Add write callback into SaveSettings function

Saving critical settings needs confirmation.
When command alters device config, it should be set "Done" only after
settings are actually saved.

BUG:25776798
Change-Id: Id8f52a2922aa0e58f66eb3e257197a47e21ef3a2
Reviewed-on: https://weave-review.googlesource.com/2199
Reviewed-by: Alex Vakulenko <avakulenko@google.com>

2 files changed, 19 insertions, 4 deletions

diff --git a/include/weave/provider/config_store.h b/include/weave/provider/config_store.h
index 991d750..128eccc 100644
--- a/include/weave/provider/config_store.h
+++ b/include/weave/provider/config_store.h
@@ -13,6 +13,7 @@
 #include <base/callback.h>
 #include <base/time/time.h>
 #include <weave/enum_to_string.h>
+#include <weave/error.h>
 #include <weave/settings.h>
 
 namespace weave {
@@ -48,9 +49,13 @@ namespace provider {
 // persistent storage (file, flash, etc).
 // For example:
 //   void FileConfigStore::SaveSettings(const std::string& name,
-//                                      const std::string& settings) {
+//                                      const std::string& settings,
+//                                      const DoneCallback& callback) {
 //     std::ofstream str("/var/lib/weave/weave_" + name + ".json");
 //     str << settings;
+//     if (!callback.is_null())
+//       task_runner_->PostDelayedTask(FROM_HERE, base::Bind(callback, nullptr),
+//                                     {});
 //   }
 // It is highly recommended to protected data using encryption with
 // hardware backed key.
@@ -75,8 +80,10 @@ class ConfigStore {
   // modifications. Data stored in settings can be sensitive, so it's highly
   // recommended to protect data, e.g. using encryption.
   // |name| is the name of settings blob. Could be used as filename.
+  // Implementation must call or post callback
   virtual void SaveSettings(const std::string& name,
-                            const std::string& settings) = 0;
+                            const std::string& settings,
+                            const DoneCallback& callback) = 0;
 
   // Deprecated: only for migration of old configs to version with |name|.
   virtual std::string LoadSettings() = 0;
diff --git a/include/weave/provider/test/mock_config_store.h b/include/weave/provider/test/mock_config_store.h
index cdae693..e6411d6 100644
--- a/include/weave/provider/test/mock_config_store.h
+++ b/include/weave/provider/test/mock_config_store.h
@@ -40,11 +40,19 @@ class MockConfigStore : public ConfigStore {
           "device_id": "TEST_DEVICE_ID"
         })"));
     EXPECT_CALL(*this, LoadSettings("config")).WillRepeatedly(Return(""));
-    EXPECT_CALL(*this, SaveSettings("config", _)).WillRepeatedly(Return());
+    EXPECT_CALL(*this, SaveSettings("config", _, _))
+        .WillRepeatedly(testing::WithArgs<1, 2>(testing::Invoke(
+            [](const std::string& json, const DoneCallback& callback) {
+              if (!callback.is_null())
+                callback.Run(nullptr);
+            })));
   }
   MOCK_METHOD1(LoadDefaults, bool(Settings*));
   MOCK_METHOD1(LoadSettings, std::string(const std::string&));
-  MOCK_METHOD2(SaveSettings, void(const std::string&, const std::string&));
+  MOCK_METHOD3(SaveSettings,
+               void(const std::string&,
+                    const std::string&,
+                    const DoneCallback&));
   MOCK_METHOD0(LoadSettings, std::string());
 };