vevenv.go RawHistoryFolder

1package app
2
3import "strings"
4
5type vevEnv struct {
6	session string
7	tab     string
8	pane    string
9}
10
11// parseVEVEnv strictly parses the identity injected into pane PTYs. All three
12// unique fields are required and components use the daemon's uppercase %XX
13// escaping.
14func parseVEVEnv(value string) (vevEnv, bool) {
15	if value == "" {
16		return vevEnv{}, false
17	}
18	var out vevEnv
19	seen := make(map[string]bool, 3)
20	for part := range strings.SplitSeq(value, ",") {
21		key, encoded, found := strings.Cut(part, "=")
22		if !found || seen[key] {
23			return vevEnv{}, false
24		}
25		decoded, ok := unescapeVEVComponent(encoded)
26		if !ok || decoded == "" {
27			return vevEnv{}, false
28		}
29		switch key {
30		case "session":
31			out.session = decoded
32		case "tab":
33			out.tab = decoded
34		case "pane":
35			out.pane = decoded
36		default:
37			return vevEnv{}, false
38		}
39		seen[key] = true
40	}
41	if len(seen) != 3 || out.session == "" || out.tab == "" || out.pane == "" {
42		return vevEnv{}, false
43	}
44	return out, true
45}
46
47func unescapeVEVComponent(value string) (string, bool) {
48	var out strings.Builder
49	for i := 0; i < len(value); i++ {
50		if value[i] != '%' {
51			if !isUnescapedVEVByte(value[i]) {
52				return "", false
53			}
54			out.WriteByte(value[i])
55			continue
56		}
57		if i+2 >= len(value) {
58			return "", false
59		}
60		hi, highOK := upperHexValue(value[i+1])
61		lo, lowOK := upperHexValue(value[i+2])
62		if !highOK || !lowOK {
63			return "", false
64		}
65		out.WriteByte(hi<<4 | lo)
66		i += 2
67	}
68	return out.String(), true
69}
70
71func isUnescapedVEVByte(value byte) bool {
72	return value >= 'A' && value <= 'Z' ||
73		value >= 'a' && value <= 'z' ||
74		value >= '0' && value <= '9' ||
75		value == '.' || value == '_' || value == '-'
76}
77
78func upperHexValue(value byte) (byte, bool) {
79	switch {
80	case value >= '0' && value <= '9':
81		return value - '0', true
82	case value >= 'A' && value <= 'F':
83		return value - 'A' + 10, true
84	default:
85		return 0, false
86	}
87}