cros: DBUS client to interact with fingerprint DBUS API.

chromeos/dbus/biod/biod_client.cc

+// 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.
+
+#include "chromeos/dbus/biod/biod_client.h"
+
+#include <stdint.h>
+
+#include "base/bind.h"
+#include "base/macros.h"
+#include "dbus/bus.h"
+#include "dbus/message.h"
+#include "dbus/object_path.h"
+#include "dbus/object_proxy.h"
+
+namespace chromeos {
+
+// The BiodClient implementation used in production.
+class BiodClientImpl : public BiodClient {
+ public:
+  BiodClientImpl() : biod_proxy_(nullptr), weak_ptr_factory_(this) {}
+
+  ~BiodClientImpl() override {}
+
+  // BiodClient overrides:
+  void AddObserver(Observer* observer) override {
+    observers_.AddObserver(observer);
+  }
+
+  void RemoveObserver(Observer* observer) override {
+    observers_.RemoveObserver(observer);
+  }
+
+  bool HasObserver(const Observer* observer) const override {
+    return observers_.HasObserver(observer);
+  }
+
+  void StartEnrollSession(const std::string& user_id,
+                          const std::string& label,
+                          const ObjectPathCallback& callback) override {
+    dbus::MethodCall method_call(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerStartEnrollSessionMethod);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendString(user_id);
+    writer.AppendString(label);
+
+    biod_proxy_->CallMethod(
+        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&BiodClientImpl::OnStartEnrollSession,
+                   weak_ptr_factory_.GetWeakPtr(), callback));
+  }
+
+  void GetRecordsForUser(const std::string& user_id,
+                         const UserRecordsCallback& callback) override {
+    dbus::MethodCall method_call(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerGetRecordsForUserMethod);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendString(user_id);
+
+    biod_proxy_->CallMethod(
+        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&BiodClientImpl::OnGetRecordsForUser,
+                   weak_ptr_factory_.GetWeakPtr(), callback));
+  }
+
+  void DestroyAllRecords() override {
+    dbus::MethodCall method_call(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerDestroyAllRecordsMethod);
+
+    biod_proxy_->CallMethod(&method_call,
+                            dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+                            dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  void StartAuthSession(const ObjectPathCallback& callback) override {
+    dbus::MethodCall method_call(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerStartAuthSessionMethod);
+
+    biod_proxy_->CallMethod(
+        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&BiodClientImpl::OnStartAuthSession,
+                   weak_ptr_factory_.GetWeakPtr(), callback));
+  }
+
+  void RequestType(const BiometricTypeCallback& callback) override {
+    dbus::MethodCall method_call(dbus::kDBusPropertiesInterface,
+                                 dbus::kDBusPropertiesGet);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendString(biod::kBiometricsManagerInterface);
+    writer.AppendString(biod::kBiometricsManagerBiometricTypeProperty);
+
+    biod_proxy_->CallMethod(
+        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&BiodClientImpl::OnRequestType,
+                   weak_ptr_factory_.GetWeakPtr(), callback));
+  }
+
+ protected:
+  void Init(dbus::Bus* bus) override {
+    biod_proxy_ = bus->GetObjectProxy(biod::kBiodServiceName,
+                                      dbus::ObjectPath(biod::kBiodServicePath));
+
+    biod_proxy_->SetNameOwnerChangedCallback(
+        base::Bind(&BiodClientImpl::NameOwnerChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    biod_proxy_->ConnectToSignal(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerEnrollScanDoneSignal,
+        base::Bind(&BiodClientImpl::EnrollScanDoneReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&BiodClientImpl::OnSignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    biod_proxy_->ConnectToSignal(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerAuthScanDoneSignal,
+        base::Bind(&BiodClientImpl::AuthScanDoneReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&BiodClientImpl::OnSignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    biod_proxy_->ConnectToSignal(
+        biod::kBiometricsManagerInterface,
+        biod::kBiometricsManagerSessionFailedSignal,
+        base::Bind(&BiodClientImpl::SessionFailedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&BiodClientImpl::OnSignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+
+ private:
+  void OnStartEnrollSession(const ObjectPathCallback& callback,
+                            dbus::Response* response) {
+    dbus::ObjectPath result;

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

you could make all of these methods shorter:

  dbus::ObjectPath result;
  if (response) {
    dbus::MessageReader ...
    if (!reader.PopObjectPath...
      LOG(ERROR) << ...
    }
  }
  callback.Run(result);

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

Done.

+    if (!response) {
+      callback.Run(result);
+      return;
+    }
+
+    dbus::MessageReader reader(response);
+    if (!reader.PopObjectPath(&result)) {
+      LOG(ERROR) << biod::kBiometricsManagerStartEnrollSessionMethod
+                 << " had incorrect response.";
+      callback.Run(result);
+      return;
+    }
+
+    callback.Run(result);
+  }
+
+  void OnGetRecordsForUser(const UserRecordsCallback& callback,
+                           dbus::Response* response) {
+    std::vector<dbus::ObjectPath> result;
+    if (!response) {
+      callback.Run(result);
+      return;
+    }
+
+    dbus::MessageReader reader(response);
+    if (!reader.PopArrayOfObjectPaths(&result)) {
+      LOG(ERROR) << biod::kBiometricsManagerGetRecordsForUserMethod
+                 << " had incorrect response.";
+      callback.Run(result);
+      return;
+    }
+
+    callback.Run(result);
+  }
+
+  void OnStartAuthSession(const ObjectPathCallback& callback,
+                          dbus::Response* response) {
+    dbus::ObjectPath result;
+    if (!response) {
+      callback.Run(result);
+      return;
+    }
+
+    dbus::MessageReader reader(response);
+    if (!reader.PopObjectPath(&result)) {
+      LOG(ERROR) << biod::kBiometricsManagerStartAuthSessionMethod
+                 << " had incorrect response.";
+      callback.Run(result);
+      return;
+    }
+
+    callback.Run(result);
+  }
+
+  void OnRequestType(const BiometricTypeCallback& callback,
+                     dbus::Response* response) {
+    uint32_t result;
+    if (!response) {
+      callback.Run(biod::BiometricType::BIOMETRIC_TYPE_UNKNOWN);
+      return;
+    }
+
+    dbus::MessageReader reader(response);
+    if (!reader.PopVariantOfUint32(&result)) {
+      LOG(ERROR) << biod::kBiometricsManagerBiometricTypeProperty
+                 << " had incorrect response.";
+      callback.Run(biod::BiometricType::BIOMETRIC_TYPE_UNKNOWN);
+      return;
+    }
+
+    callback.Run(static_cast<biod::BiometricType>(result));
+  }
+
+  // Called when the biometrics signal is initially connected.
+  void OnSignalConnected(const std::string& interface_name,
+                         const std::string& signal_name,
+                         bool success) {
+    LOG_IF(ERROR, !success)
+        << "Failed to connect to biometrics signal:" << signal_name;

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

nit: add space after ':' (also in other strings)

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

Done.

+  }
+
+  void NameOwnerChangedReceived(const std::string& /* old_owner */,
+                                const std::string& new_owner) {
+    if (!new_owner.empty()) {
+      for (auto& observer : observers_)
+        observer.BiodServiceRestarted();
+    }
+  }
+
+  void EnrollScanDoneReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    uint32_t scan_result;
+    bool enroll_session_complete;
+    if (!reader.PopUint32(&scan_result) ||
+        !reader.PopBool(&enroll_session_complete)) {
+      LOG(ERROR) << "Error reading signal from biometrics:"
+                 << signal->ToString();
+      return;
+    }
+
+    for (auto& observer : observers_) {
+      observer.BiodEnrollScanDoneReceived(
+          static_cast<biod::ScanResult>(scan_result), enroll_session_complete);
+    }
+  }
+
+  void AuthScanDoneReceived(dbus::Signal* signal) {
+    dbus::MessageReader signal_reader(signal);
+    dbus::MessageReader array_reader(nullptr);
+    uint32_t scan_result;
+    AuthScanMatches matches;
+    if (!signal_reader.PopUint32(&scan_result) ||
+        !signal_reader.PopArray(&array_reader)) {
+      LOG(ERROR) << "Error reading signal from biometrics:"
+                 << signal->ToString();
+      return;
+    }
+
+    while (array_reader.HasMoreData()) {
+      dbus::MessageReader entry_reader(nullptr);
+      std::string user_id;
+      std::vector<std::string> labels;
+      if (!array_reader.PopDictEntry(&entry_reader) ||
+          !entry_reader.PopString(&user_id) ||
+          !entry_reader.PopArrayOfStrings(&labels)) {
+        LOG(ERROR) << "Error reading signal from biometrics:"
+                   << signal->ToString();
+        return;
+      }
+
+      matches[user_id] = std::move(labels);
+    }
+
+    for (auto& observer : observers_) {
+      observer.BiodAuthScanDoneReceived(
+          static_cast<biod::ScanResult>(scan_result), matches);
+    }
+  }
+
+  void SessionFailedReceived(dbus::Signal* signal) {
+    for (auto& observer : observers_)
+      observer.BiodSessionFailedReceived();
+  }
+
+  dbus::ObjectProxy* biod_proxy_;
+  base::ObserverList<Observer> observers_;
+
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<BiodClientImpl> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(BiodClientImpl);
+};
+
+BiodClient::BiodClient() {}
+
+BiodClient::~BiodClient() {}
+
+// static
+BiodClient* BiodClient::Create(DBusClientImplementationType /* type */) {
+  return new BiodClientImpl();
+}
+
+}  // namespace chromeos