Make the DuckDBConnection support unicode file path (#197)

Author: Cricle

DuckDB.NET.Bindings/NativeMethods/NativeMethods.Startup.cs

@@ -8,9 +8,15 @@ public partial class NativeMethods
     //https://duckdb.org/docs/api/c/api#openconnect
     public static class Startup
     {
+        [DllImport(DuckDbLibrary, CallingConvention = CallingConvention.Cdecl, EntryPoint = "duckdb_open")]
+        public static extern DuckDBState DuckDBOpen(SafeUnmanagedMemoryHandle path, out DuckDBDatabase database);
+
         [DllImport(DuckDbLibrary, CallingConvention = CallingConvention.Cdecl, EntryPoint = "duckdb_open")]
         public static extern DuckDBState DuckDBOpen(string? path, out DuckDBDatabase database);
 
+        [DllImport(DuckDbLibrary, CallingConvention = CallingConvention.Cdecl, EntryPoint = "duckdb_open_ext")]
+        public static extern DuckDBState DuckDBOpen(SafeUnmanagedMemoryHandle path, out DuckDBDatabase database, DuckDBConfig config, out IntPtr error);
+
         [DllImport(DuckDbLibrary, CallingConvention = CallingConvention.Cdecl, EntryPoint = "duckdb_open_ext")]
         public static extern DuckDBState DuckDBOpen(string? path, out DuckDBDatabase database, DuckDBConfig config, out IntPtr error);
 

DuckDB.NET.Data/Internal/ConnectionManager.cs

@@ -69,7 +69,9 @@ internal ConnectionReference GetConnectionReference(DuckDBConnectionString conne
                         }
                     }
 
-                    var resultOpen = NativeMethods.Startup.DuckDBOpen(path, out var db, config, out var error);
+                    using var pathUnmanaged = path.ToUnmanagedString();
+
+                    var resultOpen = NativeMethods.Startup.DuckDBOpen(pathUnmanaged, out var db, config, out var error);
 
                     if (!resultOpen.IsSuccess())
                     {

DuckDB.NET.Samples/Program.cs

@@ -91,7 +91,7 @@ private static void AdoNetSamples()
 
         private static void LowLevelBindingsSample()
         {
-            var result = Startup.DuckDBOpen(null, out var database);
+            var result = Startup.DuckDBOpen(new SafeUnmanagedMemoryHandle(IntPtr.Zero), out var database);
 
             using (database)
             {

DuckDB.NET.Test/AppenderTests.cs

@@ -9,7 +9,7 @@ public class DuckDBAppenderTests
     [Fact]
     public void AppenderTests()
     {
-        var result = NativeMethods.Startup.DuckDBOpen(null, out var database);
+        var result = NativeMethods.Startup.DuckDBOpen((string)null, out var database);
         result.Should().Be(DuckDBState.Success);
 
         result = NativeMethods.Startup.DuckDBConnect(database, out var connection);

DuckDB.NET.Test/OpenTests.cs

@@ -0,0 +1,34 @@
+using DuckDB.NET.Data;
+using System.IO;
+using Xunit;
+
+namespace DuckDB.NET.Test;
+
+public class OpenTests
+{
+    [Theory]
+    [InlineData("中文", "中文.db")]
+    [InlineData("english", "english.db")]
+    [InlineData("한국어", "한국어.db")]
+    public void OpenWithFile(string path,string fileName)
+    {
+        var dir = Path.Combine(path);
+        if (!Directory.Exists(dir))
+        {
+            Directory.CreateDirectory(dir);
+        }
+        var file = Path.Combine(dir, fileName);
+        using (var conn=new DuckDBConnection($"Data Source={file}"))
+        {
+            conn.Open();
+        }
+        try
+        {
+            File.Delete(file);
+            Directory.Delete(dir);
+        }
+        catch (System.Exception)
+        {
+        }
+    }
+}

DuckDB.NET.Test/QueryTests.cs

@@ -9,7 +9,7 @@ public class QueryTests(DuckDBDatabaseFixture db) : DuckDBTestBase(db)
     [Fact]
     public void QueryTest()
     {
-        var result = NativeMethods.Startup.DuckDBOpen(null, out var database);
+        var result = NativeMethods.Startup.DuckDBOpen((string)null, out var database);
         result.Should().Be(DuckDBState.Success);
 
         result = NativeMethods.Startup.DuckDBConnect(database, out var connection);