Teal: convert luarocks.loader

1 files changed, 156 insertions, 92 deletions

diff --git a/src/luarocks/loader.tl b/src/luarocks/loader.tl
index 772fdfcb..527f1255 100644
--- a/src/luarocks/loader.tl
+++ b/src/luarocks/loader.tl
@@ -5,20 +5,20 @@
 -- used to load previous modules, so that the loader chooses versions
 -- that are declared to be compatible with the ones loaded earlier.
 
--- luacheck: globals luarocks
-
 local loaders = package.loaders or package.searchers
 local require, ipairs, table, type, next, tostring, error =
       require, ipairs, table, type, next, tostring, error
-local unpack = unpack or table.unpack
 
-local loader = {}
+local record loader
+   context: {string: string}
+   luarocks_loader: function(string): LoaderFn | string, any
+end
 
 local is_clean = not package.loaded["luarocks.core.cfg"]
 
 -- This loader module depends only on core modules.
 local cfg = require("luarocks.core.cfg")
-local cfg_ok, err = cfg.init()
+local cfg_ok, _err = cfg.init()
 if cfg_ok then
    cfg.init_package_paths()
 end
@@ -26,12 +26,35 @@ end
 local path = require("luarocks.core.path")
 local manif = require("luarocks.core.manif")
 local vers = require("luarocks.core.vers")
-local require = nil  -- luacheck: ignore 411
+
+local type Version = require("luarocks.core.types.version").Version
+local type TreeManifest = require("luarocks.core.types.manifest").Tree_manifest
+local type Tree = require("luarocks.core.types.tree").Tree
+local type FilterFn = function(string, string, string, Tree, integer): string
+local type LoaderFn = function()
+
+local record Provider
+   name: string
+   version: Version
+   module_name: string
+   tree: TreeManifest
+end
+
 --------------------------------------------------------------------------------
+-- Backwards compatibility
+--------------------------------------------------------------------------------
+
+local record LuaRocksGlobal
+   loader: loader
+end
+
+global luarocks: LuaRocksGlobal
 
 -- Workaround for wrappers produced by older versions of LuaRocks
 local temporary_global = false
-local status, luarocks_value = pcall(function() return luarocks end)
+local status, luarocks_value = pcall(function(): LuaRocksGlobal
+   return luarocks
+end)
 if status and luarocks_value then
    -- The site_config.lua file generated by old versions uses module(),
    -- so it produces a global `luarocks` table. Since we have the table,
@@ -52,16 +75,18 @@ else
    end
 end
 
+--------------------------------------------------------------------------------
+-- Context management
+--------------------------------------------------------------------------------
+
 loader.context = {}
 
 --- Process the dependencies of a package to determine its dependency
 -- chain for loading modules.
--- @param name string: The name of an installed rock.
--- @param version string: The version of the rock, in string format
-function loader.add_context(name, version)
-   -- assert(type(name) == "string")
-   -- assert(type(version) == "string")
-
+--
+-- @param name     The name of an installed rock.
+-- @param version  The version of the rock, in string format
+function loader.add_context(name: string, version: string)
    if temporary_global then
       -- The first thing a wrapper does is to call add_context.
       -- From here on, it's safe to clean the global environment.
@@ -71,17 +96,19 @@ function loader.add_context(name, version)
 
    local tree_manifests = manif.load_rocks_tree_manifests()
    if not tree_manifests then
-      return nil
+      return
    end
 
-   return manif.scan_dependencies(name, version, tree_manifests, loader.context)
+   manif.scan_dependencies(name, version, tree_manifests, loader.context)
 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)
+--
+-- @param a  A provider table.
+-- @param b  Another provider table.
+--
+-- @return  true if the version of a is greater than that of b.
+local function sort_versions(a: Provider, b: Provider): boolean
    return a.version > b.version
 end
 
@@ -92,67 +119,94 @@ end
 -- the version 2.0.2 needs to be loaded and it is not the current
 -- version, the module requested for the other loaders will be
 -- "socket.core_2_0_2".
--- @param module The module name requested by the user, such as "socket.core"
--- @param name The rock name, such as "luasocket"
--- @param version The rock version, such as "2.0.2-1"
--- @param module_name The actual module name, such as "socket.core" or "socket.core_2_0_2".
--- @return table or (nil, string): The module table as returned by some other loader,
--- or nil followed by an error message if no other loader managed to load the module.
-local function call_other_loaders(module, name, version, module_name)
+--
+-- @param module       The module name requested by the user, e.g. "socket.core"
+-- @param name         The rock name, such as "luasocket"
+-- @param version      The rock version, such as "2.0.2-1"
+-- @param module_name  Actual module name, such as "socket.core_2_0_2"
+--
+-- @return  The loader function returned or an error message.
+-- @return  Additional loader data, if returned by the loader.
+local function call_other_loaders(module: string, name: string, version: string, module_name: string): LoaderFn | string, any
    for _, a_loader in ipairs(loaders) do
       if a_loader ~= loader.luarocks_loader then
-         local results = { a_loader(module_name) }
-         if type(results[1]) == "function" then
-            return unpack(results)
+         local results: {any} = { a_loader(module_name) }
+         local f = results[1]
+         if f is LoaderFn then
+            if #results == 2 then
+               return f, results[2]
+            else
+               return f
+            end
          end
       end
    end
-   return "Failed loading module "..module.." in LuaRocks rock "..name.." "..version
+   return "Failed loading module " .. module .. " in LuaRocks rock " .. name .. " " .. version
 end
 
-local function add_providers(providers, entries, tree, module, filter_file_name)
+--- Find entries which provide the wanted module in the tree,
+-- and store them in the array of providers for later sorting.
+--
+-- @param providers    The array of providers being accumulated into
+-- @param entries      The packages which provide the module
+-- @param tree         TreeManifest where filenames can be found.
+-- @param module       The module name being looked up
+-- @param filter_name  A filtering function to adjust the filename.
+--
+-- @return  If the current LuaRocks loader context already resolved this
+-- dependency based on other dependencies, return the name of the module
+-- for immediate use.
+-- @return  Version of the module for immediate use, if matched.
+-- @return  File name of the module for immediate use, if matched.
+local function add_providers(providers: {Provider}, entries: {string}, tree: TreeManifest, module: string, filter_name: FilterFn): string, string, string
    for i, entry in ipairs(entries) do
       local name, version = entry:match("^([^/]*)/(.*)$")
+
       local file_name = tree.manifest.repository[name][version][1].modules[module]
       if type(file_name) ~= "string" then
-         error("Invalid data in manifest file for module "..tostring(module).." (invalid data for "..tostring(name).." "..tostring(version)..")")
+         error("Invalid data in manifest file for module " .. tostring(module) .. " (invalid data for " .. tostring(name) .. " " .. tostring(version) .. ")")
       end
-      file_name = filter_file_name(file_name, name, version, tree.tree, i)
+
+      file_name = filter_name(file_name, name, version, tree.tree, i)
+
       if loader.context[name] == version then
          return name, version, file_name
       end
-      version = vers.parse_version(version)
-      table.insert(providers, {name = name, version = version, module_name = file_name, tree = tree})
+
+      table.insert(providers, {
+         name = name,
+         version = vers.parse_version(version),
+         module_name = file_name,
+         tree = tree
+      })
    end
 end
 
---- Search for a module in the rocks trees
--- @param module string: module name (eg. "socket.core")
--- @param filter_file_name function(string, string, string, string, number):
--- a function that takes the module file name (eg "socket/core.so"), the rock name
--- (eg "luasocket"), the version (eg "2.0.2-1"), the path of the rocks tree
+--- Search for a module in the rocks trees.
+--
+-- @param module       module name (eg. "socket.core")
+-- @param filter_name  a function that takes the module file name
+-- (eg "socket/core.so"), the rock name (eg "luasocket"),
+-- the version (eg "2.0.2-1"), the path of the rocks tree
 -- (eg "/usr/local"), and the numeric index of the matching entry, so the
 -- filter function can know if the matching module was the first entry or not.
--- @return string, string, string, (string or table):
--- * name of the rock containing the module (eg. "luasocket")
--- * version of the rock (eg. "2.0.2-1")
--- * return value of filter_file_name
--- * tree of the module (string or table in `tree_manifests` format)
-local function select_module(module, filter_file_name)
-   --assert(type(module) == "string")
-   --assert(type(filter_module_name) == "function")
+--
+-- @return name of the rock containing the module (eg. "luasocket")
+-- @return version of the rock (eg. "2.0.2-1")
+-- @return return value of filter_name
+local function select_module(module: string, filter_name: FilterFn): string, string, string
 
    local tree_manifests = manif.load_rocks_tree_manifests()
    if not tree_manifests then
       return nil
    end
 
-   local providers = {}
-   local initmodule
+   local providers: {Provider} = {}
+   local initmodule: string
    for _, tree in ipairs(tree_manifests) do
       local entries = tree.manifest.modules[module]
       if entries then
-         local n, v, f = add_providers(providers, entries, tree, module, filter_file_name)
+         local n, v, f = add_providers(providers, entries, tree, module, filter_name)
          if n then
             return n, v, f
          end
@@ -160,7 +214,7 @@ local function select_module(module, filter_file_name)
          initmodule = initmodule or module .. ".init"
          entries = tree.manifest.modules[initmodule]
          if entries then
-            local n, v, f = add_providers(providers, entries, tree, initmodule, filter_file_name)
+            local n, v, f = add_providers(providers, entries, tree, initmodule, filter_name)
             if n then
                return n, v, f
             end
@@ -171,46 +225,53 @@ local function select_module(module, filter_file_name)
    if next(providers) then
       table.sort(providers, sort_versions)
       local first = providers[1]
-      return first.name, first.version.string, first.module_name, first.tree
+      return first.name, first.version.string, first.module_name
    end
 end
 
---- Search for a module
--- @param module string: module name (eg. "socket.core")
--- @return string, string, string, (string or table):
--- * name of the rock containing the module (eg. "luasocket")
--- * version of the rock (eg. "2.0.2-1")
--- * name of the module (eg. "socket.core", or "socket.core_2_0_2" if file is stored versioned).
--- * tree of the module (string or table in `tree_manifests` format)
-local function pick_module(module)
-   return
-      select_module(module, function(file_name, name, version, tree, i)
-         if i > 1 then
-            file_name = path.versioned_name(file_name, "", name, version)
-         end
-         return path.path_to_module(file_name)
-      end)
+--- Filter operation for adjusting the versioned names when multiple packages provide
+-- the same file.
+--
+-- @param file_name  The original filename
+-- @param name       The rock name
+-- @param version    The rock version
+-- @param _tree      (unused)
+-- @param i          The priority index, to determine whether to version the name.
+--
+-- @return  A filename, which may be plain or versioned.
+-- (eg. "socket.core", or "socket.core_2_0_2" if file is stored versioned).
+local function filter_module_name(file_name: string, name: string, version: string, _tree: Tree, i: integer): string
+   if i > 1 then
+      file_name = path.versioned_name(file_name, "", name, version)
+   end
+   return path.path_to_module(file_name)
+end
+
+--- Search for a module.
+--
+-- @param module  name of the module (eg. "socket.core")
+--
+-- @return  name of the rock containing the module (eg. "luasocket")
+-- @return  version of the rock (eg. "2.0.2-1")
+-- @return  name of the module (eg. "socket.core", or "socket.core_2_0_2" if file is stored versioned).
+-- @return  tree of the module (string or table in `tree_manifests` format)
+local function pick_module(module: string): string, string, string, string | TreeManifest
+   return select_module(module, filter_module_name)
 end
 
 --- Return the pathname of the file that would be loaded for a module.
--- @param module string: module name (eg. "socket.core")
--- @param where string: places to look for the module. If `where` contains
+--
+-- @param module  module name (eg. "socket.core")
+-- @param where   places to look for the module. If `where` contains
 -- "l", it will search using the LuaRocks loader; if it contains "p",
 -- it will look in the filesystem using package.path and package.cpath.
 -- You can use both at the same time.
--- @return If successful, it will return four values.
--- * If found using the LuaRocks loader, it will return:
---   * filename of the module (eg. "/usr/local/lib/lua/5.1/socket/core.so"),
---   * rock name
---   * rock version
---   * "l" to indicate the match comes from the loader.
--- * If found scanning package.path and package.cpath, it will return:
---   * filename of the module (eg. "/usr/local/lib/lua/5.1/socket/core.so"),
---   * "path" or "cpath"
---   * nil
---   * "p" to indicate the match comes from scanning package.path and cpath.
--- If unsuccessful, nothing is returned.
-function loader.which(module, where)
+--
+-- @return  If found, filename of the module (eg. "/usr/local/lib/lua/5.1/socket/core.so"),
+-- @return  If found via the loader, the rock name; otherwise, "path" or "cpath"
+-- @return  If found via the loader, the rock version; otherwise, nil
+-- @return  If found via the loader, "l"; if found via package.path or package.cpath, "p".
+function loader.which(module: string, where?: string): string, string, string, string
    where = where or "l"
    if where:match("l") then
       local rock_name, rock_version, file_name = select_module(module, path.which_i)
@@ -224,8 +285,8 @@ function loader.which(module, where)
    end
    if where:match("p") then
       local modpath = module:gsub("%.", "/")
-      for _, v in ipairs({"path", "cpath"}) do
-         for p in package[v]:gmatch("([^;]+)") do
+      for _, v in ipairs({package.path, package.cpath}) do
+         for p in v:gmatch("([^;]+)") do
             local file_name = p:gsub("%?", modpath)  -- luacheck: ignore 421
             local fd = io.open(file_name)
             if fd then
@@ -238,18 +299,21 @@ function loader.which(module, where)
 end
 
 --- Package loader for LuaRocks support.
--- A module is searched in installed rocks that match the
+-- See <a href="http://www.lua.org/manual/5.4/manual.html#pdf-require">require()</a>
+-- in the Lua reference manual for details on the require() mechanism.
+-- The LuaRocks loader works by searching 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 loader.luarocks_loader(module)
+--
+-- @param module  The module name, like in plain require().
+--
+-- @return  A function which can load the module found,
+-- or a string with an error message.
+function loader.luarocks_loader(module: string): LoaderFn | string, any
    local name, version, module_name = pick_module(module)
    if not name then
-      return "No LuaRocks module found for "..module
+      return "No LuaRocks module found for " .. module
    else
       loader.add_context(name, version)
       return call_other_loaders(module, name, version, module_name)