64 lines
1.4 KiB
Go
64 lines
1.4 KiB
Go
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package continentsdb
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import (
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"fmt"
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"sync"
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"github.com/paulmach/orb/geojson"
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)
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// Prm groups the required parameters of the DB's constructor.
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//
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// All values must comply with the requirements imposed on them.
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// Passing incorrect parameter values will result in constructor
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// failure (error or panic depending on the implementation).
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type Prm struct {
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// Path to polygons of Earth's continents in GeoJSON format.
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//
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// Must not be empty.
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Path string
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}
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// DB is a descriptor of the Earth's polygons in GeoJSON format.
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//
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// For correct operation, DB must be created
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// using the constructor (New) based on the required parameters
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// and optional components. After successful creation,
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// The DB is immediately ready to work through API.
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type DB struct {
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path string
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once sync.Once
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features []*geojson.Feature
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}
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const invalidPrmValFmt = "invalid parameter %s (%T):%v"
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func panicOnPrmValue(n string, v interface{}) {
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panic(fmt.Sprintf(invalidPrmValFmt, n, v, v))
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}
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// New creates a new instance of the DB.
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//
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// Panics if at least one value of the parameters is invalid.
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//
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// The created DB does not require additional
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// initialization and is completely ready for work.
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func New(prm Prm, opts ...Option) *DB {
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switch {
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case prm.Path == "":
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panicOnPrmValue("Path", prm.Path)
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}
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o := defaultOpts()
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for i := range opts {
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opts[i](o)
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}
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return &DB{
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path: prm.Path,
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}
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}
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