ipkg.lua: new function compare_version

* minor fix function _list() set to local
* new function compare_version() lua version of opkg compare-version

Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>

modules/luci-base/luasrc/model/ipkg.lua

@@ -122,7 +122,7 @@ function upgrade()
 end
 
 -- List helper
-function _list(action, pat, cb)
+local function _list(action, pat, cb)
 	local fd = io.popen(ipkg .. " " .. action ..
 		(pat and (" '%s'" % pat:gsub("'", "")) or ""))
 
@@ -189,3 +189,43 @@ function overlay_root()
 
 	return od
 end
+
+function compare_versions(ver1, comp, ver2)
+	if not ver1 or not ver2
+	or not comp or not (#comp > 0) then
+		error("Invalid parameters")
+		return nil
+	end
+	-- correct compare string
+	if comp == "<>" or comp == "><" or comp == "!=" or comp == "~=" then comp = "~="
+	elseif comp == "<=" or comp == "<" or comp == "=<" then comp = "<="
+	elseif comp == ">=" or comp == ">" or comp == "=>" then comp = ">="
+	elseif comp == "="  or comp == "==" then comp = "=="
+	elseif comp == "<<" then comp = "<"
+	elseif comp == ">>" then comp = ">"
+	else
+		error("Invalid compare string")
+		return nil
+	end
+
+	local av1 = util.split(ver1, "[%.%-]", nil, true)
+	local av2 = util.split(ver2, "[%.%-]", nil, true)
+
+	for i = 1, math.max(table.getn(av1),table.getn(av2)), 1  do
+		local s1 = av1[i] or ""
+		local s2 = av2[i] or ""
+
+		-- first "not equal" found return true
+		if comp == "~=" and (s1 ~= s2) then return true end
+		-- first "lower" found return true
+		if (comp == "<" or comp == "<=") and (s1 < s2) then return true end
+		-- first "greater" found return true
+		if (comp == ">" or comp == ">=") and (s1 > s2) then return true end
+		-- not equal then return false
+		if (s1 ~= s2) then return false end
+	end
+
+	-- all equal and not compare greater or lower then true
+	return not (comp == "<" or comp == ">")
+end
+

modules/luci-base/luasrc/model/ipkg.luadoc

@@ -107,3 +107,20 @@ Determines the overlay root used by opkg.
 @return		String containing the directory path of the overlay root.
 ]]
 
+---[[
+lua version of opkg compare-versions
+
+@class function
+@name compare_versions
+@param ver1	string version 1
+@param ver2	string version 2
+@param comp	string compare versions using
+		"<=" or "<" lower-equal
+		">" or ">=" greater-equal
+		"=" equal
+		"<<" lower
+		">>" greater
+		"~=" not equal
+@return Boolean indicating the status of the compare
+]]
+