aboutsummaryrefslogtreecommitdiffstats
path: root/plumbing/protocol/packp/ulreq_encoder.go
blob: 9ebc4b5ea3afea2aa3f10a7f07e03d2d0c975072 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
package packp

import (
	"fmt"
	"io"
	"sort"
	"time"

	"gopkg.in/src-d/go-git.v4/plumbing"
	"gopkg.in/src-d/go-git.v4/plumbing/format/pktline"
)

// An UlReqEncoder writes UlReq values to an output stream.
type UlReqEncoder struct {
	pe          *pktline.Encoder // where to write the encoded data
	data        *UlReq           // the data to encode
	sortedWants []string
	err         error // sticky error
}

// NewUlReqEncoder returns a new encoder that writes to w.
func NewUlReqEncoder(w io.Writer) *UlReqEncoder {
	return &UlReqEncoder{
		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 *UlReqEncoder) 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 := e.encodeFirstWant; state != nil; {
		state = state()
	}

	return e.err
}

func sortHashes(list []plumbing.Hash) []string {
	sorted := make([]string, len(list))
	for i, hash := range list {
		sorted[i] = hash.String()
	}
	sort.Strings(sorted)

	return sorted
}

func (e *UlReqEncoder) encodeFirstWant() stateFn {
	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 e.encodeAditionalWants
}

func (e *UlReqEncoder) encodeAditionalWants() stateFn {
	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 e.encodeShallows
}

func (e *UlReqEncoder) encodeShallows() stateFn {
	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 e.encodeDepth
}

func (e *UlReqEncoder) encodeDepth() stateFn {
	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 e.encodeFlush
}

func (e *UlReqEncoder) encodeFlush() stateFn {
	if err := e.pe.Flush(); err != nil {
		e.err = fmt.Errorf("encoding flush-pkt: %s", err)
		return nil
	}

	return nil
}