Add assigner support to Blimp

blimp/client/session/assignment_source.h

 // Copyright 2016 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.
 
 #ifndef BLIMP_CLIENT_SESSION_ASSIGNMENT_SOURCE_H_
 #define BLIMP_CLIENT_SESSION_ASSIGNMENT_SOURCE_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "blimp/client/blimp_client_export.h"
 #include "net/base/ip_endpoint.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
+namespace net {
+class URLFetcher;
+class URLRequestContextGetter;
+}
+
 namespace blimp {
 namespace client {
 
+// TODO(kmarshall): Take values from configuration data.
+const char kDummyClientToken[] = "MyVoiceIsMyPassport";
+
+// Potential assigner URLs.
+const char kDefaultAssignerURL[] =
+    "https://blimp-pa.googleapis.com/v1/assignment";
+
 // An Assignment contains the configuration data needed for a client
 // to connect to the engine.
 struct BLIMP_CLIENT_EXPORT Assignment {
+  enum TransportProtocol {
+    UNKNOWN = 0,
+    SSL = 1,
+    TCP = 2,
+    QUIC = 3,
+  };
+
+  Assignment();
+  ~Assignment();
+
+  TransportProtocol transport_protocol;
   net::IPEndPoint ip_endpoint;
   std::string client_token;
+  std::string certificate;
+  std::string certificate_fingerprint;
+
+  // Returns true if the net::IPEndPoint has an unspecified IP, port, or
+  // transport protocol.
+  bool is_null() const;
 };
 
 // AssignmentSource provides functionality to find out how a client should
 // connect to an engine.
-class BLIMP_CLIENT_EXPORT AssignmentSource {
+class BLIMP_CLIENT_EXPORT AssignmentSource : public net::URLFetcherDelegate {
  public:
-  typedef const base::Callback<void(const Assignment&)> AssignmentCallback;
+  // A Java counterpart will be generated for this enum.
+  // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.blimp.assignment
+  enum Result {
+    RESULT_UNKNOWN = 0,
+    RESULT_OK = 1,
+    RESULT_BAD_REQUEST = 2,
+    RESULT_BAD_RESPONSE = 3,
+    RESULT_INVALID_PROTOCOL_VERSION = 4,
+    RESULT_EXPIRED_ACCESS_TOKEN = 5,
+    RESULT_USER_INVALID = 6,
+    RESULT_OUT_OF_VMS = 7,
+    RESULT_SERVER_ERROR = 8,
+    RESULT_SERVER_INTERRUPTED = 9,
+    RESULT_NETWORK_FAILURE = 10
+  };
+
+  typedef base::Callback<void(AssignmentSource::Result, const Assignment&)>
+      AssignmentCallback;
 
   // The |main_task_runner| should be the task runner for the UI thread because
   // this will in some cases be used to trigger user interaction on the UI
   // thread.
   AssignmentSource(
-      const scoped_refptr<base::SingleThreadTaskRunner>& main_task_runner);
-  virtual ~AssignmentSource();
+      const scoped_refptr<base::SingleThreadTaskRunner>& main_task_runner,
+      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
+  ~AssignmentSource() override;
 
   // Retrieves a valid assignment for the client and posts the result to the
-  // given callback.
-  void GetAssignment(const AssignmentCallback& callback);
+  // given callback.  |client_auth_token| is the authentication token to send to

[nyquist, 2016/02/18 01:58:40]

Nit: s/authentication/OAuth2 access/

[David Trainor- moved to gerrit, 2016/02/18 16:01:54]

Done.

+  // the assigner when requesting an assignment.
+  void GetAssignment(const std::string& client_auth_token,

[nyquist, 2016/02/18 01:58:40]

Optional nit: Should you mention that you're only supposed to call this once,
and then wait for a result? Or is that implicit? They will get an error at
least, so maybe that's enough.

[David Trainor- moved to gerrit, 2016/02/18 16:01:54]

Done.

+                     const AssignmentCallback& callback);
+
+  // net::URLFetcherDelegate implementation:
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
 
  private:
+  void ParseAssignerResponse();
+
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
+  scoped_refptr<net::URLRequestContextGetter> url_request_context_;
+  scoped_ptr<net::URLFetcher> url_fetcher_;
+
+  AssignmentCallback callback_;

[nyquist, 2016/02/18 01:58:40]

Could you add a comment about the lifetime of this callback?

[David Trainor- moved to gerrit, 2016/02/18 16:01:54]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(AssignmentSource);
 };
 
 }  // namespace client
 }  // namespace blimp
 
 #endif  // BLIMP_CLIENT_SESSION_ASSIGNMENT_SOURCE_H_