Add Module methodName API.

Summary: #8363

Reviewed By: mergennachin

Differential Revision: D71918193

Author: shoumikhin

extension/apple/ExecuTorch/Exported/ExecuTorchModule.h

@@ -104,6 +104,17 @@ __attribute__((deprecated("This API is experimental.")))
  */
 - (BOOL)isMethodLoaded:(NSString *)methodName NS_SWIFT_NAME(isLoaded(_:));
 
+/**
+ * Retrieves the set of method names available in the loaded program.
+ *
+ * The method names are returned as an unordered set of strings. The program and methods
+ * are loaded as needed.
+ *
+ * @param error A pointer to an NSError pointer that is set if an error occurs.
+ * @return An unordered set of method names, or nil in case of an error.
+ */
+- (nullable NSSet<NSString *> *)methodNames:(NSError **)error;
+
 + (instancetype)new NS_UNAVAILABLE;
 - (instancetype)init NS_UNAVAILABLE;
 

extension/apple/ExecuTorch/Exported/ExecuTorchModule.mm

@@ -77,4 +77,21 @@ - (BOOL)isMethodLoaded:(NSString *)methodName {
   return _module->is_method_loaded(methodName.UTF8String);
 }
 
+- (nullable NSSet<NSString *> *)methodNames:(NSError **)error {
+  const auto result = _module->method_names();
+  if (!result.ok()) {
+    if (error) {
+      *error = [NSError errorWithDomain:ExecuTorchErrorDomain
+                                   code:(NSInteger)result.error()
+                               userInfo:nil];
+    }
+    return nil;
+  }
+  NSMutableSet<NSString *> *methods = [NSMutableSet setWithCapacity:result->size()];
+  for (const auto &name : *result) {
+    [methods addObject:(NSString *)@(name.c_str())];
+  }
+  return methods;
+}
+
 @end

extension/apple/ExecuTorch/__tests__/ModuleTest.swift

@@ -39,4 +39,16 @@ class ModuleTest: XCTestCase {
     XCTAssertNoThrow(try module.load("forward"))
     XCTAssertTrue(module.isLoaded("forward"))
   }
+
+  func testMethodNames() {
+    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)
+    var methodNames: Set<String>?
+    XCTAssertNoThrow(methodNames = try module.methodNames())
+    XCTAssertEqual(methodNames, Set(["forward"]))
+  }
 }