blob: 522f1137c42b99259b6ed6189003e7c2bb3be97b (
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
|
package bolt
import (
"unsafe"
)
const maxPageSize = 0x8000
const minKeyCount = 2
var _page page
const pageHeaderSize = int(unsafe.Offsetof(_page.ptr))
const minPageKeys = 2
const fillThreshold = 250 // 25%
const (
p_branch = 0x01
p_leaf = 0x02
p_overflow = 0x04
p_meta = 0x08
p_dirty = 0x10 /**< dirty page, also set for #P_SUBP pages */
p_sub = 0x40
p_keep = 0x8000 /**< leave this page alone during spill */
p_invalid = ^pgno(0)
)
// maxCommitPages is the maximum number of pages to commit in one writev() call.
const maxCommitPages = 64
/* max bytes to write in one call */
const maxWriteByteCount uint = 0x80000000 // TODO: #define MAX_WRITE 0x80000000U >> (sizeof(ssize_t) == 4))
// TODO:
// #if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
// #undef MDB_COMMIT_PAGES
// #define MDB_COMMIT_PAGES IOV_MAX
// #endif
// TODO: #define MDB_PS_MODIFY 1
// TODO: #define MDB_PS_ROOTONLY 2
// TODO: #define MDB_PS_FIRST 4
// TODO: #define MDB_PS_LAST 8
// TODO: #define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
type pgno uint64
type txnid uint64
type indx uint16
type page struct {
id pgno
flags int
lower indx
upper indx
overflow int
ptr int
}
type pageState struct {
head int /**< Reclaimed freeDB pages, or NULL before use */
last int /**< ID of last used record, or 0 if !mf_pghead */
}
// meta returns a pointer to the metadata section of the page.
func (p *page) meta() (*meta, error) {
// Exit if page is not a meta page.
if (p.flags & p_meta) == 0 {
return nil, InvalidMetaPageError
}
// Cast the meta section and validate before returning.
m := (*meta)(unsafe.Pointer(&p.ptr))
if err := m.validate(); err != nil {
return nil, err
}
return m, nil
}
// initMeta initializes a page as a new meta page.
func (p *page) initMeta(pageSize int) {
p.flags = p_meta
m := (*meta)(unsafe.Pointer(&p.ptr))
m.magic = magic
m.version = version
m.free.pad = uint32(pageSize)
m.pgno = 1
m.free.root = p_invalid
m.main.root = p_invalid
}
// nodeCount returns the number of nodes on the page.
func (p *page) nodeCount() int {
return 0 // (p.header.lower - unsafe.Sizeof(p.header) >> 1
}
// remainingSize returns the number of bytes left in the page.
func (p *page) remainingSize() int {
return int(p.upper - p.lower)
}
|
