Add URLPatternList

spec.bs

@@ -810,6 +810,83 @@ To <dfn>compute protocol matches a special scheme flag</dfn> given a [=construct
   1. If the result of running [=protocol component matches a special scheme=] given |protocol component| is true, then set |parser|'s [=constructor string parser/protocol matches a special scheme flag=] to true.
 </div>
 
+<h2 id=urlpatternlist-class>The {{URLPatternList}} class </h2>
+
+<xmp class="idl">
+[Exposed=(Window,Worker)]
+interface URLPatternList {
+  constructor(sequence<URLPatternListEntry> entries);
+
+  USVString? test(optional URLPatternInput input = {}, optional USVString baseURL);
+
+  URLPatternListResult? exec(optional URLPatternInput input = {}, optional USVString baseURL);
+};
+
+dictionary URLPatternListEntry {
+  required (USVString or URLPattern) pattern;
+  required USVString key;
+};
+
+dictionary URLPatternListResult {
+  URLPatternResult match;
+  USVString key;
+};
+</xmp>
+
+Note: The {{URLPatternList}} is a utility that combines many patterns into one
+matcher. This functionality can also be achieved in a naive userland
+implementation that iterates over a list of patterns and matches each one
+individually. This has the unfortunate effect of not being very fast. With the
+built-in {{URLPatternList}} implementers can use a radix tree for matching under
+the hood which can drastically improve performance over the naive userland
+implementation.
+
+Each {{URLPatternList}} has an associated <dfn for=URLPatternList>pattern list</dfn>, a [=list=] of {{URLPattern}}s.
+
+Each {{URLPatternList}} has an associated <dfn for=URLPatternList>key list</dfn>, a [=list=] of [=string=]s.
+
+<div algorithm>
+  The <dfn constructor for=URLPatternList lt="URLPatternList(entries)">new URLPattern(|entries|)</dfn> constructor steps are:
+
+  1. [=list/For each=] |entry| in |entries|, run the following steps:
+    1. [=list/Append=] the |entry|'s {{URLPatternListEntry/pattern}} to [=this=]'s [=URLPatternList/pattern list=].
+    1. Let |key| be |entry|'s {{URLPatternListEntry/key}}.
+    1. If |key| is the empty string, throw a {{TypeError}}.
+    1. If [=this=]'s [=URLPatternList/key list=] [=list/contains=] |key|, throw a {{TypeError}}.
+    1. [=list/Append=] |key| to [=this=]'s [=URLPatternList/key list=].
+  1. If [=this=]'s [=URLPatternList/pattern list=] is empty, throw a {{TypeError}}.
+
+  Issue: The patterns need to be in a "least -> most significant" sort order so
+  implementers can efficiently use a radix tree under the hood. Enforcing /
+  sorting the patterns in this order depends on
+  <a href=https://github.com/WICG/urlpattern/issues/61>https://github.com/WICG/urlpattern/issues/61</a>.
+</div>
+
+<div>
+  The <dfn method for=URLPatternList>test(|input|, |baseURL|)</dfn> method steps are:
+
+  1. Let |i| be 0.
+  1. [=list/For each=] |pattern| in [=this=]'s [=URLPatternList/pattern list=], run the following steps:
+    1. Let |result| be the result of [=match=] given |pattern|, |input|, and |baseURL| if given.
+    1. If |result| is null, [=continue=].
+    1. Return [=this=]'s [=URLPatternList/key list=][|i|].
+  1. Return null.
+</div>
+
+<div>
+  The <dfn method for=URLPatternList>match(|input|, |baseURL|)</dfn> method steps are:
+
+  1. Let |i| be 0.
+  1. [=list/For each=] |pattern| in [=this=]'s [=URLPatternList/pattern list=], run the following steps:
+    1. Let |match| be the result of [=match=] given |pattern|, |input|, and |baseURL| if given.
+    1. If |match| is null, [=continue=].
+    1. Let |result| be a new {{URLPatternListResult}} dictionary.
+    1. Set |result|'s {{URLPatternListResult/match}} to |match|.
+    1. Set |result|'s {{URLPatternListResult/key}} to [=this=]'s [=URLPatternList/key list=][|i|].
+    1. Return |result|.
+  1. Return null.
+</div>
+
 <h2 id=patterns>Patterns</h2>
 
 A <dfn>pattern string</dfn> is a string that is written to match a set of target strings.  A <dfn for="pattern string">well formed</dfn> pattern string conforms to a particular pattern syntax.  This pattern syntax is directly based on the syntax used by the popular [path-to-regexp](https://github.com/pillarjs/path-to-regexp) JavaScript library.