package ulreq
import (
"fmt"
"io"
"sort"
"time"
"gopkg.in/src-d/go-git.v4/core"
"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
)
// An Encoder writes UlReq values to an output stream.
type Encoder struct {
pe *pktline.Encoder // where to write the encoded data
data *UlReq // the data to encode
sortedWants []string
err error // sticky error
}
// NewEncoder returns a new encoder that writes to w.
func NewEncoder(w io.Writer) *Encoder {
return &Encoder{
pe: pktline.NewEncoder(w),
}
}
// Encode writes the UlReq encoding of v to the stream.
//
// All the payloads will end with a newline character. Wants and
// shallows are sorted alphabetically. A depth of 0 means no depth
// request is sent.
func (e *Encoder) Encode(v *UlReq) error {
if len(v.Wants) == 0 {
return fmt.Errorf("empty wants provided")
}
e.data = v
e.sortedWants = sortHashes(v.Wants)
for state := encodeFirstWant; state != nil; {
state = state(e)
}
return e.err
}
type encoderStateFn func(*Encoder) encoderStateFn
func sortHashes(list []core.Hash) []string {
sorted := make([]string, len(list))
for i, hash := range list {
sorted[i] = hash.String()
}
sort.Strings(sorted)
return sorted
}
func encodeFirstWant(e *Encoder) encoderStateFn {
var err error
if e.data.Capabilities.IsEmpty() {
err = e.pe.Encodef("want %s\n", e.sortedWants[0])
} else {
e.data.Capabilities.Sort()
err = e.pe.Encodef(
"want %s %s\n",
e.sortedWants[0],
e.data.Capabilities.String(),
)
}
if err != nil {
e.err = fmt.Errorf("encoding first want line: %s", err)
return nil
}
return encodeAditionalWants
}
func encodeAditionalWants(e *Encoder) encoderStateFn {
for _, w := range e.sortedWants[1:] {
if err := e.pe.Encodef("want %s\n", w); err != nil {
e.err = fmt.Errorf("encoding want %q: %s", w, err)
return nil
}
}
return encodeShallows
}
func encodeShallows(e *Encoder) encoderStateFn {
sorted := sortHashes(e.data.Shallows)
for _, s := range sorted {
if err := e.pe.Encodef("shallow %s\n", s); err != nil {
e.err = fmt.Errorf("encoding shallow %q: %s", s, err)
return nil
}
}
return encodeDepth
}
func encodeDepth(e *Encoder) encoderStateFn {
switch depth := e.data.Depth.(type) {
case DepthCommits:
if depth != 0 {
commits := int(depth)
if err := e.pe.Encodef("deepen %d\n", commits); err != nil {
e.err = fmt.Errorf("encoding depth %d: %s", depth, err)
return nil
}
}
case DepthSince:
when := time.Time(depth).UTC()
if err := e.pe.Encodef("deepen-since %d\n", when.Unix()); err != nil {
e.err = fmt.Errorf("encoding depth %s: %s", when, err)
return nil
}
case DepthReference:
reference := string(depth)
if err := e.pe.Encodef("deepen-not %s\n", reference); err != nil {
e.err = fmt.Errorf("encoding depth %s: %s", reference, err)
return nil
}
default:
e.err = fmt.Errorf("unsupported depth type")
return nil
}
return encodeFlush
}
func encodeFlush(e *Encoder) encoderStateFn {
if err := e.pe.Flush(); err != nil {
e.err = fmt.Errorf("encoding flush-pkt: %s", err)
return nil
}
return nil
}
