Add a configuration option to specify manually installed rocks.

The patch adds a new configuration option - cfg.rocks_provided.
This option contains a list of packages that are either builtin or
manually installed outside of LuaRocks package management system:

    rocks_provided = {
      [module_name] = module_version.."-"..rockspec_version,
      -- ...
    }

These settings are taken into account during dependency resolution
and when search and install commands are used. An attempt to install
a rock from the list causes an error.

LuaRocks automatically adds following modules to the list:

    rocks_provided = {
       lua = lua_version.."-1",

       -- For Lua 5.2 or later:
       bit32 = lua_version.."-1",

       -- For LuaJIT:
       luajit = lj_version.."-1",
       jit = lj_version.."-1",
       ffi = lj_version.."-1",
       bit = lj_version.."-1",
       luabitop = lj_version.."-1"
    }

where lua_version extracted from _VERSION (e.g. 5.2),
      lj_version extracted from jit.version (e.g. 2.0.2).

Built-in values can be overridden by configuration options.

Closes #177.

3 files changed, 49 insertions, 12 deletions

diff --git a/src/luarocks/cfg.lua b/src/luarocks/cfg.lua
index f66ad1d9..3267389a 100644
--- a/src/luarocks/cfg.lua
+++ b/src/luarocks/cfg.lua
@@ -265,6 +265,8 @@ local defaults = {
       lib = "lib",
       include = "include"
    },
+
+   rocks_provided = {}
 }
 
 if detected.windows then
@@ -453,6 +455,24 @@ defaults.variables.OBJ_EXTENSION = defaults.obj_extension
 defaults.variables.LUAROCKS_PREFIX = site_config.LUAROCKS_PREFIX
 defaults.variables.LUA = site_config.LUA_DIR_SET and (defaults.variables.LUA_BINDIR.."/"..defaults.lua_interpreter) or defaults.lua_interpreter
 
+-- Add built-in modules to rocks_provided
+defaults.rocks_provided["lua"] = lua_version.."-1"
+
+if lua_version >= "5.2" then
+   -- Lua 5.2+
+   defaults.rocks_provided["bit32"] = lua_version.."-1"
+end
+
+if package.loaded.jit then
+   -- LuaJIT
+   local lj_version = package.loaded.jit.version:match("LuaJIT (%d%.%d%.%d)")
+   defaults.rocks_provided["luajit"] = lj_version.."-1"
+   defaults.rocks_provided["jit"] = lj_version.."-1"
+   defaults.rocks_provided["ffi"] = lj_version.."-1"
+   defaults.rocks_provided["bit"] = lj_version.."-1"
+   defaults.rocks_provided["luabitop"] = lj_version.."-1"
+end
+
 -- Use defaults:
 
 -- Populate values from 'defaults.variables' in 'variables' if they were not
@@ -466,6 +486,17 @@ for k,v in pairs(defaults.variables) do
    end
 end
 
+-- Populate values from 'defaults.rocks_provided' in 'rocks_provided' if they
+-- were not already set by user.
+if not type(_M.rocks_provided) == "table" then
+   _M.rocks_provided = {}
+end
+for k,v in pairs(defaults.rocks_provided) do
+   if not _M.rocks_provided[k] then
+      _M.rocks_provided[k] = v
+   end
+end
+
 -- For values not set in the config file, use values from the 'defaults' table.
 local cfg_mt = {
    __index = function(t, k)
diff --git a/src/luarocks/deps.lua b/src/luarocks/deps.lua
index 732f587c..1098779c 100644
--- a/src/luarocks/deps.lua
+++ b/src/luarocks/deps.lua
@@ -323,9 +323,10 @@ end
 local function match_dep(dep, blacklist, deps_mode)
    assert(type(dep) == "table")
 
-   local versions
-   if dep.name == "lua" then
-      versions = { cfg.lua_version }
+   local versions = cfg.rocks_provided[dep.name]
+   if not cfg.rocks_provided[dep.name] then
+      -- provided rocks have higher priority than manifest's rocks
+      versions = { cfg.rocks_provided[dep.name] }
    else
       versions = manif_core.get_versions(dep.name, deps_mode)
    end
@@ -360,11 +361,6 @@ local function match_dep(dep, blacklist, deps_mode)
    end
 end
 
-local whitelist = {}
-if cfg.lua_version == "5.2" then
-   whitelist["bit32"] = true
-end
-
 --- Attempt to match dependencies of a rockspec to installed rocks.
 -- @param rockspec table: The rockspec loaded as a table.
 -- @param blacklist table or nil: Program versions to not use as valid matches.
@@ -382,12 +378,10 @@ function match_deps(rockspec, blacklist, deps_mode)
    local matched, missing, no_upgrade = {}, {}, {}
    
    for _, dep in ipairs(rockspec.dependencies) do
-      if not whitelist[dep.name] then
+      if not cfg.rocks_provided[dep.name] then
          local found = match_dep(dep, blacklist and blacklist[dep.name] or nil, deps_mode)
          if found then
-            if dep.name ~= "lua" then 
-               matched[dep] = found
-            end
+            matched[dep] = found
          else
             if dep.constraints[1] and dep.constraints[1].no_upgrade then
                no_upgrade[dep.name] = dep
diff --git a/src/luarocks/search.lua b/src/luarocks/search.lua
index 1fc1f9a1..2db55d9e 100644
--- a/src/luarocks/search.lua
+++ b/src/luarocks/search.lua
@@ -209,6 +209,12 @@ function search_repos(query)
          end
       end
    end
+   -- search through rocks in cfg.rocks_provided
+   local provided_repo = "built-in or listed in cfg.rocks_provided"
+   local name, versions
+   for name, versions in pairs(cfg.rocks_provided) do
+      store_if_match(results, provided_repo, name, versions, "installed", query)
+   end
    return results
 end
 
@@ -273,6 +279,12 @@ function find_suitable_rock(query)
    if not first then
       return nil, "No results matching query were found."
    elseif not next(results, first) then
+      if cfg.rocks_provided[query.name] ~= nil then
+         -- do not install versions that listed in cfg.rocks_provided
+         return nil, "The found rock "..query.name..
+                     " "..cfg.rocks_provided[query.name]..
+                     " is either built-in or listed in cfg.rocks_provided!"
+      end
       return pick_latest_version(query.name, results[first])
    else
       return results