Change print statements to logs

lua/oil/init.lua

@@ -551,6 +551,7 @@ M.select = function(opts, callback)
   local cache = require("oil.cache")
   local config = require("oil.config")
   local constants = require("oil.constants")
+  local log = require("oil.log")
   local util = require("oil.util")
   local FIELD_META = constants.FIELD_META
   opts = vim.tbl_extend("keep", opts or {}, {})
@@ -585,12 +586,10 @@ M.select = function(opts, callback)
   if not adapter then
     return finish("Not an oil buffer")
   end
-  print(
+  log.info(
-    "0 buf name:",
+    "0 buf name: %s  current bufnr: %d  current buffer name: %s",
     vim.api.nvim_buf_get_name(0),
-    "current bufnr:",
     vim.api.nvim_get_current_buf(),
-    "current buffer name:",
     vim.api.nvim_buf_get_name(vim.api.nvim_get_current_buf())
   )
 
@@ -649,12 +648,10 @@ M.select = function(opts, callback)
 
   local prev_win = vim.api.nvim_get_current_win()
   local oil_bufnr = vim.api.nvim_get_current_buf()
-  print(
+  log.info(
-    "oil_bufnr:",
+    "oil_bufnr: %d  name: %s  0 buf name: %s",
     oil_bufnr,
-    "name:",
     vim.api.nvim_buf_get_name(oil_bufnr),
-    "0 buf name:",
     vim.api.nvim_buf_get_name(0)
   )
 

lua/oil/log.lua

@@ -0,0 +1,124 @@
+local uv = vim.uv or vim.loop
+local levels_reverse = {}
+for k, v in pairs(vim.log.levels) do
+  levels_reverse[v] = k
+end
+
+local Log = {}
+
+---@type integer
+Log.level = vim.log.levels.INFO
+
+---@return string
+Log.get_logfile = function()
+  local fs = require("oil.fs")
+
+  local ok, stdpath = pcall(vim.fn.stdpath, "log")
+  if not ok then
+    stdpath = vim.fn.stdpath("cache")
+  end
+  assert(type(stdpath) == "string")
+  return fs.join(stdpath, "oil.log")
+end
+
+---@param level integer
+---@param msg string
+---@param ... any[]
+---@return string
+local function format(level, msg, ...)
+  local args = vim.F.pack_len(...)
+  for i = 1, args.n do
+    local v = args[i]
+    if type(v) == "table" then
+      args[i] = vim.inspect(v)
+    elseif v == nil then
+      args[i] = "nil"
+    end
+  end
+  local ok, text = pcall(string.format, msg, vim.F.unpack_len(args))
+  local timestr = vim.fn.strftime("%H:%M:%S")
+  if ok then
+    local str_level = levels_reverse[level]
+    return string.format("%s[%s] %s", timestr, str_level, text)
+  else
+    return string.format(
+      "%s[ERROR] error formatting log line: '%s' args %s",
+      timestr,
+      vim.inspect(msg),
+      vim.inspect(args)
+    )
+  end
+end
+
+---@param line string
+local function write(line)
+  -- This will be replaced during initialization
+end
+
+local initialized = false
+local function initialize()
+  if initialized then
+    return
+  end
+  initialized = true
+  local filepath = Log.get_logfile()
+
+  local stat = uv.fs_stat(filepath)
+  if stat and stat.size > 10 * 1024 * 1024 then
+    local backup = filepath .. ".1"
+    uv.fs_unlink(backup)
+    uv.fs_rename(filepath, backup)
+  end
+
+  local parent = vim.fs.dirname(filepath)
+  vim.fn.mkdir(parent, "p")
+
+  local logfile, openerr = io.open(filepath, "a+")
+  if not logfile then
+    local err_msg = string.format("Failed to open oil.nvim log file: %s", openerr)
+    vim.notify(err_msg, vim.log.levels.ERROR)
+  else
+    write = function(line)
+      logfile:write(line)
+      logfile:write("\n")
+      logfile:flush()
+    end
+  end
+end
+
+---Override the file handler e.g. for tests
+---@param handler fun(line: string)
+function Log.set_handler(handler)
+  write = handler
+  initialized = true
+end
+
+function Log.log(level, msg, ...)
+  if Log.level <= level then
+    initialize()
+    local text = format(level, msg, ...)
+    write(text)
+  end
+end
+
+function Log.trace(...)
+  Log.log(vim.log.levels.TRACE, ...)
+end
+
+function Log.debug(...)
+  Log.log(vim.log.levels.DEBUG, ...)
+end
+
+function Log.info(...)
+  Log.log(vim.log.levels.INFO, ...)
+end
+
+function Log.warn(...)
+  Log.log(vim.log.levels.WARN, ...)
+end
+
+function Log.error(...)
+  Log.log(vim.log.levels.ERROR, ...)
+end
+
+return Log