Initial skeletal implementation of the PrincipalService. Also, use the Login()/GetUserBlessing()

examples/bank_app/customer.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <stdio.h>
+
+#include "examples/bank_app/bank.mojom.h"
+#include "mojo/public/c/system/main.h"
+#include "mojo/public/cpp/application/application_impl.h"
+#include "mojo/public/cpp/application/application_runner.h"
+#include "mojo/public/cpp/utility/run_loop.h"
+#include "mojo/services/vanadium/security/public/interfaces/principal.mojom.h"
+
+namespace examples {
+
+class LoginHandler {
+ public:
+  void Run(const vanadium::BlessingPtr& b) const {
+    std::string user;
+    if (b) {
+      for (size_t i = 0; i < b->chain.size(); i++) {
+        user += vanadium::ChainSeparator;
+        user += b->chain[i]->extension;
+      }
+    }
+    if (!user.empty()) {
+      MOJO_LOG(INFO) << "Welcome: " << user;
+    }
+  }
+};
+
+class BankCustomer : public mojo::ApplicationDelegate {
+ public:
+  void Initialize(mojo::ApplicationImpl* app) override {
+    // Get user login credentials
+    app->ConnectToService("mojo:principal_service", &login_service_);
+    login_service_->Login(LoginHandler());
+    // Check and see whether we got a valid user blessing.
+    if (!login_service_.WaitForIncomingResponse()) {
+      MOJO_LOG(INFO) << "Login() to the principal service failed\n";
+    }
+    BankPtr bank;
+    app->ConnectToService("mojo:bank", &bank);
+    bank->Deposit(500/*usd*/);
+    bank->Withdraw(100/*usd*/);
+    auto gb_callback = [](const int32_t& balance) {
+      MOJO_LOG(INFO) << "Bank balance: " << balance;
+    };
+    bank->GetBalance(mojo::Callback<void(const int32_t&)>(gb_callback));
+    bank.WaitForIncomingResponse();
+  }
+  void Quit() override {
+    login_service_->Logout();
+  }
+ private:
+  vanadium::PrincipalServicePtr login_service_;
+};
+
+}  // namespace examples
+
+MojoResult MojoMain(MojoHandle application_request) {
+  mojo::ApplicationRunner runner(new examples::BankCustomer);
+  return runner.Run(application_request);
+}