Add Module API to query for the number of methods (pytorch#9441)

Author: shoumikhin

extension/module/module.cpp

@@ -164,6 +164,11 @@ runtime::Error Module::load(const runtime::Program::Verification verification) {
   return runtime::Error::Ok;
 }
 
+runtime::Result<size_t> Module::num_methods() {
+  ET_CHECK_OK_OR_RETURN_ERROR(load());
+  return program_->num_methods();
+}
+
 runtime::Result<std::unordered_set<std::string>> Module::method_names() {
   ET_CHECK_OK_OR_RETURN_ERROR(load());
   const auto method_count = program_->num_methods();

extension/module/module.h

@@ -138,6 +138,14 @@ class Module {
     return program_;
   }
 
+  /**
+   * Get the number of methods available in the loaded program.
+   *
+   * @returns A Result object containing either the number of methods available
+   *          or an error to indicate failure.
+   */
+  runtime::Result<size_t> num_methods();
+
   /**
    * Get a list of method names available in the loaded program.
    * Loads the program and method if needed.

extension/module/test/module_test.cpp

@@ -69,6 +69,14 @@ TEST_F(ModuleTest, TestMethodNames) {
   EXPECT_EQ(method_names.get(), std::unordered_set<std::string>{"forward"});
 }
 
+TEST_F(ModuleTest, TestNumMethods) {
+  Module module(model_path_);
+
+  const auto num_methods = module.num_methods();
+  EXPECT_EQ(num_methods.error(), Error::Ok);
+  EXPECT_EQ(num_methods.get(), 1);
+}
+
 TEST_F(ModuleTest, TestNonExistentMethodNames) {
   Module module("/path/to/nonexistent/file.pte");