83 lines
1.8 KiB
Go
83 lines
1.8 KiB
Go
package airportsdb
|
|
|
|
import (
|
|
"fmt"
|
|
"io/fs"
|
|
"sync"
|
|
)
|
|
|
|
// Prm groups the required parameters of the DB's constructor.
|
|
//
|
|
// All values must comply with the requirements imposed on them.
|
|
// Passing incorrect parameter values will result in constructor
|
|
// failure (error or panic depending on the implementation).
|
|
type Prm struct {
|
|
// Path to OpenFlights Airport csv table.
|
|
//
|
|
// Must not be empty.
|
|
AirportsPath string
|
|
|
|
// Path to OpenFlights Countries csv table.
|
|
//
|
|
// Must not be empty.
|
|
CountriesPath string
|
|
}
|
|
|
|
// DB is a descriptor of the OpenFlights database in csv format.
|
|
//
|
|
// For correct operation, DB must be created
|
|
// using the constructor (New) based on the required parameters
|
|
// and optional components. After successful creation,
|
|
// The DB is immediately ready to work through API.
|
|
type DB struct {
|
|
airports, countries pathMode
|
|
|
|
airportsOnce, countriesOnce sync.Once
|
|
|
|
mCountries map[string]string
|
|
|
|
mAirports map[string][]record
|
|
}
|
|
|
|
type pathMode struct {
|
|
path string
|
|
mode fs.FileMode
|
|
}
|
|
|
|
const invalidPrmValFmt = "invalid parameter %s (%T):%v"
|
|
|
|
func panicOnPrmValue(n string, v any) {
|
|
panic(fmt.Sprintf(invalidPrmValFmt, n, v, v))
|
|
}
|
|
|
|
// New creates a new instance of the DB.
|
|
//
|
|
// Panics if at least one value of the parameters is invalid.
|
|
//
|
|
// The created DB does not require additional
|
|
// initialization and is completely ready for work.
|
|
func New(prm Prm, opts ...Option) *DB {
|
|
switch {
|
|
case prm.AirportsPath == "":
|
|
panicOnPrmValue("AirportsPath", prm.AirportsPath)
|
|
case prm.CountriesPath == "":
|
|
panicOnPrmValue("CountriesPath", prm.CountriesPath)
|
|
}
|
|
|
|
o := defaultOpts()
|
|
|
|
for i := range opts {
|
|
opts[i](o)
|
|
}
|
|
|
|
return &DB{
|
|
airports: pathMode{
|
|
path: prm.AirportsPath,
|
|
mode: o.airportMode,
|
|
},
|
|
countries: pathMode{
|
|
path: prm.CountriesPath,
|
|
mode: o.countryMode,
|
|
},
|
|
}
|
|
}
|