package yqlib import ( "fmt" yaml "gopkg.in/yaml.v3" ) type NodeContext struct { Node *yaml.Node Head interface{} Tail []interface{} PathStack []interface{} } func NewNodeContext(node *yaml.Node, head interface{}, tail []interface{}, pathStack []interface{}) NodeContext { newTail := make([]interface{}, len(tail)) copy(newTail, tail) newPathStack := make([]interface{}, len(pathStack)) copy(newPathStack, pathStack) return NodeContext{ Node: node, Head: head, Tail: newTail, PathStack: newPathStack, } } type NavigationStrategy interface { FollowAlias(nodeContext NodeContext) bool AutoCreateMap(nodeContext NodeContext) bool Visit(nodeContext NodeContext) error // node key is the string value of the last element in the path stack // we use it to match against the pathExpression in head. ShouldTraverse(nodeContext NodeContext, nodeKey string) bool ShouldDeeplyTraverse(nodeContext NodeContext) bool GetVisitedNodes() []*NodeContext DebugVisitedNodes() GetPathParser() PathParser } type NavigationStrategyImpl struct { followAlias func(nodeContext NodeContext) bool autoCreateMap func(nodeContext NodeContext) bool visit func(nodeContext NodeContext) error shouldVisitExtraFn func(nodeContext NodeContext) bool shouldDeeplyTraverse func(nodeContext NodeContext) bool visitedNodes []*NodeContext pathParser PathParser } func (ns *NavigationStrategyImpl) GetPathParser() PathParser { return ns.pathParser } func (ns *NavigationStrategyImpl) GetVisitedNodes() []*NodeContext { return ns.visitedNodes } func (ns *NavigationStrategyImpl) FollowAlias(nodeContext NodeContext) bool { return ns.followAlias(nodeContext) } func (ns *NavigationStrategyImpl) AutoCreateMap(nodeContext NodeContext) bool { return ns.autoCreateMap(nodeContext) } func (ns *NavigationStrategyImpl) ShouldDeeplyTraverse(nodeContext NodeContext) bool { return ns.shouldDeeplyTraverse(nodeContext) } func (ns *NavigationStrategyImpl) ShouldTraverse(nodeContext NodeContext, nodeKey string) bool { // we should traverse aliases (if enabled), but not visit them :/ if len(nodeContext.PathStack) == 0 { return true } if ns.alreadyVisited(nodeContext.PathStack) { return false } return (nodeKey == "<<" && ns.FollowAlias(nodeContext)) || (nodeKey != "<<" && ns.pathParser.MatchesNextPathElement(nodeContext, nodeKey)) } func (ns *NavigationStrategyImpl) shouldVisit(nodeContext NodeContext) bool { pathStack := nodeContext.PathStack if len(pathStack) == 0 { return true } log.Debug("tail len %v", len(nodeContext.Tail)) if ns.alreadyVisited(pathStack) || len(nodeContext.Tail) != 0 { return false } nodeKey := fmt.Sprintf("%v", pathStack[len(pathStack)-1]) log.Debug("nodeKey: %v, nodeContext.Head: %v", nodeKey, nodeContext.Head) // only visit aliases if its an exact match return ((nodeKey == "<<" && nodeContext.Head == "<<") || (nodeKey != "<<" && ns.pathParser.MatchesNextPathElement(nodeContext, nodeKey))) && (ns.shouldVisitExtraFn == nil || ns.shouldVisitExtraFn(nodeContext)) } func (ns *NavigationStrategyImpl) Visit(nodeContext NodeContext) error { log.Debug("Visit?, %v, %v", nodeContext.Head, pathStackToString(nodeContext.PathStack)) DebugNode(nodeContext.Node) if ns.shouldVisit(nodeContext) { log.Debug("yep, visiting") // pathStack array must be // copied, as append() may sometimes reuse and modify the array ns.visitedNodes = append(ns.visitedNodes, &nodeContext) ns.DebugVisitedNodes() return ns.visit(nodeContext) } log.Debug("nope, skip it") return nil } func (ns *NavigationStrategyImpl) DebugVisitedNodes() { log.Debug("Visited Nodes:") for _, candidate := range ns.visitedNodes { log.Debug(" - %v", pathStackToString(candidate.PathStack)) } } func (ns *NavigationStrategyImpl) alreadyVisited(pathStack []interface{}) bool { log.Debug("checking already visited pathStack: %v", pathStackToString(pathStack)) for _, candidate := range ns.visitedNodes { candidatePathStack := candidate.PathStack if patchStacksMatch(candidatePathStack, pathStack) { log.Debug("paths match, already seen it") return true } } log.Debug("never seen it before!") return false } func patchStacksMatch(path1 []interface{}, path2 []interface{}) bool { log.Debug("checking against path: %v", pathStackToString(path1)) if len(path1) != len(path2) { return false } for index, p1Value := range path1 { p2Value := path2[index] if p1Value != p2Value { return false } } return true }