118 lines
2.6 KiB
Go
118 lines
2.6 KiB
Go
package hstore
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import (
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"database/sql"
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"database/sql/driver"
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"strings"
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)
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// Hstore is a wrapper for transferring Hstore values back and forth easily.
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type Hstore struct {
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Map map[string]sql.NullString
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}
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// escapes and quotes hstore keys/values
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// s should be a sql.NullString or string
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func hQuote(s interface{}) string {
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var str string
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switch v := s.(type) {
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case sql.NullString:
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if !v.Valid {
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return "NULL"
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}
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str = v.String
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case string:
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str = v
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default:
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panic("not a string or sql.NullString")
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}
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str = strings.Replace(str, "\\", "\\\\", -1)
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return `"` + strings.Replace(str, "\"", "\\\"", -1) + `"`
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}
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// Scan implements the Scanner interface.
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//
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// Note h.Map is reallocated before the scan to clear existing values. If the
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// hstore column's database value is NULL, then h.Map is set to nil instead.
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func (h *Hstore) Scan(value interface{}) error {
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if value == nil {
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h.Map = nil
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return nil
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}
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h.Map = make(map[string]sql.NullString)
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var b byte
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pair := [][]byte{{}, {}}
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pi := 0
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inQuote := false
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didQuote := false
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sawSlash := false
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bindex := 0
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for bindex, b = range value.([]byte) {
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if sawSlash {
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pair[pi] = append(pair[pi], b)
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sawSlash = false
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continue
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}
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switch b {
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case '\\':
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sawSlash = true
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continue
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case '"':
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inQuote = !inQuote
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if !didQuote {
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didQuote = true
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}
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continue
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default:
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if !inQuote {
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switch b {
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case ' ', '\t', '\n', '\r':
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continue
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case '=':
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continue
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case '>':
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pi = 1
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didQuote = false
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continue
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case ',':
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s := string(pair[1])
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if !didQuote && len(s) == 4 && strings.ToLower(s) == "null" {
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h.Map[string(pair[0])] = sql.NullString{String: "", Valid: false}
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} else {
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h.Map[string(pair[0])] = sql.NullString{String: string(pair[1]), Valid: true}
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}
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pair[0] = []byte{}
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pair[1] = []byte{}
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pi = 0
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continue
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}
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}
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}
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pair[pi] = append(pair[pi], b)
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}
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if bindex > 0 {
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s := string(pair[1])
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if !didQuote && len(s) == 4 && strings.ToLower(s) == "null" {
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h.Map[string(pair[0])] = sql.NullString{String: "", Valid: false}
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} else {
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h.Map[string(pair[0])] = sql.NullString{String: string(pair[1]), Valid: true}
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}
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}
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return nil
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}
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// Value implements the driver Valuer interface. Note if h.Map is nil, the
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// database column value will be set to NULL.
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func (h Hstore) Value() (driver.Value, error) {
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if h.Map == nil {
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return nil, nil
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}
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parts := []string{}
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for key, val := range h.Map {
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thispart := hQuote(key) + "=>" + hQuote(val)
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parts = append(parts, thispart)
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}
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return []byte(strings.Join(parts, ",")), nil
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}
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