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package parser
import "github.com/hashicorp/hcl/hcl/ast"
// flattenObjects takes an AST node, walks it, and flattens
func flattenObjects(node ast.Node) {
ast.Walk(node, func(n ast.Node) (ast.Node, bool) {
// We only care about lists, because this is what we modify
list, ok := n.(*ast.ObjectList)
if !ok {
return n, true
}
// Rebuild the item list
items := make([]*ast.ObjectItem, 0, len(list.Items))
frontier := make([]*ast.ObjectItem, len(list.Items))
copy(frontier, list.Items)
for len(frontier) > 0 {
// Pop the current item
n := len(frontier)
item := frontier[n-1]
frontier = frontier[:n-1]
switch v := item.Val.(type) {
case *ast.ObjectType:
items, frontier = flattenObjectType(v, item, items, frontier)
case *ast.ListType:
items, frontier = flattenListType(v, item, items, frontier)
default:
items = append(items, item)
}
}
// Reverse the list since the frontier model runs things backwards
for i := len(items)/2 - 1; i >= 0; i-- {
opp := len(items) - 1 - i
items[i], items[opp] = items[opp], items[i]
}
// Done! Set the original items
list.Items = items
return n, true
})
}
func flattenListType(
ot *ast.ListType,
item *ast.ObjectItem,
items []*ast.ObjectItem,
frontier []*ast.ObjectItem) ([]*ast.ObjectItem, []*ast.ObjectItem) {
// All the elements of this object must also be objects!
for _, subitem := range ot.List {
if _, ok := subitem.(*ast.ObjectType); !ok {
items = append(items, item)
return items, frontier
}
}
// Great! We have a match go through all the items and flatten
for _, elem := range ot.List {
// Add it to the frontier so that we can recurse
frontier = append(frontier, &ast.ObjectItem{
Keys: item.Keys,
Assign: item.Assign,
Val: elem,
LeadComment: item.LeadComment,
LineComment: item.LineComment,
})
}
return items, frontier
}
func flattenObjectType(
ot *ast.ObjectType,
item *ast.ObjectItem,
items []*ast.ObjectItem,
frontier []*ast.ObjectItem) ([]*ast.ObjectItem, []*ast.ObjectItem) {
// If the list has no items we do not have to flatten anything
if ot.List.Items == nil {
items = append(items, item)
return items, frontier
}
// All the elements of this object must also be objects!
for _, subitem := range ot.List.Items {
if _, ok := subitem.Val.(*ast.ObjectType); !ok {
items = append(items, item)
return items, frontier
}
}
// Great! We have a match go through all the items and flatten
for _, subitem := range ot.List.Items {
// Copy the new key
keys := make([]*ast.ObjectKey, len(item.Keys)+len(subitem.Keys))
copy(keys, item.Keys)
copy(keys[len(item.Keys):], subitem.Keys)
// Add it to the frontier so that we can recurse
frontier = append(frontier, &ast.ObjectItem{
Keys: keys,
Assign: item.Assign,
Val: subitem.Val,
LeadComment: item.LeadComment,
LineComment: item.LineComment,
})
}
return items, frontier
}
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