Add valid checking to codec. Fixes: #254 (#270)

* Add valid checking to codec. Fixes: #254

* Loosen requirement and make sure nil get empty string

Author: Sparky

lua/advdupe2/cl_ghost.lua

@@ -57,10 +57,10 @@ function AdvDupe2.LoadGhosts(dupe, info, moreinfo, name, preview)
 		AdvDupe2.HeadAngle = AdvDupe2.GhostToSpawn[AdvDupe2.HeadEnt].PhysicsObjects[0].Angle
 
 	else
-		time = info["time"]
-		desc = dupe["Description"]
-		date = info["date"]
-		creator = info["name"]
+		time = info["time"] or ""
+		desc = dupe["Description"] or ""
+		date = info["date"] or ""
+		creator = info["name"] or ""
 
 		AdvDupe2.HeadEnt = dupe["HeadEnt"].Index
 		AdvDupe2.HeadZPos = dupe["HeadEnt"].Z

lua/advdupe2/sh_codec.lua

@@ -417,6 +417,21 @@ versions[5] = function(encodedDupe)
 	return deserialize(decompress(dupestring), read5), info
 end
 
+
+function AdvDupe2.CheckValidDupe(dupe, info)
+	if not dupe.HeadEnt then return false, "Missing HeadEnt table" end
+	if not dupe.HeadEnt.Index then return false, "Missing HeadEnt.Index" end
+	if not dupe.HeadEnt.Z then return false, "Missing HeadEnt.Z" end
+	if not dupe.HeadEnt.Pos then return false, "Missing HeadEnt.Pos" end
+	if not dupe.Entities then return false, "Missing Entities table" end
+	if not dupe.Entities[dupe.HeadEnt.Index] then return false, "Missing HeadEnt index from Entities table" end
+	if not dupe.Entities[dupe.HeadEnt.Index].PhysicsObjects then return false, "Missing PhysicsObject table from HeadEnt Entity table" end
+	if not dupe.Entities[dupe.HeadEnt.Index].PhysicsObjects[0] then return false, "Missing PhysicsObject[0] table from HeadEnt Entity table" end
+	if not dupe.Entities[dupe.HeadEnt.Index].PhysicsObjects[0].Pos then return false, "Missing PhysicsObject[0].Pos from HeadEnt Entity table" end
+	if not dupe.Entities[dupe.HeadEnt.Index].PhysicsObjects[0].Angle then return false, "Missing PhysicsObject[0].Angle from HeadEnt Entity table" end
+	return true, dupe
+end
+
 --[[
 	Name:	Decode
 	Desc:	Generates the table for a dupe from the given string. Inverse of Encode
@@ -437,6 +452,8 @@ function AdvDupe2.Decode(encodedDupe)
 		if sig == "[Inf" then --legacy support, ENGAGE (AD1 dupe detected)
 			local success, tbl, info, moreinfo = pcall(AdvDupe2.LegacyDecoders[0], encodedDupe)
 
+			success, tbl = AdvDupe2.CheckValidDupe(tbl, info)
+
 			if success then
 				info.size = #encodedDupe
 				info.revision = 0
@@ -455,13 +472,15 @@ function AdvDupe2.Decode(encodedDupe)
 		return false, format("attempt to use an invalid format revision (rev %d)", rev)
 	else
 		local success, tbl, info = pcall(versions[rev], encodedDupe)
+
+		success, tbl = AdvDupe2.CheckValidDupe(tbl, info)
 
 		if success then
 			info.revision = rev
 		else
 			ErrorNoHalt(tbl)
 		end
-		
+
 		return success, tbl, info
 	end
 end