yq/pkg/yqlib/data_navigator.go
2020-01-09 21:27:52 +11:00

246 lines
8.8 KiB
Go

package yqlib
import (
"strconv"
errors "github.com/pkg/errors"
yaml "gopkg.in/yaml.v3"
)
type DataNavigator interface {
Traverse(value *yaml.Node, path []string) error
}
type navigator struct {
navigationStrategy NavigationStrategy
}
func NewDataNavigator(NavigationStrategy NavigationStrategy) DataNavigator {
return &navigator{
navigationStrategy: NavigationStrategy,
}
}
func (n *navigator) Traverse(value *yaml.Node, path []string) error {
realValue := value
emptyArray := make([]interface{}, 0)
if realValue.Kind == yaml.DocumentNode {
log.Debugf("its a document! returning the first child")
return n.doTraverse(value.Content[0], "", path, emptyArray)
}
return n.doTraverse(value, "", path, emptyArray)
}
func (n *navigator) doTraverse(value *yaml.Node, head string, tail []string, pathStack []interface{}) error {
log.Debug("head %v", head)
DebugNode(value)
var errorDeepSplatting error
if head == "**" && value.Kind != yaml.ScalarNode {
errorDeepSplatting = n.recurse(value, head, tail, pathStack)
// ignore errors here, we are deep splatting so we may accidently give a string key
// to an array sequence
if len(tail) > 0 {
_ = n.recurse(value, tail[0], tail[1:], pathStack)
}
return errorDeepSplatting
}
if len(tail) > 0 {
log.Debugf("diving into %v", tail[0])
DebugNode(value)
return n.recurse(value, tail[0], tail[1:], pathStack)
}
return n.navigationStrategy.Visit(NewNodeContext(value, head, tail, pathStack))
}
func (n *navigator) getOrReplace(original *yaml.Node, expectedKind yaml.Kind) *yaml.Node {
if original.Kind != expectedKind {
log.Debug("wanted %v but it was %v, overriding", expectedKind, original.Kind)
return &yaml.Node{Kind: expectedKind}
}
return original
}
func (n *navigator) recurse(value *yaml.Node, head string, tail []string, pathStack []interface{}) error {
log.Debug("recursing, processing %v", head)
switch value.Kind {
case yaml.MappingNode:
log.Debug("its a map with %v entries", len(value.Content)/2)
return n.recurseMap(value, head, tail, pathStack)
case yaml.SequenceNode:
log.Debug("its a sequence of %v things!", len(value.Content))
if head == "*" || head == "**" {
return n.splatArray(value, head, tail, pathStack)
} else if head == "+" {
return n.appendArray(value, head, tail, pathStack)
}
return n.recurseArray(value, head, tail, pathStack)
case yaml.AliasNode:
log.Debug("its an alias!")
DebugNode(value.Alias)
if n.navigationStrategy.FollowAlias(NewNodeContext(value, head, tail, pathStack)) {
log.Debug("following the alias")
return n.recurse(value.Alias, head, tail, pathStack)
}
return nil
default:
return nil
}
}
func (n *navigator) recurseMap(value *yaml.Node, head string, tail []string, pathStack []interface{}) error {
traversedEntry := false
errorVisiting := n.visitMatchingEntries(value, head, tail, pathStack, func(contents []*yaml.Node, indexInMap int) error {
log.Debug("recurseMap: visitMatchingEntries")
n.navigationStrategy.DebugVisitedNodes()
newPathStack := append(pathStack, contents[indexInMap].Value)
log.Debug("appended %v", contents[indexInMap].Value)
n.navigationStrategy.DebugVisitedNodes()
log.Debug("should I traverse? %v, %v", head, pathStackToString(newPathStack))
DebugNode(value)
if n.navigationStrategy.ShouldTraverse(NewNodeContext(contents[indexInMap+1], head, tail, newPathStack), contents[indexInMap].Value) {
log.Debug("recurseMap: Going to traverse")
traversedEntry = true
// contents[indexInMap+1] = n.getOrReplace(contents[indexInMap+1], guessKind(head, tail, contents[indexInMap+1].Kind))
errorTraversing := n.doTraverse(contents[indexInMap+1], head, tail, newPathStack)
log.Debug("recurseMap: Finished traversing")
n.navigationStrategy.DebugVisitedNodes()
return errorTraversing
} else {
log.Debug("nope not traversing")
}
return nil
})
if errorVisiting != nil {
return errorVisiting
}
if traversedEntry || head == "*" || head == "**" || !n.navigationStrategy.AutoCreateMap(NewNodeContext(value, head, tail, pathStack)) {
return nil
}
mapEntryKey := yaml.Node{Value: head, Kind: yaml.ScalarNode}
value.Content = append(value.Content, &mapEntryKey)
mapEntryValue := yaml.Node{Kind: guessKind(head, tail, 0)}
value.Content = append(value.Content, &mapEntryValue)
log.Debug("adding new node %v", head)
return n.doTraverse(&mapEntryValue, head, tail, append(pathStack, head))
}
// need to pass the node in, as it may be aliased
type mapVisitorFn func(contents []*yaml.Node, index int) error
func (n *navigator) visitDirectMatchingEntries(node *yaml.Node, head string, tail []string, pathStack []interface{}, visit mapVisitorFn) error {
var contents = node.Content
for index := 0; index < len(contents); index = index + 2 {
content := contents[index]
log.Debug("index %v, checking %v, %v", index, content.Value, content.Tag)
n.navigationStrategy.DebugVisitedNodes()
errorVisiting := visit(contents, index)
if errorVisiting != nil {
return errorVisiting
}
}
return nil
}
func (n *navigator) visitMatchingEntries(node *yaml.Node, head string, tail []string, pathStack []interface{}, visit mapVisitorFn) error {
var contents = node.Content
log.Debug("visitMatchingEntries %v", head)
DebugNode(node)
// value.Content is a concatenated array of key, value,
// so keys are in the even indexes, values in odd.
// merge aliases are defined first, but we only want to traverse them
// if we don't find a match directly on this node first.
errorVisitedDirectEntries := n.visitDirectMatchingEntries(node, head, tail, pathStack, visit)
if errorVisitedDirectEntries != nil || !n.navigationStrategy.FollowAlias(NewNodeContext(node, head, tail, pathStack)) {
return errorVisitedDirectEntries
}
return n.visitAliases(contents, head, tail, pathStack, visit)
}
func (n *navigator) visitAliases(contents []*yaml.Node, head string, tail []string, pathStack []interface{}, visit mapVisitorFn) error {
// merge aliases are defined first, but we only want to traverse them
// if we don't find a match on this node first.
// traverse them backwards so that the last alias overrides the preceding.
// a node can either be
// an alias to one other node (e.g. <<: *blah)
// or a sequence of aliases (e.g. <<: [*blah, *foo])
log.Debug("checking for aliases")
for index := len(contents) - 2; index >= 0; index = index - 2 {
if contents[index+1].Kind == yaml.AliasNode {
valueNode := contents[index+1]
log.Debug("found an alias")
DebugNode(contents[index])
DebugNode(valueNode)
errorInAlias := n.visitMatchingEntries(valueNode.Alias, head, tail, pathStack, visit)
if errorInAlias != nil {
return errorInAlias
}
} else if contents[index+1].Kind == yaml.SequenceNode {
// could be an array of aliases...
errorVisitingAliasSeq := n.visitAliasSequence(contents[index+1].Content, head, tail, pathStack, visit)
if errorVisitingAliasSeq != nil {
return errorVisitingAliasSeq
}
}
}
return nil
}
func (n *navigator) visitAliasSequence(possibleAliasArray []*yaml.Node, head string, tail []string, pathStack []interface{}, visit mapVisitorFn) error {
// need to search this backwards too, so that aliases defined last override the preceding.
for aliasIndex := len(possibleAliasArray) - 1; aliasIndex >= 0; aliasIndex = aliasIndex - 1 {
child := possibleAliasArray[aliasIndex]
if child.Kind == yaml.AliasNode {
log.Debug("found an alias")
DebugNode(child)
errorInAlias := n.visitMatchingEntries(child.Alias, head, tail, pathStack, visit)
if errorInAlias != nil {
return errorInAlias
}
}
}
return nil
}
func (n *navigator) splatArray(value *yaml.Node, head string, tail []string, pathStack []interface{}) error {
for index, childValue := range value.Content {
log.Debug("processing")
DebugNode(childValue)
childValue = n.getOrReplace(childValue, guessKind(head, tail, childValue.Kind))
var err = n.doTraverse(childValue, head, tail, append(pathStack, index))
if err != nil {
return err
}
}
return nil
}
func (n *navigator) appendArray(value *yaml.Node, head string, tail []string, pathStack []interface{}) error {
var newNode = yaml.Node{Kind: guessKind(head, tail, 0)}
value.Content = append(value.Content, &newNode)
log.Debug("appending a new node, %v", value.Content)
return n.doTraverse(&newNode, head, tail, append(pathStack, len(value.Content)-1))
}
func (n *navigator) recurseArray(value *yaml.Node, head string, tail []string, pathStack []interface{}) error {
var index, err = strconv.ParseInt(head, 10, 64) // nolint
if err != nil {
return errors.Wrapf(err, "Error parsing array index '%v' for '%v'", head, pathStackToString(pathStack))
}
for int64(len(value.Content)) <= index {
value.Content = append(value.Content, &yaml.Node{Kind: guessKind(head, tail, 0)})
}
value.Content[index] = n.getOrReplace(value.Content[index], guessKind(head, tail, value.Content[index].Kind))
return n.doTraverse(value.Content[index], head, tail, append(pathStack, index))
}