Datastorage: do not create unnecessary folders (#10162)

datastorage.lua

@@ -1,4 +1,4 @@
--- need low-level mechnism to detect android to avoid recursive dependency
+-- need low-level mechanism to detect android to avoid recursive dependency
 local isAndroid, android = pcall(require, "android")
 local lfs = require("libs/libkoreader-lfs")
 
@@ -60,13 +60,23 @@ end
 
 local function initDataDir()
     local sub_data_dirs = {
-        "cache", "clipboard",
-        "data", "data/dict", "data/tessdata", "docsettings",
-        "history", "ota", "patches", "plugins",
-        "screenshots", "settings", "styletweaks",
+        "cache",
+        "clipboard",
+        "data",
+        "data/dict",
+        "data/tessdata",
+        -- "docsettings", -- created when needed
+        -- "history", -- legacy/obsolete sidecar files
+        "ota",
+        -- "patches", -- must be created manually by the interested user
+        "plugins",
+        "screenshots",
+        "settings",
+        "styletweaks",
     }
+    local datadir = DataStorage:getDataDir()
     for _, dir in ipairs(sub_data_dirs) do
-        local sub_data_dir = string.format("%s/%s", DataStorage:getDataDir(), dir)
+        local sub_data_dir = string.format("%s/%s", datadir, dir)
         if lfs.attributes(sub_data_dir, "mode") ~= "directory" then
             lfs.mkdir(sub_data_dir)
         end

frontend/readhistory.lua

@@ -125,10 +125,12 @@ function ReadHistory:_read(force_read)
     end
 end
 
---- Reads history from legacy history folder.
+--- Reads history from legacy history folder and remove it iff empty.
+-- Legacy history file is deleted when respective book is opened or deleted.
 function ReadHistory:_readLegacyHistory()
-    local history_updated
     local history_dir = DataStorage:getHistoryDir()
+    if not lfs.attributes(history_dir) then return end
+    local history_updated
     for f in lfs.dir(history_dir) do
         local legacy_history_file = joinPath(history_dir, f)
         if lfs.attributes(legacy_history_file, "mode") == "file" then
@@ -145,6 +147,7 @@ function ReadHistory:_readLegacyHistory()
         self:_reduce()
         self:_flush()
     end
+    os.remove(history_dir)
 end
 
 function ReadHistory:_init()

spec/unit/commonrequire.lua

@@ -42,8 +42,10 @@ require("dbg"):turnOff()
 local logger = require("logger")
 logger:setLevel(logger.levels.warn)
 
--- global defaults
 local DataStorage = require("datastorage")
+require("libs/libkoreader-lfs").mkdir(DataStorage:getHistoryDir()) -- for legacy history tests
+
+-- global defaults
 os.remove(DataStorage:getDataDir() .. "/defaults.tests.lua")
 os.remove(DataStorage:getDataDir() .. "/defaults.tests.lua.old")
 G_defaults = require("luadefaults"):open(DataStorage:getDataDir() .. "/defaults.tests.lua")

spec/unit/filemanager_spec.lua

@@ -89,6 +89,7 @@ describe("FileManager module", function()
         local tmpsf = io.open(tmp_sidecar_file, "w")
         tmpsf:write("{}")
         tmpsf:close()
+        lfs.mkdir(require("datastorage"):getHistoryDir())
         local tmp_history = docsettings:getHistoryPath(tmp_fn)
         local tmpfp = io.open(tmp_history, "w")
         tmpfp:write("{}")

spec/unit/readhistory_spec.lua

@@ -92,6 +92,7 @@ describe("ReadHistory module", function()
         local h = reload()
         now = now + 61
         h:addItem(test_file("a"), now)
+        mkdir(DataStorage:getHistoryDir())
         touch(legacy_history_file("b"))
         h = reload()
         assert.is.same(2, #h.hist)
@@ -113,6 +114,7 @@ describe("ReadHistory module", function()
         local h = reload()
         now = now + 61
         h:addItem(test_file("f"), now)
+        mkdir(DataStorage:getHistoryDir())
         touch(legacy_history_file("c"))
         touch(legacy_history_file("b"))
         now = now + 61