mirror of https://github.com/etcd-io/bbolt.git
122 lines
2.6 KiB
Go
122 lines
2.6 KiB
Go
package bolt
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import (
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"unsafe"
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)
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// RWTransaction represents a transaction that can read and write data.
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// Only one read/write transaction can be active for a DB at a time.
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type RWTransaction struct {
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Transaction
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branches map[pgid]*branch
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leafs map[pgid]*leaf
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}
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// CreateBucket creates a new bucket.
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func (t *RWTransaction) CreateBucket(name string) error {
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// Check if bucket already exists.
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if b := t.Bucket(name); b != nil {
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return &Error{"bucket already exists", nil}
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}
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// Create a new bucket entry.
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var buf [unsafe.Sizeof(bucket{})]byte
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var raw = (*bucket)(unsafe.Pointer(&buf[0]))
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raw.root = 0
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// Insert new node.
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c := t.sys.cursor()
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c.Goto([]byte(name))
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t.leaf(c.page().id).put([]byte(name), buf[:])
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return nil
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}
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// DropBucket deletes a bucket.
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func (t *RWTransaction) DeleteBucket(b *Bucket) error {
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// TODO: Remove from main DB.
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// TODO: Delete entry from system bucket.
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// TODO: Free all pages.
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// TODO: Remove cursor.
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return nil
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}
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func (t *RWTransaction) Put(name string, key []byte, value []byte) error {
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b := t.Bucket(name)
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if b == nil {
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return &Error{"bucket not found", nil}
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}
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// Validate the key and data size.
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if len(key) == 0 {
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return &Error{"key required", nil}
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} else if len(key) > MaxKeySize {
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return &Error{"key too large", nil}
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} else if len(value) > MaxDataSize {
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return &Error{"data too large", nil}
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}
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// Insert a new node.
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c := b.cursor()
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c.Goto(key)
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t.leaf(c.page().id).put(key, value)
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return nil
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}
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func (t *RWTransaction) Delete(key []byte) error {
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// TODO: Traverse to the correct node.
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// TODO: If missing, exit.
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// TODO: Remove node from page.
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// TODO: If page is empty then add it to the freelist.
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return nil
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}
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func (t *RWTransaction) Commit() error {
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// TODO(benbjohnson): Use vectorized I/O to write out dirty pages.
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// TODO: Flush data.
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// TODO: Update meta.
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// TODO: Write meta.
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return nil
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}
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func (t *RWTransaction) Rollback() error {
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return t.close()
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}
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func (t *RWTransaction) close() error {
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// Clear temporary pages.
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t.leafs = nil
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// TODO: Release writer lock.
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return nil
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}
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// allocate returns a contiguous block of memory starting at a given page.
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func (t *RWTransaction) allocate(size int) (*page, error) {
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// TODO: Find a continuous block of free pages.
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// TODO: If no free pages are available, resize the mmap to allocate more.
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return nil, nil
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}
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// leaf returns a deserialized leaf page.
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func (t *RWTransaction) leaf(id pgid) *leaf {
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if t.leafs != nil {
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if l := t.leafs[id]; l != nil {
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return l
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}
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}
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// Read raw page and deserialize.
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l := &leaf{}
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l.read(t.page(id))
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t.leafs[id] = l
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return l
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}
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