload(raw []byte) error {
+	if f.Header.Length != len(raw) {
+		return fmt.Errorf("Invalid Payload length %d != %d", f.Header.Length, len(raw))
+	}
+
+	if f.Header.Length%6 != 0 {
+		return fmt.Errorf("Invalid Payload length %d", f.Header.Length)
+	}
+
+	f.Params = make([]SettingsParameter, 0, f.Header.Length/6)
+	for i := 0; i < len(raw); i += 6 {
+		f.Params = append(f.Params, SettingsParameter{
+			Identifier: SettingsIdentifier(binary.BigEndian.Uint16(raw[i : i+2])),
+			Value:      binary.BigEndian.Uint32(raw[i+2 : i+6]),
+		})
+	}
+	return nil
+}
+
+func (f *SettingsFrame) MarshalPayload() ([]byte, error) {
+	raw := make([]byte, len(f.Params)*6)
+	for i, p := range f.Params {
+		binary.BigEndian.PutUint16(raw[i*6:i*6+2], uint16(p.Identifier))
+		binary.BigEndian.PutUint32(raw[i*6+2:i*6+6], p.Value)
+	}
+	return raw, nil
+}
+
+func (f *SettingsFrame) MarshalBinary() ([]byte, error) {
+	payload, err := f.MarshalPayload()
+	if err != nil {
+		return nil, err
+	}
+
+	f.Header.Length = len(payload)
+	f.Header.Type = SettingsFrameType
+	header, err := f.Header.MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+	header = append(header, payload...)
+
+	return header, nil
+}