The current article is saved to pages history user data before any
navigation to another page and before reloading the current page.
Therefore saving it each time the user activates an article is
redundant. This redundancy is not consistent, because when a user
activates an article by clicking on it, the current article changes in
the UI, but is not immediately saved in history as setCurrentArticle()
is not called. The inconsistent redundancy is a waste of CPU time and
can hide bugs.
This variable overrides history user data, which makes the current
article and position restoring code in ArticleView::loadFinished()
difficult to understand.
Encode the same logic in the history user data instead. This should make
the code more straightforward and less brittle in the face of changes.
MainWindow calls ArticleView::reload() when the group list is updated.
This updating may add/remove/reorder dictionaries in the active group.
MainWindow also calls ArticleView::reload() when the display or addon
style changes.
In both of the above scenarios uncontrolled jumps and current article
change can occur (see also the parent commit message).
Move setting articleToJump from above the only ArticleView's reload()
call into ArticleView::reload() itself.
When the first article in the list is current, expanding or collapsing
optional parts results in:
1) uncontrolled jumps due to the content height changes if the scroll
position is not (0, 0);
2) current article change if a non-first article is saved in history
user data (e.g. if a mouse click had made the first article active).
Treat the first current article in the same way as non-first ones.
This change also affects the case when the current article is not
present in the article list. If the current article is simply empty,
then there is no behavior change. If the current article is not empty,
it *must* be in the list, unless something else went wrong.
This way it is clearer that the pages history is updated just before
each navigation to a different page.
The call to ArticleView::saveHistoryUserData() now occurs slightly later
in ArticleView::showDefinition(). I don't think the intervening code can
affect the current article or window position. So the reordering most
likely does not affect application behavior.
Without the added saveHistoryUserData() call, returning back from the
enlarged picture page ("gdpicture") restores the current article and the
window position that were last saved. At this commit the "gdpicture"
behavior is consistent with regular links: returning back from the
enlarged picture page sets the article with the picture as current and
restores the window position at the time of the click on the picture.
https://doc.qt.io/archives/qt-5.5/qtwebkit-bridge.html#internet-security
Qt WebKit Bridge documentation recommends:
When exposing native objects to an open web environment, it is
important to understand the security implications. Think whether the
exposed object enables the web environment access things that
shouldn't be open, and whether the web content loaded by that web page
comes from a trusted source.
The author of Qt WebChannel has said the following in a talk that
introduced this Qt module (WebKit Bridge replacement for Qt WebEngine):
My suggestion here is to write dedicated QObjects with a slim, minimal
API that only have the signals and methods that you deem safe to be
used from the outside.
- see a comment under https://redirect.invidious.io/watch?v=KnvnTi6XafA
When the current article is set and the user expands or collapses
optional parts (e.g. via the Ctrl+* shortcut),
ArticleView::setCurrentArticle() is called twice from
ArticleView::loadFinished(). Furthermore, the window scroll position is
restored before the second jump. This is wasteful. Move the
higher-priority setCurrentArticle() call up and, if it succeeds, skip
the other call and the scrolling.
I have measured the time spent running the affected code fragment on my
GNU/Linux system before and at this commit. When the loaded articles are
not very large, the performance gain of this commit is only about 1 ms.
However, when one of the displayed articles was huge (the
"United States" English Wikipedia article), the time went from 120 ms to
5 ms.
The wall time of calls to ArticleView::highlightAllFtsOccurences() on my
GNU/Linux system before and at this commit:
allMatches.size() uniqueMatches.size() before(ms) at(ms)
79 1 277 4
98 1 380 4
267 1 16803 65
Extracting this function allows to simplify the code and facilitates
optimizing it in the next commit.
Remove `#if QT_VERSION >= 0x040600` along the way as GoldenDict does not
support Qt versions older than 4.6 for several years now.
