Add Module loadMethod API.

Summary: #8363

Reviewed By: mergennachin

Differential Revision: D71917236

Author: shoumikhin

extension/apple/ExecuTorch/Exported/ExecuTorchModule.h

@@ -86,6 +86,24 @@ __attribute__((deprecated("This API is experimental.")))
  */
 - (BOOL)isLoaded;
 
+/**
+ * Loads a specific method from the program.
+ *
+ * @param methodName A string representing the name of the method to load.
+ * @param error A pointer to an NSError pointer that is set if an error occurs.
+ * @return YES if the method was successfully loaded; otherwise, NO.
+ */
+- (BOOL)loadMethod:(NSString *)methodName
+             error:(NSError **)error NS_SWIFT_NAME(load(_:));
+
+/**
+ * Checks if a specific method is loaded.
+ *
+ * @param methodName A string representing the method name.
+ * @return YES if the method is loaded; otherwise, NO.
+ */
+- (BOOL)isMethodLoaded:(NSString *)methodName NS_SWIFT_NAME(isLoaded(_:));
+
 + (instancetype)new NS_UNAVAILABLE;
 - (instancetype)init NS_UNAVAILABLE;
 

extension/apple/ExecuTorch/Exported/ExecuTorchModule.mm

@@ -59,4 +59,22 @@ - (BOOL)isLoaded {
   return _module->is_loaded();
 }
 
+- (BOOL)loadMethod:(NSString *)methodName
+             error:(NSError **)error {
+  const auto errorCode = _module->load_method(methodName.UTF8String);
+  if (errorCode != Error::Ok) {
+    if (error) {
+      *error = [NSError errorWithDomain:ExecuTorchErrorDomain
+                                   code:(NSInteger)errorCode
+                               userInfo:nil];
+    }
+    return NO;
+  }
+  return YES;
+}
+
+- (BOOL)isMethodLoaded:(NSString *)methodName {
+  return _module->is_method_loaded(methodName.UTF8String);
+}
+
 @end

extension/apple/ExecuTorch/__tests__/ModuleTest.swift

@@ -28,4 +28,15 @@ class ModuleTest: XCTestCase {
     XCTAssertNoThrow(try module.load())
     XCTAssertTrue(module.isLoaded())
   }
+
+  func testLoadMethod() {
+    let bundle = Bundle(for: type(of: self))
+    guard let modelPath = bundle.path(forResource: "add", ofType: "pte") else {
+      XCTFail("Couldn't find the model file")
+      return
+    }
+    let module = Module(filePath: modelPath)
+    XCTAssertNoThrow(try module.load("forward"))
+    XCTAssertTrue(module.isLoaded("forward"))
+  }
 }