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Expand bidi-trie usage in static network filtering engine
Related issues: - uBlockOrigin/uBlock-issues#761 - uBlockOrigin/uBlock-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] https://github.com/gorhill/uBlock/blob/135a45a878f5b93bc538f822981e3a42b1e9073f/src/js/strie.js#L120 [2] e94024d [3] https://github.com/gorhill/uBlock/blob/135a45a878f5b93bc538f822981e3a42b1e9073f/src/js/static-net-filtering.js#L1630 [4] https://github.com/gorhill/uBlock/blob/135a45a878f5b93bc538f822981e3a42b1e9073f/src/js/static-net-filtering.js#L1566
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@gorhill After this commit, a filter like
*image_widget_c4w274ug7kv01.png
is ignored by uBlock Origin.found by @gwarser
Discussion src -
https://www.reddit.com/r/uBlockOrigin/comments/ex8ggg/need_help_with_a_reddit_filter/
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I don't see any
image_widget
reported in the logger athttps://www.reddit.com/r/nba/
.If there is an issue, I need a formal issue created along with a reproducible case.
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I found another image on the page and I can reproduce with
*communityIcon_1podsfdai4301.png
-- the logo of the page.7971b22
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Try at
https://new.reddit.com/r/nba/
The widget is only present in new reddit design.
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Ok I have identified and fixed the issue. I need to assess the severity to decide whether this must be an emergency fix.
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I see no filters affected in EasyList, EasyPrivacy -- searching with
/^(\|\|?)?\*[0-9a-z%]{2,}[^0-9a-z%$]+[0-9a-z%]{2,}/
. I see two filters affected in uBlock filters:Given how trivial the fix is, I lean toward an emergency fix since the next release is not going to happen soon.