yq/pkg/yqlib/treeops/leaf_traverser.go
2020-10-17 22:10:47 +11:00

133 lines
3.6 KiB
Go

package treeops
import (
"fmt"
"gopkg.in/yaml.v3"
)
type traverser struct {
prefs NavigationPrefs
}
type LeafTraverser interface {
Traverse(matchingNode *CandidateNode, pathNode *PathElement) ([]*CandidateNode, error)
}
func NewLeafTraverser(navigationPrefs NavigationPrefs) LeafTraverser {
return &traverser{navigationPrefs}
}
func (t *traverser) keyMatches(key *yaml.Node, pathNode *PathElement) bool {
return pathNode.Value == "[]" || Match(key.Value, pathNode.StringValue)
}
func (t *traverser) traverseMap(candidate *CandidateNode, pathNode *PathElement) ([]*CandidateNode, error) {
// 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.
//TODO ALIASES, auto creation?
var newMatches = make([]*CandidateNode, 0)
node := candidate.Node
var contents = node.Content
for index := 0; index < len(contents); index = index + 2 {
key := contents[index]
value := contents[index+1]
log.Debug("checking %v (%v)", key.Value, key.Tag)
if t.keyMatches(key, pathNode) {
log.Debug("MATCHED")
newMatches = append(newMatches, &CandidateNode{
Node: value,
Path: append(candidate.Path, key.Value),
Document: candidate.Document,
})
}
}
return newMatches, nil
}
func (t *traverser) traverseArray(candidate *CandidateNode, pathNode *PathElement) ([]*CandidateNode, error) {
log.Debug("pathNode Value %v", pathNode.Value)
if pathNode.Value == "[]" {
var contents = candidate.Node.Content
var newMatches = make([]*CandidateNode, len(contents))
for index := 0; index < len(contents); index = index + 1 {
newMatches[index] = &CandidateNode{
Document: candidate.Document,
Path: append(candidate.Path, index),
Node: contents[index],
}
}
return newMatches, nil
}
index := pathNode.Value.(int64)
indexToUse := index
contentLength := int64(len(candidate.Node.Content))
if contentLength <= index {
// handle auto append here
return make([]*CandidateNode, 0), nil
}
if indexToUse < 0 {
indexToUse = contentLength + indexToUse
}
if indexToUse < 0 {
return nil, fmt.Errorf("Index [%v] out of range, array size is %v", index, contentLength)
}
return []*CandidateNode{&CandidateNode{
Node: candidate.Node.Content[indexToUse],
Document: candidate.Document,
Path: append(candidate.Path, index),
}}, nil
}
func (t *traverser) Traverse(matchingNode *CandidateNode, pathNode *PathElement) ([]*CandidateNode, error) {
log.Debug(NodeToString(matchingNode))
value := matchingNode.Node
switch value.Kind {
case yaml.MappingNode:
log.Debug("its a map with %v entries", len(value.Content)/2)
return t.traverseMap(matchingNode, pathNode)
case yaml.SequenceNode:
log.Debug("its a sequence of %v things!", len(value.Content))
return t.traverseArray(matchingNode, pathNode)
// default:
// if head == "+" {
// return n.appendArray(value, head, tail, pathStack)
// } else if len(value.Content) == 0 && head == "**" {
// return n.navigationStrategy.Visit(nodeContext)
// }
// return n.splatArray(value, head, tail, pathStack)
// }
// case yaml.AliasNode:
// log.Debug("its an alias!")
// DebugNode(value.Alias)
// if n.navigationStrategy.FollowAlias(nodeContext) {
// log.Debug("following the alias")
// return n.recurse(value.Alias, head, tail, pathStack)
// }
// return nil
case yaml.DocumentNode:
log.Debug("digging into doc node")
return t.Traverse(&CandidateNode{
Node: matchingNode.Node.Content[0],
Document: matchingNode.Document}, pathNode)
default:
return nil, nil
}
}