1 files changed, 146 insertions, 0 deletions
diff --git a/mpv/scripts/file-browser/modules/addons/cache.lua b/mpv/scripts/file-browser/modules/addons/cache.lua
new file mode 100644
index 0000000..b1011fd
--- /dev/null
+++ b/mpv/scripts/file-browser/modules/addons/cache.lua
@@ -0,0 +1,146 @@
+--[[
+    This file is an internal file-browser addon.
+    It should not be imported like a normal module.
+
+    Maintains a cache of the accessed directories to improve
+    parsing speed. Disabled by default.
+]]
+
+local mp = require 'mp'
+local msg = require 'mp.msg'
+local utils = require 'mp.utils'
+
+local fb = require 'file-browser'
+
+---@type ParserConfig
+local cacheParser = {
+    name = 'cache',
+    priority = 0,
+    api_version = '1.9',
+}
+
+---@class CacheEntry
+---@field list List
+---@field opts Opts?
+---@field timeout MPTimer
+
+---@type table<string,CacheEntry>
+local cache = {}
+
+---@type table<string,(async fun(list: List?, opts: Opts?))[]>
+local pending_parses = {}
+
+---@param directories? string[]
+local function clear_cache(directories)
+    if directories then
+        msg.debug('clearing cache for', #directories, 'directorie(s)')
+        for _, dir in ipairs(directories) do
+            if cache[dir] then
+                msg.trace('clearing cache for', dir)
+                cache[dir].timeout:kill()
+                cache[dir] = nil
+            end
+        end
+    else
+        msg.debug('clearing cache')
+        for _, entry in pairs(cache) do
+            entry.timeout:kill()
+        end
+        cache = {}
+    end
+end
+
+---@type string
+local prev_directory = ''
+
+function cacheParser:can_parse(directory, parse_state)
+    -- allows the cache to be forcibly used or bypassed with the
+    -- cache/use parse property.
+    if parse_state.properties.cache and parse_state.properties.cache.use ~= nil then
+        if parse_state.source == 'browser' then prev_directory = directory end
+        return parse_state.properties.cache.use
+    end
+
+    -- the script message is guaranteed to always bypass the cache
+    if parse_state.source == 'script-message' then return false end
+    if not fb.get_opt('cache') or directory == '' then return false end
+
+    -- clear the cache if reloading the current directory in the browser
+    -- this means that fb.rescan() should maintain expected behaviour
+    if parse_state.source == 'browser' then
+        if prev_directory == directory then clear_cache({directory}) end
+        prev_directory = directory
+    end
+
+    return true
+end
+
+---@async
+function cacheParser:parse(directory)
+    if cache[directory] then
+        msg.verbose('fetching', directory, 'contents from cache')
+        cache[directory].timeout:kill()
+        cache[directory].timeout:resume()
+        return cache[directory].list, cache[directory].opts
+    end
+
+    ---@type List?, Opts?
+    local list, opts
+
+    -- if another parse is already running on the same directory, then wait and use the same result
+    if not pending_parses[directory] then
+        pending_parses[directory] = {}
+        list, opts = self:defer(directory)
+    else
+        msg.debug('parse for', directory, 'already running - waiting for other parse to finish...')
+        table.insert(pending_parses[directory], fb.coroutine.callback(30))
+        list, opts = coroutine.yield()
+    end
+
+    local pending = pending_parses[directory]
+    -- need to clear the pending parses before resuming them or they will also attempt to resume the parses
+    pending_parses[directory] = nil
+    if pending and #pending > 0 then
+        msg.debug('resuming', #pending, 'pending parses for', directory)
+        for _, cb in ipairs(pending) do
+            cb(list, opts)
+        end
+    end
+
+    if not list then return end
+
+    -- pending will be truthy for the original parse and falsy for any parses that were pending
+    if pending then
+        msg.debug('storing', directory, 'contents in cache')
+        cache[directory] = {
+            list = list,
+            opts = opts,
+            timeout = mp.add_timeout(120, function() cache[directory] = nil end),
+        }
+    end
+
+    return list, opts
+end
+
+cacheParser.keybinds = {
+    {
+        key = 'Ctrl+Shift+r',
+        name = 'clear',
+        command = function() clear_cache() ; fb.rescan() end,
+    }
+}
+
+-- provide method of clearing the cache through script messages
+mp.register_script_message('cache/clear', function(dirs)
+    if not dirs then
+        return clear_cache()
+    end
+
+    ---@type string[]?
+    local directories = utils.parse_json(dirs)
+    if not directories then msg.error('unable to parse', dirs) end
+
+    clear_cache(directories)
+end)
+
+return cacheParser