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settings.go
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settings.go
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// Copyright 2014 Jamie Hall. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package frames
import (
"bytes"
"errors"
"fmt"
"io"
"sort"
"github.com/SlyMarbo/spdy/common"
)
type SETTINGS struct {
Flags common.Flags
Settings common.Settings
}
func (frame *SETTINGS) Add(flags common.Flags, id uint32, value uint32) {
frame.Settings[id] = &common.Setting{flags, id, value}
}
func (frame *SETTINGS) Compress(comp common.Compressor) error {
return nil
}
func (frame *SETTINGS) Decompress(decomp common.Decompressor) error {
return nil
}
func (frame *SETTINGS) Name() string {
return "SETTINGS"
}
func (frame *SETTINGS) ReadFrom(reader io.Reader) (int64, error) {
c := common.ReadCounter{R: reader}
data, err := common.ReadExactly(&c, 12)
if err != nil {
return c.N, err
}
err = controlFrameCommonProcessing(data[:5], _SETTINGS, common.FLAG_SETTINGS_CLEAR_SETTINGS)
if err != nil {
return c.N, err
}
// Get and check length.
length := int(common.BytesToUint24(data[5:8]))
if length < 4 {
return c.N, common.IncorrectDataLength(length, 8)
} else if length > common.MAX_FRAME_SIZE-8 {
return c.N, common.FrameTooLarge
}
// Check size.
numSettings := int(common.BytesToUint32(data[8:12]))
if length != 4+(8*numSettings) {
return c.N, common.IncorrectDataLength(length, 4+(8*numSettings))
}
// Read in data.
settings, err := common.ReadExactly(&c, 8*numSettings)
if err != nil {
return c.N, err
}
frame.Flags = common.Flags(data[4])
frame.Settings = make(common.Settings)
for i := 0; i < numSettings; i++ {
j := i * 8
setting := decodeSetting(settings[j:])
if setting == nil {
return c.N, errors.New("Error: Failed to parse settings.")
}
frame.Settings[setting.ID] = setting
}
return c.N, nil
}
func (frame *SETTINGS) String() string {
buf := new(bytes.Buffer)
flags := ""
if frame.Flags.CLEAR_SETTINGS() {
flags += " FLAG_SETTINGS_CLEAR_SETTINGS"
}
if flags == "" {
flags = "[NONE]"
} else {
flags = flags[1:]
}
buf.WriteString("SETTINGS {\n\t")
buf.WriteString(fmt.Sprintf("Version: 3\n\t"))
buf.WriteString(fmt.Sprintf("Flags: %s\n\t", flags))
buf.WriteString(fmt.Sprintf("Settings:\n"))
settings := frame.Settings.Settings()
for _, setting := range settings {
buf.WriteString("\t\t" + setting.String() + "\n")
}
buf.WriteString("}\n")
return buf.String()
}
func (frame *SETTINGS) WriteTo(writer io.Writer) (int64, error) {
c := common.WriteCounter{W: writer}
settings := encodeSettings(frame.Settings)
numSettings := uint32(len(frame.Settings))
length := 4 + len(settings)
out := make([]byte, 12)
out[0] = 128 // Control bit and Version
out[1] = 3 // Version
out[2] = 0 // Type
out[3] = 4 // Type
out[4] = byte(frame.Flags) // Flags
out[5] = byte(length >> 16) // Length
out[6] = byte(length >> 8) // Length
out[7] = byte(length) // Length
out[8] = byte(numSettings >> 24) // Number of Entries
out[9] = byte(numSettings >> 16) // Number of Entries
out[10] = byte(numSettings >> 8) // Number of Entries
out[11] = byte(numSettings) // Number of Entries
err := common.WriteExactly(&c, out)
if err != nil {
return c.N, err
}
err = common.WriteExactly(&c, settings)
if err != nil {
return c.N, err
}
return c.N, nil
}
func decodeSetting(data []byte) *common.Setting {
if len(data) < 8 {
return nil
}
setting := new(common.Setting)
setting.Flags = common.Flags(data[0])
setting.ID = common.BytesToUint24(data[1:])
setting.Value = common.BytesToUint32(data[4:])
return setting
}
func encodeSettings(s common.Settings) []byte {
if len(s) == 0 {
return []byte{}
}
ids := make([]int, 0, len(s))
for id := range s {
ids = append(ids, int(id))
}
sort.Sort(sort.IntSlice(ids))
out := make([]byte, 8*len(s))
offset := 0
for _, id := range ids {
setting := s[uint32(id)]
out[offset] = byte(setting.Flags)
out[offset+1] = byte(setting.ID >> 16)
out[offset+2] = byte(setting.ID >> 8)
out[offset+3] = byte(setting.ID)
out[offset+4] = byte(setting.Value >> 24)
out[offset+5] = byte(setting.Value >> 16)
out[offset+6] = byte(setting.Value >> 8)
out[offset+7] = byte(setting.Value)
offset += 8
}
return out
}