mirror of https://github.com/databricks/cli.git
68 lines
1.7 KiB
Go
68 lines
1.7 KiB
Go
package merge
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import "github.com/databricks/cli/libs/dyn"
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type elementsByKey struct {
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key string
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keyFunc func(dyn.Value) string
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}
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func (e elementsByKey) Map(_ dyn.Path, v dyn.Value) (dyn.Value, error) {
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// We know the type of this value is a sequence.
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// For additional defence, return self if it is not.
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elements, ok := v.AsSequence()
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if !ok {
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return v, nil
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}
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seen := make(map[string]dyn.Value, len(elements))
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keys := make([]string, 0, len(elements))
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// Iterate in natural order. For a given key, we first see the
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// base definition and merge instances that come after it.
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for i := range elements {
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kv := elements[i].Get(e.key)
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key := e.keyFunc(kv)
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// Register element with key if not yet seen before.
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ref, ok := seen[key]
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if !ok {
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keys = append(keys, key)
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seen[key] = elements[i]
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continue
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}
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// Merge this instance into the reference.
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nv, err := Merge(ref, elements[i])
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if err != nil {
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return v, err
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}
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// Overwrite reference.
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seen[key] = nv
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}
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// Gather resulting elements in natural order.
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out := make([]dyn.Value, 0, len(keys))
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for _, key := range keys {
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nv, err := dyn.Set(seen[key], e.key, dyn.V(key))
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if err != nil {
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return dyn.InvalidValue, err
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}
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out = append(out, nv)
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}
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return dyn.NewValue(out, v.Locations()), nil
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}
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// ElementsByKey returns a [dyn.MapFunc] that operates on a sequence
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// where each element is a map. It groups elements by a key and merges
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// elements with the same key.
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//
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// The function that extracts the key from an element is provided as
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// a parameter. The resulting elements get their key field overwritten
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// with the value as returned by the key function.
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func ElementsByKey(key string, keyFunc func(dyn.Value) string) dyn.MapFunc {
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return elementsByKey{key, keyFunc}.Map
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}
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