exposed_optimistic_locking

interface VersionedTable {
    val versionColumn: Column<Int>
}

fun <T> T.updateWithVersion(where: (SqlExpressionBuilder.() -> Op<Boolean>)? = null,
                            version: Int,
                            limit: Int? = null,
                            body: T.(UpdateStatement) -> Unit
): Int where T : Table, T : VersionedTable {
    val whereClauseWithVersion: (SqlExpressionBuilder.() -> Op<Boolean>) = {
        val versionEquals = this@updateWithVersion.versionColumn eq version
        when (where != null) {
            true -> where(this).and(versionEquals)
            else -> versionEquals
        }
    }

    val updateWithVersion: T.(UpdateStatement) -> Unit = {
        body(it)
        it[this.versionColumn] = version + 1
    }

    return this.update(whereClauseWithVersion, limit, updateWithVersion)
}