cros: DBUS client to interact with fingerprint DBUS API.

chromeos/dbus/biod/biod_client.h

Index: chromeos/dbus/biod/biod_client.h
diff --git a/chromeos/dbus/biod/biod_client.h b/chromeos/dbus/biod/biod_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..aa30b151bc62275591848441206873906284fb4e
--- /dev/null
+++ b/chromeos/dbus/biod/biod_client.h
@@ -0,0 +1,115 @@
+// Copyright 2017 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 CHROMEOS_DBUS_BIOD_BIOD_CLIENT_H_
+#define CHROMEOS_DBUS_BIOD_BIOD_CLIENT_H_
+
+#include <stdint.h>

[Daniel Erat, 2017/03/31 04:30:09]

are you actually using this?

[sammiequon, 2017/03/31 22:52:13]

Nope. That was for when the scan results were uint32_t. Done.

+

[Daniel Erat, 2017/03/31 04:30:10]

#include <string>

[sammiequon, 2017/03/31 22:52:12]

Done.

+#include <unordered_map>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "chromeos/chromeos_export.h"
+#include "chromeos/dbus/dbus_client.h"
+#include "chromeos/dbus/dbus_client_implementation_type.h"
+#include "chromeos/dbus/dbus_method_call_status.h"
+#include "third_party/cros_system_api/dbus/service_constants.h"
+
+namespace chromeos {
+
+// Each time the sensor detects a scan, an object containing all the users, each
+// with the labels of all the matched stored fingerprints is returned.

[Daniel Erat, 2017/03/31 04:30:10]

please go into more details about the actual values that are stored. are "the
users" account ids (in which case you should probably use the AccountId class)
or something else? what's the format for the fingerprints? (it's fine to point
at another class if they're documented there.)

[sammiequon, 2017/03/31 22:52:12]

Theres another ongoing discussion (not involving me) about what |user_id| should
be. But I was under impression the string -> AccountId would be translated at a
higher level, or do you think it belongs down here?

[Daniel Erat, 2017/04/01 00:46:26]

i think it's okay to document it as being assigned by chrome here. if it ends up
being a specific type that //chromeos/dbus is allowed to depend on (note that
chromeos/DEPS permits components/signin/core/account_id/account_id.h), it'd
probably be clearer to other developers to use the actual type.

[sammiequon, 2017/04/01 01:22:43]

Acknowledged.

+using AuthScanMatches =
+    std::unordered_map<std::string, std::vector<std::string>>;
+
+// BiodClient is used to communicate with a biod D-Bus manager
+// interface.
+class CHROMEOS_EXPORT BiodClient : public DBusClient {
+ public:
+  // Interface for observing changes from the biometrics manager.
+  class Observer {
+   public:
+    // Called when biometrics manager powers up or is restarted.

[Daniel Erat, 2017/03/31 04:30:10]

does this actually get called if biod is already running before chrome starts,
or only if it crashes and is restarted later?

[sammiequon, 2017/03/31 22:52:13]

Let me quickly test this out and I'll get back to this soon.

[sammiequon, 2017/04/01 01:22:43]

Yeah it gets called when biod is already running and chrome starts.

+    virtual void BiodServiceRestarted() {}
+
+    // Called whenever a user attempts a scan. |scan_result| tells whether the

[Daniel Erat, 2017/03/31 04:30:10]

Called whenever a user attempts a scan during enrollment.

[sammiequon, 2017/03/31 22:52:12]

Done.

+    // scan was succesful. |enroll_session_complete| tells whether enroll
+    // session is complete and is now over.
+    virtual void BiodEnrollScanDoneReceived(biod::ScanResult scan_result,
+                                            bool enroll_session_complete) {}
+
+    // Called to indicate a bad scan of any kind, or a successful scan. If scan

[Daniel Erat, 2017/03/31 04:30:09]

Called when an authentication scan is performed.

[sammiequon, 2017/03/31 22:52:12]

Done.

+    // is successful, |matches| will equal all the enrollment IDs that match the
+    // scan, and the labels of the matched fingeprints.
+    virtual void BiodAuthScanDoneReceived(biod::ScanResult scan_result,
+                                          const AuthScanMatches& matches) {}
+
+    // Called during either session to indicate a failure. Any enrollment that

[Daniel Erat, 2017/03/31 04:30:10]

s/either session/an enrollment or authentication session/

[sammiequon, 2017/03/31 22:52:12]

Done.

+    // was underway is thrown away and auth will no longer be happening.
+    virtual void BiodSessionFailedReceived() {}
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  ~BiodClient() override;
+
+  // Adds and removes the observer.
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+
+  // Returns true if this object has the given observer.
+  virtual bool HasObserver(const Observer* observer) const = 0;
+
+  // UserRecordsCallback is used for the GetRecordsForUser method. It receives
+  // one argument which contains a list of the stored records object paths for

[Daniel Erat, 2017/03/31 04:30:10]

s/records/records'/

[sammiequon, 2017/03/31 22:52:12]

Done.

+  // a given user.
+  using UserRecordsCallback =
+      base::Callback<void(const std::vector<dbus::ObjectPath>&)>;
+
+  // BiometricTypeCallback is used for the GetType method. It receives
+  // one argument which states the type of biometric.
+  using BiometricTypeCallback = base::Callback<void(biod::BiometricType)>;
+
+  // Starts the biometric enroll session. |callback| is called with the object
+  // path of the current enroll session after the method succeeds.
+  virtual void StartEnrollSession(const std::string& user_id,

[Daniel Erat, 2017/03/31 04:30:10]

same comment re |user_id|, also document what |label| is

[sammiequon, 2017/03/31 22:52:12]

Done.

+                                  const std::string& label,
+                                  const ObjectPathCallback& callback) = 0;
+
+  // Gets all the records registered with this biometric. |callback| is called

[Daniel Erat, 2017/03/31 04:30:09]

do you mean "... with this user"?

[sammiequon, 2017/03/31 22:52:12]

Done.

+  // with all the object paths of the records after this method succeeds.
+  virtual void GetRecordsForUser(const std::string& user_id,

[Daniel Erat, 2017/03/31 04:30:10]

as above, document what the id actually is and ideally use a non-std::string
type as well.

[sammiequon, 2017/03/31 22:52:13]

Done.

+                                 const UserRecordsCallback& callback) = 0;
+
+  // Irreversibly destroys all records registered with this biometric.

[Daniel Erat, 2017/03/31 04:30:09]

should you drop text like "with this biometric" if there's only one manager?

[sammiequon, 2017/03/31 22:52:12]

Done.

+  virtual void DestroyAllRecords() = 0;
+
+  // Starts the biometric auth session. |callback| is called with the object
+  // path of the auth session after the method succeeds.
+  virtual void StartAuthSession(const ObjectPathCallback& callback) = 0;
+
+  // Requests the type of biometric. |callback| is called with the biometric
+  // type after the method succeeds.
+  virtual void RequestType(const BiometricTypeCallback& callback) = 0;
+
+  // Creates the instance.
+  static BiodClient* Create(DBusClientImplementationType type);
+
+ protected:
+  friend class BiodClientTest;
+
+  // Create() should be used instead.
+  BiodClient();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BiodClient);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_DBUS_BIOD_BIOD_CLIENT_H_