jinzhu/gorm

package gorm

import (
    "bytes"
    "strings"
)

// Namer is a function type which is given a string and return a string
type Namer func(string) string

// NamingStrategy represents naming strategies
type NamingStrategy struct {
    DB     Namer
    Table  Namer
    Column Namer
}

// TheNamingStrategy is being initialized with defaultNamingStrategy
var TheNamingStrategy = &NamingStrategy{
    DB:     defaultNamer,
    Table:  defaultNamer,
    Column: defaultNamer,
}

// AddNamingStrategy sets the naming strategy
func AddNamingStrategy(ns *NamingStrategy) {
    if ns.DB == nil {
        ns.DB = defaultNamer
    }
    if ns.Table == nil {
        ns.Table = defaultNamer
    }
    if ns.Column == nil {
        ns.Column = defaultNamer
    }
    TheNamingStrategy = ns
}

// DBName alters the given name by DB
func (ns *NamingStrategy) DBName(name string) string {
    return ns.DB(name)
}

// TableName alters the given name by Table
func (ns *NamingStrategy) TableName(name string) string {
    return ns.Table(name)
}

// ColumnName alters the given name by Column
func (ns *NamingStrategy) ColumnName(name string) string {
    return ns.Column(name)
}

// ToDBName convert string to db name
func ToDBName(name string) string {
    return TheNamingStrategy.DBName(name)
}

// ToTableName convert string to table name
func ToTableName(name string) string {
    return TheNamingStrategy.TableName(name)
}

// ToColumnName convert string to db name
func ToColumnName(name string) string {
    return TheNamingStrategy.ColumnName(name)
}

var smap = newSafeMap()

func defaultNamer(name string) string {
    const (
        lower = false
        upper = true
    )

    if v := smap.Get(name); v != "" {
        return v
    }

    if name == "" {
        return ""
    }

    var (
        value                                    = commonInitialismsReplacer.Replace(name)
        buf                                      = bytes.NewBufferString("")
        lastCase, currCase, nextCase, nextNumber bool
    )

    for i, v := range value[:len(value)-1] {
        nextCase = bool(value[i+1] >= 'A' && value[i+1] <= 'Z')
        nextNumber = bool(value[i+1] >= '0' && value[i+1] <= '9')

        if i > 0 {
            if currCase == upper {
                if lastCase == upper && (nextCase == upper || nextNumber == upper) {
                    buf.WriteRune(v)
                } else {
                    if value[i-1] != '_' && value[i+1] != '_' {
                        buf.WriteRune('_')
                    }
                    buf.WriteRune(v)
                }
            } else {
                buf.WriteRune(v)
                if i == len(value)-2 && (nextCase == upper && nextNumber == lower) {
                    buf.WriteRune('_')
                }
            }
        } else {
            currCase = upper
            buf.WriteRune(v)
        }
        lastCase = currCase
        currCase = nextCase
    }

    buf.WriteByte(value[len(value)-1])

    s := strings.ToLower(buf.String())
    smap.Set(name, s)
    return s
}