add wip version of new package loader

git-svn-id: http://luarocks.org/svn/luarocks/trunk@40 9ca3f7c1-7366-0410-b1a3-b5c78f85698c

1 files changed, 147 insertions, 0 deletions

diff --git a/src/luarocks2.lua b/src/luarocks2.lua
new file mode 100644
index 00000000..0ca2f505
--- /dev/null
+++ b/src/luarocks2.lua
@@ -0,0 +1,147 @@
+
+local global_env = _G
+local package, require, assert, ipairs, pairs, os, print, table, type, next, unpack =
+      package, require, assert, ipairs, pairs, os, print, table, type, next, unpack
+
+module("luarocks")
+
+local path = require("luarocks.path")
+local manif_core = require("luarocks.manif_core")
+local deps = require("luarocks.deps")
+local cfg = require("luarocks.cfg")
+
+context = {}
+
+-- Contains a table when rocks trees are loaded,
+-- or 'false' to indicate rocks trees failed to load.
+-- 'nil' indicates rocks trees were not attempted to be loaded yet.
+rocks_trees = nil
+
+local function load_rocks_trees() 
+   local any_ok = false
+   local trees = {}
+   
+   -- FIXME select correctly file to be fetched
+   local persist = require("luarocks.persist")
+   table.insert(trees, { manifest = persist.load_into_table("manifest2") } )
+   any_ok = true
+
+   if not any_ok then
+      rocks_trees = false
+      return false
+   end
+   rocks_trees = trees
+   return true
+end
+
+--- Process the dependencies of a package to determine its dependency
+-- chain for loading modules.
+-- @parse name string: The name of an installed rock.
+-- @parse version string: The version of the rock, in string format
+-- @parse manifest table: The local manifest table where this rock
+-- is installed.
+local function add_context(name, version)
+   -- assert(type(name) == "string")
+   -- assert(type(version) == "string")
+   -- assert(type(manifest) == "table")
+
+   if context[name] then
+      return
+   end
+   context[name] = version
+   --[[
+
+   local pkgdeps = manifest.dependencies and manifest.dependencies[name][version]
+   if not pkgdeps then
+      return
+   end
+   for _, dep in ipairs(pkgdeps) do
+      local package, constraints = dep.name, dep.constraints
+
+      for _, tree in pairs(rocks_trees) do
+         local entries = tree.manifest.repository[package]
+         if entries then
+            for version, packages in pairs(entries) do
+               if (not constraints) or deps.match_constraints(deps.parse_version(version), constraints) then
+                  add_context(package, version, tree.manifest)
+               end
+            end
+         end
+      end
+   end
+   ]]
+end
+
+--- Internal sorting function.
+-- @param a table: A provider table.
+-- @param b table: Another provider table.
+-- @return boolean: True if the version of a is greater than that of b.
+local function sort_versions(a,b)
+   return a.version > b.version
+end
+
+local function call_other_loaders(module, name, version, file)
+   
+   local actual_module = file:match("(.*)%.[^.]+$")
+   
+   for i, loader in pairs(package.loaders) do
+      if loader ~= luarocks_loader then
+         local results = { loader(actual_module) }
+         if type(results[1]) == "function" then
+            return unpack(results)
+         end
+      end
+   end
+   return nil, "Failed loading module "..module.." in LuaRocks rock "..name.." "..version
+end
+
+local function pick_module(module)
+   --assert(type(module) == "string")
+
+   if not rocks_trees and not load_rocks_trees() then
+      return nil
+   end
+
+   local providers = {}
+   for _, tree in pairs(rocks_trees) do
+      local entries = tree.manifest.modules[module]
+      if entries then
+         for entry, file in pairs(entries) do
+            local name, version = entry:match("^([^/]*)/(.*)$")
+            if context[name] == version then
+               return name, version, file
+            end
+            version = deps.parse_version(version)
+            table.insert(providers, {name = name, version = version, file = file})
+         end
+      end
+   end
+
+   if next(providers) then
+      table.sort(providers, sort_versions)
+      local first = providers[1]
+      return first.name, first.version.string, first.file
+   end
+end
+
+--- Package loader for LuaRocks support.
+-- A module is searched in installed rocks that match the
+-- current LuaRocks context. If module is not part of the
+-- context, or if a context has not yet been set, the module
+-- in the package with the highest version is used.
+-- @param module string: The module name, like in plain require().
+-- @return table: The module table (typically), like in plain
+-- require(). See <a href="http://www.lua.org/manual/5.1/manual.html#pdf-require">require()</a>
+-- in the Lua reference manual for details.
+
+function luarocks_loader(module)
+   local name, version, file = pick_module(module)
+   if not name then
+      return nil, "No LuaRocks module found for "..module
+   else
+      add_context(name, version)
+      return call_other_loaders(module, name, version, file)
+   end
+end
+
+table.insert(global_env.package.loaders, 1, luarocks_loader)