Screenshoter: fix screenshot folder (#12750)

Check for existance and create if absent.
Closes #12742.

frontend/ui/widget/screenshoter.lua

@@ -6,6 +6,7 @@ local GestureRange = require("ui/gesturerange")
 local InputContainer = require("ui/widget/container/inputcontainer")
 local UIManager = require("ui/uimanager")
 local filemanagerutil = require("apps/filemanager/filemanagerutil")
+local util = require("util")
 local Screen = require("device").screen
 local _ = require("gettext")
 
@@ -39,7 +40,10 @@ end
 
 function Screenshoter:getScreenshotDir()
     local screenshot_dir = G_reader_settings:readSetting("screenshot_dir")
-    return screenshot_dir and screenshot_dir:gsub("/$", "") or self.default_dir
+    if screenshot_dir and util.makePath(screenshot_dir) then
+        return screenshot_dir:gsub("/$", "")
+    end
+    return self.default_dir
 end
 
 function Screenshoter:onScreenshot(screenshot_name, caller_callback)
@@ -47,7 +51,7 @@ function Screenshoter:onScreenshot(screenshot_name, caller_callback)
         screenshot_name = os.date(self:getScreenshotDir() .. "/" .. self.prefix .. "_%Y-%m-%d_%H%M%S.png")
     end
     Screen:shot(screenshot_name)
-    local file = self.ui and self.ui.document and self.ui.document.file -- currently opened book
+    local file = self.ui.document and self.ui.document.file -- currently opened book
     local dialog
     local buttons = {
         {
@@ -97,10 +101,10 @@ function Screenshoter:onScreenshot(screenshot_name, caller_callback)
         modal = true,
         buttons = buttons,
         tap_close_callback = function()
-            if caller_callback then
+            if type(caller_callback) == "function" then
                 caller_callback()
             end
-            local current_path = self.ui and self.ui.file_chooser and self.ui.file_chooser.path
+            local current_path = self.ui.file_chooser and self.ui.file_chooser.path
             if current_path and current_path .. "/" == screenshot_name:match(".*/") then
                 self.ui.file_chooser:refreshPath()
             end
@@ -112,6 +116,10 @@ function Screenshoter:onScreenshot(screenshot_name, caller_callback)
     return true
 end
 
+Screenshoter.onKeyPressShoot = Screenshoter.onScreenshot
+Screenshoter.onTapDiagonal = Screenshoter.onScreenshot
+Screenshoter.onSwipeDiagonal = Screenshoter.onScreenshot
+
 function Screenshoter:chooseFolder()
     local title_header = _("Current screenshot folder:")
     local current_path = G_reader_settings:readSetting("screenshot_dir")
@@ -122,29 +130,15 @@ function Screenshoter:chooseFolder()
     filemanagerutil.showChooseDialog(title_header, caller_callback, current_path, default_path)
 end
 
-function Screenshoter:onKeyPressShoot()
-    return self:onScreenshot()
-end
-
-function Screenshoter:onTapDiagonal()
-    return self:onScreenshot()
-end
-
-function Screenshoter:onSwipeDiagonal()
-    return self:onScreenshot()
-end
-
 function Screenshoter:registerKeyEvents()
     if Device:hasKeyboard() then
         self.key_events.KeyPressShoot = {
             { "Alt", "Shift", "G" }, -- same as stock Kindle firmware
-            event = "KeyPressShoot",
         }
     elseif Device:hasScreenKB() then
         -- kindle 4 case: same as stock firmware.
         self.key_events.KeyPressShoot = {
             { "ScreenKB", "Menu" },
-            event = "KeyPressShoot",
         }
         -- unable to add other non-touch devices as simultaneous key presses won't work without modifiers
     end