piotrkowalczuk/mnemosyne

package model

import (
    "bytes"
    "database/sql/driver"
    "encoding/gob"
    "errors"
)

// Bag is a simple abstraction on the top of a map.
// It can be stored in a SQL database as a gob BLOB.
type Bag map[string]string

// Scan satisfy sql.Scanner interface.
func (b *Bag) Scan(src interface{}) (err error) {
    switch t := src.(type) {
    case []byte:
        err = gob.NewDecoder(bytes.NewReader(t)).Decode(b)
    default:
        return errors.New("unsupported data source type")
    }

    return
}

// Value satisfy driver.Valuer interface.
func (b Bag) Value() (driver.Value, error) {
    buf := bytes.NewBuffer(nil)
    err := gob.NewEncoder(buf).Encode(b)
    if err != nil {
        return nil, err
    }

    return buf.Bytes(), nil
}

// Set assigns the value to a given key.
func (b *Bag) Set(key, value string) {
    (*b)[key] = value
}

// Get returns a value for the given key.
func (b *Bag) Get(key string) string {
    return (*b)[key]
}

// Has checks if the given key is set.
func (b *Bag) Has(key string) bool {
    _, ok := (*b)[key]

    return ok
}