plugin loader(feat): support loading plugins from user defined direct…

…ories

Extra plugin lookup paths can be set in global reader setting via key
extra_plugin_paths. Value of the key can either be a string or an array
of strings.

frontend/pluginloader.lua

@@ -1,42 +1,66 @@
 local lfs = require("libs/libkoreader-lfs")
 local logger = require("logger")
 
-local PluginLoader = {
-    plugin_path = "plugins"
-}
+local DEFAULT_PLUGIN_PATH = "plugins"
+
+local PluginLoader = {}
 
 function PluginLoader:loadPlugins()
     if self.plugins then return self.plugins end
 
     self.plugins = {}
-    for f in lfs.dir(self.plugin_path) do
-        local path = self.plugin_path.."/"..f
-        local mode = lfs.attributes(path, "mode")
-        -- valid koreader plugin directory
-        if mode == "directory" and f:find(".+%.koplugin$") then
-            local mainfile = path.."/".."main.lua"
-            local package_path = package.path
-            local package_cpath = package.cpath
-            package.path = path.."/?.lua;"..package.path
-            package.cpath = path.."/lib/?.so;"..package.cpath
-            local ok, plugin_module = pcall(dofile, mainfile)
-            if not ok or not plugin_module then
-                logger.warn("Error when loading", mainfile, plugin_module)
-            elseif type(plugin_module.disabled) ~= "boolean" or not plugin_module.disabled then
+    local lookup_path_list = { DEFAULT_PLUGIN_PATH }
+    local extra_paths = G_reader_settings:readSetting("extra_plugin_paths")
+    if extra_paths then
+        if type(extra_paths) == "string" then
+            extra_paths = { extra_paths }
+        end
+        if type(extra_paths) == "table" then
+            for _,extra_path in ipairs(extra_paths) do
+                local extra_path_mode = lfs.attributes(extra_path, "mode")
+                if extra_path_mode == "directory" and extra_path ~= DEFAULT_PLUGIN_PATH then
+                    table.insert(lookup_path_list, extra_path)
+                end
+            end
+        else
+            logger.err("extra_plugin_paths config only accepts string or table value")
+        end
+    end
+
+    -- keep reference to old value so they can be restored later
+    local package_path = package.path
+    local package_cpath = package.cpath
+
+    for _,lookup_path in ipairs(lookup_path_list) do
+        logger.info('Loading plugins from directory:', lookup_path)
+        for entry in lfs.dir(lookup_path) do
+            local plugin_root = lookup_path.."/"..entry
+            local mode = lfs.attributes(plugin_root, "mode")
+            -- valid koreader plugin directory
+            if mode == "directory" and entry:find(".+%.koplugin$") then
+                local mainfile = plugin_root.."/main.lua"
+                package.path = string.format("%s/?.lua;%s", plugin_root, package_path)
+                package.cpath = string.format("%s/lib/?.so;%s", plugin_root, package_cpath)
+                local ok, plugin_module = pcall(dofile, mainfile)
+                if not ok or not plugin_module then
+                    logger.warn("Error when loading", mainfile, plugin_module)
+                elseif type(plugin_module.disabled) ~= "boolean" or not plugin_module.disabled then
+                    plugin_module.path = plugin_root
+                    plugin_module.name = plugin_module.name or plugin_root:match("/(.-)%.koplugin")
+                    table.insert(self.plugins, plugin_module)
+                else
+                    logger.info("Plugin ", mainfile, " has been disabled.")
+                end
                 package.path = package_path
                 package.cpath = package_cpath
-                plugin_module.path = path
-                plugin_module.name = plugin_module.name or path:match("/(.-)%.koplugin")
-                table.insert(self.plugins, plugin_module)
-            else
-                logger.info("Plugin ", mainfile, " has been disabled.")
             end
         end
     end
 
+    -- set package path for all loaded plugins
     for _,plugin in ipairs(self.plugins) do
-        package.path = package.path..";"..plugin.path.."/?.lua"
-        package.cpath = package.cpath..";"..plugin.path.."/lib/?.so"
+        package.path = string.format("%s;%s/?.lua", package.path, plugin.path)
+        package.cpath = string.format("%s;%s/lib/?.so", package.cpath, plugin.path)
     end
 
     table.sort(self.plugins, function(v1,v2) return v1.path < v2.path end)

plugins/kobolight.koplugin/main.lua

@@ -9,7 +9,6 @@ local ConfirmBox = require("ui/widget/confirmbox")
 local ImageWidget = require("ui/widget/imagewidget")
 local InfoMessage = require("ui/widget/infomessage")
 local Notification = require("ui/widget/notification")
-local PluginLoader = require("pluginloader")
 local Screen = require("device").screen
 local UIManager = require("ui/uimanager")
 local WidgetContainer = require("ui/widget/container/widgetcontainer")
@@ -165,7 +164,7 @@ function KoboLight:addToMainMenu(menu_items)
         text = _("Frontlight gesture controller"),
         callback = function()
             local image = ImageWidget:new{
-                file = PluginLoader.plugin_path .. "/kobolight.koplugin/demo.png",
+                file = self.path .. "/demo.png",
                 height = Screen:getHeight(),
                 width = Screen:getWidth(),
                 scale_factor = 0,

plugins/timesync.koplugin/main.lua

@@ -1,4 +1,3 @@
-
 local Device = require("device")
 
 local command