From bcb9d82a1f4d5b168d11270d7e3fdfd1b9591831 Mon Sep 17 00:00:00 2001
From: David Vazgenovich Shakaryan <dvshakaryan@gmail.com>
Date: Tue, 20 May 2025 18:52:15 -0700
Subject: reimplement downloader using async subprocesses

---
 downloader.lua   | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 iptv-menu-dl.lua | 48 ------------------------------------------------
 main.lua         | 27 +++++++++++++--------------
 3 files changed, 68 insertions(+), 62 deletions(-)
 create mode 100644 downloader.lua
 delete mode 100644 iptv-menu-dl.lua

diff --git a/downloader.lua b/downloader.lua
new file mode 100644
index 0000000..67fb675
--- /dev/null
+++ b/downloader.lua
@@ -0,0 +1,55 @@
+-- Copyright 2025 David Vazgenovich Shakaryan
+
+local utils = require('mp.utils')
+
+local downloader = {}
+local mt = {}
+mt.__index = mt
+
+function downloader.new()
+	return setmetatable({
+		pending = {},
+		running = false,
+	}, mt)
+end
+
+function mt:exec(url, file, cb)
+	if utils.file_info(file) then
+		self:exec_next()
+		return
+	end
+
+	local cmd = {'curl', '-sSfLo', file, url}
+	print('exec: ' .. utils.to_string(cmd))
+
+	self.running = true
+	mp.command_native_async({
+		name = 'subprocess',
+		args = cmd,
+		playback_only = false,
+	}, function(success, res)
+		self.running = false
+		self:exec_next()
+		if cb and success and res.status == 0 then
+			cb(url, file)
+		end
+	end)
+end
+
+function mt:exec_next()
+	if #self.pending > 0 then
+		self:exec(unpack(table.remove(self.pending)))
+	end
+end
+
+-- more recently requested downloads are executed first, as they are more
+-- likely to be used for the current display state
+function mt:schedule(...)
+	if self.running then
+		self.pending[#self.pending+1] = {...}
+	else
+		self:exec(...)
+	end
+end
+
+return downloader
diff --git a/iptv-menu-dl.lua b/iptv-menu-dl.lua
deleted file mode 100644
index a207c91..0000000
--- a/iptv-menu-dl.lua
+++ /dev/null
@@ -1,48 +0,0 @@
--- Copyright 2025 David Vazgenovich Shakaryan
-
-local utils = require('mp.utils')
-
-local queue = {}
-
-function download(target, name, url, path)
-	if utils.file_info(path) then
-		return
-	end
-
-	local cmd = 'curl -sSfLo \'' .. path .. '\'' .. ' \'' .. url .. '\''
-	print('exec: ' .. cmd)
-	local ret = os.execute(cmd)
-
-	if ret == 0 then
-		mp.commandv('script-message-to', target, name, url, path)
-	end
-end
-
-function process_next()
-	download(unpack(table.remove(queue)))
-
-	if #queue > 0 then
-		mp.add_timeout(0, process_next)
-	end
-end
-
-mp.register_script_message('download-file', function(...)
-	queue[#queue+1] = {...}
-
-	-- we want the ability for a later request to be downloaded before
-	-- earlier ones, e.g., to prioritise the image for the current menu.
-	--
-	-- using a small timeout between receiving a message and processing it
-	-- allows for multiple pending messages to be received before any are
-	-- processed. however, immediately scheduling a timer for each request
-	-- does not work, as all elapsed timeouts are executed before any new
-	-- messages are received.
-	--
-	-- the workaround is to schedule a timeout only when adding to an empty
-	-- queue and have each callback schedule an additional timeout if the
-	-- queue is not empty after completion. this effectively results in new
-	-- messages being received after each download.
-	if #queue == 1 then
-		mp.add_timeout(0, process_next)
-	end
-end)
diff --git a/main.lua b/main.lua
index 1d2d252..88e15bc 100644
--- a/main.lua
+++ b/main.lua
@@ -1,6 +1,7 @@
 -- Copyright 2025 David Vazgenovich Shakaryan
 
-local xclib = require('xc')
+local _downloader = require('downloader')
+local _xc = require('xc')
 
 local utils = require('mp.utils')
 
@@ -26,7 +27,8 @@ local colours = {
 
 local script_name = mp.get_script_name()
 local script_dir = mp.get_script_directory()
-local xc = xclib.new({
+local downloader = _downloader.new()
+local xc = _xc.new({
 	server = mp.get_opt('iptv_menu.xc_server'),
 	user = mp.get_opt('iptv_menu.xc_user'),
 	pass = mp.get_opt('iptv_menu.xc_pass'),
@@ -133,6 +135,8 @@ local function write_json_file(fn, data)
 	f:close()
 end
 
+local update_osd
+
 local function get_image_path(url, dl)
 	local path = 'img/' .. url:gsub('%W', '_')
 
@@ -142,10 +146,12 @@ local function get_image_path(url, dl)
 	end
 
 	if dl then
-		mp.commandv('script-message-to',
-			'iptv_menu_dl', 'download-file',
-			script_name, 'downloaded-image', -- callback
-			url, path)
+		downloader:schedule(url, path, function(_, file)
+			if osd_img and file == osd_img.path then
+				update_osd()
+			end
+		end)
+
 		return path
 	end
 end
@@ -480,7 +486,7 @@ local function remove_osd_image()
 	osd_img = nil
 end
 
-local function update_osd()
+function update_osd()
 	local out = {}
 
 	if depth > 1 then
@@ -1366,12 +1372,6 @@ local function toggle_menu()
 	end
 end
 
-mp.register_script_message('downloaded-image', function(url, path)
-	if osd_img and path == osd_img.path then
-		update_osd()
-	end
-end)
-
 mp.observe_property('osd-dimensions', 'native', function(_, val)
 	osd_width = val.w
 	osd_height = val.h
@@ -1394,4 +1394,3 @@ mp.add_forced_key_binding('TAB', 'toggle-menu', toggle_menu)
 bind_menu_keys()
 load_data()
 push_group_menu(objects['root'])
-mp.commandv('load-script', script_dir .. '/iptv-menu-dl.lua')
-- 
cgit v1.2.3-70-g09d2