From eb9b5a74086a72af1920d43f65705e655544db5f Mon Sep 17 00:00:00 2001
From: Gaurav Atreya <allmanpride@gmail.com>
Date: Thu, 28 Nov 2024 13:30:50 -0500
Subject: [PATCH] Add `Dataset::has_capability` for dataset capabilities test

---
 src/dataset.rs      | 50 +++++++++++++++++++++++++++++++++++++++++++--
 src/vector/layer.rs |  2 +-
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/src/dataset.rs b/src/dataset.rs
index 280edd6c..970253d3 100644
--- a/src/dataset.rs
+++ b/src/dataset.rs
@@ -1,4 +1,9 @@
-use std::{ffi::CString, ffi::NulError, path::Path, ptr};
+use std::{
+    ffi::NulError,
+    ffi::{CStr, CString},
+    path::Path,
+    ptr,
+};
 
 use gdal_sys::{CPLErr, GDALDatasetH, GDALMajorObjectH};
 
@@ -11,6 +16,29 @@ use crate::{
     gdal_major_object::MajorObject, spatial_ref::SpatialRef, Driver, GeoTransform, Metadata,
 };
 
+pub struct DatasetCapability(&'static CStr);
+
+/// Dataset capabilities
+impl DatasetCapability {
+    /// datasource can create new layers
+    pub const CREATE_LAYER: DatasetCapability = DatasetCapability(c"CreateLayer");
+    /// datasource can delete existing layers
+    pub const DELETE_LAYER: DatasetCapability = DatasetCapability(c"DeleteLayer");
+    /// layers of this datasource support CreateGeomField() just after layer creation
+    pub const CREATE_GEOM_FIELD_AFTER_CREATE_LAYER: DatasetCapability =
+        DatasetCapability(c"CreateGeomFieldAfterCreateLayer");
+    /// datasource supports curve geometries
+    pub const CURVE_GEOMETRIES: DatasetCapability = DatasetCapability(c"CurveGeometries");
+    /// datasource supports (efficient) transactions
+    pub const TRANSACTIONS: DatasetCapability = DatasetCapability(c"Transactions");
+    /// datasource supports transactions through emulation
+    pub const EMULATED_TRANSACTIONS: DatasetCapability = DatasetCapability(c"EmulatedTransactions");
+    /// datasource has a dedicated GetNextFeature() implementation, potentially returning features from layers in a non sequential way
+    pub const RANDOM_LAYER_READ: DatasetCapability = DatasetCapability(c"RandomLayerRead");
+    /// datasource supports calling CreateFeature() on layers in a non sequential way
+    pub const RANDOM_LAYER_WRITE: DatasetCapability = DatasetCapability(c"RandomLayerWrite");
+}
+
 /// Wrapper around a [`GDALDataset`][GDALDataset] object.
 ///
 /// Represents both a [vector dataset][vector-data-model]
@@ -327,6 +355,10 @@ impl Dataset {
         }
         Ok(transformation)
     }
+
+    pub fn has_capability(&self, capability: DatasetCapability) -> bool {
+        unsafe { gdal_sys::GDALDatasetTestCapability(self.c_dataset(), capability.0.as_ptr()) == 1 }
+    }
 }
 
 impl MajorObject for Dataset {
@@ -351,7 +383,8 @@ impl Drop for Dataset {
 mod tests {
     use gdal_sys::GDALAccess;
 
-    use crate::test_utils::fixture;
+    use crate::dataset::DatasetCapability;
+    use crate::test_utils::{fixture, open_gpkg_for_update};
     use crate::GdalOpenFlags;
 
     use super::*;
@@ -446,6 +479,19 @@ mod tests {
         .unwrap_err();
     }
 
+    #[test]
+    fn test_dataset_capabilities() {
+        let ds = Dataset::open(fixture("poly.gpkg")).unwrap();
+        assert!(!ds.has_capability(DatasetCapability::CREATE_LAYER));
+        assert!(!ds.has_capability(DatasetCapability::DELETE_LAYER));
+        assert!(ds.has_capability(DatasetCapability::TRANSACTIONS));
+
+        let (_tmp_path, ds) = open_gpkg_for_update(&fixture("poly.gpkg"));
+        assert!(ds.has_capability(DatasetCapability::CREATE_LAYER));
+        assert!(ds.has_capability(DatasetCapability::DELETE_LAYER));
+        assert!(ds.has_capability(DatasetCapability::TRANSACTIONS));
+    }
+
     #[test]
     fn test_raster_count_on_vector() {
         let ds = Dataset::open(fixture("roads.geojson")).unwrap();
diff --git a/src/vector/layer.rs b/src/vector/layer.rs
index 826e4372..456f031e 100644
--- a/src/vector/layer.rs
+++ b/src/vector/layer.rs
@@ -41,7 +41,7 @@ pub enum LayerCaps {
     OLCAlterFieldDefn,
     /// Layer capability for transactions
     OLCTransactions,
-    /// Layer capability for feature deletiond
+    /// Layer capability for feature deletion
     OLCDeleteFeature,
     /// Layer capability for setting next feature index
     OLCFastSetNextByIndex,