Implement wrapper for OGR_L_TestCapability

Author: dmarteau

CHANGES.md

@@ -1,6 +1,8 @@
 # Changes
 
 ## Unreleased
+* Implement wrapper for `OGR_L_TestCapability`
+    * <https://github.com/georust/gdal/pull/160>
 * **Breaking**: Use `DatasetOptions` to pass as `Dataset::open_ex` parameters and
     add support for extended open flags.
 

src/vector/layer.rs

@@ -13,6 +13,73 @@ use std::{convert::TryInto, ffi::CString, marker::PhantomData};
 
 use crate::errors::*;
 
+/// Layer capabilities
+pub enum LayerCaps {
+    /// Layer capability for random read
+    OLCRandomRead,
+    /// Layer capability for sequential write
+    OLCSequentialWrite,
+    /// Layer capability for random write
+    OLCRandomWrite,
+    /// Layer capability for fast spatial filter
+    OLCFastSpatialFilter,
+    /// Layer capability for fast feature count retrieval
+    OLCFastFeatureCount,
+    /// Layer capability for fast extent retrieval
+    OLCFastGetExtent,
+    /// Layer capability for field creation
+    OLCCreateField,
+    /// Layer capability for field deletion
+    OLCDeleteField,
+    /// Layer capability for field reordering
+    OLCReorderFields,
+    /// Layer capability for field alteration
+    OLCAlterFieldDefn,
+    /// Layer capability for transactions
+    OLCTransactions,
+    /// Layer capability for feature deletiond
+    OLCDeleteFeature,
+    /// Layer capability for setting next feature index
+    OLCFastSetNextByIndex,
+    /// Layer capability for strings returned with UTF-8 encoding
+    OLCStringsAsUTF8,
+    /// Layer capability for field ignoring
+    OLCIgnoreFields,
+    /// Layer capability for geometry field creation
+    OLCCreateGeomField,
+    /// Layer capability for curve geometries support
+    OLCCurveGeometries,
+    /// Layer capability for measured geometries support
+    OLCMeasuredGeometries,
+}
+
+// Manage conversion to Gdal values
+impl LayerCaps {
+    fn into_cstring(self) -> CString {
+        CString::new(match self {
+            Self::OLCRandomRead => "RandomRead",
+            Self::OLCSequentialWrite => "SequentialWrite",
+            Self::OLCRandomWrite => "RandomWrite",
+            Self::OLCFastSpatialFilter => "FastSpatialFilter",
+            Self::OLCFastFeatureCount => "FastFeatureCount",
+            Self::OLCFastGetExtent => "FastGetExtent",
+            Self::OLCCreateField => "CreateField",
+            Self::OLCDeleteField => "DeleteField",
+            Self::OLCReorderFields => "ReorderFields",
+            Self::OLCAlterFieldDefn => "AlterFieldDefn",
+            Self::OLCTransactions => "Transactions",
+            Self::OLCDeleteFeature => "DeleteFeature",
+            Self::OLCFastSetNextByIndex => "FastSetNextByIndex",
+            Self::OLCStringsAsUTF8 => "StringsAsUTF8",
+            Self::OLCIgnoreFields => "IgnoreFields",
+            Self::OLCCreateGeomField => "CreateGeomField",
+            Self::OLCCurveGeometries => "CurveGeometries",
+            Self::OLCMeasuredGeometries => "MeasuredGeometries",
+        })
+        .unwrap()
+    }
+}
+
 /// Layer in a vector dataset
 ///
 /// ```
@@ -101,6 +168,12 @@ impl<'a> Layer<'a> {
         _string(rv)
     }
 
+    pub fn has_capability(&self, capability: LayerCaps) -> bool {
+        unsafe {
+            gdal_sys::OGR_L_TestCapability(self.c_layer, capability.into_cstring().as_ptr()) == 1
+        }
+    }
+
     pub fn defn(&self) -> &Defn {
         &self.defn
     }

src/vector/mod.rs

@@ -27,7 +27,7 @@ pub use defn::{Defn, Field, FieldIterator};
 pub use feature::{Feature, FieldValue, FieldValueIterator};
 pub use gdal_sys::{OGRFieldType, OGRwkbGeometryType};
 pub use geometry::Geometry;
-pub use layer::{FeatureIterator, FieldDefn, Layer};
+pub use layer::{FeatureIterator, FieldDefn, Layer, LayerCaps};
 pub use ops::GeometryIntersection;
 
 use crate::errors::Result;

src/vector/vector_tests/mod.rs

@@ -1,5 +1,6 @@
 use super::{
-    Feature, FeatureIterator, FieldValue, Geometry, Layer, OGRFieldType, OGRwkbGeometryType,
+    Feature, FeatureIterator, FieldValue, Geometry, Layer, LayerCaps::*, OGRFieldType,
+    OGRwkbGeometryType,
 };
 use crate::spatial_ref::SpatialRef;
 use crate::{assert_almost_eq, Dataset, Driver};
@@ -63,6 +64,18 @@ fn test_layer_spatial_ref() {
     assert_eq!(srs.auth_code().unwrap(), 4326);
 }
 
+#[test]
+fn test_layer_capabilities() {
+    let mut ds = Dataset::open(fixture!("roads.geojson")).unwrap();
+    let layer = ds.layer(0).unwrap();
+
+    assert_eq!(layer.has_capability(OLCFastSpatialFilter), false);
+    assert_eq!(layer.has_capability(OLCFastFeatureCount), true);
+    assert_eq!(layer.has_capability(OLCFastGetExtent), false);
+    assert_eq!(layer.has_capability(OLCRandomRead), true);
+    assert_eq!(layer.has_capability(OLCStringsAsUTF8), true);
+}
+
 fn ds_with_layer<F>(ds_name: &str, layer_name: &str, f: F)
 where
     F: Fn(Layer),