console.lua: allow persisting the command history

DOCS/man/console.rst

@@ -185,6 +185,16 @@ Configurable Options
 
     Remove duplicate entries in history as to only keep the latest one.
 
+``persist_history``
+    Default: no
+
+    Whether to save the command history to a file and load it at startup.
+
+``history_path``
+    Default: ``~~state/command_history.txt``
+
+    The file path for ``persist_history`` (see `PATHS`_).
+
 ``font_hw_ratio``
     Default: auto
 

player/lua/console.lua

@@ -35,6 +35,8 @@ local opts = {
     scale_with_window = "auto",
     case_sensitive = platform ~= 'windows' and true or false,
     history_dedup = true,
+    persist_history = false,
+    history_path = '~~state/command_history.txt',
     font_hw_ratio = 'auto',
 }
 
@@ -82,6 +84,7 @@ local histories = {[id] = {}}
 local history = histories[id]
 local history_pos = 1
 local searching_history = false
+local history_is_dirty = false
 local log_buffers = {[id] = {}}
 local key_bindings = {}
 local dont_bind_up_down = false
@@ -655,6 +658,10 @@ local function history_add(text)
     end
 
     history[#history + 1] = text
+
+    if id == default_id then
+        history_is_dirty = true
+    end
 end
 
 local function handle_cursor_move()
@@ -1722,6 +1729,24 @@ local function show_and_type(text, cursor_pos)
     end
 end
 
+local function read_history()
+    if opts.persist_history == false then
+        return
+    end
+
+    local history_file = io.open(mp.command_native({'expand-path', opts.history_path}))
+
+    if history_file == nil then
+        return
+    end
+
+    for command in history_file:lines() do
+        history[#history + 1] = command
+    end
+
+    history_file:close()
+end
+
 -- Add a global binding for enabling the REPL. While it's enabled, its bindings
 -- will take over and it can be closed with ESC.
 mp.add_key_binding(nil, 'enable', function()
@@ -1883,6 +1908,48 @@ mp.register_event('log-message', function(e)
             terminal_styles[e.level])
 end)
 
+mp.register_event('shutdown', function ()
+    if opts.persist_history == false or history_is_dirty == false then
+        return
+    end
+
+    history = histories[default_id]
+    local history_to_save = table.concat(history, '\n') .. '\n'
+    local history_path = mp.command_native({'expand-path', opts.history_path})
+
+    -- Reread the history file to get lines that other mpv instances may have
+    -- added.
+    local history_file = io.open(history_path)
+    if history_file then
+        local history_map = {}
+        for _, command in pairs(history) do
+            history_map[command] = true
+        end
+
+        for command in history_file:lines() do
+            if not history_map[command] then
+                history_to_save = history_to_save .. command .. '\n'
+            end
+        end
+
+        history_file:close()
+    end
+
+    local error_message
+    history_file, error_message = io.open(history_path, 'w')
+
+    if history_file == nil then
+        mp.msg.error('Failed to write console history: ' .. error_message)
+
+        return
+    end
+
+    history_file:write(history_to_save)
+    history_file:close()
+end)
+
 require 'mp.options'.read_options(opts, nil, update)
 
+read_history()
+
 collectgarbage()