From 7eaa58567d6c5c195e7a833e00ee6a5c230d997a Mon Sep 17 00:00:00 2001
From: Matthew Wild <mwild1@gmail.com>
Date: Sat, 27 Nov 2010 19:46:07 +0000
Subject: storagemanager: Much refactoring and renaming of options. Untested,
 needs storage plugin(s) to be brought into line.

---
 core/storagemanager.lua | 84 +++++++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 30 deletions(-)

(limited to 'core')

diff --git a/core/storagemanager.lua b/core/storagemanager.lua
index 94cea3b3..811b7f48 100644
--- a/core/storagemanager.lua
+++ b/core/storagemanager.lua
@@ -4,7 +4,6 @@ local setmetatable = setmetatable;
 
 local config = require "core.configmanager";
 local datamanager = require "util.datamanager";
-local multitable = require "util.multitable";
 local modulemanager = require "core.modulemanager";
 local hosts = hosts;
 local log = require "util.logger".init("storagemanager");
@@ -12,12 +11,9 @@ local log = require "util.logger".init("storagemanager");
 local olddm = {}; -- maintain old datamanager, for backwards compatibility
 for k,v in pairs(datamanager) do olddm[k] = v; end
 
-local driver_cache = multitable.new();
-local store_cache = multitable.new();
-
 module("storagemanager")
 
-local default_driver_mt = {};
+local default_driver_mt = { name = "internal" };
 default_driver_mt.__index = default_driver_mt;
 function default_driver_mt:open(store)
 	return setmetatable({ host = self.host, store = store }, default_driver_mt);
@@ -25,37 +21,65 @@ end
 function default_driver_mt:get(user) return olddm.load(user, self.host, self.store); end
 function default_driver_mt:set(user, data) return olddm.store(user, self.host, self.store, data); end
 
-local function load_driver_for_host(host)
-	if driver_cache:get(host) then return driver_cache:get(host); end
-	
-	local host_session = hosts[host];
-	if not host_session then error("No such host"); end
-	
-	local driver_plugin = config.get(host, "core", "datastore");
-	if not driver_plugin then return setmetatable({ host = host }, default_driver_mt); end
-	
-	local provider;
-	local function handler(event) provider = event.item; end
-	host_session.events.add_handler("item-added/data-driver", handler);
-	local success, err = modulemanager.load(host, driver_plugin);
-	host_session.events.remove_handler("item-added/data-driver", handler);
-	if not success then error(err); end
-	if not provider then error("Module didn't add a provider"); end
+local stores_available = multitable.new();
+
+function initialize_host(host)
+	host_session.events.add_handler("item-added/data-driver", function (event)
+		local item = event.item;
+		stores_available:set(host, item.name, item);
+	end);
 	
-	driver_cache:set(host, provider);
-	log("debug", "Data driver '%s' loaded for host '%s'", driver_plugin, host);
-	return provider;
+	host_session.events.add_handler("item-removed/data-driver", function (event)
+		local item = event.item;
+		stores_available:set(host, item.name, nil);
+	end);
+end
+
+local function load_driver(host, driver_name)
+	if not driver_name then
+		return;
+	end
+	local driver = stores_available:get(host, driver_name);
+	if not driver then
+		if driver_name ~= "internal" then
+			modulemanager.load(host, "storage_"..driver_name);
+		else
+			return setmetatable({host = host}, default_driver_mt);
+		end
+	end
 end
 
 function open(host, store, typ)
-	local ret = store_cache:get(host, store);
+	local storage = config.get(host, "core", "storage");
+	local driver_name;
+	local option_type = type(storage);
+	if option_type == "string" then
+		driver_name = storage;
+	elseif option_type == "table" then
+		driver_name = storage[store];
+	end
+	
+	local driver = load_driver(host, driver_name);
+	if not driver then
+		driver_name = config.get(host, "core", "default_storage");
+		driver = load_driver(host, driver_name);
+		if not driver then
+			driver_name = "internal";
+			log("warn", "Falling back to default driver for %s storage on %s", store, host);
+			driver = load_driver(host, driver_name);
+		end
+	end
+	
+	local ret, err = driver:open(store, typ);
 	if not ret then
-		local driver = load_driver_for_host(host);
-		ret = driver:open(store, typ);
-		if not ret then ret = setmetatable({ host = host, store = store }, default_driver_mt); end -- default to default driver
-		store_cache:set(host, store, ret);
+		if err == "unsupported-store" then
+			log("debug", "Storage driver %s does not support store %s (%s), falling back to internal driver",
+				driver_name, store, typ);
+			ret = setmetatable({ host = host, store = store }, default_driver_mt); end -- default to default driver
+			err = nil;
+		end
 	end
-	return ret;
+	return ret, err;
 end
 
 function datamanager.load(username, host, datastore)
-- 
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