Take the field index, not name, in the feature getters and setters

CHANGES.md

@@ -7,13 +7,19 @@
   - Drop support for GDAL <3.4 ([#578](https://github.com/georust/gdal/pull/578))
   - Regenerate the pre-built bindings with `std::ffi` instead of `libc` for C types ([#573](https://github.com/georust/gdal/pull/573))
   - Upgrade `ndarray` dependency to 0.16 ([#569](https://github.com/georust/gdal/pull/569))
+  - Update `Feature::field`, `Feature::set_field`, `Feature::set_field_string`, `Feature::set_field_string_list`, `Feature::set_field_double`, `Feature::set_field_double_list`, `Feature::set_field_integer`, `Feature::set_field_integer_list`, `Feature::set_field_integer64`, `Feature::set_field_integer64_list`, `Feature::set_field_datetime`, `Feature::set_field_null`, `Feature::unset_field` to take a field index, not a name ([#581](https://github.com/georust/gdal/pull/581))
+  - Drop `Feature::field_as_integer_by_name`, `Feature::field_as_integer64_by_name`, `Feature::field_as_double_by_name`, `Feature::field_as_string_by_name`, `Feature::field_as_datetime_by_name` ([#581](https://github.com/georust/gdal/pull/581))
+  - Update `Feature::field_count` to return `usize` instead of `i32` ([#581](https://github.com/georust/gdal/pull/581))
+  - Update `Feature::field_as_integer`, `Feature::field_as_integer64`, `Feature::field_as_double`, `Feature::field_as_string`, `Feature::field_as_datetime` to take the field index as `usize` instead of `i32` ([#581](https://github.com/georust/gdal/pull/581))
+  - Drop `LayerAccess::create_feature_fields` ([#581](https://github.com/georust/gdal/pull/581))
 
 ### Added
 
   - Add a `bundled` feature for `gdal-sys` for building and statically linking a minimal bundled version of GDAL ([#517](https://github.com/georust/gdal/pull/517))
   - Add pre-built bindings for GDAL 3.10 ([#573](https://github.com/georust/gdal/pull/573))
   - Add methods `alternative_name`, `is_nullable`, `is_unique`, `default_value` to `Field` ([#561](https://github.com/georust/gdal/pull/561))
   - Add `Defn::geometry_type` ([#562](https://github.com/georust/gdal/pull/562))
+  - Add `Defn::field_index` and `Feature::field_index` ([#581](https://github.com/georust/gdal/pull/581))
 
 ### Fixed
 

examples/read_write_ogr.rs

@@ -52,9 +52,9 @@ fn run() -> Result<()> {
         }
 
         // copy each field value of the feature:
-        for fd in &fields_defn {
-            if let Some(value) = feature_a.field(&fd.0)? {
-                ft.set_field(&fd.0, &value)?;
+        for idx in 0..fields_defn.len() {
+            if let Some(value) = feature_a.field(idx)? {
+                ft.set_field(idx, &value)?;
             }
         }
         // Add the feature to the layer:

examples/read_write_ogr_datetime.rs

@@ -35,10 +35,10 @@ fn run() -> gdal::errors::Result<()> {
             ft.set_geometry(geom.clone())?;
         }
         // copy each field value of the feature:
-        for field in defn.fields() {
+        for (idx, field) in defn.fields().enumerate() {
             ft.set_field(
-                &field.name(),
-                &match feature_a.field(field.name())?.unwrap() {
+                idx,
+                &match feature_a.field(idx)?.unwrap() {
                     // add one day to dates
                     FieldValue::DateValue(value) => {
                         println!("{} = {}", field.name(), value);

examples/write_ogr.rs

@@ -1,10 +1,10 @@
 use gdal::errors::Result;
-use gdal::vector::{Defn, Feature, FieldDefn, FieldValue, Geometry, LayerAccess, OGRFieldType};
+use gdal::vector::{Defn, Feature, FieldDefn, Geometry, OGRFieldType};
 use gdal::DriverManager;
 use std::fs;
 
 /// Example 1, the detailed way:
-fn example_1() -> Result<()> {
+fn main() -> Result<()> {
     let path = std::env::temp_dir().join("output1.geojson");
     let _ = fs::remove_file(&path);
     let drv = DriverManager::get_driver_by_name("GeoJSON")?;
@@ -21,81 +21,32 @@ fn example_1() -> Result<()> {
 
     let defn = Defn::from_layer(&lyr);
 
+    let name_idx = defn.field_index("Name")?;
+    let value_idx = defn.field_index("Value")?;
+
     // 1st feature:
     let mut ft = Feature::new(&defn)?;
     ft.set_geometry(Geometry::from_wkt("POINT (45.21 21.76)")?)?;
-    ft.set_field_string("Name", "Feature 1")?;
-    ft.set_field_double("Value", 45.78)?;
+    ft.set_field_string(name_idx, "Feature 1")?;
+    ft.set_field_double(value_idx, 45.78)?;
     ft.create(&lyr)?;
 
     // 2nd feature:
     let mut ft = Feature::new(&defn)?;
-    ft.set_field_double("Value", 0.789)?;
+    ft.set_field_double(value_idx, 0.789)?;
     ft.set_geometry(Geometry::from_wkt("POINT (46.50 22.50)")?)?;
-    ft.set_field_string("Name", "Feature 2")?;
+    ft.set_field_string(name_idx, "Feature 2")?;
     ft.create(&lyr)?;
 
     // Feature triggering an error due to a wrong field name:
     let mut ft = Feature::new(&defn)?;
     ft.set_geometry(Geometry::from_wkt("POINT (46.50 22.50)")?)?;
-    ft.set_field_string("Name", "Feature 2")?;
-    match ft.set_field_double("Values", 0.789) {
+    ft.set_field_string(name_idx, "Feature 2")?;
+    match ft.set_field_double(value_idx, 0.789) {
         Ok(v) => v,
         Err(err) => println!("{err}"),
     };
     ft.create(&lyr)?;
 
     Ok(())
 }
-
-/// Example 2, same output, shortened way:
-fn example_2() -> Result<()> {
-    let path = std::env::temp_dir().join("output2.geojson");
-    let _ = fs::remove_file(&path);
-    let driver = DriverManager::get_driver_by_name("GeoJSON")?;
-    let mut ds = driver.create_vector_only(path.to_str().unwrap())?;
-    let mut layer = ds.create_layer(Default::default())?;
-
-    layer.create_defn_fields(&[
-        ("Name", OGRFieldType::OFTString),
-        ("Value", OGRFieldType::OFTReal),
-    ])?;
-
-    layer.create_feature_fields(
-        Geometry::from_wkt("POINT (45.21 21.76)")?,
-        &["Name", "Value"],
-        &[
-            FieldValue::StringValue("Feature 1".to_string()),
-            FieldValue::RealValue(45.78),
-        ],
-    )?;
-
-    layer.create_feature_fields(
-        Geometry::from_wkt("POINT (46.50 22.50)")?,
-        &["Name", "Value"],
-        &[
-            FieldValue::StringValue("Feature 2".to_string()),
-            FieldValue::RealValue(0.789),
-        ],
-    )?;
-
-    // Feature creation triggering an error due to a wrong field name:
-    match layer.create_feature_fields(
-        Geometry::from_wkt("POINT (46.50 22.50)")?,
-        &["Abcd", "Value"],
-        &[
-            FieldValue::StringValue("Feature 2".to_string()),
-            FieldValue::RealValue(0.789),
-        ],
-    ) {
-        Ok(v) => v,
-        Err(err) => println!("{err}"),
-    };
-
-    Ok(())
-}
-
-fn main() {
-    example_1().unwrap();
-    example_2().unwrap();
-}

src/vector/defn.rs

@@ -1,4 +1,4 @@
-use std::ffi::c_int;
+use std::ffi::{c_int, CString};
 
 use gdal_sys::{
     OGRFeatureDefnH, OGRFieldDefnH, OGRFieldType, OGRGeomFieldDefnH, OGRwkbGeometryType,
@@ -66,6 +66,25 @@ impl Defn {
     pub fn geometry_type(&self) -> OGRwkbGeometryType::Type {
         unsafe { gdal_sys::OGR_FD_GetGeomType(self.c_defn) }
     }
+
+    /// Get the index of a field.
+    ///
+    /// If the field is missing, returns [`GdalError::InvalidFieldName`].
+    ///
+    pub fn field_index<S: AsRef<str>>(&self, field_name: S) -> Result<usize> {
+        let c_str_field_name = CString::new(field_name.as_ref())?;
+        let field_id =
+            unsafe { gdal_sys::OGR_FD_GetFieldIndex(self.c_defn(), c_str_field_name.as_ptr()) };
+        if field_id == -1 {
+            return Err(GdalError::InvalidFieldName {
+                field_name: field_name.as_ref().to_string(),
+                method_name: "OGR_FD_GetFieldIndex",
+            });
+        }
+
+        let idx = field_id.try_into()?;
+        Ok(idx)
+    }
 }
 
 pub struct FieldIterator<'a> {