btrfs: Split off btrfstree and btrfsprim sub-packages

1 files changed, 0 insertions, 503 deletions

diff --git a/lib/btrfs/btree_ops.go b/lib/btrfs/btree_ops.go
deleted file mode 100644
index b590aa7..0000000
--- a/lib/btrfs/btree_ops.go
+++ /dev/null
@@ -1,503 +0,0 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package btrfs
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	iofs "io/fs"
-	"math"
-
-	"github.com/datawire/dlib/derror"
-
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
-	"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
-	"git.lukeshu.com/btrfs-progs-ng/lib/slices"
-)
-
-type Trees interface {
-	// TreeWalk walks a tree, triggering callbacks for every node,
-	// key-pointer, and item; as well as for any errors encountered.
-	//
-	// If the tree is valid, then everything is walked in key-order; but if
-	// the tree is broken, then ordering is not guaranteed.
-	//
-	// Canceling the Context causes TreeWalk to return early; no
-	// values from the Context are used.
-	//
-	// The lifecycle of callbacks is:
-	//
-	//     001 .PreNode()
-	//     002 (read node)
-	//     003 .Node() (or .BadNode())
-	//         for item in node.items:
-	//           if internal:
-	//     004     .PreKeyPointer()
-	//     005     (recurse)
-	//     006     .PostKeyPointer()
-	//           else:
-	//     004     .Item() (or .BadItem())
-	//     007 .PostNode()
-	TreeWalk(ctx context.Context, treeID ObjID, errHandle func(*TreeError), cbs TreeWalkHandler)
-
-	TreeLookup(treeID ObjID, key Key) (Item, error)
-	TreeSearch(treeID ObjID, fn func(key Key, size uint32) int) (Item, error) // size is math.MaxUint32 for key-pointers
-
-	// If some items are able to be read, but there is an error reading the
-	// full set, then it might return *both* a list of items and an error.
-	//
-	// If no such item is found, an error that is io/fs.ErrNotExist is
-	// returned.
-	TreeSearchAll(treeID ObjID, fn func(key Key, size uint32) int) ([]Item, error) // size is math.MaxUint32 for key-pointers
-
-	// For bootstrapping purposes.
-	Superblock() (*Superblock, error)
-
-	// For reading raw data extants pointed at by tree items.
-	ReadAt(p []byte, off btrfsvol.LogicalAddr) (int, error)
-}
-
-type TreeWalkHandler struct {
-	// Callbacks for entire nodes.
-	//
-	// If any of these return an error that is io/fs.SkipDir, the
-	// node immediately stops getting processed; if PreNode, Node,
-	// or BadNode return io/fs.SkipDir then key pointers and items
-	// within the node are not processed.
-	PreNode  func(TreePath) error
-	Node     func(TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node]) error
-	BadNode  func(TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) error
-	PostNode func(TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node]) error
-	// Callbacks for items on internal nodes
-	PreKeyPointer  func(TreePath, KeyPointer) error
-	PostKeyPointer func(TreePath, KeyPointer) error
-	// Callbacks for items on leaf nodes
-	Item    func(TreePath, Item) error
-	BadItem func(TreePath, Item) error
-}
-
-type TreeError struct {
-	Path TreePath
-	Err  error
-}
-
-func (e *TreeError) Unwrap() error { return e.Err }
-
-func (e *TreeError) Error() string {
-	return fmt.Sprintf("%v: %v", e.Path, e.Err)
-}
-
-// TreeWalk implements the 'Trees' interface.
-func (fs *FS) TreeWalk(ctx context.Context, treeID ObjID, errHandle func(*TreeError), cbs TreeWalkHandler) {
-	rootInfo, err := LookupTreeRoot(fs, treeID)
-	if err != nil {
-		errHandle(&TreeError{Path: TreePath{{FromTree: treeID}}, Err: err})
-		return
-	}
-	fs.RawTreeWalk(ctx, *rootInfo, errHandle, cbs)
-}
-
-// TreeWalk is a utility function to help with implementing the 'Trees'
-// interface.
-func (fs *FS) RawTreeWalk(ctx context.Context, rootInfo TreeRoot, errHandle func(*TreeError), cbs TreeWalkHandler) {
-	path := TreePath{{
-		FromTree:       rootInfo.TreeID,
-		FromGeneration: rootInfo.Generation,
-		FromItemIdx:    -1,
-		ToNodeAddr:     rootInfo.RootNode,
-		ToNodeLevel:    rootInfo.Level,
-	}}
-	fs.treeWalk(ctx, path, errHandle, cbs)
-}
-
-func (fs *FS) treeWalk(ctx context.Context, path TreePath, errHandle func(*TreeError), cbs TreeWalkHandler) {
-	if ctx.Err() != nil {
-		return
-	}
-	if path.Node(-1).ToNodeAddr == 0 {
-		return
-	}
-
-	if cbs.PreNode != nil {
-		if err := cbs.PreNode(path); err != nil {
-			if errors.Is(err, iofs.SkipDir) {
-				return
-			}
-			errHandle(&TreeError{Path: path, Err: err})
-		}
-		if ctx.Err() != nil {
-			return
-		}
-	}
-	node, err := fs.ReadNode(path)
-	if ctx.Err() != nil {
-		return
-	}
-	if err != nil && node != nil && cbs.BadNode != nil {
-		// opportunity to fix the node
-		err = cbs.BadNode(path, node, err)
-		if errors.Is(err, iofs.SkipDir) {
-			return
-		}
-	}
-	if err != nil {
-		errHandle(&TreeError{Path: path, Err: err})
-	} else {
-		if cbs.Node != nil {
-			if err := cbs.Node(path, node); err != nil {
-				if errors.Is(err, iofs.SkipDir) {
-					return
-				}
-				errHandle(&TreeError{Path: path, Err: err})
-			}
-		}
-	}
-	if ctx.Err() != nil {
-		return
-	}
-	if node != nil {
-		for i, item := range node.Data.BodyInternal {
-			itemPath := append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    i,
-				ToNodeAddr:     item.BlockPtr,
-				ToNodeLevel:    node.Data.Head.Level - 1,
-			})
-			if cbs.PreKeyPointer != nil {
-				if err := cbs.PreKeyPointer(itemPath, item); err != nil {
-					errHandle(&TreeError{Path: itemPath, Err: err})
-				}
-				if ctx.Err() != nil {
-					return
-				}
-			}
-			fs.treeWalk(ctx, itemPath, errHandle, cbs)
-			if cbs.PostKeyPointer != nil {
-				if err := cbs.PostKeyPointer(itemPath, item); err != nil {
-					errHandle(&TreeError{Path: itemPath, Err: err})
-				}
-				if ctx.Err() != nil {
-					return
-				}
-			}
-		}
-		for i, item := range node.Data.BodyLeaf {
-			itemPath := append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    i,
-			})
-			if errBody, isErr := item.Body.(btrfsitem.Error); isErr {
-				if cbs.BadItem == nil {
-					errHandle(&TreeError{Path: itemPath, Err: errBody.Err})
-				} else {
-					if err := cbs.BadItem(itemPath, item); err != nil {
-						errHandle(&TreeError{Path: itemPath, Err: err})
-					}
-					if ctx.Err() != nil {
-						return
-					}
-				}
-			} else {
-				if cbs.Item != nil {
-					if err := cbs.Item(itemPath, item); err != nil {
-						errHandle(&TreeError{Path: itemPath, Err: err})
-					}
-					if ctx.Err() != nil {
-						return
-					}
-				}
-			}
-		}
-	}
-	if cbs.PostNode != nil {
-		if err := cbs.PostNode(path, node); err != nil {
-			if errors.Is(err, iofs.SkipDir) {
-				return
-			}
-			errHandle(&TreeError{Path: path, Err: err})
-		}
-	}
-}
-
-func (fs *FS) treeSearch(treeRoot TreeRoot, fn func(Key, uint32) int) (TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
-	path := TreePath{{
-		FromTree:       treeRoot.TreeID,
-		FromGeneration: treeRoot.Generation,
-		FromItemIdx:    -1,
-		ToNodeAddr:     treeRoot.RootNode,
-		ToNodeLevel:    treeRoot.Level,
-	}}
-	for {
-		if path.Node(-1).ToNodeAddr == 0 {
-			return TreePath{}, nil, iofs.ErrNotExist
-		}
-		node, err := fs.ReadNode(path)
-		if err != nil {
-			return TreePath{}, nil, err
-		}
-
-		if node.Data.Head.Level > 0 {
-			// internal node
-
-			// Search for the right-most node.Data.BodyInternal item for which
-			// `fn(item.Key) >= 0`.
-			//
-			//    + + + + 0 - - - -
-			//
-			// There may or may not be a value that returns '0'.
-			//
-			// i.e. find the highest value that isn't too high.
-			lastGood, ok := slices.SearchHighest(node.Data.BodyInternal, func(kp KeyPointer) int {
-				return slices.Min(fn(kp.Key, math.MaxUint32), 0) // don't return >0; a key can't be "too low"
-			})
-			if !ok {
-				return TreePath{}, nil, iofs.ErrNotExist
-			}
-			path = append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    lastGood,
-				ToNodeAddr:     node.Data.BodyInternal[lastGood].BlockPtr,
-				ToNodeLevel:    node.Data.Head.Level - 1,
-			})
-		} else {
-			// leaf node
-
-			// Search for a member of node.Data.BodyLeaf for which
-			// `fn(item.Head.Key) == 0`.
-			//
-			//    + + + + 0 - - - -
-			//
-			// Such an item might not exist; in this case, return nil/ErrNotExist.
-			// Multiple such items might exist; in this case, it does not matter which
-			// is returned.
-			//
-			// Implement this search as a binary search.
-			idx, ok := slices.Search(node.Data.BodyLeaf, func(item Item) int {
-				return fn(item.Key, item.BodySize)
-			})
-			if !ok {
-				return TreePath{}, nil, iofs.ErrNotExist
-			}
-			path = append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    idx,
-			})
-			return path, node, nil
-		}
-	}
-}
-
-func (fs *FS) prev(path TreePath, node *diskio.Ref[btrfsvol.LogicalAddr, Node]) (TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
-	var err error
-	path = path.DeepCopy()
-
-	// go up
-	for path.Node(-1).FromItemIdx < 1 {
-		path = path.Parent()
-		if len(path) == 0 {
-			return TreePath{}, nil, nil
-		}
-	}
-	// go left
-	path.Node(-1).FromItemIdx--
-	if path.Node(-1).ToNodeAddr != 0 {
-		if node.Addr != path.Node(-2).ToNodeAddr {
-			node, err = fs.ReadNode(path.Parent())
-			if err != nil {
-				return TreePath{}, nil, err
-			}
-			path.Node(-1).ToNodeAddr = node.Data.BodyInternal[path.Node(-1).FromItemIdx].BlockPtr
-		}
-	}
-	// go down
-	for path.Node(-1).ToNodeAddr != 0 {
-		if node.Addr != path.Node(-1).ToNodeAddr {
-			node, err = fs.ReadNode(path)
-			if err != nil {
-				return TreePath{}, nil, err
-			}
-		}
-		if node.Data.Head.Level > 0 {
-			path = append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    len(node.Data.BodyInternal) - 1,
-				ToNodeAddr:     node.Data.BodyInternal[len(node.Data.BodyInternal)-1].BlockPtr,
-				ToNodeLevel:    node.Data.Head.Level - 1,
-			})
-		} else {
-			path = append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    len(node.Data.BodyLeaf) - 1,
-			})
-		}
-	}
-	// return
-	if node.Addr != path.Node(-2).ToNodeAddr {
-		node, err = fs.ReadNode(path.Parent())
-		if err != nil {
-			return TreePath{}, nil, err
-		}
-	}
-	return path, node, nil
-}
-
-func (fs *FS) next(path TreePath, node *diskio.Ref[btrfsvol.LogicalAddr, Node]) (TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
-	var err error
-	path = path.DeepCopy()
-
-	// go up
-	if node.Addr != path.Node(-2).ToNodeAddr {
-		node, err = fs.ReadNode(path.Parent())
-		if err != nil {
-			return TreePath{}, nil, err
-		}
-		path.Node(-2).ToNodeLevel = node.Data.Head.Level
-	}
-	for path.Node(-1).FromItemIdx+1 >= int(node.Data.Head.NumItems) {
-		path = path.Parent()
-		if len(path) == 1 {
-			return TreePath{}, nil, nil
-		}
-		if node.Addr != path.Node(-2).ToNodeAddr {
-			node, err = fs.ReadNode(path.Parent())
-			if err != nil {
-				return TreePath{}, nil, err
-			}
-			path.Node(-2).ToNodeLevel = node.Data.Head.Level
-		}
-	}
-	// go right
-	path.Node(-1).FromItemIdx++
-	if path.Node(-1).ToNodeAddr != 0 {
-		if node.Addr != path.Node(-2).ToNodeAddr {
-			node, err = fs.ReadNode(path.Parent())
-			if err != nil {
-				return TreePath{}, nil, err
-			}
-			path.Node(-1).ToNodeAddr = node.Data.BodyInternal[path.Node(-1).FromItemIdx].BlockPtr
-		}
-	}
-	// go down
-	for path.Node(-1).ToNodeAddr != 0 {
-		if node.Addr != path.Node(-1).ToNodeAddr {
-			node, err = fs.ReadNode(path)
-			if err != nil {
-				return TreePath{}, nil, err
-			}
-			path.Node(-1).ToNodeLevel = node.Data.Head.Level
-		}
-		if node.Data.Head.Level > 0 {
-			path = append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    0,
-				ToNodeAddr:     node.Data.BodyInternal[len(node.Data.BodyInternal)-1].BlockPtr,
-				ToNodeLevel:    node.Data.Head.Level - 1,
-			})
-		} else {
-			path = append(path, TreePathElem{
-				FromTree:       node.Data.Head.Owner,
-				FromGeneration: node.Data.Head.Generation,
-				FromItemIdx:    0,
-			})
-		}
-	}
-	// return
-	if node.Addr != path.Node(-2).ToNodeAddr {
-		node, err = fs.ReadNode(path.Parent())
-		if err != nil {
-			return TreePath{}, nil, err
-		}
-	}
-	return path, node, nil
-}
-
-// TreeSearch implements the 'Trees' interface.
-func (fs *FS) TreeSearch(treeID ObjID, fn func(Key, uint32) int) (Item, error) {
-	rootInfo, err := LookupTreeRoot(fs, treeID)
-	if err != nil {
-		return Item{}, err
-	}
-	path, node, err := fs.treeSearch(*rootInfo, fn)
-	if err != nil {
-		return Item{}, err
-	}
-	return node.Data.BodyLeaf[path.Node(-1).FromItemIdx], nil
-}
-
-// KeySearch returns a comparator suitable to be passed to TreeSearch.
-func KeySearch(fn func(Key) int) func(Key, uint32) int {
-	return func(key Key, _ uint32) int {
-		return fn(key)
-	}
-}
-
-// TreeLookup implements the 'Trees' interface.
-func (fs *FS) TreeLookup(treeID ObjID, key Key) (Item, error) {
-	item, err := fs.TreeSearch(treeID, KeySearch(key.Cmp))
-	if err != nil {
-		err = fmt.Errorf("item with key=%v: %w", key, err)
-	}
-	return item, err
-}
-
-// TreeSearchAll implements the 'Trees' interface.
-func (fs *FS) TreeSearchAll(treeID ObjID, fn func(Key, uint32) int) ([]Item, error) {
-	rootInfo, err := LookupTreeRoot(fs, treeID)
-	if err != nil {
-		return nil, err
-	}
-	middlePath, middleNode, err := fs.treeSearch(*rootInfo, fn)
-	if err != nil {
-		return nil, err
-	}
-	middleItem := middleNode.Data.BodyLeaf[middlePath.Node(-1).FromItemIdx]
-
-	var ret = []Item{middleItem}
-	var errs derror.MultiError
-	for prevPath, prevNode := middlePath, middleNode; true; {
-		prevPath, prevNode, err = fs.prev(prevPath, prevNode)
-		if err != nil {
-			errs = append(errs, err)
-			break
-		}
-		if len(prevPath) == 0 {
-			break
-		}
-		prevItem := prevNode.Data.BodyLeaf[prevPath.Node(-1).FromItemIdx]
-		if fn(prevItem.Key, prevItem.BodySize) != 0 {
-			break
-		}
-		ret = append(ret, prevItem)
-	}
-	slices.Reverse(ret)
-	for nextPath, nextNode := middlePath, middleNode; true; {
-		nextPath, nextNode, err = fs.next(nextPath, nextNode)
-		if err != nil {
-			errs = append(errs, err)
-			break
-		}
-		if len(nextPath) == 0 {
-			break
-		}
-		nextItem := nextNode.Data.BodyLeaf[nextPath.Node(-1).FromItemIdx]
-		if fn(nextItem.Key, nextItem.BodySize) != 0 {
-			break
-		}
-		ret = append(ret, nextItem)
-	}
-	if errs != nil {
-		err = errs
-	}
-	return ret, err
-}