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use std::fmt;
use std::str::FromStr;
use json::{self, Deserialize, Deserializer, JsonObject, Serialize, Serializer};
use {Error, Feature, FeatureCollection, Geometry};
#[derive(Clone, Debug, PartialEq)]
pub enum GeoJson {
Geometry(Geometry),
Feature(Feature),
FeatureCollection(FeatureCollection),
}
impl<'a> From<&'a GeoJson> for JsonObject {
fn from(geojson: &'a GeoJson) -> JsonObject {
match *geojson {
GeoJson::Geometry(ref geometry) => geometry.into(),
GeoJson::Feature(ref feature) => feature.into(),
GeoJson::FeatureCollection(ref fc) => fc.into(),
}
}
}
impl From<Geometry> for GeoJson {
fn from(geometry: Geometry) -> Self {
GeoJson::Geometry(geometry)
}
}
impl From<Feature> for GeoJson {
fn from(feature: Feature) -> Self {
GeoJson::Feature(feature)
}
}
impl From<FeatureCollection> for GeoJson {
fn from(feature_collection: FeatureCollection) -> GeoJson {
GeoJson::FeatureCollection(feature_collection)
}
}
impl GeoJson {
pub fn from_json_object(object: JsonObject) -> Result<Self, Error> {
let type_ = match object.get("type") {
Some(json::JsonValue::String(t)) => Type::from_str(t),
_ => return Err(Error::ExpectedProperty("type".to_owned())),
};
let type_ = type_.ok_or(Error::GeoJsonUnknownType)?;
match type_ {
Type::Point
| Type::MultiPoint
| Type::LineString
| Type::MultiLineString
| Type::Polygon
| Type::MultiPolygon
| Type::GeometryCollection => Geometry::from_json_object(object).map(GeoJson::Geometry),
Type::Feature => Feature::from_json_object(object).map(GeoJson::Feature),
Type::FeatureCollection => {
FeatureCollection::from_json_object(object).map(GeoJson::FeatureCollection)
}
}
}
}
#[derive(PartialEq, Clone, Copy)]
enum Type {
Point,
MultiPoint,
LineString,
MultiLineString,
Polygon,
MultiPolygon,
GeometryCollection,
Feature,
FeatureCollection,
}
impl Type {
fn from_str(s: &str) -> Option<Self> {
match s {
"Point" => Some(Type::Point),
"MultiPoint" => Some(Type::MultiPoint),
"LineString" => Some(Type::LineString),
"MultiLineString" => Some(Type::MultiLineString),
"Polygon" => Some(Type::Polygon),
"MultiPolygon" => Some(Type::MultiPolygon),
"GeometryCollection" => Some(Type::GeometryCollection),
"Feature" => Some(Type::Feature),
"FeatureCollection" => Some(Type::FeatureCollection),
_ => None,
}
}
}
impl Serialize for GeoJson {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
JsonObject::from(self).serialize(serializer)
}
}
impl<'de> Deserialize<'de> for GeoJson {
fn deserialize<D>(deserializer: D) -> Result<GeoJson, D::Error>
where
D: Deserializer<'de>,
{
use serde::de::Error as SerdeError;
use std::error::Error as StdError;
let val = JsonObject::deserialize(deserializer)?;
GeoJson::from_json_object(val).map_err(|e| D::Error::custom(e.description()))
}
}
impl FromStr for GeoJson {
type Err = Error;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let object = get_object(s)?;
GeoJson::from_json_object(object)
}
}
fn get_object(s: &str) -> Result<json::JsonObject, Error> {
::serde_json::from_str(s)
.ok()
.and_then(json_value_into_json_object)
.ok_or(Error::MalformedJson)
}
fn json_value_into_json_object(json_value: json::JsonValue) -> Option<json::JsonObject> {
if let json::JsonValue::Object(geo) = json_value {
Some(geo)
} else {
None
}
}
impl fmt::Display for GeoJson {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
::serde_json::to_string(self)
.map_err(|_| fmt::Error)
.and_then(|s| f.write_str(&s))
}
}