59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
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package schema
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import (
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"sort"
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"sync"
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)
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// Set is a set data structure that is returned for elements of type
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// TypeSet.
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type Set struct {
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F SchemaSetFunc
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m map[int]interface{}
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once sync.Once
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}
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// Add adds an item to the set if it isn't already in the set.
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func (s *Set) Add(item interface{}) {
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s.add(item)
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}
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// List returns the elements of this set in slice format.
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//
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// The order of the returned elements is deterministic. Given the same
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// set, the order of this will always be the same.
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func (s *Set) List() []interface{}{
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result := make([]interface{}, len(s.m))
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for i, k := range s.listCode() {
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result[i] = s.m[k]
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}
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return result
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}
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func (s *Set) init() {
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s.m = make(map[int]interface{})
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}
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func (s *Set) add(item interface{}) int {
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s.once.Do(s.init)
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code := s.F(item)
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if _, ok := s.m[code]; !ok {
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s.m[code] = item
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}
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return code
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}
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func (s *Set) listCode() []int{
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// Sort the hash codes so the order of the list is deterministic
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keys := make([]int, 0, len(s.m))
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for k, _ := range s.m {
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keys = append(keys, k)
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}
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sort.Sort(sort.IntSlice(keys))
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return keys
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}
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