Significantly improved performance of exploding anchors (improves to json speed)

cmd/utils.go

@@ -149,25 +149,91 @@ func writeString(writer io.Writer, txt string) error {
 	return errorWriting
 }
 
+func setIfNotThere(node *yaml.Node, key string, value *yaml.Node) {
+	for index := 0; index < len(node.Content); index = index + 2 {
+		keyNode := node.Content[index]
+		if keyNode.Value == key {
+			return
+		}
+	}
+	// need to add it to the map
+	mapEntryKey := yaml.Node{Value: key, Kind: yaml.ScalarNode}
+	node.Content = append(node.Content, &mapEntryKey)
+	node.Content = append(node.Content, value)
+}
+
+func applyAlias(node *yaml.Node, alias *yaml.Node) {
+	for index := 0; index < len(alias.Content); index = index + 2 {
+		keyNode := alias.Content[index]
+		log.Debugf("applying alias key %v", keyNode.Value)
+		valueNode := alias.Content[index+1]
+		setIfNotThere(node, keyNode.Value, valueNode)
+	}
+}
+
+func explodeNode(node *yaml.Node) error {
+	node.Anchor = ""
+	switch node.Kind {
+	case yaml.SequenceNode, yaml.DocumentNode:
+		for index, contentNode := range node.Content {
+			log.Debugf("exploding index %v", index)
+			errorInContent := explodeNode(contentNode)
+			if errorInContent != nil {
+				return errorInContent
+			}
+		}
+		return nil
+	case yaml.AliasNode:
+		log.Debugf("its an alias!")
+		node.Kind = node.Alias.Kind
+		node.Style = node.Alias.Style
+		node.Tag = node.Alias.Tag
+		node.Content = node.Alias.Content
+		node.Value = node.Alias.Value
+		node.Alias = nil
+		return nil
+	case yaml.MappingNode:
+		for index := 0; index < len(node.Content); index = index + 2 {
+			keyNode := node.Content[index]
+			valueNode := node.Content[index+1]
+			log.Debugf("traversing %v", keyNode.Value)
+			if keyNode.Value != "<<" {
+				errorInContent := explodeNode(valueNode)
+				if errorInContent != nil {
+					return errorInContent
+				}
+			} else {
+				if valueNode.Kind == yaml.SequenceNode {
+					log.Debugf("an alias merge list!")
+					for index := len(valueNode.Content) - 1; index >= 0; index = index - 1 {
+						aliasNode := valueNode.Content[index]
+						applyAlias(node, aliasNode.Alias)
+					}
+				} else {
+					log.Debugf("an alias merge!")
+					applyAlias(node, valueNode.Alias)
+				}
+				node.Content = append(node.Content[:index], node.Content[index+2:]...)
+				//replay that index, since the array is shorter now.
+				index = index - 2
+			}
+		}
+
+		return nil
+	default:
+		return nil
+	}
+}
+
 func explode(matchingNodes []*yqlib.NodeContext) error {
 	log.Debug("exploding nodes")
 	for _, nodeContext := range matchingNodes {
-		var targetNode = yaml.Node{Kind: nodeContext.Node.Kind}
-		explodedNodes, errorRetrieving := lib.Get(nodeContext.Node, "**", true)
-		if errorRetrieving != nil {
-			return errorRetrieving
-		}
-		for _, matchingNode := range explodedNodes {
-			mergePath := lib.MergePathStackToString(matchingNode.PathStack, appendFlag)
-			updateCommand := yqlib.UpdateCommand{Command: "update", Path: mergePath, Value: matchingNode.Node, Overwrite: overwriteFlag}
-			errorUpdating := lib.Update(&targetNode, updateCommand, true)
-			if errorUpdating != nil {
-				return errorUpdating
+		log.Debugf("exploding %v", nodeContext.Head)
+		errorExplodingNode := explodeNode(nodeContext.Node)
+		if errorExplodingNode != nil {
+			return errorExplodingNode
 		}
 	}
-		nodeContext.Node = &targetNode
-	}
-	log.Debug("done exploding nodes")
 	return nil
 }