Merge pull request #5 from artichoke/lopopolo/state-opaque

Make `sysdir_search_path_enumeration_state` opaque

Rakefile

@@ -126,6 +126,7 @@ task :bindgen do
     bindgen --use-core
     --allowlist-function sysdir.*
     --allowlist-type sysdir.*
+    --blocklist-type sysdir_search_path_enumeration_state
     --allowlist-var PATH_MAX
     --default-enum-style rust_non_exhaustive
     --constified-enum sysdir_search_path_domain_mask_t
@@ -150,6 +151,29 @@ task :bindgen do
     f.puts ''
 
     IO.copy_stream(bindgen_io, f)
+
+    f.puts ''
+    f.puts <<~NEWTYPE
+      /// Opaque type for holding sysdir enumeration state.
+      #[repr(transparent)]
+      #[derive(Debug)]
+      #[allow(missing_copy_implementations)]
+      pub struct sysdir_search_path_enumeration_state(::core::ffi::c_uint);
+
+      impl PartialEq<::core::ffi::c_uint> for sysdir_search_path_enumeration_state {
+          fn eq(&self, other: &::core::ffi::c_uint) -> bool {
+              self.0 == *other
+          }
+      }
+
+      impl sysdir_search_path_enumeration_state {
+          /// Return true if the state indicates the enumeration is finished.
+          #[must_use]
+          pub fn is_finished(&self) -> bool {
+              self.0 == 0
+          }
+      }
+    NEWTYPE
   end
 end
 

src/lib.rs

@@ -143,4 +143,30 @@ mod tests {
 
         assert_eq!(count, 1, "Should iterate once and find `/Users`");
     }
+
+    #[test]
+    fn example_and_linkage_with_opaque_state_helpers() {
+        let mut count = 0_usize;
+        let mut path = [0; PATH_MAX as usize];
+
+        let dir = sysdir_search_path_directory_t::SYSDIR_DIRECTORY_USER;
+        let domain_mask = SYSDIR_DOMAIN_MASK_LOCAL;
+
+        unsafe {
+            let mut state = sysdir_start_search_path_enumeration(dir, domain_mask);
+            loop {
+                let path = path.as_mut_ptr().cast::<c_char>();
+                state = sysdir_get_next_search_path_enumeration(state, path);
+                if state.is_finished() {
+                    break;
+                }
+                let path = CStr::from_ptr(path);
+                let s = path.to_str().unwrap();
+                assert_eq!(s, "/Users");
+                count += 1;
+            }
+        }
+
+        assert_eq!(count, 1, "Should iterate once and find `/Users`");
+    }
 }

src/sys.rs

@@ -48,7 +48,6 @@ pub const SYSDIR_DOMAIN_MASK_NETWORK: sysdir_search_path_domain_mask_t = 4;
 pub const SYSDIR_DOMAIN_MASK_SYSTEM: sysdir_search_path_domain_mask_t = 8;
 pub const SYSDIR_DOMAIN_MASK_ALL: sysdir_search_path_domain_mask_t = 65535;
 pub type sysdir_search_path_domain_mask_t = ::core::ffi::c_uint;
-pub type sysdir_search_path_enumeration_state = ::core::ffi::c_uint;
 extern "C" {
     pub fn sysdir_start_search_path_enumeration(
         dir: sysdir_search_path_directory_t,
@@ -61,3 +60,23 @@ extern "C" {
         path: *mut ::core::ffi::c_char,
     ) -> sysdir_search_path_enumeration_state;
 }
+
+/// Opaque type for holding sysdir enumeration state.
+#[repr(transparent)]
+#[derive(Debug)]
+#[allow(missing_copy_implementations)]
+pub struct sysdir_search_path_enumeration_state(::core::ffi::c_uint);
+
+impl PartialEq<::core::ffi::c_uint> for sysdir_search_path_enumeration_state {
+    fn eq(&self, other: &::core::ffi::c_uint) -> bool {
+        self.0 == *other
+    }
+}
+
+impl sysdir_search_path_enumeration_state {
+    /// Return true if the state indicates the enumeration is finished.
+    #[must_use]
+    pub fn is_finished(&self) -> bool {
+        self.0 == 0
+    }
+}