package continentsdb import ( "fmt" "sync" "github.com/paulmach/orb/geojson" ) // 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 polygons of Earth's continents in GeoJSON format. // // Must not be empty. Path string } // DB is a descriptor of the Earth's polygons in GeoJSON 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 { path string once sync.Once features []*geojson.Feature } const invalidPrmValFmt = "invalid parameter %s (%T):%v" func panicOnPrmValue(n string, v interface{}) { 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.Path == "": panicOnPrmValue("Path", prm.Path) } o := defaultOpts() for i := range opts { opts[i](o) } return &DB{ path: prm.Path, } }