Principal Service: Add support for multiple user accounts

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/interfaces/principal.mojom.h"
 
 namespace examples {
 
 class LoginHandler {
  public:
-  void Run(const vanadium::BlessingPtr& b) const {
-    std::string user;
-    if (b && b->chain.size() > 0) {
-      user = b->chain[0]->extension;
-      for (size_t i = 1; i < b->chain.size(); i++) {
-        user += vanadium::ChainSeparator;
-        user += b->chain[i]->extension;
-      }
-    }
-    if (!user.empty()) {
-      MOJO_LOG(INFO) << "Welcome: " << user;
+  void Run(const vanadium::UserPtr& u) const {
+    if (u) {
+      MOJO_LOG(INFO) << "User logged-in as " << u->email;
     }
   }
 };
 
 class BankCustomer : public mojo::ApplicationDelegate {
  public:
   void Initialize(mojo::ApplicationImpl* app) override {
-    // Get user login credentials
     app->ConnectToService("mojo:principal_service", &login_service_);
+
+    // Login to the principal service to get a user identity.
     login_service_->Login(LoginHandler());
-    // Check and see whether we got a valid user blessing.
+    // Check and see whether we got a valid user id.
     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);
 }