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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfstree
import (
"fmt"
"strings"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
)
type SearchItemType int8
const (
ItemTypeAny SearchItemType = iota
ItemTypeExact
)
type SearchOffset int8
const (
OffsetAny SearchOffset = iota
OffsetExact
OffsetRange // .Search behaves same as OffsetAny (TODO?)
OffsetName // .Search behaves same as OffsetAny
)
// Search is a fairly generic and reusable implementation of
// TreeSearcher.
type Search struct {
ObjectID btrfsprim.ObjID
ItemTypeMatching SearchItemType
ItemType btrfsprim.ItemType
// Offset is totally ignored if .ItemTypeMatching=ItemTypeany.
OffsetMatching SearchOffset
OffsetLow uint64 // only for .OffsetMatching==OffsetExact or .OffsetMatching==OffsetRange
OffsetHigh uint64 // only for .OffsetMatching==OffsetRange
OffsetName string // only for .OffsetMatching==OffsetName
}
var (
_ containers.Ordered[Search] = Search{}
_ TreeSearcher = Search{}
)
// Compare implements containers.Ordered.
func (a Search) Compare(b Search) int {
if d := containers.NativeCompare(a.ObjectID, b.ObjectID); d != 0 {
return d
}
if d := containers.NativeCompare(a.ItemType, b.ItemType); d != 0 {
return d
}
if d := containers.NativeCompare(a.OffsetMatching, b.OffsetMatching); d != 0 {
return d
}
if d := containers.NativeCompare(a.OffsetLow, b.OffsetLow); d != 0 {
return d
}
if d := containers.NativeCompare(a.OffsetHigh, b.OffsetHigh); d != 0 {
return d
}
if d := containers.NativeCompare(a.OffsetName, b.OffsetName); d != 0 {
return d
}
return 0
}
// String implements fmt.Stringer (and TreeSearcher).
func (o Search) String() string {
var buf strings.Builder
fmt.Fprintf(&buf, "(%v ", o.ObjectID)
switch o.ItemTypeMatching {
case ItemTypeAny:
buf.WriteString("? ?)")
return buf.String()
case ItemTypeExact:
fmt.Fprintf(&buf, "%v", o.ItemType)
default:
panic(fmt.Errorf("should not happen: ItemTypeMatching=%#v", o.ItemTypeMatching))
}
buf.WriteString(" ")
switch o.OffsetMatching {
case OffsetAny:
buf.WriteString("?")
case OffsetExact:
fmt.Fprintf(&buf, "%v", o.OffsetLow)
case OffsetRange:
fmt.Fprintf(&buf, "%v-%v", o.OffsetLow, o.OffsetHigh)
case OffsetName:
fmt.Fprintf(&buf, "name=%q", o.OffsetName)
default:
panic(fmt.Errorf("should not happen: OffsetMatching=%#v", o.OffsetMatching))
}
buf.WriteString(")")
return buf.String()
}
// Search implements TreeSearcher.
func (o Search) Search(k btrfsprim.Key, _ uint32) int {
if d := containers.NativeCompare(o.ObjectID, k.ObjectID); d != 0 {
return d
}
switch o.ItemTypeMatching {
case ItemTypeAny:
return 0
case ItemTypeExact:
if d := containers.NativeCompare(o.ItemType, k.ItemType); d != 0 {
return d
}
default:
panic(fmt.Errorf("should not happen: ItemTypeMatching=%#v", o.ItemTypeMatching))
}
switch o.OffsetMatching {
case OffsetAny, OffsetRange, OffsetName:
return 0
case OffsetExact:
return containers.NativeCompare(o.OffsetLow, k.Offset)
default:
panic(fmt.Errorf("should not happen: OffsetMatching=%#v", o.OffsetMatching))
}
}
////////////////////////////////////////////////////////////////////////////////
// SearchObject returns a Search that searches all items belonging to
// a given object.
func SearchObject(objID btrfsprim.ObjID) Search {
return Search{
ObjectID: objID,
ItemTypeMatching: ItemTypeAny,
}
}
// SearchExactKey returns a Search that searches for the exact key.
func SearchExactKey(k btrfsprim.Key) Search {
return Search{
ObjectID: k.ObjectID,
ItemTypeMatching: ItemTypeExact,
ItemType: k.ItemType,
OffsetMatching: OffsetExact,
OffsetLow: k.Offset,
}
}
// SearchRootItem returns a Search that searches for the root item for
// the given tree.
func SearchRootItem(treeID btrfsprim.ObjID) Search {
return Search{
ObjectID: treeID,
ItemTypeMatching: ItemTypeExact,
ItemType: btrfsprim.ROOT_ITEM_KEY,
OffsetMatching: OffsetAny,
}
}
type csumSearcher struct {
laddr btrfsvol.LogicalAddr
algSize int
}
func (s csumSearcher) String() string { return fmt.Sprintf("csum for laddr=%v", s.laddr) }
func (s csumSearcher) Search(key btrfsprim.Key, size uint32) int {
if d := containers.NativeCompare(btrfsprim.EXTENT_CSUM_OBJECTID, key.ObjectID); d != 0 {
return d
}
if d := containers.NativeCompare(btrfsprim.EXTENT_CSUM_KEY, key.ItemType); d != 0 {
return d
}
itemBeg := btrfsvol.LogicalAddr(key.Offset)
numSums := int64(size) / int64(s.algSize)
itemEnd := itemBeg + btrfsvol.LogicalAddr(numSums*btrfssum.BlockSize)
switch {
case itemEnd <= s.laddr:
return 1
case s.laddr < itemBeg:
return -1
default:
return 0
}
}
// SearchCSum returns a TreeSearcher that searches for a csum-run
// containing the csum for a given LogicalAddress.
func SearchCSum(laddr btrfsvol.LogicalAddr, algSize int) TreeSearcher {
return csumSearcher{
laddr: laddr,
algSize: algSize,
}
}
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