Speculation Rules

Modify parse a speculation rule set string as follows:

• Remove the typesToTreatAsPrefetch construct, and instead parse parsed["prerender"] into the prerender rules list, in an identical manner to what is done for parsed["prefetch"] and the prefetch rules.

• Discard rules parsed from parsed["prefetch"] if the target navigable name hint is not null.

Implementations will still be allowed to treat prerender candidates as prefetches, per the modifications in § 3 Processing model.

Modify parse a speculation rule by adding the following steps:

1. Let targetHint be null.

2. If input["target_hint"] exists:

   1. If input["target_hint"] is not a valid navigable target name or keyword:

      1. The user agent may report a warning to the console indicating that the supplied target hint was invalid.

      2. Return null.

   2. Set targetHint to input["target_hint"].

and then updating the final step which returns a speculation rule to include setting the target navigable name hint to targetHint.

Update the inner consider speculative loads steps algorithm by appending the following steps near the beginning, after assembling prefetchCandidates:

1. Let prerenderCandidates be an empty list.

2. For each ruleSet of document’s speculation rule sets:

   1. For each rule of ruleSet’s prerender rules:

      1. For each url of rule’s URLs:

         1. Let referrerPolicy be the result of computing a speculative load referrer policy given rule and null.

         2. Append a new prerender candidate with

            URL

            url

            No-Vary-Search hint

            rule’s No-Vary-Search hint

            eagerness

            rule’s eagerness

            referrer policy

            referrerPolicy

            tags

            rule’s tags

            target navigable name hint

            rule’s target navigable name hint

            to prerenderCandidates.

      2. If rule’s predicate is not null, then:

         1. Let links be the result of finding matching links given document and rule’s predicate.

         2. For each link of links:

            1. Let target be rule’s target navigable name hint.

            2. If target is null, set it to the result of getting an element’s target given link.

            3. Let referrerPolicy be the result of computing a speculative load referrer policy given rule and link.

            4. Append a prerender candidate with

               URL

               link’s url

               No-Vary-Search hint

               rule’s No-Vary-Search hint

               eagerness

               rule’s eagerness

               referrer policy

               referrerPolicy

               tags

               rule’s tags

               target navigable name hint

               target

               to prerenderCandidates.

3. Let speculativeLoadCandidates be the union of prefetchCandidates and prerenderCandidates.

Update subsequent steps for canceling not-still-being-speculated prefetch records to operate on speculativeLoadCandidates instead of prefetchCandidates.

Replace the step which performs the actual prefetching by looping over prefetchCandidates with the following:

1. For each candidate of speculativeLoadCandidates:

   1. The user agent may run the following steps:

      1. Let tagCandidates be speculativeLoadCandidates.

      2. If candidate is a prerender candidate, then set tagCandidates to prerenderCandidates.

      3. Let tagsToSend be the result of collecting tags for matching speculative load candidates given candidate and tagCandidates.

      4. Let prefetchRecord be a new prefetch record with

         source

         "speculation rules"

         URL

         candidate’s URL

         No-Vary-Search hint

         candidate’s No-Vary-Search hint

         referrer policy

         candidate’s referrer policy

         tags

         tagsToSend

      5. If candidate is a prefetch candidate, then set prefetchRecord’s anonymization policy to candidate’s anonymization policy.

      6. If candidate is a prerender candidate, then the user agent may run the following steps:

         1. Set prefetchRecord’s prerendering traversable to "to be created"

         2. Set prefetchRecord’s prerendering target navigable name hint to candidate’s target navigable name hint.

         3. Start a referrer-initiated navigational prerender given document and prefetchRecord.

      7. If the user agent did not run the previous step, then start a referrer-initiated navigational prefetch given document and prefetchRecord.