storagemanager: Add keyval+ (combined keyval + map) store type

This combines the two most common store types, which modules often end up
opening with both interfaces separately anyway.

As well as combining them, I've taken the opportunity to improve some of the
method names to make them clearer.

1 files changed, 73 insertions, 0 deletions

diff --git a/core/storagemanager.lua b/core/storagemanager.lua
index 856acad3..8cc19378 100644
--- a/core/storagemanager.lua
+++ b/core/storagemanager.lua
@@ -203,6 +203,37 @@ local map_shim_mt = {
 	};
 }
 
+local combined_store_mt = {
+	__index = {
+		-- keyval
+		get = function (self, name)
+			return self.keyval_store:get(name);
+		end;
+		set = function (self, name, data)
+			return self.keyval_store:set(name, data);
+		end;
+		items = function (self)
+			return self.keyval_store:users();
+		end;
+		-- map
+		get_key = function (self, name, key)
+			return self.map_store:get(name, key);
+		end;
+		set_key = function (self, name, key, value)
+			return self.map_store:set(name, key, value);
+		end;
+		set_keys = function (self, name, map)
+			return self.map_store:set_keys(name, map);
+		end;
+		get_key_from_all = function (self, key)
+			return self.map_store:get_all(key);
+		end;
+		delete_key_from_all = function (self, key)
+			return self.map_store:delete_all(key);
+		end;
+	};
+};
+
 local open; -- forward declaration
 
 local function create_map_shim(host, store)
@@ -213,7 +244,49 @@ local function create_map_shim(host, store)
 	}, map_shim_mt);
 end
 
+local function open_combined(host, store)
+	local driver, driver_name = get_driver(host, store);
+
+	-- Open keyval
+	local keyval_store, err = driver:open(store, "keyval");
+	if not keyval_store then
+		if err == "unsupported-store" then
+			log("debug", "Storage driver %s does not support store %s (keyval), falling back to null driver",
+				driver_name, store);
+			keyval_store, err = null_storage_driver, nil;
+		end
+	end
+
+	local map_store;
+	if keyval_store then
+		-- Open map
+		map_store, err = driver:open(store, "map");
+		if not map_store then
+			if err == "unsupported-store" then
+				log("debug", "Storage driver %s does not support store %s (map), falling back to shim",
+					driver_name, store);
+				map_store, err = setmetatable({ keyval_store = keyval_store }, map_shim_mt), nil;
+			end
+		end
+	end
+
+	if not(keyval_store and map_store) then
+		return nil, err;
+	end
+	local combined_store = setmetatable({
+		keyval_store = keyval_store;
+		map_store = map_store;
+		remove = map_store.remove;
+	}, combined_store_mt);
+	local event_data = { host = host, store_name = store, store_type = "keyval+", store = combined_store };
+	hosts[host].events.fire_event("store-opened", event_data);
+	return event_data.store, event_data.store_err;
+end
+
 function open(host, store, typ)
+	if typ == "keyval+" then -- TODO: default in some release?
+		return open_combined(host, store);
+	end
 	local driver, driver_name = get_driver(host, store);
 	local ret, err = driver:open(store, typ);
 	if not ret then