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// Copyright 2016 Google Inc.  All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package uuid
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import (
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	"database/sql/driver"
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	"fmt"
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)
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// Scan implements sql.Scanner so UUIDs can be read from databases transparently.
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// Currently, database types that map to string and []byte are supported. Please
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// consult database-specific driver documentation for matching types.
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func (uuid *UUID) Scan(src interface{}) error {
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	switch src := src.(type) {
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	case nil:
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		return nil
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	case string:
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		// if an empty UUID comes from a table, we return a null UUID
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		if src == "" {
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			return nil
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		}
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		// see Parse for required string format
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		u, err := Parse(src)
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		if err != nil {
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			return fmt.Errorf("Scan: %v", err)
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		}
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		*uuid = u
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	case []byte:
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		// if an empty UUID comes from a table, we return a null UUID
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		if len(src) == 0 {
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			return nil
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		}
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		// assumes a simple slice of bytes if 16 bytes
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		// otherwise attempts to parse
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		if len(src) != 16 {
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			return uuid.Scan(string(src))
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		}
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		copy((*uuid)[:], src)
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	default:
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		return fmt.Errorf("Scan: unable to scan type %T into UUID", src)
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	}
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	return nil
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}
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// Value implements sql.Valuer so that UUIDs can be written to databases
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// transparently. Currently, UUIDs map to strings. Please consult
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// database-specific driver documentation for matching types.
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func (uuid UUID) Value() (driver.Value, error) {
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	return uuid.String(), nil
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}
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