Check router rule recursion depth

w3c · Jan 31, 2025 · f427b1a · f427b1a
1 parent 9f380a1
commit f427b1a
Showing 1 changed file with 55 additions and 11 deletions.
diff --git a/docs/index.bs b/docs/index.bs
@@ -212,10 +212,6 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
 
     A [=/service worker=] has an associated <dfn>list of router rules</dfn> (a [=list=] of {{RouterRule}}s). It is initially an empty [=list=].
 
-    A [=/service worker=] has an associated <dfn>router rule count</dfn> (the number of registered {{RouterRule}}s). It is initially set to zero.
-
-    Note: [=router rule count=] is defined as the limit of the total number of registered router rules. This prevents the user agent from spending much resources by evaluating too many router rules. The limit is 1024.
-
     A [=/service worker=] is said to be <dfn>running</dfn> if its [=event loop=] is running.
 
     <section>
@@ -1604,7 +1600,9 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
       };
     </pre>
 
-    Note: {{RouterCondition/_or}} and {{RouterCondition/not}} might have the other {{RouterCondition/_or}} or {{RouterCondition/not}} inside. To avoid spending much resources by the nested condition or performance penalty on evaluation, depth of such nested conditions can be limited.
+    A <dfn export id="dfn-count-router-condition-result">count router condition result</dfn> is a [=struct=] that consists of:
+      * A <dfn export id="dfn-count-router-condition-result-total-count" for="count router condition result">total count</dfn> (a number).
+      * A <dfn export id="dfn-dfn-count-router-condition-result-depth" for="count router condition result">depth</dfn> (a number).
 
     <section>
       <h4 id="register-router-method">{{InstallEvent/addRoutes(rules)|event.addRoutes(rules)}}</h4>
@@ -1620,6 +1618,7 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
             1. If running the [=Verify Router Condition=] algorithm with |rule|["{{RouterRule/condition}}"] and |serviceWorker| returns false, return [=a promise rejected with=] a {{TypeError}}.
             1. Append |rule| to |routerRules|.
         1. If |routerRules| [=list/contains=] a {{RouterRule}} whose {{RouterRule/source}} is either of "{{RouterSourceEnum/fetch-event}}" or "{{RouterSourceEnum/race-network-and-fetch-handler}}", and |serviceWorker|'s [=set of event types to handle=] does not [=set/contain=] {{ServiceWorkerGlobalScope/fetch!!event}}, return [=a promise rejected with=] a {{TypeError}}.
+        1. If running the [=Check Router Registration Limit=] with |serviceWorker| returns false, return [=a promise rejected with=] a {{TypeError}}.
         1. Set |serviceWorker|'s [=service worker/list of router rules=] to |routerRules|.
         1. Return [=a promise resolved with=] undefined.
 
@@ -3405,9 +3404,6 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
               Note: For ease of understanding the router rule, the "or" condition is mutually exclusive with other conditions.
 
           1. Let |orConditions| be |condition|["{{RouterCondition/_or}}"].
-
-              Note: To limit the resource usage and a condition evaluation time, |orConditions|'s [=list/size=] can be limited.
-
           1. For each |orCondition| of |orConditions|:
               1. If running the [=Verify Router Condition=] algorithm with |orCondition| and |serviceWorker| returns false, return false.
           1. Set |hasCondition| to true.
@@ -3418,9 +3414,6 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
 
           1. If running the [=Verify Router Condition=] algorithm with |condition|["{{RouterCondition/not}}"] and |serviceWorker| returns false, return false.
           1. Set |hasCondition| to true.
-      1. If |hasCondition| is true, then:
-          1. Increament |serviceWorker|'s [=service worker/router rule count=] by one.
-          1. If |serviceWorker|'s [=service worker/router rule count=] exceeds 1024, which is the limit of registered router rules, return false.
       1. Return |hasCondition|.
   </section>
 
@@ -3468,6 +3461,57 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
           1. Return true.
   </section>
 
+  <section algorithm>
+    <h3 id="check-router-registration-limit"><dfn>Check Router Registration Limit</dfn></h3>
+
+      : Input
+      :: |serviceWorker|, a [=/service worker=]
+      : Output
+      :: a boolean
+
+      Note: Router conditions can be complex and nested using {{RouterCondition/_or}} and {{RouterCondition/not}}. To prevent excessive processing, this algorithm introduces two limits. First, the total number of conditions, counting all nested conditions, cannot exceed 1024. Second, the nesting depth is limited to 10 levels to avoid exponential computation.
+
+      1. Let |result| be a [=count router condition result=].
+      1. Set |result|'s [=count router condition result/total count=] to 0.
+      1. Set |result|'s [=count router condition result/depth=] to 1.
+      1. Let |maxCount| be 1024.
+      1. Let |maxDepth| be 10.
+      1. [=list/For each=] |rule| of |serviceWorker|'s [=service worker/list of router rules=]:
+          1. Let |currentResult| be the result of running [=Count Router Inner Conditions=] with |rule|["{{RouterRule/condition}}"], |result|, |maxCount|, and |maxDepth|.
+          1. If |currentResult|'s [=count router condition result/total count=] exceeds |maxCount|, return false.
+          1. If |currentResult|'s [=count router condition result/depth=] exceeds |maxDepth|, return false.
+          1. Set |result|'s [=count router condition result/total count=] to |currentResult|'s [=count router condition result/total count=].
+      1. return true.
+  </section> 
+
+  <section algorithm>
+    <h3 id="count-router-inner-conditions"><dfn>Count Router Inner Conditions</dfn></h3>
+
+      : Input
+      :: |condition|, a {{RouterCondition}}
+      :: |result|, a [=count router condition result=]
+      :: |maxCount|, a number
+      :: |maxDepth|, a number
+      : Output
+      :: |result|, a [=count router condition result=]
+
+      1. Increment |result|'s [=count router condition result/total count=] by one.
+      1. If |result|'s [=count router condition result/total count=] exceeds |maxCount|, return |result|.
+      1. If |result|'s [=count router condition result/depth=] exceeds |maxDepth|, return |result|.
+      1. If |condition|["{{RouterCondition/_or}}"] [=map/exists=], then:
+          1. Increment |result|'s [=count router condition result/depth=] by one.
+          1. For each |orCondition| of |condition|["{{RouterCondition/_or}}"]:
+              1. Set |result| to be the result of running [=Count Router Inner Conditions=] with |orCondition|, |result|, |maxCount|, and |maxDepth|.
+              1. If |result|'s [=count router condition result/total count=] exceeds |maxCount|, return |result|.
+              1. If |result|'s [=count router condition result/depth=] exceeds |maxDepth|, return |result|.
+      1. Else if |condition|["{{RouterCondition/not}}"] [=map/exists=], then:
+          1. Increment |result|'s [=count router condition result/depth=] by one.
+          1. Set |result| to be the result of running [=Count Router Inner Conditions=] with |condition|["{{RouterCondition/not}}"], |result|, |maxCount|, and |maxDepth|.
+          1. If |result|'s [=count router condition result/total count=] exceeds |maxCount|, return |result|.
+          1. If |result|'s [=count router condition result/depth=] exceeds |maxDepth|, return |result|. 
+      1. Return |result|.
+  </section>
+
   <section algorithm>
     <h3 id="get-router-source-algorithm"><dfn>Get Router Source</dfn></h3>
       : Input