new persistence functionality

cache.lua

@@ -9,6 +9,8 @@ aux_auctionable_items = {}
 aux_merchant_buy = {}
 aux_merchant_sell = {}
 
+local merchant_buy_schema = {'record', '#', {'number', 'boolean'}}
+
 function public.on_load()
 	private.scan_wdb()
 	Aux.control.event_listener('MERCHANT_SHOW', private.scan_merchant).start()
@@ -21,8 +23,7 @@ end
 function public.merchant_info(item_id)
 	local unit_price, limited
 	if aux_merchant_buy[item_id] then
-		local buy_fields = Aux.util.split(aux_merchant_buy[item_id], '#')
+		local unit_price, limited = Aux.persistence.read(merchant_buy_schema, aux_merchant_buy[item_id])
-		unit_price, limited = tonumber(buy_fields[1]), not not tonumber(buy_fields[2])
 	end
 
 	return aux_merchant_sell[item_id], unit_price, limited
@@ -67,10 +68,9 @@ function private.scan_merchant()
 		if link then
 			local item_id = Aux.info.parse_hyperlink(link)
 			local _, _, price, count, stock = GetMerchantItemInfo(i)
-			local new_unit_price, new_limited = price / count, Aux.persistence.blizzard_boolean(stock >= 0)
+			local new_unit_price, new_limited = price / count, stock >= 0
 			if aux_merchant_buy[item_id] then
-				local fields = Aux.util.split(aux_merchant_buy[item_id], '#')
+				local old_unit_price, old_limited = Aux.persistence.read(merchant_buy_schema, aux_merchant_buy[item_id])
-				local old_unit_price, old_limited = tonumber(fields[1]), tonumber(fields[2])
 
 				local unit_price
 				if old_limited and not new_limited then
@@ -81,15 +81,9 @@ function private.scan_merchant()
 					unit_price = min(old_unit_price, new_unit_price)
 				end
 
-				aux_merchant_buy[item_id] = Aux.util.join({
+				aux_merchant_buy[item_id] = Aux.persistence.write(merchant_buy_schema, unit_price, old_limited or new_limited)
-					unit_price,
-					tostring(old_limited or new_limited),
-				}, '#')
 			else
-				aux_merchant_buy[item_id] = Aux.util.join({
+				aux_merchant_buy[item_id] = Aux.persistence.write(merchant_buy_schema, new_unit_price, new_limited)
-					new_unit_price,
-					tostring(new_limited),
-				}, '#')
 			end
 		end
 	end

persistence.lua

@@ -18,45 +18,98 @@ function public.load_dataset()
     return aux_datasets[dataset_key]
 end
 
-function private.read(type, str)
+function public.read(schema, str)
-    if type == 'string' then
+    if type(schema) == 'table' and schema[1] == 'record' then
+        return unpack(private.read(schema, str))
+    else
+        return private.read(schema, str)
+    end
+end
+
+function public.write(schema, ...)
+    if type(schema) == 'table' and schema[1] == 'record' then
+        return private.write(schema, arg)
+    else
+        return private.write(schema, arg[1])
+    end
+end
+
+function private.read(schema, str)
+    if schema == 'string' then
         return str
-    elseif type == 'boolean' then
+    elseif schema == 'boolean' then
         return str == '1'
-    elseif type == 'number' then
+    elseif schema == 'number' then
         return tonumber(str)
+    elseif type(schema) == 'table' and schema[1] == 'list' then
+        return private.read_list(schema, str)
+    elseif type(schema) == 'table' and schema[1] == 'record' then
+        return private.read_record(schema, str)
+    else
+        error('Unknown schema.')
     end
 end
 
-function private.write(type, obj)
+function private.write(schema, obj)
-    if type == 'string' then
+    if schema == 'string' then
-        return obj
+        return obj or ''
-    elseif type == 'boolean' then
+    elseif schema == 'boolean' then
         return obj and '1' or '0'
-    elseif type == 'number' then
+    elseif schema == 'number' then
-        return tostring(obj)
+        return obj and tostring(obj) or ''
+    elseif type(schema) == 'table' and schema[1] == 'list' then
+        return private.write_list(schema, obj)
+    elseif type(schema) == 'table' and schema[1] == 'record' then
+        return private.write_record(schema, obj)
+    else
+        error('Unknown schema.')
     end
 end
 
-function public.schema(separator, ...)
+function private.read_list(schema, str)
-    return function(record)
+    if str == '' then
-        local fields
+        return {}
-        local parts = Aux.util.split(record, separator)
-        for i=1,arg.n do
-            tinsert(fields, private.read(arg[i], parts[i]))
-        end
-        return fields
-    end, function(fields)
-        local parts = {}
-        for i=1,arg.n do
-            tinsert(parts, private.write(arg[i], fields[i]))
-        end
-        return Aux.util.join(parts, '#')
     end
+
+    local separator = schema[2]
+    local element_type = schema[3]
+    local parts = Aux.util.split(str, separator)
+    return Aux.util.map(parts, function(part)
+        return private.read(element_type, part)
+    end)
 end
 
-function public.blizzard_boolean(boolean)
+function private.write_list(schema, list)
-    return boolean and 1 or nil
+    local separator = schema[2]
+    local element_type = schema[3]
+    local parts = Aux.util.map(list, function(element)
+        return private.write(element_type, element)
+    end)
+    return Aux.util.join(parts, separator)
+end
+
+function private.read_record(schema, str)
+    local separator = schema[2]
+    local record = {}
+    local parts = Aux.util.split(str, separator)
+    for i, type in ipairs(schema[3]) do
+        local field = private.read(type, parts[i])
+        if field ~= nil then
+            tinsert(record, field)
+        else
+            tinsert(record, nil)
+        end
+    end
+    return record
+end
+
+function private.write_record(schema, record)
+    local separator = schema[2]
+    local parts = {}
+    for i, type in ipairs(schema[3]) do
+        tinsert(parts, private.write(type, record[i]))
+    end
+    return Aux.util.join(parts, separator)
 end
 
 function public.serialize(data, separator, compactor)