Merge pull request #415 from ahrtr/page_flags_20230308

Encapsulate the logic of checking the page type

bucket.go

@@ -410,7 +410,7 @@ func (b *Bucket) Stats() BucketStats {
 		s.InlineBucketN += 1
 	}
 	b.forEachPage(func(p *common.Page, depth int, pgstack []common.Pgid) {
-		if (p.Flags() & common.LeafPageFlag) != 0 {
+		if p.IsLeafPage() {
 			s.KeyN += int(p.Count())
 
 			// used totals the used bytes for the page
@@ -450,7 +450,7 @@ func (b *Bucket) Stats() BucketStats {
 					}
 				}
 			}
-		} else if (p.Flags() & common.BranchPageFlag) != 0 {
+		} else if p.IsBranchPage() {
 			s.BranchPageN++
 			lastElement := p.BranchPageElement(p.Count() - 1)
 
@@ -514,7 +514,7 @@ func (b *Bucket) _forEachPageNode(pgId common.Pgid, depth int, fn func(*common.P
 
 	// Recursively loop over children.
 	if p != nil {
-		if (p.Flags() & common.BranchPageFlag) != 0 {
+		if p.IsBranchPage() {
 			for i := 0; i < int(p.Count()); i++ {
 				elem := p.BranchPageElement(uint16(i))
 				b._forEachPageNode(elem.Pgid(), depth+1, fn)

cursor.go

@@ -272,7 +272,7 @@ func (c *Cursor) prev() (key []byte, value []byte, flags uint32) {
 // search recursively performs a binary search against a given page/node until it finds a given key.
 func (c *Cursor) search(key []byte, pgId common.Pgid) {
 	p, n := c.bucket.pageNode(pgId)
-	if p != nil && (p.Flags()&(common.BranchPageFlag|common.LeafPageFlag)) == 0 {
+	if p != nil && !p.IsBranchPage() && !p.IsLeafPage() {
 		panic(fmt.Sprintf("invalid page type: %d: %x", p.Id(), p.Flags()))
 	}
 	e := elemRef{page: p, node: n}
@@ -410,7 +410,7 @@ func (r *elemRef) isLeaf() bool {
 	if r.node != nil {
 		return r.node.isLeaf
 	}
-	return (r.page.Flags() & common.LeafPageFlag) != 0
+	return r.page.IsLeafPage()
 }
 
 // count returns the number of inodes or page elements.

freelist.go

@@ -166,7 +166,7 @@ func (f *freelist) free(txid common.Txid, p *common.Page) {
 	allocTxid, ok := f.allocs[p.Id()]
 	if ok {
 		delete(f.allocs, p.Id())
-	} else if (p.Flags() & common.FreelistPageFlag) != 0 {
+	} else if p.IsFreelistPage() {
 		// Freelist is always allocated by prior tx.
 		allocTxid = txid - 1
 	}
@@ -265,7 +265,7 @@ func (f *freelist) freed(pgId common.Pgid) bool {
 
 // read initializes the freelist from a freelist page.
 func (f *freelist) read(p *common.Page) {
-	if (p.Flags() & common.FreelistPageFlag) == 0 {
+	if !p.IsFreelistPage() {
 		panic(fmt.Sprintf("invalid freelist page: %d, page type is %s", p.Id(), p.Typ()))
 	}
 

internal/common/page.go

@@ -45,18 +45,34 @@ func NewPage(id Pgid, flags, count uint16, overflow uint32) *Page {
 
 // Typ returns a human-readable page type string used for debugging.
 func (p *Page) Typ() string {
-	if (p.flags & BranchPageFlag) != 0 {
+	if p.IsBranchPage() {
 		return "branch"
-	} else if (p.flags & LeafPageFlag) != 0 {
+	} else if p.IsLeafPage() {
 		return "leaf"
-	} else if (p.flags & MetaPageFlag) != 0 {
+	} else if p.IsMetaPage() {
 		return "meta"
-	} else if (p.flags & FreelistPageFlag) != 0 {
+	} else if p.IsFreelistPage() {
 		return "freelist"
 	}
 	return fmt.Sprintf("unknown<%02x>", p.flags)
 }
 
+func (p *Page) IsBranchPage() bool {
+	return p.flags&BranchPageFlag != 0
+}
+
+func (p *Page) IsLeafPage() bool {
+	return p.flags&LeafPageFlag != 0
+}
+
+func (p *Page) IsMetaPage() bool {
+	return p.flags&MetaPageFlag != 0
+}
+
+func (p *Page) IsFreelistPage() bool {
+	return p.flags&FreelistPageFlag != 0
+}
+
 // Meta returns a pointer to the metadata section of the page.
 func (p *Page) Meta() *Meta {
 	return (*Meta)(UnsafeAdd(unsafe.Pointer(p), unsafe.Sizeof(*p)))

node.go

@@ -162,7 +162,7 @@ func (n *node) del(key []byte) {
 // read initializes the node from a page.
 func (n *node) read(p *common.Page) {
 	n.pgid = p.Id()
-	n.isLeaf = (p.Flags() & common.LeafPageFlag) != 0
+	n.isLeaf = p.IsLeafPage()
 	n.inodes = make(common.Inodes, int(p.Count()))
 
 	for i := 0; i < int(p.Count()); i++ {

tx.go

@@ -548,7 +548,7 @@ func (tx *Tx) forEachPageInternal(pgidstack []common.Pgid, fn func(*common.Page,
 	fn(p, len(pgidstack)-1, pgidstack)
 
 	// Recursively loop over children.
-	if (p.Flags() & common.BranchPageFlag) != 0 {
+	if p.IsBranchPage() {
 		for i := 0; i < int(p.Count()); i++ {
 			elem := p.BranchPageElement(uint16(i))
 			tx.forEachPageInternal(append(pgidstack, elem.Pgid()), fn)

tx_check.go

@@ -99,7 +99,7 @@ func (tx *Tx) checkBucket(b *Bucket, reachable map[common.Pgid]*common.Page, fre
 		// We should only encounter un-freed leaf and branch pages.
 		if freed[p.Id()] {
 			ch <- fmt.Errorf("page %d: reachable freed", int(p.Id()))
-		} else if (p.Flags()&common.BranchPageFlag) == 0 && (p.Flags()&common.LeafPageFlag) == 0 {
+		} else if !p.IsBranchPage() && !p.IsLeafPage() {
 			ch <- fmt.Errorf("page %d: invalid type: %s (stack: %v)", int(p.Id()), p.Typ(), stack)
 		}
 	})
@@ -135,7 +135,7 @@ func (tx *Tx) recursivelyCheckPagesInternal(
 	p := tx.page(pgId)
 	pagesStack = append(pagesStack, pgId)
 	switch {
-	case p.Flags()&common.BranchPageFlag != 0:
+	case p.IsBranchPage():
 		// For branch page we navigate ranges of all subpages.
 		runningMin := minKeyClosed
 		for i := range p.BranchPageElements() {
@@ -150,7 +150,7 @@ func (tx *Tx) recursivelyCheckPagesInternal(
 			runningMin = maxKeyInSubtree
 		}
 		return maxKeyInSubtree
-	case p.Flags()&common.LeafPageFlag != 0:
+	case p.IsLeafPage():
 		runningMin := minKeyClosed
 		for i := range p.LeafPageElements() {
 			elem := p.LeafPageElement(uint16(i))