[.NET] Use separate function in CLib for external logging

Restores original definition of ct_setLogWriter by introducing ct_setLogCallback.

include/cantera/base/ExternalLogger.h

@@ -13,7 +13,7 @@ namespace Cantera {
 class ExternalLogger : public Logger
 {
 public:
-    explicit ExternalLogger(Writer writer) {
+    explicit ExternalLogger(LogCallback writer) {
         if (writer == nullptr) {
             throw CanteraError("ExternalLogger::ExternalLogger",
                 "Argument “writer” must not be null!");
@@ -55,7 +55,7 @@ class ExternalLogger : public Logger
 private:
     std::string m_writeBuffer;
 
-    Writer m_writer = nullptr;
+    LogCallback m_writer = nullptr;
 };
 
 }

include/cantera/clib/clib_defs.h

@@ -38,7 +38,9 @@
 
 // Used by external logger
 enum LogLevel { INFO, WARN , ERROR };
+
+//! Represents a callback that is invoked to produce log output.
 typedef void
-    (*Writer)(enum LogLevel logLevel, const char* category, const char* message);
+    (*LogCallback)(enum LogLevel logLevel, const char* category, const char* message);
 
 #endif

include/cantera/clib/ct.h

@@ -155,7 +155,8 @@ extern "C" {
                                          const double* state2, double delta, double* fluxes);
 
     CANTERA_CAPI int ct_getCanteraError(int buflen, char* buf);
-    CANTERA_CAPI int ct_setLogWriter(Writer writer);
+    CANTERA_CAPI int ct_setLogWriter(void* logger);
+    CANTERA_CAPI int ct_setLogCallback(LogCallback writer);
     CANTERA_CAPI int ct_addCanteraDirectory(size_t buflen, const char* buf);
     CANTERA_CAPI int ct_getDataDirectories(int buflen, char* buf, const char* sep);
     CANTERA_CAPI int ct_getCanteraVersion(int buflen, char* buf);

interfaces/dotnet/Cantera.Tests/src/ApplicationTest.cs

@@ -155,7 +155,7 @@ static void ProduceMockLogOutput()
 
         Assert.NotNull(eventField);
 
-        var del = (LibCantera.Writer) eventField!.GetValue(null)!;
+        var del = (LibCantera.LogCallback) eventField!.GetValue(null)!;
 
         Assert.NotNull(del);
 

interfaces/dotnet/Cantera/src/Application.cs

@@ -50,7 +50,7 @@ static Application()
         };
 
         InteropUtil.CheckReturn(
-            LibCantera.ct_setLogWriter(s_invokeMessageLoggedDelegate));
+            LibCantera.ct_setLogCallback(s_invokeMessageLoggedDelegate));
     }
 
     /// <summary>
@@ -64,7 +64,7 @@ static Application()
     /// storing it as
     /// a class member, we ensure it is not collected until the class is.
     /// </remarks>
-    static readonly LibCantera.Writer? s_invokeMessageLoggedDelegate;
+    static readonly LibCantera.LogCallback s_invokeMessageLoggedDelegate;
 
     unsafe static readonly Lazy<string> s_version =
         new(() => InteropUtil.GetString(10, LibCantera.ct_getCanteraVersion));

interfaces/dotnet/Cantera/src/Interop/LibCantera.cs

@@ -1,8 +1,6 @@
 // This file is part of Cantera. See License.txt in the top-level directory or
 // at https://cantera.org/license.txt for license and copyright information.
 
-using System.Runtime.InteropServices;
-
 namespace Cantera.Interop;
 
 static partial class LibCantera
@@ -15,8 +13,5 @@ static partial class LibCantera
     const string LibFile = "cantera.3.0.0.so";
 #endif
 
-    public delegate void Writer(LogLevel logLevel, string category, string message);
-
-    [DllImport(LibFile)]
-    public static extern int ct_setLogWriter(Writer writer);
+    public delegate void LogCallback(LogLevel logLevel, string category, string message);
 }

src/clib/ct.cpp

@@ -1470,7 +1470,18 @@ extern "C" {
         }
     }
 
-    int ct_setLogWriter(Writer writer)
+    int ct_setLogWriter(void* logger)
+    {
+        try {
+            Logger* logwriter = (Logger*)logger;
+            setLogger(logwriter);
+            return 0;
+        } catch (...) {
+            return handleAllExceptions(-1, ERR);
+        }
+    }
+
+    int ct_setLogCallback(LogCallback writer)
     {
         static unique_ptr<Logger> logwriter;
         try {