reimplement downloader using async subprocesses

1 files changed, 55 insertions, 0 deletions

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