[CoreCLR] Add support for mono_assembly_open.

This includes going through all uses of mono_assembly_open, and make sure the release
the returned assembly.

runtime/coreclr-bridge.m

@@ -77,7 +77,9 @@ xamarin_bridge_call_runtime_initialize (struct InitializationOptions* options, G
 void
 xamarin_bridge_register_product_assembly (GCHandle* exception_gchandle)
 {
-	xamarin_open_and_register (PRODUCT_DUAL_ASSEMBLY, exception_gchandle);
+	MonoAssembly *assembly;
+	assembly = xamarin_open_and_register (PRODUCT_DUAL_ASSEMBLY, exception_gchandle);
+	xamarin_mono_object_release (&assembly);
 }
 
 MonoClass *
@@ -143,4 +145,19 @@ xamarin_mono_object_release (MonoObject **mobj_ref)
 	*mobj_ref = NULL;
 }
 
+/* Implementation of the Mono Embedding API */
+
+// returns a retained MonoAssembly *
+MonoAssembly *
+mono_assembly_open (const char * filename, MonoImageOpenStatus * status)
+{
+	assert (status == NULL);
+
+	MonoAssembly *rv = xamarin_find_assembly (filename);
+
+	LOG_CORECLR (stderr, "mono_assembly_open (%s, %p) => MonoObject=%p GCHandle=%p\n", filename, status, rv, rv->gchandle);
+
+	return rv;
+}
+
 #endif // CORECLR_RUNTIME

runtime/delegates.t4

@@ -287,6 +287,14 @@
 			OnlyDynamicUsage = false,
 		},
 
+		new XDelegate ("MonoAssembly *", "IntPtr", "xamarin_find_assembly",
+			"const char *","IntPtr", "assembly_name"
+		) {
+			WrappedManagedFunction = "FindAssembly",
+			OnlyDynamicUsage = false,
+			OnlyCoreCLR = true,
+		},
+
 	};
 	delegates.CalculateLengths ();
 #><#+

runtime/exports.t4

@@ -251,7 +251,9 @@
 		new Export ("MonoAssembly *", "mono_assembly_open",
 			"const char *",          "filename",
 			"MonoImageOpenStatus *", "status"
-		),
+		) {
+			HasCoreCLRBridgeFunction = true,
+		},
 
 		new Export ("MonoImage *", "mono_assembly_get_image",
 			"MonoAssembly *", "assembly"

runtime/launcher.m

@@ -550,6 +550,8 @@ run_application_init (xamarin_initialize_data *data)
 
 	MonoImage *image = mono_assembly_get_image (assembly);
 
+	xamarin_mono_object_release (&assembly);
+
 	MonoClass *app_class = mono_class_from_name (image, "AppKit", "NSApplication");
 	if (!app_class)
 		xamarin_assertion_message ("Fatal error: failed to load the NSApplication class");

runtime/mono-runtime.h.t4

@@ -65,7 +65,12 @@ char *xamarin_get_mono_runtime_build_info (); // returns NULL if libmono couldn'
 typedef int32_t	mono_bool;
 
 /* metadata/image.h */
+#if defined (CORECLR_RUNTIME)
+// In Mono, MonoAssembly is not related to MonoObject, but for the CoreCLR bridge we use the same memory representation for both types.
+typedef struct _MonoObject MonoAssembly;
+#else
 typedef struct _MonoAssembly MonoAssembly;
+#endif
 typedef struct _MonoAssemblyName MonoAssemblyName;
 typedef struct _MonoImage MonoImage;
 

runtime/monotouch-main.m

@@ -472,5 +472,7 @@ xamarin_main (int argc, char *argv[], enum XamarinLaunchMode launch_mode)
 		break;
 	}
 
+	xamarin_mono_object_release (&assembly);
+	
 	return rv;
 }

runtime/monovm-bridge.m

@@ -143,6 +143,8 @@ void
 xamarin_bridge_register_product_assembly (GCHandle* exception_gchandle)
 {
 	xamarin_register_monoassembly (entry_assembly, exception_gchandle);
+	// We don't need the entry_assembly around anymore, so release it.
+	xamarin_mono_object_release (&entry_assembly);
 }
 
 MonoClass *

runtime/runtime.m

@@ -941,6 +941,7 @@ xamarin_file_exists (const char *path)
 	return stat (path, &buffer) == 0;
 }
 
+// Returns a retained MonoObject. Caller must release.
 MonoAssembly *
 xamarin_open_assembly (const char *name)
 {
@@ -996,6 +997,7 @@ xamarin_register_monoassembly (MonoAssembly *assembly, GCHandle *exception_gchan
 	return *exception_gchandle == INVALID_GCHANDLE;
 }
 
+// Returns a retained MonoObject. Caller must release.
 MonoAssembly *
 xamarin_open_and_register (const char *aname, GCHandle *exception_gchandle)
 {

src/ObjCRuntime/Runtime.CoreCLR.cs

@@ -10,6 +10,7 @@
 
 using System;
 using System.IO;
+using System.Reflection;
 using System.Runtime.InteropServices;
 
 namespace ObjCRuntime {
@@ -29,6 +30,35 @@ namespace ObjCRuntime {
 			xamarin_log (message);
 		}
 
+		// Returns a retained MonoObject. Caller must release.
+		static IntPtr FindAssembly (IntPtr assembly_name)
+		{
+			var path = Marshal.PtrToStringAuto (assembly_name);
+			var name = Path.GetFileNameWithoutExtension (path);
+
+			log_coreclr ($"Runtime.FindAssembly (0x{assembly_name.ToString ("x")} = {name})");
+
+			foreach (var asm in AppDomain.CurrentDomain.GetAssemblies ()) {
+				log_coreclr ($"    Assembly from app domain: {asm.GetName ().Name}");
+				if (asm.GetName ().Name == name) {
+					log_coreclr ($"        Match!");
+					return GetMonoObject (asm);
+				}
+			}
+
+			log_coreclr ($"    Did not find the assembly in the app domain's loaded assemblies. Will try to load it.");
+
+			var loadedAssembly = Assembly.LoadFrom (path);
+			if (loadedAssembly != null) {
+				log_coreclr ($"    Loaded {loadedAssembly.GetName ().Name}");
+				return GetMonoObject (loadedAssembly);
+			}
+
+			log_coreclr ($"    Found no assembly named {name}");
+
+			throw new InvalidOperationException ($"Could not find any assemblies named {name}");
+		}
+
 		// Returns a retained MonoObject. Caller must release.
 		static IntPtr GetMonoObject (object obj)
 		{