Fix native candidate and schema list handling

RimeSharp/Rime.cs

@@ -342,14 +342,22 @@ public RimeCandidate[] GetCandidates(RimeSessionId sessionId, int start = 0, int
         {
             var iterator = new RimeCandidateListIterator();
             if (!_api.CandidateListFromIndex(sessionId, ref iterator, start)) return [];
+
             var candidates = new List<RimeCandidate>();
-            var i = 0;
-            while (i < count && _api.CandidateListNext(ref iterator))
+            try
+            {
+                var i = 0;
+                while (i < count && _api.CandidateListNext(ref iterator))
+                {
+                    candidates.Add(iterator.Candidate);
+                    ++i;
+                }
+            }
+            finally
             {
-                candidates.Add(iterator.Candidate);
-                ++i;
+                _api.CandidateListEnd(ref iterator);
             }
-            _api.CandidateListEnd(ref iterator);
+
             return [.. candidates];
         }
 

RimeSharp/RimeCustomSettings.cs

@@ -28,15 +28,22 @@ public class RimeSwitcherSettings() : RimeCustomSettings(s_api.SwitcherSettingsI
     private RimeSchemaListItem[] GetSchemaList(SchemaListAccess access)
     {
         if (!access(handle, out var list)) return [];
-        var size = Marshal.SizeOf<RimeSchemaListItem>();
-        var items = new RimeSchemaListItem[(int)list.Size];
-        for (var i = 0; i < (int)list.Size; ++i)
+
+        try
+        {
+            var size = Marshal.SizeOf<RimeSchemaListItem>();
+            var items = new RimeSchemaListItem[(int)list.Size];
+            for (var i = 0; i < (int)list.Size; ++i)
+            {
+                var ptr = IntPtr.Add(list.List, i * size);
+                items[i] = Marshal.PtrToStructure<RimeSchemaListItem>(ptr);
+            }
+            return items;
+        }
+        finally
         {
-            var ptr = IntPtr.Add(list.List, i * size);
-            items[i] = Marshal.PtrToStructure<RimeSchemaListItem>(ptr);
+            s_api.SchemaListDestroy(ref list);
         }
-        s_api.SchemaListDestroy(ref list);
-        return items;
     }
 
     public RimeSchemaListItem[] GetAvailableSchemaList()
@@ -47,4 +54,4 @@ public RimeSchemaListItem[] GetSelectedSchemaList()
 
     public bool SelectSchemas(string[] schemaIdList)
         => s_api.SelectSchemas(handle, schemaIdList, schemaIdList.Length);
-}
+}

RimeSharp/RimeLevers.cs

@@ -57,7 +57,7 @@ internal bool GetAvailableSchemaList(IntPtr ptr, out RimeSchemaList list)
             => _levers.GetAvailableSchemaList(ptr, out list);
 
         internal bool GetSelectedSchemaList(IntPtr ptr, out RimeSchemaList list)
-            => _levers.GetAvailableSchemaList(ptr, out list);
+            => _levers.GetSelectedSchemaList(ptr, out list);
 
         internal void SchemaListDestroy(ref RimeSchemaList list)
             => _levers.SchemaListDestroy(ref list);

RimeSharp/RimeStructs.cs

@@ -214,9 +214,29 @@ public struct RimeCandidateListIterator
     {
         public UIntPtr Ptr;
         public int Index;
+        // librime owns these pointers and replaces them during iteration.
+        private NativeRimeCandidate _candidate;
 
-        [MarshalAs(UnmanagedType.Struct)]
-        public RimeCandidate Candidate;
+        public readonly RimeCandidate Candidate => _candidate.ToManaged();
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct NativeRimeCandidate
+    {
+        internal IntPtr Text;
+        internal IntPtr Comment;
+        private readonly IntPtr _reserved;
+
+        internal readonly RimeCandidate ToManaged()
+        {
+            return new RimeCandidate
+            {
+                Text = UTF8Marshal.PtrToStringUTF8(Text),
+                Comment = Comment == IntPtr.Zero
+                    ? null
+                    : UTF8Marshal.PtrToStringUTF8(Comment),
+            };
+        }
     }
 
     [StructLayout(LayoutKind.Sequential)]