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koreader/frontend/docsettings.lua
poire-z 04d9a557aa Use fsync() for more robust setting files saving
Bump base for util.fsyncOpenedFile() and util.fsyncDirectory().

Use these to force flush to storage device when
saving luasetting, docsetting, and history.lua.
Also dont rotate them to .old until they are at least
60 seconds old.
Also make auto_save_paging_count count right.

Also bump crengine: open (as text) small or empty files
2019-12-10 23:57:32 +01:00

251 lines
9.0 KiB
Lua

--[[--
This module is responsible for reading and writing `metadata.lua` files
in the so-called sidecar directory
([Wikipedia definition](https://en.wikipedia.org/wiki/Sidecar_file)).
]]
local DataStorage = require("datastorage")
local dump = require("dump")
local ffiutil = require("ffi/util")
local lfs = require("libs/libkoreader-lfs")
local logger = require("logger")
local DocSettings = {}
local HISTORY_DIR = DataStorage:getHistoryDir()
local function buildCandidate(file_path)
-- Ignore empty files.
if file_path and lfs.attributes(file_path, "mode") == "file" then
return { file_path, lfs.attributes(file_path, "modification") }
else
return nil
end
end
--- Returns path to sidecar directory (`filename.sdr`).
--
-- Sidecar directory is the file without _last_ suffix.
-- @string doc_path path to the document (e.g., `/foo/bar.pdf`)
-- @treturn string path to the sidecar directory (e.g., `/foo/bar.sdr`)
function DocSettings:getSidecarDir(doc_path)
if doc_path == nil or doc_path == '' then return '' end
local file_without_suffix = doc_path:match("(.*)%.")
if file_without_suffix then
return file_without_suffix..".sdr"
end
return doc_path..".sdr"
end
--- Returns path to `metadata.lua` file.
-- @string doc_path path to the document (e.g., `/foo/bar.pdf`)
-- @treturn string path to `/foo/bar.sdr/metadata.lua` file
function DocSettings:getSidecarFile(doc_path)
if doc_path == nil or doc_path == '' then return '' end
-- If the file does not have a suffix or we are working on a directory, we
-- should ignore the suffix part in metadata file path.
local suffix = doc_path:match(".*%.(.+)")
if suffix == nil then
suffix = ''
end
return self:getSidecarDir(doc_path) .. "/metadata." .. suffix .. ".lua"
end
--- Returns `true` if there is a `metadata.lua` file.
-- @string doc_path path to the document (e.g., `/foo/bar.pdf`)
-- @treturn bool
function DocSettings:hasSidecarFile(doc_path)
return lfs.attributes(self:getSidecarFile(doc_path), "mode") == "file"
end
function DocSettings:getHistoryPath(fullpath)
return HISTORY_DIR .. "/[" .. fullpath:gsub("(.*/)([^/]+)","%1] %2"):gsub("/","#") .. ".lua"
end
function DocSettings:getPathFromHistory(hist_name)
if hist_name == nil or hist_name == '' then return '' end
if hist_name:sub(-4) ~= ".lua" then return '' end -- ignore .lua.old backups
-- 1. select everything included in brackets
local s = string.match(hist_name,"%b[]")
if s == nil or s == '' then return '' end
-- 2. crop the bracket-sign from both sides
-- 3. and finally replace decorative signs '#' to dir-char '/'
return string.gsub(string.sub(s,2,-3),"#","/")
end
function DocSettings:getNameFromHistory(hist_name)
if hist_name == nil or hist_name == '' then return '' end
if hist_name:sub(-4) ~= ".lua" then return '' end -- ignore .lua.old backups
local s = string.match(hist_name, "%b[]")
if s == nil or s == '' then return '' end
-- at first, search for path length
-- and return the rest of string without 4 last characters (".lua")
return string.sub(hist_name, string.len(s)+2, -5)
end
function DocSettings:ensureSidecar(sidecar)
if lfs.attributes(sidecar, "mode") ~= "directory" then
lfs.mkdir(sidecar)
end
end
--- Opens a document's individual settings (font, margin, dictionary, etc.)
-- @string docfile path to the document (e.g., `/foo/bar.pdf`)
-- @treturn DocSettings object
function DocSettings:open(docfile)
--- @todo (zijiehe): Remove history_path, use only sidecar.
local new = {}
new.history_file = self:getHistoryPath(docfile)
local sidecar = self:getSidecarDir(docfile)
new.sidecar = sidecar
DocSettings:ensureSidecar(sidecar)
-- If there is a file which has a same name as the sidecar directory, or
-- the file system is read-only, we should not waste time to read it.
if lfs.attributes(sidecar, "mode") == "directory" then
-- New sidecar file name is metadata.{file last suffix}.lua. So we
-- can handle two files with only different suffixes.
new.sidecar_file = self:getSidecarFile(docfile)
new.legacy_sidecar_file = sidecar.."/"..
docfile:match("([^%/]+%..+)")..".lua"
end
local candidates = {}
-- New sidecar file
table.insert(candidates, buildCandidate(new.sidecar_file))
-- Backup file of new sidecar file
table.insert(candidates, buildCandidate(new.sidecar_file and (new.sidecar_file .. ".old")))
-- Legacy sidecar file
table.insert(candidates, buildCandidate(new.legacy_sidecar_file))
-- Legacy history folder
table.insert(candidates, buildCandidate(new.history_file))
-- Backup file in legacy history folder
table.insert(candidates, buildCandidate(new.history_file .. ".old"))
-- Legacy kpdfview setting
table.insert(candidates, buildCandidate(docfile..".kpdfview.lua"))
table.sort(candidates, function(l, r)
if l == nil then
return false
elseif r == nil then
return true
else
return l[2] > r[2]
end
end)
local ok, stored
for _, k in pairs(candidates) do
-- Ignore empty files
if lfs.attributes(k[1], "size") > 0 then
ok, stored = pcall(dofile, k[1])
-- Ignore the empty table.
if ok and next(stored) ~= nil then
logger.dbg("data is read from ", k[1])
break
end
end
logger.dbg(k[1], " is invalid, remove.")
os.remove(k[1])
end
if ok and stored then
new.data = stored
new.candidates = candidates
else
new.data = {}
end
return setmetatable(new, {__index = DocSettings})
end
--- Reads a setting.
function DocSettings:readSetting(key)
return self.data[key]
end
--- Saves a setting.
function DocSettings:saveSetting(key, value)
self.data[key] = value
end
--- Deletes a setting.
function DocSettings:delSetting(key)
self.data[key] = nil
end
--- Serializes settings and writes them to `metadata.lua`.
function DocSettings:flush()
-- write serialized version of the data table into one of
-- i) sidecar directory in the same directory of the document or
-- ii) history directory in root directory of KOReader
if not self.history_file and not self.sidecar_file then
return
end
-- If we can write to sidecar_file, we do not need to write to history_file
-- anymore.
local serials = { self.sidecar_file, self.history_file }
self:ensureSidecar(self.sidecar)
local s_out = dump(self.data)
os.setlocale('C', 'numeric')
for _, f in pairs(serials) do
local directory_updated = false
if lfs.attributes(f, "mode") == "file" then
-- As an additional safety measure (to the ffiutil.fsync* calls
-- used below), we only backup the file to .old when it has
-- not been modified in the last 60 seconds. This should ensure
-- in the case the fsync calls are not supported that the OS
-- may have itself sync'ed that file content in the meantime.
local mtime = lfs.attributes(f, "modification")
if mtime < os.time() - 60 then
logger.dbg("Rename ", f, " to ", f .. ".old")
os.rename(f, f .. ".old")
directory_updated = true -- fsync directory content too below
end
end
logger.dbg("Write to ", f)
local f_out = io.open(f, "w")
if f_out ~= nil then
f_out:write("-- we can read Lua syntax here!\nreturn ")
f_out:write(s_out)
f_out:write("\n")
ffiutil.fsyncOpenedFile(f_out) -- force flush to the storage device
f_out:close()
if self.candidates ~= nil
and not G_reader_settings:readSetting(
"preserve_legacy_docsetting") then
for _, k in pairs(self.candidates) do
if k[1] ~= f and k[1] ~= f .. ".old" then
logger.dbg("Remove legacy file ", k[1])
os.remove(k[1])
-- We should not remove sidecar folder, as it may
-- contain Kindle history files.
end
end
end
if directory_updated then
-- Ensure the file renaming is flushed to storage device
ffiutil.fsyncDirectory(f)
end
break
end
end
end
function DocSettings:close()
self:flush()
end
--- Purges (removes) sidecar directory.
function DocSettings:purge()
if self.history_file then
os.remove(self.history_file)
end
if lfs.attributes(self.sidecar, "mode") == "directory" then
ffiutil.purgeDir(self.sidecar)
end
self.data = {}
end
return DocSettings