feat(autosave): implement autosave plugin in lua

lua/spacevim/plugin/autosave.lua

@@ -0,0 +1,112 @@
+--=============================================================================
+-- autosave.lua --- autosave plugin
+-- Copyright (c) 2016-2019 Wang Shidong & Contributors
+-- Author: Wang Shidong < wsdjeg@outlook.com >
+-- URL: https://spacevim.org
+-- License: GPLv3
+--=============================================================================
+
+
+local default_opt = {
+    timeoutlen = 60 * 5 * 1000,
+    backupdir = '~/.cache/SpaceVim/backup/',
+    save_all_buffers = false,
+    event = {'InsertLeave', 'TextChanged'},
+    filetype = {},
+    filetypeExclude = {},
+    buftypeExclude = {},
+    bufNameExclude = {}
+}
+
+local logger = require('spacevim.logger').derive('autosave')
+local f = require('spacevim.api').import('file')
+
+
+local autosave_timer = -1
+
+local M = {}
+
+
+function M.config(opt)
+    for option, value in ipairs(default_opt) do
+        if opt[option] ~= nil then
+            logger.debug('set option`' .. option .. '` to :' .. opt[option])
+            default_opt[option] = opt[option]
+            if option == 'timeoutlen' then
+                setup_timer(default_opt[option])
+            elseif option == 'event' then
+                setup_events()
+            end
+        end
+    end
+
+end
+
+local function location_path(bufname)
+    if vim.fn.empty(default_opt.backupdir) == 1 then
+        return bufname
+    else
+        return default_opt.backupdir .. '/' .. f.path_to_fname(bufname, '+=') .. '.backup'
+    end
+end
+
+local function save_buffer(bufnr)
+    if vim.fn.getbufvar(bufnr, '&modified') == 1 and
+        vim.fn.empty(vim.fn.getbufvar(bufnr, '&buftype')) == 1 and
+        vim.fn.filewritable(vim.fn.bufname(bufnr)) == 1 and
+        vim.fn.empty(vim.fn.bufname(bufnr)) == 0 then
+        local lines = vim.fn.getbufline(bufnr, 1, '$')
+        vim.fn.writefile(lines, location_path(vim.fn.bufname(bufnr)))
+        if vim.fn.empty(default_opt.backupdir) == 1 then
+            vim.fn.setbufvar(bufnr, '&modified', 0)
+            vim.cmd('silent checktime ' .. bufnr)
+        end
+    end
+
+end
+
+local function auto_dosave(...)
+    if default_opt.save_all_buffers then
+        for _, nr in ipairs(vim.fn.range(1, vim.fn.bufnr('$'))) do
+            save_buffer(nr)
+        end
+    else
+        save_buffer(vim.fn.bufnr('%'))
+    end
+
+end
+
+local function setup_timer(_timeoutlen)
+    if vim.fn.has('timers') == 0 then
+        logger.warn('failed to setup timer, needs `+timers` feature!')
+        return
+    end
+    if _timeoutlen == 0 then
+        vim.fn.timer_stop(autosave_timer)
+        logger.debug('disabled autosave timer!')
+    end
+    if _timeoutlen < 1000 or _timeoutlen > 60 * 100 * 1000 then
+        local msg = "timeoutlen must be given in millisecods and can't be > 100*60*1000 (100 minutes) or < 1000 (1 second)"
+        logger.warn(msg)
+        return
+    end
+    vim.fn.timer_stop(autosave_timer)
+    autosave_timer = vim.fn.timer_start(_timeoutlen, auto_dosave, {['repeat'] =  -1})
+    if vim.fn.empty(autosave_timer) == 0 then
+        logger.debug('setup new autosave timer, timeoutlen:' .. _timeoutlen)
+    end
+
+end
+
+
+local function setup_events()
+    vim.api.nvim_create_autocmd(default_opt.event, {
+        pattern = {'*'},
+        callback = auto_dosave,
+    })
+end
+
+setup_timer(default_opt.timeoutlen)
+setup_events()
+
+return M