Impl Clone for ExifKey

exif/exif.h

@@ -35,6 +35,7 @@ EXIF_API int exif_image_write_metadata(ExifImage* image);
 EXIF_API void free_exif_image(ExifImage* img);
 EXIF_API ExifKey* exif_create_key_by_key(const char* key);
 EXIF_API ExifKey* exif_create_key_by_id(uint16_t id, const char* group_name);
+EXIF_API ExifKey* exif_create_key_by_another(ExifKey* key);
 EXIF_API char* exif_get_key_key(ExifKey* key);
 EXIF_API char* exif_get_key_family_name(ExifKey* key);
 EXIF_API char* exif_get_key_group_name(ExifKey* key);

exif/src/exif.cpp

@@ -95,6 +95,19 @@ end:
     return nullptr;
 }
 
+ExifKey* exif_create_key_by_another(ExifKey* key) {
+    if (!key) return nullptr;
+    ExifKey* k = new ExifKey;
+    if (!k) return nullptr;
+    Exiv2::ExifKey* ek = new Exiv2::ExifKey(*(key->key));
+    if (!ek) {
+        delete k;
+        return nullptr;
+    }
+    k->key = ek;
+    return k;
+}
+
 char* exif_get_key_key(ExifKey* key) {
     if (!key || !key->key) return nullptr;
     auto s = key->key->key();

src/exif.rs

@@ -130,6 +130,16 @@ impl Drop for ExifKey {
     }
 }
 
+impl Clone for ExifKey {
+    fn clone(&self) -> Self {
+        let key = unsafe { _exif::exif_create_key_by_another(self.key) };
+        if key.is_null() {
+            panic!("Out of memory.");
+        }
+        Self { key }
+    }
+}
+
 impl ToRawHandle<_exif::ExifKey> for ExifKey {
     unsafe fn to_raw_handle(&self) -> *mut _exif::ExifKey {
         self.key
@@ -782,6 +792,8 @@ fn test_exif_key() {
     assert!(k2.is_ok());
     let k2 = k2.unwrap();
     assert_eq!(Some(String::from("Exif.Image.XPTitle")), k2.key());
+    let k3 = k2.clone();
+    assert_eq!(Some(String::from("Exif.Image.XPTitle")), k3.key());
 }
 
 #[test]