rss-tools/vendor/go.etcd.io/bbolt/internal/common/meta.go (view raw)
| 1 | package common |
| 2 | |
| 3 | import ( |
| 4 | "fmt" |
| 5 | "hash/fnv" |
| 6 | "io" |
| 7 | "unsafe" |
| 8 | |
| 9 | "go.etcd.io/bbolt/errors" |
| 10 | ) |
| 11 | |
| 12 | type Meta struct { |
| 13 | magic uint32 |
| 14 | version uint32 |
| 15 | pageSize uint32 |
| 16 | flags uint32 |
| 17 | root InBucket |
| 18 | freelist Pgid |
| 19 | pgid Pgid |
| 20 | txid Txid |
| 21 | checksum uint64 |
| 22 | } |
| 23 | |
| 24 | // Validate checks the marker bytes and version of the meta page to ensure it matches this binary. |
| 25 | func (m *Meta) Validate() error { |
| 26 | if m.magic != Magic { |
| 27 | return errors.ErrInvalid |
| 28 | } else if m.version != Version { |
| 29 | return errors.ErrVersionMismatch |
| 30 | } else if m.checksum != m.Sum64() { |
| 31 | return errors.ErrChecksum |
| 32 | } |
| 33 | return nil |
| 34 | } |
| 35 | |
| 36 | // Copy copies one meta object to another. |
| 37 | func (m *Meta) Copy(dest *Meta) { |
| 38 | *dest = *m |
| 39 | } |
| 40 | |
| 41 | // Write writes the meta onto a page. |
| 42 | func (m *Meta) Write(p *Page) { |
| 43 | if m.root.root >= m.pgid { |
| 44 | panic(fmt.Sprintf("root bucket pgid (%d) above high water mark (%d)", m.root.root, m.pgid)) |
| 45 | } else if m.freelist >= m.pgid && m.freelist != PgidNoFreelist { |
| 46 | // TODO: reject pgidNoFreeList if !NoFreelistSync |
| 47 | panic(fmt.Sprintf("freelist pgid (%d) above high water mark (%d)", m.freelist, m.pgid)) |
| 48 | } |
| 49 | |
| 50 | // Page id is either going to be 0 or 1 which we can determine by the transaction ID. |
| 51 | p.id = Pgid(m.txid % 2) |
| 52 | p.SetFlags(MetaPageFlag) |
| 53 | |
| 54 | // Calculate the checksum. |
| 55 | m.checksum = m.Sum64() |
| 56 | |
| 57 | m.Copy(p.Meta()) |
| 58 | } |
| 59 | |
| 60 | // Sum64 generates the checksum for the meta. |
| 61 | func (m *Meta) Sum64() uint64 { |
| 62 | var h = fnv.New64a() |
| 63 | _, _ = h.Write((*[unsafe.Offsetof(Meta{}.checksum)]byte)(unsafe.Pointer(m))[:]) |
| 64 | return h.Sum64() |
| 65 | } |
| 66 | |
| 67 | func (m *Meta) Magic() uint32 { |
| 68 | return m.magic |
| 69 | } |
| 70 | |
| 71 | func (m *Meta) SetMagic(v uint32) { |
| 72 | m.magic = v |
| 73 | } |
| 74 | |
| 75 | func (m *Meta) Version() uint32 { |
| 76 | return m.version |
| 77 | } |
| 78 | |
| 79 | func (m *Meta) SetVersion(v uint32) { |
| 80 | m.version = v |
| 81 | } |
| 82 | |
| 83 | func (m *Meta) PageSize() uint32 { |
| 84 | return m.pageSize |
| 85 | } |
| 86 | |
| 87 | func (m *Meta) SetPageSize(v uint32) { |
| 88 | m.pageSize = v |
| 89 | } |
| 90 | |
| 91 | func (m *Meta) Flags() uint32 { |
| 92 | return m.flags |
| 93 | } |
| 94 | |
| 95 | func (m *Meta) SetFlags(v uint32) { |
| 96 | m.flags = v |
| 97 | } |
| 98 | |
| 99 | func (m *Meta) SetRootBucket(b InBucket) { |
| 100 | m.root = b |
| 101 | } |
| 102 | |
| 103 | func (m *Meta) RootBucket() *InBucket { |
| 104 | return &m.root |
| 105 | } |
| 106 | |
| 107 | func (m *Meta) Freelist() Pgid { |
| 108 | return m.freelist |
| 109 | } |
| 110 | |
| 111 | func (m *Meta) SetFreelist(v Pgid) { |
| 112 | m.freelist = v |
| 113 | } |
| 114 | |
| 115 | func (m *Meta) IsFreelistPersisted() bool { |
| 116 | return m.freelist != PgidNoFreelist |
| 117 | } |
| 118 | |
| 119 | func (m *Meta) Pgid() Pgid { |
| 120 | return m.pgid |
| 121 | } |
| 122 | |
| 123 | func (m *Meta) SetPgid(id Pgid) { |
| 124 | m.pgid = id |
| 125 | } |
| 126 | |
| 127 | func (m *Meta) Txid() Txid { |
| 128 | return m.txid |
| 129 | } |
| 130 | |
| 131 | func (m *Meta) SetTxid(id Txid) { |
| 132 | m.txid = id |
| 133 | } |
| 134 | |
| 135 | func (m *Meta) IncTxid() { |
| 136 | m.txid += 1 |
| 137 | } |
| 138 | |
| 139 | func (m *Meta) DecTxid() { |
| 140 | m.txid -= 1 |
| 141 | } |
| 142 | |
| 143 | func (m *Meta) Checksum() uint64 { |
| 144 | return m.checksum |
| 145 | } |
| 146 | |
| 147 | func (m *Meta) SetChecksum(v uint64) { |
| 148 | m.checksum = v |
| 149 | } |
| 150 | |
| 151 | func (m *Meta) Print(w io.Writer) { |
| 152 | fmt.Fprintf(w, "Version: %d\n", m.version) |
| 153 | fmt.Fprintf(w, "Page Size: %d bytes\n", m.pageSize) |
| 154 | fmt.Fprintf(w, "Flags: %08x\n", m.flags) |
| 155 | fmt.Fprintf(w, "Root: <pgid=%d>\n", m.root.root) |
| 156 | fmt.Fprintf(w, "Freelist: <pgid=%d>\n", m.freelist) |
| 157 | fmt.Fprintf(w, "HWM: <pgid=%d>\n", m.pgid) |
| 158 | fmt.Fprintf(w, "Txn ID: %d\n", m.txid) |
| 159 | fmt.Fprintf(w, "Checksum: %016x\n", m.checksum) |
| 160 | fmt.Fprintf(w, "\n") |
| 161 | } |