mirror of https://github.com/databricks/cli.git
71 lines
1.9 KiB
Go
71 lines
1.9 KiB
Go
package dyn
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import "errors"
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// WalkValueFunc is the type of the function called by Walk to traverse the configuration tree.
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type WalkValueFunc func(p Path, v Value) (Value, error)
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// ErrDrop may be returned by WalkValueFunc to remove a value from the subtree.
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var ErrDrop = errors.New("drop value from subtree")
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// ErrSkip may be returned by WalkValueFunc to skip traversal of a subtree.
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var ErrSkip = errors.New("skip traversal of subtree")
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// Walk walks the configuration tree and calls the given function on each node.
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// The callback may return ErrDrop to remove a value from the subtree.
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// The callback may return ErrSkip to skip traversal of a subtree.
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// If the callback returns another error, the walk is aborted, and the error is returned.
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func Walk(v Value, fn func(p Path, v Value) (Value, error)) (Value, error) {
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return walk(v, EmptyPath, fn)
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}
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// Unexported counterpart to Walk.
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// It carries the path leading up to the current node,
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// such that it can be passed to the WalkValueFunc.
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func walk(v Value, p Path, fn func(p Path, v Value) (Value, error)) (Value, error) {
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v, err := fn(p, v)
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if err != nil {
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if err == ErrSkip {
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return v, nil
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}
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return NilValue, err
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}
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switch v.Kind() {
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case KindMap:
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m := v.MustMap()
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out := newMappingWithSize(m.Len())
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// Iterate over the pairs in sorted order to ensure a deterministic order.
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for _, pair := range m.SortedPairs() {
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pk := pair.Key
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pv := pair.Value
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nv, err := walk(pv, append(p, Key(pk.MustString())), fn)
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if err == ErrDrop {
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continue
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}
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if err != nil {
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return NilValue, err
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}
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out.Set(pk, nv)
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}
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v.v = out
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case KindSequence:
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s := v.MustSequence()
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out := make([]Value, 0, len(s))
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for i := range s {
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nv, err := walk(s[i], append(p, Index(i)), fn)
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if err == ErrDrop {
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continue
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}
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if err != nil {
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return NilValue, err
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}
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out = append(out, nv)
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}
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v.v = out
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}
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return v, nil
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}
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