libs/LibStub/LibStub.lua

   1 -- $Id: LibStub.lua 48018 2007-09-03 01:50:17Z mikk $
   2 -- LibStub is a simple versioning stub meant for use in Libraries.  http://www.wowace.com/wiki/LibStub for more info
   3 -- LibStub is hereby placed in the Public Domain
   4 -- Credits: Kaelten, Cladhaire, ckknight, Mikk, Ammo, Nevcairiel, joshborke
   5 local LIBSTUB_MAJOR, LIBSTUB_MINOR = "LibStub", 2  -- NEVER MAKE THIS AN SVN REVISION! IT NEEDS TO BE USABLE IN ALL REPOS!
   6 local LibStub = _G[LIBSTUB_MAJOR]
   7
   8 -- Check to see is this version of the stub is obsolete
   9 if not LibStub or LibStub.minor < LIBSTUB_MINOR then
  10         LibStub = LibStub or {libs = {}, minors = {} }
  11         _G[LIBSTUB_MAJOR] = LibStub
  12         LibStub.minor = LIBSTUB_MINOR
  13
  14         -- LibStub:NewLibrary(major, minor)
  15         -- major (string) - the major version of the library
  16         -- minor (string or number ) - the minor version of the library
  17         --
  18         -- returns nil if a newer or same version of the lib is already present
  19         -- returns empty library object or old library object if upgrade is needed
  20         function LibStub:NewLibrary(major, minor)
  21                 assert(type(major) == "string", "Bad argument #2 to `NewLibrary' (string expected)")
  22                 minor = assert(tonumber(strmatch(minor, "%d+")), "Minor version must either be a number or contain a number.")
  23
  24                 local oldminor = self.minors[major]
  25                 if oldminor and oldminor >= minor then return nil end
  26                 self.minors[major], self.libs[major] = minor, self.libs[major] or {}
  27                 return self.libs[major], oldminor
  28         end
  29
  30         -- LibStub:GetLibrary(major, [silent])
  31         -- major (string) - the major version of the library
  32         -- silent (boolean) - if true, library is optional, silently return nil if its not found
  33         --
  34         -- throws an error if the library can not be found (except silent is set)
  35         -- returns the library object if found
  36         function LibStub:GetLibrary(major, silent)
  37                 if not self.libs[major] and not silent then
  38                         error(("Cannot find a library instance of %q."):format(tostring(major)), 2)
  39                 end
  40                 return self.libs[major], self.minors[major]
  41         end
  42
  43         -- LibStub:IterateLibraries()
  44         --
  45         -- Returns an iterator for the currently registered libraries
  46         function LibStub:IterateLibraries()
  47                 return pairs(self.libs)
  48         end
  49
  50         setmetatable(LibStub, { __call = LibStub.GetLibrary })
  51 end