frostfs-node/pkg/util/locode/db/continents/geojson/db.go
Leonard Lyubich 9669afdfc7 [#316] locode: Implement polygons DB based on GeoJSON polygons
Define database of Earth's polygons in GeoJSON format. Implement resolving
of geo point to continent in which it is located through point-in-polygon
calculation.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
2021-02-09 11:05:55 +03:00

63 lines
1.4 KiB
Go

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,
}
}