bbolt/internal/surgeon/xray.go

103 lines
2.7 KiB
Go

package surgeon
// Library contains raw access to bbolt files for sake of testing or fixing of corrupted files.
//
// The library must not be used bbolt btree - just by CLI or tests.
// It's not optimized for performance.
import (
"bytes"
"fmt"
"go.etcd.io/bbolt/internal/common"
"go.etcd.io/bbolt/internal/guts_cli"
)
type XRay struct {
path string
}
func NewXRay(path string) XRay {
return XRay{path}
}
func (n XRay) traverse(stack []common.Pgid, callback func(page *common.Page, stack []common.Pgid) error) error {
p, data, err := guts_cli.ReadPage(n.path, uint64(stack[len(stack)-1]))
if err != nil {
return fmt.Errorf("failed reading page (stack %v): %w", stack, err)
}
err = callback(p, stack)
if err != nil {
return fmt.Errorf("failed callback for page (stack %v): %w", stack, err)
}
switch p.Typ() {
case "meta":
{
m := common.LoadPageMeta(data)
r := m.RootBucket().RootPage()
return n.traverse(append(stack, r), callback)
}
case "branch":
{
for i := uint16(0); i < p.Count(); i++ {
bpe := p.BranchPageElement(i)
if err := n.traverse(append(stack, bpe.Pgid()), callback); err != nil {
return err
}
}
}
case "leaf":
for i := uint16(0); i < p.Count(); i++ {
lpe := p.LeafPageElement(i)
if lpe.IsBucketEntry() {
pgid := lpe.Bucket().RootPage()
if pgid > 0 {
if err := n.traverse(append(stack, pgid), callback); err != nil {
return err
}
} else {
inlinePage := lpe.Bucket().InlinePage(lpe.Value())
if err := callback(inlinePage, stack); err != nil {
return fmt.Errorf("failed callback for inline page (stack %v): %w", stack, err)
}
}
}
}
case "freelist":
return nil
// Free does not have children.
}
return nil
}
// FindPathsToKey finds all paths from root to the page that contains the given key.
// As it traverses multiple buckets, so in theory there might be multiple keys with the given name.
// Note: For simplicity it's currently implemented as traversing of the whole reachable tree.
// If key is a bucket name, a page-path referencing the key will be returned as well.
func (n XRay) FindPathsToKey(key []byte) ([][]common.Pgid, error) {
var found [][]common.Pgid
rootPage, _, err := guts_cli.GetRootPage(n.path)
if err != nil {
return nil, err
}
err = n.traverse([]common.Pgid{rootPage},
func(page *common.Page, stack []common.Pgid) error {
if page.Typ() == "leaf" {
for i := uint16(0); i < page.Count(); i++ {
if bytes.Equal(page.LeafPageElement(i).Key(), key) {
var copyPath []common.Pgid
copyPath = append(copyPath, stack...)
found = append(found, copyPath)
}
}
}
return nil
})
if err != nil {
return nil, err
} else {
return found, nil
}
}