166 lines
3.4 KiB
Go
166 lines
3.4 KiB
Go
package pointer
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import (
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"bufio"
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"bytes"
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"errors"
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"fmt"
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"github.com/hawser/git-hawser/hawser"
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"io"
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"regexp"
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"strconv"
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"strings"
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)
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var (
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MediaWarning = []byte("# git-media\n")
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alpha = "http://git-media.io/v/1"
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beta = "http://git-media.io/v/2"
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latest = "https://hawser.github.com/spec/v1"
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oidType = "sha256"
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alphaHeaderRE = regexp.MustCompile(`\A# (.*git-media|external)`)
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oidRE = regexp.MustCompile(`\A[0-9a-fA-F]{64}`)
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template = `version %s
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oid sha256:%s
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size %d
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`
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matcherRE = regexp.MustCompile("git-media|hawser")
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pointerKeys = []string{"version", "oid", "size"}
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)
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type Pointer struct {
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Version string
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Oid string
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Size int64
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OidType string
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}
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func NewPointer(oid string, size int64) *Pointer {
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return &Pointer{latest, oid, size, oidType}
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}
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func (p *Pointer) Smudge(writer io.Writer, cb hawser.CopyCallback) error {
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return Smudge(writer, p, cb)
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}
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func (p *Pointer) Encode(writer io.Writer) (int, error) {
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return Encode(writer, p)
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}
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func (p *Pointer) Encoded() string {
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return fmt.Sprintf(template, latest, p.Oid, p.Size)
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}
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func Encode(writer io.Writer, pointer *Pointer) (int, error) {
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return writer.Write([]byte(pointer.Encoded()))
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}
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func Decode(reader io.Reader) (*Pointer, error) {
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buf := make([]byte, 200)
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written, err := reader.Read(buf)
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if err != nil {
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return nil, err
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}
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data := bytes.TrimSpace(buf[0:written])
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if alphaHeaderRE.Match(data) {
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return decodeAlpha(data)
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} else {
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return decodeKV(data)
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}
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}
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func decodeKV(data []byte) (*Pointer, error) {
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parsed, err := decodeKVData(data)
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if err != nil {
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return nil, err
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}
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v, ok := parsed["version"]
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if !ok || (v != latest && v != beta) {
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if len(v) == 0 {
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v = "--"
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}
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return nil, errors.New("Invalid version: " + v)
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}
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oidValue, ok := parsed["oid"]
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if !ok {
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return nil, errors.New("Invalid Oid")
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}
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oidParts := strings.SplitN(oidValue, ":", 2)
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if len(oidParts) != 2 {
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return nil, errors.New("Invalid Oid type in" + oidValue)
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}
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if oidParts[0] != oidType {
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return nil, errors.New("Invalid Oid type: " + oidParts[0])
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}
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oid := oidParts[1]
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var size int64
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sizeStr, ok := parsed["size"]
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if !ok {
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return nil, errors.New("Invalid Oid")
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} else {
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size, err = strconv.ParseInt(sizeStr, 10, 0)
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if err != nil {
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return nil, errors.New("Invalid size: " + sizeStr)
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}
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}
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return NewPointer(oid, size), nil
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}
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func decodeKVData(data []byte) (map[string]string, error) {
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m := make(map[string]string)
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if !matcherRE.Match(data) {
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return m, fmt.Errorf("Not a valid Git Media pointer file.")
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}
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scanner := bufio.NewScanner(bytes.NewBuffer(data))
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line := 0
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numKeys := len(pointerKeys)
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for scanner.Scan() {
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text := scanner.Text()
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if len(text) == 0 {
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continue
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}
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parts := strings.SplitN(text, " ", 2)
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key := parts[0]
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if numKeys <= line {
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return m, fmt.Errorf("Extra line: %s", text)
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}
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if expected := pointerKeys[line]; key != expected {
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return m, fmt.Errorf("Expected key %s, got %s", expected, key)
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}
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line += 1
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if len(parts) < 2 {
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return m, fmt.Errorf("Error reading line %d: %s", line, text)
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}
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m[key] = parts[1]
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}
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return m, scanner.Err()
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}
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func decodeAlpha(data []byte) (*Pointer, error) {
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lines := bytes.Split(data, []byte("\n"))
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last := len(lines) - 1
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if last == 0 {
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return nil, errors.New("No OID in pointer file")
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}
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if !oidRE.Match(lines[last]) {
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return nil, errors.New("Invalid OID in pointer file")
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}
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return &Pointer{alpha, string(lines[last]), 0, oidType}, nil
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}
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