Install Wizard: Add derivation path scanner #2199
Conversation
This allows a user to scan a set of known derivation paths for transactions when restoring a wallet from a seed.
electroncash_gui/qt/installwizard.py
Outdated
| time.sleep(0.1) | ||
| num_tx = len(wallet.get_history()) | ||
| wallet.clear_history() | ||
| self.progress_cb(i, str(num_tx)) |
There was a problem hiding this comment.
Hey man; this is touching the GUI from a thread that is not the main thread. That's UB.
The typical way to do this is you leverage Qt's signal/slot mechanism to emit a signal which gets delivered to the main thread. An example of this can be found in main_window.py where you have def on_network(): which is executed as a callback in the network thread, and all that does is immediately emit a signal that gets caught in the main thread in def on_network_qt():...
Here is more background on how to work with Qt across threads: https://doc.qt.io/qt-5/threads-qobject.html
Although QObject is reentrant, the GUI classes, notably QWidget and all its subclasses, are not reentrant. They can only be used from the main thread. As noted earlier, QCoreApplication::exec() must also be called from that thread.
In practice, the impossibility of using GUI classes in other threads than the main thread can easily be worked around ...
There was a problem hiding this comment.
Hey man; this is touching the GUI from a thread that is not the main thread. That's UB.
Oh, I see. That shouldn't be too hard to work around and I'll see if I get time for it this weekend.
Thanks for the review.
There was a problem hiding this comment.
Alternatively I could also work on this and "finish it up" for you to handle this. I like this feature.. and I think it's a valuable addition. So. whomever makes it first wins I guess :)
The callback will not emit a signal and the table update will be done in the main thread. Also add early return if there isn't any network so we don't have to mess around with any keys, wallets or stuff like that if we can't really scan.
|
Nice solution. Elegant. I love this feature. Thanks man! |
* Install Wizard: Add derivation path scanner This allows a user to scan a set of known derivation paths for transactions when restoring a wallet from a seed. * Use global network instance * Do not touch GUI stuff from other thread The callback will not emit a signal and the table update will be done in the main thread. Also add early return if there isn't any network so we don't have to mess around with any keys, wallets or stuff like that if we can't really scan.
* Install Wizard: Add derivation path scanner This allows a user to scan a set of known derivation paths for transactions when restoring a wallet from a seed. * Use global network instance * Do not touch GUI stuff from other thread The callback will not emit a signal and the table update will be done in the main thread. Also add early return if there isn't any network so we don't have to mess around with any keys, wallets or stuff like that if we can't really scan.
* Install Wizard: Add derivation path scanner This allows a user to scan a set of known derivation paths for transactions when restoring a wallet from a seed. * Use global network instance * Do not touch GUI stuff from other thread The callback will not emit a signal and the table update will be done in the main thread. Also add early return if there isn't any network so we don't have to mess around with any keys, wallets or stuff like that if we can't really scan.
* Install Wizard: Add derivation path scanner This allows a user to scan a set of known derivation paths for transactions when restoring a wallet from a seed. * Use global network instance * Do not touch GUI stuff from other thread The callback will not emit a signal and the table update will be done in the main thread. Also add early return if there isn't any network so we don't have to mess around with any keys, wallets or stuff like that if we can't really scan.
This allows a user to scan a set of known derivation paths for
transactions when restoring a wallet from a seed.