Do not override the existing history

[Hzj-jie]

For #25, @mergen3107 would you mind take a shot if it works for your scenario?

You may just copy the file https://raw.githubusercontent.com/koreader/contrib/0413b13de4cde84a46be177e8b5c492c7123ec11/findhistory.koplugin/main.lua to replace the existing one in the plugin folder and restart the koreader.

Highly suggest backing up history before hand in case anything goes wrong.

This change is 

[mergen3107]

Hi @Hzj-jie
Thanks for looking into this!

I tried the new main.lua file.
It worked fine, but it created duplicates in history.
One of the the duplicated books somehow did not have cover (just triple dots) nor title/description upon long-press (empty). KOReader crashed after I tapped on it:

./luajit: frontend/apps/reader/readerui.lua:607: bad argument #1 to 'attributes' (string expected, got nil)
stack traceback:
	[C]: in function 'attributes'
	frontend/apps/reader/readerui.lua:607: in function 'showReader'
	frontend/apps/reader/readerui.lua:882: in function 'switchDocument'
	frontend/apps/filemanager/filemanagerhistory.lua:129: in function 'onMenuChoice'
	frontend/ui/widget/menu.lua:1339: in function 'onMenuSelect'
	plugins/coverbrowser.koplugin/mosaicmenu.lua:851: in function 'handleEvent'
	frontend/ui/widget/container/inputcontainer.lua:266: in function 'handleEvent'
	frontend/ui/widget/container/widgetcontainer.lua:83: in function 'propagateEvent'
	frontend/ui/widget/container/widgetcontainer.lua:101: in function 'handleEvent'
	frontend/ui/widget/container/widgetcontainer.lua:83: in function 'propagateEvent'
	frontend/ui/widget/container/widgetcontainer.lua:101: in function 'handleEvent'
	...
	frontend/ui/widget/container/widgetcontainer.lua:101: in function 'handleEvent'
	frontend/ui/widget/container/widgetcontainer.lua:83: in function 'propagateEvent'
	frontend/ui/widget/container/widgetcontainer.lua:101: in function 'handleEvent'
	frontend/ui/uimanager.lua:911: in function 'sendEvent'
	frontend/ui/uimanager.lua:53: in function '__default__'
	frontend/ui/uimanager.lua:1438: in function 'handleInputEvent'
	frontend/ui/uimanager.lua:1538: in function 'handleInput'
	frontend/ui/uimanager.lua:1582: in function 'run'
	./reader.lua:265: in main chunk
	[C]: at 0x00013ead
lipc-wait-event exited normally with status: 0

After next restart, I was able to see that this was a duplicate, and it opens by tapping on either of the copy (but only one gets updates in History with a timestamp, the other stay in the same place, but still works).

I'll revert to my backup history for now.

[Hzj-jie]

Thank you for the test, it looks more than I thought. I haven't touched the code in koreader for a while, likely something got changed. I will take a deeper look.