X-Git-Url: https://git.giacomolli.uk/onechat/blobdiff_plain/d8f3785bb69288663f4cc46bf4d609c6770452d5..6c7859cfea123479aba046614ee81028651ddaf5:/tree.go?ds=sidebyside

diff --git a/tree.go b/tree.go
index 4309597..765016e 100644
--- a/tree.go
+++ b/tree.go
@@ -93,19 +93,19 @@ func (t *Tree) open(ctx context.Context, total int) error {
 
 	t.order, err = openRecords(filepath.Join(t.dir, "tree.idx"), treeRecordBytes)
 	if err != nil {
-		return err
+		return fmt.Errorf("open node order index: %w", err)
 	}
 
 	start := Position{}
 	if t.order.count == 0 {
 		err = t.removeLevels()
 		if err != nil {
-			return err
+			return fmt.Errorf("remove empty level indexes: %w", err)
 		}
 	} else {
 		record, _, err := t.order.Read(t.order.count - 1)
 		if err != nil {
-			return err
+			return fmt.Errorf("read last node order: %w", err)
 		}
 
 		// A crash can stop an add between the two index writes, so the
@@ -113,7 +113,7 @@ func (t *Tree) open(ctx context.Context, total int) error {
 		node, last := treeDecodeRecord(record)
 		err = t.writeLevel(node, last)
 		if err != nil {
-			return err
+			return fmt.Errorf("restore last node level: %w", err)
 		}
 
 		start = Position{
@@ -122,7 +122,7 @@ func (t *Tree) open(ctx context.Context, total int) error {
 		}
 	}
 
-	return t.journal.Scan(ctx, start, func(line []byte, place Position) error {
+	err = t.journal.Scan(ctx, start, func(line []byte, place Position) error {
 		var node Node
 
 		err := json.Unmarshal(line, &node)
@@ -132,15 +132,25 @@ func (t *Tree) open(ctx context.Context, total int) error {
 
 		err = t.check(node)
 		if err != nil {
-			return err
+			return fmt.Errorf("validate scanned node: %w", err)
 		}
 
 		if nodeEnd(node.Level, node.Index) > total {
 			return fmt.Errorf("node (%d, %d) covers messages after the log", node.Level, node.Index)
 		}
 
-		return t.addIndex(NodeKey{node.Level, node.Index}, place)
+		err = t.addIndex(NodeKey{node.Level, node.Index}, place)
+		if err != nil {
+			return fmt.Errorf("index scanned node: %w", err)
+		}
+
+		return nil
 	})
+	if err != nil {
+		return fmt.Errorf("scan node journal: %w", err)
+	}
+
+	return nil
 }
 
 // Close closes the files of the tree.
@@ -182,13 +192,18 @@ func (t *Tree) removeLevels() error {
 func (t *Tree) writeLevel(node NodeKey, place Position) error {
 	level, err := t.level(node.level)
 	if err != nil {
-		return err
+		return fmt.Errorf("open node level index: %w", err)
 	}
 
 	record := make([]byte, positionBytes)
 	encodePosition(record, place)
 
-	return level.Write(node.index, record)
+	err = level.Write(node.index, record)
+	if err != nil {
+		return fmt.Errorf("write node level record: %w", err)
+	}
+
+	return nil
 }
 
 // check makes sure that node is valid and can join the tree now.
@@ -203,7 +218,7 @@ func (t *Tree) check(node Node) error {
 
 	built, err := t.Built(node.Level, node.Index)
 	if err != nil {
-		return err
+		return fmt.Errorf("check target node: %w", err)
 	}
 
 	if built {
@@ -217,7 +232,7 @@ func (t *Tree) check(node Node) error {
 	for _, index := range []int{2 * node.Index, 2*node.Index + 1} {
 		built, err = t.Built(node.Level-1, index)
 		if err != nil {
-			return err
+			return fmt.Errorf("check child node: %w", err)
 		}
 
 		if !built {
@@ -237,10 +252,15 @@ func (t *Tree) addIndex(node NodeKey, place Position) error {
 
 	err := t.order.Append(record)
 	if err != nil {
-		return err
+		return fmt.Errorf("append node order: %w", err)
+	}
+
+	err = t.writeLevel(node, place)
+	if err != nil {
+		return fmt.Errorf("write indexed node level: %w", err)
 	}
 
-	return t.writeLevel(node, place)
+	return nil
 }
 
 // level returns the index of level, and opens it at first use.
@@ -274,12 +294,16 @@ func (t *Tree) place(level, index int) (Position, bool, error) {
 
 	records, err := t.level(level)
 	if err != nil {
-		return Position{}, false, err
+		return Position{}, false, fmt.Errorf("open node level index: %w", err)
 	}
 
 	record, found, err := records.Read(index)
 	if err != nil || !found {
-		return Position{}, false, err
+		if err != nil {
+			return Position{}, false, fmt.Errorf("read node level record: %w", err)
+		}
+
+		return Position{}, false, nil
 	}
 
 	place := decodePosition(record)
@@ -295,7 +319,7 @@ func (t *Tree) Add(node Node) error {
 
 	err := t.check(node)
 	if err != nil {
-		return err
+		return fmt.Errorf("validate node: %w", err)
 	}
 
 	line, err := json.Marshal(node)
@@ -320,7 +344,11 @@ func (t *Tree) Add(node Node) error {
 func (t *Tree) Node(level, index int) (Node, bool, error) {
 	place, built, err := t.place(level, index)
 	if err != nil || !built {
-		return Node{}, false, err
+		if err != nil {
+			return Node{}, false, fmt.Errorf("find node position: %w", err)
+		}
+
+		return Node{}, false, nil
 	}
 
 	line, err := t.journal.Read(place)