Add to_geo_feature to get properties HashMap with geo::Geometry

This works for any FeatureProcessor — like GeoJson, Flatgeobuf,
Shapefile, etc.

geozero/src/geo_types/geo_types_feature_writer.rs

@@ -0,0 +1,319 @@
+use crate::error::{GeozeroError, Result};
+use crate::geo_types::GeoWriter;
+use crate::{
+    ColumnValue, CoordDimensions, FeatureProcessor, GeomProcessor, PropertyProcessor,
+    PropertyReadType,
+};
+use std::collections::HashMap;
+
+pub type GeoProperties = HashMap<String, OwnedColumnValue>;
+
+#[derive(Debug, PartialEq)]
+pub struct GeoFeature {
+    geometry: geo_types::Geometry,
+    properties: GeoProperties,
+}
+
+#[derive(Debug, Default)]
+pub struct GeoFeatureWriter {
+    geometry_writer: GeoWriter,
+    next_properties: Option<GeoProperties>,
+    pub(crate) features: Vec<GeoFeature>,
+}
+
+impl GeomProcessor for GeoFeatureWriter {
+    fn dimensions(&self) -> CoordDimensions {
+        self.geometry_writer.dimensions()
+    }
+    fn multi_dim(&self) -> bool {
+        self.geometry_writer.multi_dim()
+    }
+    fn srid(&mut self, srid: Option<i32>) -> Result<()> {
+        self.geometry_writer.srid(srid)
+    }
+    fn xy(&mut self, x: f64, y: f64, idx: usize) -> Result<()> {
+        self.geometry_writer.xy(x, y, idx)
+    }
+    fn coordinate(
+        &mut self,
+        x: f64,
+        y: f64,
+        z: Option<f64>,
+        m: Option<f64>,
+        t: Option<f64>,
+        tm: Option<u64>,
+        idx: usize,
+    ) -> Result<()> {
+        self.geometry_writer.coordinate(x, y, z, m, t, tm, idx)
+    }
+    fn empty_point(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.empty_point(idx)
+    }
+    fn point_begin(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.point_begin(idx)
+    }
+    fn point_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.point_end(idx)
+    }
+    fn multipoint_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.multipoint_begin(size, idx)
+    }
+    fn multipoint_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.multipoint_end(idx)
+    }
+    fn linestring_begin(&mut self, tagged: bool, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.linestring_begin(tagged, size, idx)
+    }
+    fn linestring_end(&mut self, tagged: bool, idx: usize) -> Result<()> {
+        self.geometry_writer.linestring_end(tagged, idx)
+    }
+    fn multilinestring_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.multilinestring_begin(size, idx)
+    }
+    fn multilinestring_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.multilinestring_end(idx)
+    }
+    fn polygon_begin(&mut self, tagged: bool, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.polygon_begin(tagged, size, idx)
+    }
+    fn polygon_end(&mut self, tagged: bool, idx: usize) -> Result<()> {
+        self.geometry_writer.polygon_end(tagged, idx)
+    }
+    fn multipolygon_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.multipolygon_begin(size, idx)
+    }
+    fn multipolygon_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.multipolygon_end(idx)
+    }
+    fn geometrycollection_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.geometrycollection_begin(size, idx)
+    }
+    fn geometrycollection_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.geometrycollection_end(idx)
+    }
+    fn circularstring_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.circularstring_begin(size, idx)
+    }
+    fn circularstring_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.circularstring_end(idx)
+    }
+    fn compoundcurve_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.compoundcurve_begin(size, idx)
+    }
+    fn compoundcurve_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.compoundcurve_end(idx)
+    }
+    fn curvepolygon_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.curvepolygon_begin(size, idx)
+    }
+    fn curvepolygon_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.curvepolygon_end(idx)
+    }
+    fn multicurve_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.multicurve_begin(size, idx)
+    }
+    fn multicurve_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.multicurve_end(idx)
+    }
+    fn multisurface_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.multisurface_begin(size, idx)
+    }
+    fn multisurface_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.multisurface_end(idx)
+    }
+    fn triangle_begin(&mut self, tagged: bool, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.triangle_begin(tagged, size, idx)
+    }
+    fn triangle_end(&mut self, tagged: bool, idx: usize) -> Result<()> {
+        self.geometry_writer.triangle_end(tagged, idx)
+    }
+    fn polyhedralsurface_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.polyhedralsurface_begin(size, idx)
+    }
+    fn polyhedralsurface_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.polyhedralsurface_end(idx)
+    }
+    fn tin_begin(&mut self, size: usize, idx: usize) -> Result<()> {
+        self.geometry_writer.tin_begin(size, idx)
+    }
+    fn tin_end(&mut self, idx: usize) -> Result<()> {
+        self.geometry_writer.tin_end(idx)
+    }
+}
+
+impl PropertyProcessor for GeoFeatureWriter {
+    fn property(&mut self, _idx: usize, name: &str, value: &ColumnValue) -> Result<bool> {
+        let properties = self
+            .next_properties
+            .as_mut()
+            .expect("properties should be initialized before traversing properties");
+        properties.insert(name.to_string(), OwnedColumnValue::from(value));
+        Ok(true)
+    }
+}
+
+/// Feature property value.
+///
+/// Like [`ColumnValue`], but owns it's data.
+#[derive(Clone, PartialEq, Debug)]
+pub enum OwnedColumnValue {
+    Byte(i8),
+    UByte(u8),
+    Bool(bool),
+    Short(i16),
+    UShort(u16),
+    Int(i32),
+    UInt(u32),
+    Long(i64),
+    ULong(u64),
+    Float(f32),
+    Double(f64),
+    String(String),
+    /// A JSON-formatted string
+    Json(String),
+    /// A datetime stored as an ISO8601-formatted string
+    DateTime(String),
+    Binary(Vec<u8>),
+}
+
+impl<'a> From<&'a OwnedColumnValue> for ColumnValue<'a> {
+    fn from(value: &'a OwnedColumnValue) -> Self {
+        match value {
+            OwnedColumnValue::Byte(v) => ColumnValue::Byte(*v),
+            OwnedColumnValue::UByte(v) => ColumnValue::UByte(*v),
+            OwnedColumnValue::Bool(v) => ColumnValue::Bool(*v),
+            OwnedColumnValue::Short(v) => ColumnValue::Short(*v),
+            OwnedColumnValue::UShort(v) => ColumnValue::UShort(*v),
+            OwnedColumnValue::Int(v) => ColumnValue::Int(*v),
+            OwnedColumnValue::UInt(v) => ColumnValue::UInt(*v),
+            OwnedColumnValue::Long(v) => ColumnValue::Long(*v),
+            OwnedColumnValue::ULong(v) => ColumnValue::ULong(*v),
+            OwnedColumnValue::Float(v) => ColumnValue::Float(*v),
+            OwnedColumnValue::Double(v) => ColumnValue::Double(*v),
+            OwnedColumnValue::String(v) => ColumnValue::String(v),
+            OwnedColumnValue::Json(v) => ColumnValue::Json(v),
+            OwnedColumnValue::DateTime(v) => ColumnValue::DateTime(v),
+            OwnedColumnValue::Binary(v) => ColumnValue::Binary(v),
+        }
+    }
+}
+
+impl From<&ColumnValue<'_>> for OwnedColumnValue {
+    fn from(value: &ColumnValue) -> Self {
+        match value {
+            ColumnValue::Byte(v) => OwnedColumnValue::Byte(*v),
+            ColumnValue::UByte(v) => OwnedColumnValue::UByte(*v),
+            ColumnValue::Bool(v) => OwnedColumnValue::Bool(*v),
+            ColumnValue::Short(v) => OwnedColumnValue::Short(*v),
+            ColumnValue::UShort(v) => OwnedColumnValue::UShort(*v),
+            ColumnValue::Int(v) => OwnedColumnValue::Int(*v),
+            ColumnValue::UInt(v) => OwnedColumnValue::UInt(*v),
+            ColumnValue::Long(v) => OwnedColumnValue::Long(*v),
+            ColumnValue::ULong(v) => OwnedColumnValue::ULong(*v),
+            ColumnValue::Float(v) => OwnedColumnValue::Float(*v),
+            ColumnValue::Double(v) => OwnedColumnValue::Double(*v),
+            ColumnValue::String(str) => OwnedColumnValue::String(str.to_string()),
+            ColumnValue::Json(str) => OwnedColumnValue::Json(str.to_string()),
+            ColumnValue::DateTime(str) => OwnedColumnValue::DateTime(str.to_string()),
+            ColumnValue::Binary(bytes) => OwnedColumnValue::Binary(bytes.to_vec()),
+        }
+    }
+}
+
+impl FeatureProcessor for GeoFeatureWriter {
+    fn feature_begin(&mut self, _idx: u64) -> Result<()> {
+        debug_assert!(self.geometry_writer.is_empty());
+        debug_assert!(self.next_properties.is_none());
+        self.next_properties = Some(GeoProperties::new());
+        Ok(())
+    }
+    fn feature_end(&mut self, _idx: u64) -> Result<()> {
+        let Some(geometry) = self.geometry_writer.take_geometry() else {
+            return Err(GeozeroError::FeatureGeometry("missing geometry".to_string()));
+        };
+        let Some(properties) = self.next_properties.take() else {
+            return Err(GeozeroError::Feature("missing properties".to_string()));
+        };
+
+        self.features.push(GeoFeature {
+            geometry,
+            properties,
+        });
+
+        Ok(())
+    }
+    fn geometry_begin(&mut self) -> Result<()> {
+        debug_assert!(self.geometry_writer.is_empty());
+        Ok(())
+    }
+}
+
+impl GeoFeatureWriter {
+    pub(crate) fn new() -> Self {
+        Self::default()
+    }
+}
+
+impl GeoFeature {
+    pub fn geometry(&self) -> &geo_types::Geometry {
+        &self.geometry
+    }
+
+    pub fn geometry_mut(&mut self) -> &mut geo_types::Geometry {
+        &mut self.geometry
+    }
+
+    pub fn properties(&self) -> &GeoProperties {
+        &self.properties
+    }
+
+    pub fn properties_mut(&mut self) -> &mut GeoProperties {
+        &mut self.properties
+    }
+
+    pub fn property<T: PropertyReadType>(&self, name: &str) -> Result<T> {
+        let Some(owned_column_value) = self.properties.get(name) else {
+            return Err(GeozeroError::ColumnNotFound);
+        };
+
+        let column_value = ColumnValue::from(owned_column_value);
+        T::get_value(&column_value)
+    }
+
+    pub fn into_inner(self) -> (geo_types::Geometry, GeoProperties) {
+        (self.geometry, self.properties)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::geojson::GeoJsonReader;
+    use crate::ToGeoFeatures;
+    use std::fs::File;
+    #[test]
+    fn from_json() {
+        let f = File::open("tests/data/places.json").unwrap();
+        let mut geojson = GeoJsonReader(f);
+        let feature_iter = geojson.to_geo_features().unwrap();
+        let features: Vec<_> = feature_iter.collect();
+        let first = features.first().unwrap();
+        assert_eq!(first.property::<String>("NAME").unwrap(), "Bombo");
+        assert_eq!(
+            first.geometry(),
+            &geo_types::Geometry::Point(geo_types::Point::new(
+                32.533299524864844,
+                0.583299105614628
+            ))
+        );
+
+        let last = features.last().unwrap();
+        assert_eq!(last.property::<String>("NAME").unwrap(), "Hong Kong");
+        assert_eq!(
+            last.geometry(),
+            &geo_types::Geometry::Point(geo_types::Point::new(
+                114.18306345846304,
+                22.30692675357551
+            ))
+        );
+    }
+}

geozero/src/geo_types/geo_types_writer.rs

@@ -7,7 +7,7 @@ use geo_types::{
 use std::mem;
 
 /// Generator for geo-types geometry type.
-#[derive(Default)]
+#[derive(Debug, Default)]
 pub struct GeoWriter {
     geoms: Vec<Geometry<f64>>,
     /// Stack of any in-progress (potentially nested) GeometryCollections
@@ -36,6 +36,10 @@ impl GeoWriter {
         }
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.geoms.is_empty()
+    }
+
     fn finish_geometry(&mut self, geometry: Geometry<f64>) -> Result<()> {
         // Add the geometry to a collection if we're in the middle of processing
         // a (potentially nested) collection

geozero/src/geo_types/mod.rs

@@ -1,4 +1,5 @@
 //! geo-types conversions.
+mod geo_types_feature_writer;
 pub(crate) mod geo_types_reader;
 pub(crate) mod geo_types_writer;
 
@@ -7,8 +8,9 @@ pub use geo_types_writer::*;
 
 pub(crate) mod conversion {
     use crate::error::{GeozeroError, Result};
+    use crate::geo_types::geo_types_feature_writer::{GeoFeature, GeoFeatureWriter};
     use crate::geo_types::GeoWriter;
-    use crate::GeozeroGeometry;
+    use crate::{GeozeroDatasource, GeozeroGeometry};
 
     /// Convert to geo-types Geometry.
     pub trait ToGeo {
@@ -24,6 +26,18 @@ pub(crate) mod conversion {
                 .ok_or(GeozeroError::Geometry("Missing Geometry".to_string()))
         }
     }
+
+    pub trait ToGeoFeatures {
+        fn to_geo_features(&mut self) -> Result<impl Iterator<Item = GeoFeature>>;
+    }
+
+    impl<DS: GeozeroDatasource> ToGeoFeatures for DS {
+        fn to_geo_features(&mut self) -> Result<impl Iterator<Item = GeoFeature>> {
+            let mut geo = GeoFeatureWriter::new();
+            self.process(&mut geo)?;
+            Ok(geo.features.into_iter())
+        }
+    }
 }
 
 #[cfg(feature = "with-wkb")]