mirror of
https://github.com/koreader/koreader
synced 2024-11-13 19:11:25 +00:00
52 lines
1.6 KiB
Markdown
52 lines
1.6 KiB
Markdown
Hacking
|
|
=======
|
|
|
|
## How to Debug
|
|
|
|
We have a helper function called `logger.dbg` to help with debugging. You can use that function to print string and tables:
|
|
|
|
```lua
|
|
local logger = require("logger")
|
|
a = {"1", "2", "3"}
|
|
logger.dbg("table a: ", a)
|
|
```
|
|
|
|
Anything printed by `logger.dbg` starts with `DEBUG`.
|
|
|
|
On most target platforms, log output is saved to `crash.log` in the `koreader` directory.
|
|
|
|
```
|
|
04/06/17-21:44:53 DEBUG foo
|
|
```
|
|
|
|
In production code, remember that arguments are *always* evaluated in Lua, so,
|
|
don't inline complex computations in logger functions' arguments.
|
|
If you *really* have to, hide the whole thing behind a `dbg.is_on` branch,
|
|
like in [frontend/device/input.lua](https://github.com/koreader/koreader/blob/ba6fef4d7ba217ca558072f090849000e72ba142/frontend/device/input.lua#L1131-L1134).
|
|
|
|
## Bug hunting in KPV (KOReader's predecessor)
|
|
|
|
A real example of bug hunting in KPV's cache system: <https://github.com/koreader/kindlepdfviewer/pull/475>
|
|
|
|
|
|
## Developing UI widgets ##
|
|
|
|
`tools/wbuilder.lua` is your friend, if you need to create new UI widgets. It
|
|
sets up a minimal environment to bootstrap KOReader's UI framework to avoid
|
|
starting the whole reader. This gives you quick feedback loop while iterating
|
|
through your widget changes. It's also a handy tool for debugging widget
|
|
issues.
|
|
|
|
To get a taste of how it works, try running this command at the root of
|
|
KOReader's source tree:
|
|
|
|
```
|
|
./kodev wbuilder
|
|
```
|
|
|
|
It will spawn up an emulator window with a grid and simple timer widget for
|
|
demonstration.
|
|
|
|
You can add more `UIManager:show` call at the end of `tools/wbuilder.lua` to
|
|
test your new widgets.
|