support loading from model bytes in common code

Author: edgchen1

mobile/examples/model_tester/common/include/model_runner.h

@@ -1,11 +1,14 @@
 #pragma once
 
+#include <cstddef>
 #include <cstdint>
 
 #include <chrono>
 #include <optional>
+#include <span>
 #include <string>
 #include <unordered_map>
+#include <variant>
 #include <vector>
 
 namespace model_runner {
@@ -14,8 +17,10 @@ using Clock = std::chrono::steady_clock;
 using Duration = Clock::duration;
 
 struct RunConfig {
-  // Path to the model to run.
-  std::string model_path{};
+  using ModelPathOrBytes = std::variant<std::string, std::span<const std::byte>>;
+
+  // Path or bytes of the model to run.
+  ModelPathOrBytes model_path_or_bytes{};
 
   // Whether to run a warmup iteration before running the measured (timed) iterations.
   bool run_warmup_iteration{true};

mobile/examples/model_tester/common/model_runner.cpp

@@ -182,8 +182,19 @@ RunResult Run(const RunConfig& run_config) {
   }
 
   Timer timer{};
-  auto session = Ort::Session{env, run_config.model_path.c_str(), session_options};
-  run_result.load_duration = timer.Elapsed();
+
+  auto session = Ort::Session{nullptr};
+  if (std::holds_alternative<std::string>(run_config.model_path_or_bytes)) {
+    const auto& model_path = std::get<std::string>(run_config.model_path_or_bytes);
+    timer.Reset();
+    session = Ort::Session{env, model_path.c_str(), session_options};
+    run_result.load_duration = timer.Elapsed();
+  } else {
+    const auto& model_bytes = std::get<std::span<const std::byte>>(run_config.model_path_or_bytes);
+    timer.Reset();
+    session = Ort::Session{env, model_bytes.data(), model_bytes.size(), session_options};
+    run_result.load_duration = timer.Elapsed();
+  }
 
   auto input_names = GetModelInputNames(session);
   auto input_name_cstrs = GetCstrs(input_names);

mobile/examples/model_tester/ios/ModelRunner/model_runner_objc_wrapper.mm

@@ -15,7 +15,7 @@ @implementation ModelRunnerRunConfig {
 }
 
 - (void)setModelPath:(nonnull NSString*)modelPath {
-  _runConfig.model_path = modelPath.UTF8String;
+  _runConfig.model_path_or_bytes = std::string{modelPath.UTF8String};
 }
 
 - (void)setNumIterations:(NSUInteger)numIterations {