A new standalone static filtering parser is introduced,
vAPI.StaticFilteringParser. It's purpose is to parse
line of text into representation suitable for
compiling filters. It can additionally serves for
syntax highlighting purpose.
As a side effect, this solves:
- https://github.com/uBlockOrigin/uBlock-issues/issues/1038
This is a first draft, there are more work left to do
to further perfect the implementation and extend its
capabilities, especially those useful to assist filter
authors.
For the time being, this commits break line-continuation
syntax highlighting -- which was already flaky prior to
this commit anyway.
This concerns the static network filtering engine.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/943
* * *
New static network filter type: `cname`
By default, network requests which are result of
resolving a canonical name are subject to filtering.
This filtering can be bypassed by creating exception
filters using the `cname` option. For example:
@@*$cname
The filter above tells the network filtering engine
to except network requests which fulfill all the
following conditions:
- network request is blocked
- network request is that of an unaliased hostname
Filter list authors are discouraged from using
exception filters of `cname` type, unless there no
other practical solution such that maintenance
burden become the greater issue. Of course, such
exception filters should be as narrow as possible,
i.e. apply to specific domain, etc.
* * *
New static network filter option: `denyallow`
The purpose of `denyallow` is bring
default-deny/allow-exceptionally ability into static
network filtering arsenal. Example of usage:
*$3p,script, \
denyallow=x.com|y.com \
domain=a.com|b.com
The above filter tells the network filtering engine that
when the context is `a.com` or `b.com`, block all
3rd-party scripts except those from `x.com` and `y.com`.
Essentially, the new `denyallow` option makes it easier
to implement default-deny/allow-exceptionally in static
filter lists, whereas before this had to be done with
unwieldy regular expressions[1], or through the mix of
broadly blocking filters along with exception filters[2].
[1] https://hg.adblockplus.org/ruadlist/rev/f362910bc9a0
[2] Typically filters which pattern are of the
form `|http*://`
Related issues:
- https://github.com/uBlockOrigin/uBlock-issues/issues/761
- https://github.com/uBlockOrigin/uBlock-issues/issues/528
The previous bidi-trie code could only hold filters which
are plain pattern, i.e. no wildcard characters, and which
had no origin option (`domain=`), right and/or left anchor,
and no `csp=` option.
Example of filters that could be moved into a bidi-trie
data structure:
&ad_box_
/w/d/capu.php?z=$script,third-party
||liveonlinetv247.com/images/muvixx-150x50-watch-now-in-hd-play-btn.gif
Examples of filters that could NOT be moved to a bidi-trie:
-adap.$domain=~l-adap.org
/tsc.php?*&ses=
||ibsrv.net/*forumsponsor$domain=[...]
@@||imgspice.com/jquery.cookie.js|$script
||view.atdmt.com^*/iview/$third-party
||postimg.cc/image/$csp=[...]
Ideally the filters above should be able to be moved to a
bidi-trie since they are basically plain patterns, or at
least partially moved to a bidi-trie when there is only a
single wildcard (i.e. made of two plain patterns).
Also, there were two distinct bidi-tries in which
plain-pattern filters can be moved to: one for patterns
without hostname anchoring and another one for patterns
with hostname-anchoring. This was required because the
hostname-anchored patterns have an extra condition which
is outside the bidi-trie knowledge.
This commit expands the number of filters which can be
stored in the bidi-trie, and also remove the need to
use two distinct bidi-tries.
- Added ability to associate a pattern with an integer
in the bidi-trie [1].
- The bidi-trie match code passes this externally
provided integer when calling an externally
provided method used for testing extra conditions
that may be present for a plain pattern found to
be matching in the bidi-trie.
- Decomposed existing filters into smaller logical units:
- FilterPlainLeftAnchored =>
FilterPatternPlain +
FilterAnchorLeft
- FilterPlainRightAnchored =>
FilterPatternPlain +
FilterAnchorRight
- FilterExactMatch =>
FilterPatternPlain +
FilterAnchorLeft +
FilterAnchorRight
- FilterPlainHnAnchored =>
FilterPatternPlain +
FilterAnchorHn
- FilterWildcard1 =>
FilterPatternPlain + [
FilterPatternLeft or
FilterPatternRight
]
- FilterWildcard1HnAnchored =>
FilterPatternPlain + [
FilterPatternLeft or
FilterPatternRight
] +
FilterAnchorHn
- FilterGenericHnAnchored =>
FilterPatternGeneric +
FilterAnchorHn
- FilterGenericHnAndRightAnchored =>
FilterPatternGeneric +
FilterAnchorRight +
FilterAnchorHn
- FilterOriginMixedSet =>
FilterOriginMissSet +
FilterOriginHitSet
- Instances of FilterOrigin[...], FilterDataHolder
can also be added to a composite filter to
represent `domain=` and `csp=` options.
- Added a new filter class, FilterComposite, for
filters which are a combination of two or more
logical units. A FilterComposite instance is a
match when *all* filters composing it are a
match.
Since filters are now encoded into combination of
smaller units, it becomes possible to extract the
FilterPatternPlain component and store it in the
bidi-trie, and use the integer as a handle for the
remaining extra conditions, if any.
Since a single pattern in the bidi-trie may be a
component for different filters, the associated
integer points to a sequence of extra conditions,
and a match occurs as soon as one of the extra
conditions (which may itself be a sequence of
conditions) is fulfilled.
Decomposing filters which are currently single
instance into sequences of smaller logical filters
means increasing the storage and CPU overhead when
evaluating such filters. The CPU overhead is
compensated by the fact that more filters can now
moved into the bidi-trie, where the first match is
efficiently evaluated. The extra conditions have to
be evaluated if and only if there is a match in the
bidi-trie.
The storage overhead is compensated by the
bidi-trie's intrinsic nature of merging similar
patterns.
Furthermore, the storage overhead is reduced by no
longer using JavaScript array to store collection
of filters (which is what FilterComposite is):
the same technique used in [2] is imported to store
sequences of filters.
A sequence of filters is a sequence of integer pairs
where the first integer is an index to an actual
filter instance stored in a global array of filters
(`filterUnits`), while the second integer is an index
to the next pair in the sequence -- which means all
sequences of filters are encoded in one single array
of integers (`filterSequences` => Uint32Array). As
a result, a sequence of filters can be represented by
one single integer -- an index to the first pair --
regardless of the number of filters in the sequence.
This representation is further leveraged to replace
the use of JavaScript array in FilterBucket [3],
which used a JavaScript array to store collection
of filters. Doing so means there is no more need for
FilterPair [4], which purpose was to be a lightweight
representation when there was only two filters in a
collection.
As a result of the above changes, the map of `token`
(integer) => filter instance (object) used to
associate tokens to filters or collections of filters
is replaced with a more efficient map of `token`
(integer) to filter unit index (integer) to lookup a
filter object from the global `filterUnits` array.
Another consequence of using one single global
array to store all filter instances means we can reuse
existing instances when a logical filter instance is
parameter-less, which is the case for FilterAnchorLeft,
FilterAnchorRight, FilterAnchorHn, the index to these
single instances is reused where needed.
`urlTokenizer` now stores the character codes of the
scanned URL into a bidi-trie buffer, for reuse when
string matching methods are called.
New method: `tokenHistogram()`, used to generate
histograms of occurrences of token extracted from URLs
in built-in benchmark. The top results of the "miss"
histogram are used as "bad tokens", i.e. tokens to
avoid if possible when compiling filter lists.
All plain pattern strings are now stored in the
bidi-trie memory buffer, regardless of whether they
will be used in the trie proper or not.
Three methods have been added to the bidi-trie to test
stored string against the URL which is also stored in
then bidi-trie.
FilterParser is now instanciated on demand and
released when no longer used.
***
[1] 135a45a878/src/js/strie.js (L120)
[2] e94024d350
[3] 135a45a878/src/js/static-net-filtering.js (L1630)
[4] 135a45a878/src/js/static-net-filtering.js (L1566)
Related documentation:
- https://help.eyeo.com/en/adblockplus/how-to-write-filters#element-hiding
Related feedback/discussion:
- https://www.reddit.com/r/uBlockOrigin/comments/d6vxzj/
The `elemhide` filter option as per ABP semantic is
now supported. Previously uBO would consider `elemhide`
to be an alias of `generichide`.
The support of `elemhide` is through the convenient
conversion of `elemhide` option into existing
`generichide` option and new `specifichide` option.
The purpose of the new `specifichide` filter option
is to disable all specific cosmetic filters, i.e.
those who target a specific site.
Additionally, for convenience purpose, the filter
options `generichide`, `specifichide` and `elemhide`
can be aliased using the shorter forms `ghide`,
`shide` and `ehide` respectively.
* refactoring assets management code
* finalizing refactoring of assets management
* various code review of new assets management code
* fix#2281
* fix#1961
* fix#1293
* fix#1275
* fix update scheduler timing logic
* forward compatibility (to be removed once 1.11+ is widespread)
* more codereview; give admins ability to specify own assets.json
* "assetKey" is more accurate than "path"
* fix group count update when building dom incrementally
* reorganize content (order, added URLs, etc.)
* ability to customize updater through advanced settings
* better spinner icon
