forked from perkeep/perkeep
-
Notifications
You must be signed in to change notification settings - Fork 0
/
etc.go
156 lines (129 loc) · 2.59 KB
/
etc.go
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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
// Copyright 2014 The dbm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package dbm
import (
"bytes"
"fmt"
"camlistore.org/third_party/github.com/cznic/exp/lldb"
"camlistore.org/third_party/github.com/cznic/fileutil"
"camlistore.org/third_party/github.com/cznic/mathutil"
)
type header struct {
magic []byte
ver byte
reserved []byte
}
func (h *header) rd(b []byte) error {
if len(b) != 16 {
panic("internal error")
}
if h.magic = b[:4]; bytes.Compare(h.magic, []byte(magic)) != 0 {
return fmt.Errorf("Unknown file format")
}
b = b[4:]
h.ver = b[0]
h.reserved = b[1:]
return nil
}
// Get a 7B int64 from b
func b2h(b []byte) (h int64) {
for _, v := range b[:7] {
h = h<<8 | int64(v)
}
return
}
// Put a 7B int64 into b
func h2b(b []byte, h int64) []byte {
for i := range b[:7] {
b[i], h = byte(h>>48), h<<8
}
return b
}
func collate(a, b []byte) (r int) {
da, err := lldb.DecodeScalars(a)
if err != nil {
panic(err)
}
db, err := lldb.DecodeScalars(b)
if err != nil {
panic(err)
}
r, err = lldb.Collate(da, db, nil)
if err != nil {
panic(err)
}
return
}
type treeCache map[string]*lldb.BTree
func (t *treeCache) get() (r map[string]*lldb.BTree) {
if r = *t; r != nil {
return
}
*t = map[string]*lldb.BTree{}
return *t
}
func (t *treeCache) getTree(db *DB, prefix int, name string, canCreate bool, cacheSize int) (r *lldb.BTree, err error) {
m := t.get()
r, ok := m[name]
if ok {
return
}
root, err := db.root()
if err != nil {
return
}
val, err := root.get(prefix, name)
if err != nil {
return
}
switch x := val.(type) {
case nil:
if !canCreate {
return
}
var h int64
r, h, err = lldb.CreateBTree(db.alloc, collate)
if err != nil {
return nil, err
}
if err = root.set(h, prefix, name); err != nil {
return nil, err
}
case int64:
if r, err = lldb.OpenBTree(db.alloc, collate, x); err != nil {
return nil, err
}
default:
return nil, &lldb.ErrINVAL{Src: "corrupted root directory value for", Val: fmt.Sprintf("%q, %q", prefix, name)}
}
if len(m) > cacheSize {
i, j, n := 0, cacheSize/2, mathutil.Min(cacheSize/20, 10)
loop:
for k := range m {
if i++; i >= j {
delete(m, k)
if n == 0 {
break loop
}
n--
}
}
}
m[name] = r
return
}
func encVal(val interface{}) (r []byte, err error) {
switch x := val.(type) {
case []interface{}:
return lldb.EncodeScalars(x...)
default:
return lldb.EncodeScalars(x)
}
}
func noEof(e error) (err error) {
if !fileutil.IsEOF(e) {
err = e
}
return
}