Basic fixes to calibre-sync (#3558)

* Properly create intermediate directories when receiving books from Calibre.

This fixes an issue where you can't receive books except into directories that
already exist on the Kobo, which, in particular, causes problems when your
configuration in Calibre is something like "put books in $Author/$Title.epub"
and you haven't previously synced any books by that author.

* Wake up periodically to process ZMQs if any are registered.

This fixes an issue where if there are any timed events (such as the suspend
timer) in the queue, ZMQ events may not get processed until the timed event
fires, which is a problem when (for example) the suspend timer goes off in
an hour and you have something trying to send a book to the kobo over wifi
*right now*.

With this change, the event loop will wake up every 50ms to check for ZMQ
events and process them if necessary. If there are no ZMQs registered (which
is typical), it uses the original behaviour -- so this won't affect battery
life under normal usage.

frontend/ui/uimanager.lua

@@ -21,6 +21,9 @@ local UIManager = {
         G_reader_settings:readSetting("full_refresh_count") or DRCOUNTMAX,
     refresh_count = 0,
 
+    -- How long to wait between ZMQ wakeups: 50ms.
+    ZMQ_TIMEOUT = 50 * 1000,
+
     event_handlers = nil,
 
     _running = true,
@@ -660,6 +663,27 @@ function UIManager:resetInputTimeout()
     self.INPUT_TIMEOUT = nil
 end
 
+function UIManager:handleInputEvent(input_event)
+    if input_event.handler ~= "onInputError" then
+        self.event_hook:execute("InputEvent", input_event)
+    end
+    local handler = self.event_handlers[input_event]
+    if handler then
+        handler(input_event)
+    else
+        self.event_handlers["__default__"](input_event)
+    end
+end
+
+-- Process all pending events on all registered ZMQs.
+function UIManager:processZMQs()
+    for _, zeromq in ipairs(self._zeromqs) do
+        for input_event in zeromq.waitEvent,zeromq do
+            self:handleInputEvent(input_event)
+        end
+    end
+end
+
 function UIManager:handleInput()
     local wait_until, now
     -- run this in a loop, so that paints can trigger events
@@ -683,42 +707,32 @@ function UIManager:handleInput()
         self:_repaint()
     until not self._task_queue_dirty
 
-    -- wait for next event
-    -- note that we will skip that if we have tasks that are ready to run
-    local input_event = nil
-    if not wait_until then
-        if #self._zeromqs > 0 then
-            -- pending message queue, wait 100ms for input
-            input_event = Input:waitEvent(1000*100)
-            if not input_event or input_event.handler == "onInputError" then
-                for _, zeromq in ipairs(self._zeromqs) do
-                    input_event = zeromq:waitEvent()
-                    if input_event then break end
-                end
-            end
-        else
-            -- no pending task, wait without timeout
-            input_event = Input:waitEvent(self.INPUT_TIMEOUT)
-        end
-    elseif wait_until[1] > now[1]
-    or wait_until[1] == now[1] and wait_until[2] > now[2] then
-        -- wait until next task is pending
-        local wait_us = (wait_until[1] - now[1]) * MILLION
-                        + (wait_until[2] - now[2])
-        input_event = Input:waitEvent(wait_us)
+    -- run ZMQs if any
+    self:processZMQs()
+
+    -- Figure out how long to wait.
+    -- Default to INPUT_TIMEOUT (which may be nil, i.e. block until an event happens).
+    local wait_us = self.INPUT_TIMEOUT
+
+    -- If there's a timed event pending, that puts an upper bound on how long to wait.
+    if wait_until then
+        wait_us = math.min(
+            wait_us or math.huge,
+            (wait_until[1] - now[1]) * MILLION
+            + (wait_until[2] - now[2]))
     end
 
+    -- If we have any ZMQs registered, ZMQ_TIMEOUT is another upper bound.
+    if #self._zeromqs > 0 then
+        wait_us = math.min(wait_us or math.huge, self.ZMQ_TIMEOUT)
+    end
+
+    -- wait for next event
+    local input_event = Input:waitEvent(wait_us)
+
     -- delegate input_event to handler
     if input_event then
-        if input_event.handler ~= "onInputError" then
-            self.event_hook:execute("InputEvent", input_event)
-        end
-        local handler = self.event_handlers[input_event]
-        if handler then
-            handler(input_event)
-        else
-            self.event_handlers["__default__"](input_event)
-        end
+        self:handleInputEvent(input_event)
     end
 
     if self.looper then

frontend/util.lua

@@ -304,6 +304,32 @@ function util.isEmptyDir(path)
     return true
 end
 
+--- Checks if the given path exists. Doesn't care if it's a file or directory.
+---- @string path
+---- @treturn bool
+function util.pathExists(path)
+    local lfs = require("libs/libkoreader-lfs")
+    return lfs.attributes(path, "mode") ~= nil
+end
+
+--- As `mkdir -p`.
+--- Unlike lfs.mkdir(), does not error if the directory already exists, and
+--- creates intermediate directories as needed.
+---- @string path the directory to create
+---- @treturn bool true on success; nil, err_message on error
+function util.makePath(path)
+    path = path:gsub("/+$", "")
+    if util.pathExists(path) then return true end
+
+    local success, err = util.makePath((util.splitFilePathName(path)))
+    if not success then
+        return nil, err.." (creating "..path..")"
+    end
+
+    local lfs = require("libs/libkoreader-lfs")
+    return lfs.mkdir(path)
+end
+
 --- Replaces characters that are invalid filenames.
 --
 -- Replaces the characters <code>\/:*?"<>|</code> with an <code>_</code>.
@@ -326,7 +352,9 @@ function util.replaceSlashChar(str)
     end
 end
 
---- Splits a file into its path and name
+--- Splits a file into its directory path and file name.
+--- If the given path has a trailing /, returns the entire path as the directory
+--- path and "" as the file name.
 ---- @string file
 ---- @treturn string path, filename
 function util.splitFilePathName(file)

plugins/calibrecompanion.koplugin/main.lua

@@ -5,6 +5,7 @@ local JSON = require("json")
 local DEBUG = require("dbg")
 local _ = require("gettext")
 local NetworkMgr = require("ui/network/manager")
+local util = require("frontend/util")
 
 require("ffi/zeromq_h")
 
@@ -320,6 +321,7 @@ function CalibreCompanion:sendBook(arg)
     local inbox_dir = G_reader_settings:readSetting("inbox_dir")
     local filename = inbox_dir .. "/" .. arg.lpath
     DEBUG("write to file", filename)
+    util.makePath((util.splitFilePathName(filename)))
     local outfile = io.open(filename, "wb")
     local to_write_bytes = arg.length
     local calibre_device = self