Show notifications on low disk space.

chromeos/dbus/cryptohome_client.cc

Index: chromeos/dbus/cryptohome_client.cc
diff --git a/chromeos/dbus/cryptohome_client.cc b/chromeos/dbus/cryptohome_client.cc
index a52fe016294ce04866fad7e30b5a3de27141c8de..160ab71e2475b3563b6d3434dc9e353a95c1bcbd 100644
--- a/chromeos/dbus/cryptohome_client.cc
+++ b/chromeos/dbus/cryptohome_client.cc
@@ -63,6 +63,14 @@ class CryptohomeClientImpl : public CryptohomeClient {
   }
 
   // CryptohomeClient override.
+  void SetLowDiskSpaceHandler(const LowDiskSpaceHandler& handler) override {
+    low_disk_space_handler_ = handler;
+  }
+
+  // CryptohomeClient override.
+  void ResetLowDiskSpaceHandler() override { low_disk_space_handler_.Reset(); }
+
+  // CryptohomeClient override.
   void WaitForServiceToBeAvailable(
       const WaitForServiceToBeAvailableCallback& callback) override {
     proxy_->WaitForServiceToBeAvailable(callback);
@@ -928,6 +936,12 @@ class CryptohomeClientImpl : public CryptohomeClient {
                    weak_ptr_factory_.GetWeakPtr()),
         base::Bind(&CryptohomeClientImpl::OnSignalConnected,
                    weak_ptr_factory_.GetWeakPtr()));
+    proxy_->ConnectToSignal(cryptohome::kCryptohomeInterface,
+                            cryptohome::kSignalLowDiskSpace,
+                            base::Bind(&CryptohomeClientImpl::OnLowDiskSpace,
+                                       weak_ptr_factory_.GetWeakPtr()),
+                            base::Bind(&CryptohomeClientImpl::OnSignalConnected,
+                                       weak_ptr_factory_.GetWeakPtr()));
   }
 
  private:
@@ -1149,6 +1163,17 @@ class CryptohomeClientImpl : public CryptohomeClient {
     }
   }
 
+  // Handles LowDiskSpace signal.
+  void OnLowDiskSpace(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    uint64_t disk_free_bytes = 0;
+    if (!reader.PopUint64(&disk_free_bytes)) {
+      LOG(ERROR) << "Invalid signal: " << signal->ToString();
+      return;
+    }
+    low_disk_space_handler_.Run(disk_free_bytes);

[yoshiki, 2016/06/23 08:00:45]

low_disk_space_handler_ may be null so null check is necessary.

[dspaid, 2016/06/27 05:40:04]

Using WeakPtr now, which will result in a no-op if low_disk_space_handler_ is
already destroyed.

+  }
+
   // Handles the result of signal connection setup.
   void OnSignalConnected(const std::string& interface,
                          const std::string& signal,
@@ -1161,6 +1186,7 @@ class CryptohomeClientImpl : public CryptohomeClient {
   std::unique_ptr<BlockingMethodCaller> blocking_method_caller_;
   AsyncCallStatusHandler async_call_status_handler_;
   AsyncCallStatusWithDataHandler async_call_status_data_handler_;
+  LowDiskSpaceHandler low_disk_space_handler_;
 
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.