Bring latest changes to procedural cosmetic filtering to uBOL.
Fix procedural filtering used in HTML filters.
Standardize quick hash algorithm used throughout to DJB2
(except that initialization step is skipped):
- http://www.cse.yorku.ca/~oz/hash.html#djb2
Related feedback:
- https://www.reddit.com/r/uBlockOrigin/comments/ye6abt/
Possibly because the Opera sidebar window is a special
case, it appears the scriptlets must be injected at a
later time.
Use a global isolated window variable to detect whether
the scriptlets have really be injected, and ultimately
inject them at main content script time when it is found
they haven't been injected at that point.
This commit make it so scriptlet injections will occur
at the earliest possible time on all platform.
This should also fix the case reported at:
- https://www.reddit.com/r/uBlockOrigin/comments/ye6abt/
Which is caused by the fact that there is no webNavigation
events being fired by the browser. In such case, the changes
here will make it so that uBO will detect that the scriptlet
were not injected and will inject them at main content script
injection time.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/1692
The ids/classes from html/body elements will leave out
looking up lowly generic cosmetic filters made of a single
identifier.
This does not absolutely guarantee that html/body elements
will never be targeted, but it should greatly mitigate the
probability that this erroneously happens.
Related issue:
- https://github.com/gorhill/uBlock/issues/3212
The element picker will now properly work on sites where
cosmetic filtering is disabled, but will not allow the
creation of cosmetic filters when specific cosmetic filters
are not meant to be enforced in the current page.
When specific cosmetic filters are not meant to be enforced,
the element picker will still allow the creation of network
filters, that is unless the current page is trusted, in which
case using the element picker is pointless.
The procedural cosmetic filtering code has been split from
the content script code injected unconditionally and will
from now on be injected only when it is needed, i.e. when
there are procedural cosmetic filters to enforce.
The motivation for this is:
https://www.debugbear.com/blog/2020-chrome-extension-performance-report#what-can-extension-developers-do-to-keep-their-extensions-fast
Though uBO's content script injected unconditionally in all
pages/frames is relatively small, I still wanted to further
reduce the amount of content script code injected
unconditionally: The procedural cosmetic filtering code
represents roughly 14KB of code the browser won't have to
parse/execute unconditionally unless there exists procedural
cosmetic filters to enforce for a page or frame.
At the time the above article was published, the total
size of unconditional content scripts injected by uBO was
~101 KB, while after this commit, the total size will be
~57 KB (keeping in mind uBO does not minify and does not
remove comments from its JavaScript code).
Additionally, some refactoring on how user stylesheets are
injected so as to ensure that `:style`-based procedural
filters which are essentially declarative are injected
earlier along with plain, non-procedural cosmetic filters.
Content scripts can't properly look up effective context
for sandboxed frames. This commit add ability to extract
effective context from already existing store of frames
used for each tab.
`about:srcdoc` frames are their own origin, trying to
use the origin of the parent context causes an
exception to be thrown when accessing location.href.
Injecting declarative CSS `:style()` selector could cause
the instatiation of the procedural filterer, even when
there was no actual procedural cosmetic filter to
enforce.
This commit ensure that the procedural cosmetic filterer
is instantiated only when there are actual procedural
filters to enforce.
The pseudo user styles code served only browsers based
on Chromium 65 and earlier -- Chromium 66 supports
native user styles and was first released more than two
years ago.
In Chromium-based browsers, the pseudo user styles code
is being unconditionally injected in every page/frame
just in case the browser is version 65 or earlier.
Removing pseudo user styles reduce uBO's main content
script in Chromium-based browsers by more than 20K.
Related thread:
- https://github.com/NanoAdblocker/NanoCore/issues/348#issuecomment-653646507
***
New procedural cosmetic operator: `:remove()`
Related issue:
- https://github.com/gorhill/uBlock/issues/2252
The purpose is to outright remove elements from the
DOM tree. Since `:remove()` is an "action" operator,
it must only be used as a trailing operator (just
like the `:style()` operator).
AdGuard's cosmetic filter syntax `{ remove: true; }`
will be converted to uBO's `:remove()` operator
internally.
***
New procedural cosmetic operator: `:upward(...)`
The purpose is to lookup an ancestor element.
When used with an integer argument, it is synonym of
`:nth-ancestor()`, which will be deprecated and which
will no longer be supported once no longer used in
mainstream filter lists.
Filter lists maintainers must only use `:upward(int)`
instead of `:nth-ancestor(int)` once the new operator
become available in all stable releases of uBO.
`:upward()` can also accept a CSS selector as argument,
in which case the nearest ancestor which matches the
CSS selector will be selected.
Raymond Hill