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Update algorithm to only share quota for direct relatives
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@noamr
noamr committed Dec 15, 2024
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253 changes: 116 additions & 137 deletions fetch.bs
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Expand Up @@ -6765,14 +6765,12 @@ sources, specifically task sources that can result in running scripts such as th
<a method><code>fetchLater()</code></a> call before running any scripts that might depend on it.

<div algorithm>
<p>To <dfn>queue a deferred fetch</dfn> given a
<a for=/>request</a> <var>request</var>, a null or {{DOMHighResTimeStamp}}
<p>To <dfn>queue a deferred fetch</dfn> given a <a for=/>request</a> <var>request</var>, a
<a for=fetch>fetch group</a> <var>fetchGroup</var> a null or {{DOMHighResTimeStamp}}
<var>activateAfter</var>, an <var>onActivatedWithoutTermination</var>, which is an algorithm that
takes no arguments:

<ol>
<li><p>Assert: <var>request</var>'s <a for=request>client</a> is a {{Document}}.

<li><p><a>Populate request from client</a> given <var>request</var>.

<li><p>Set <var>request</var>'s <a for=request>service-workers mode</a> to "<code>none</code>".
Expand All @@ -6782,19 +6780,9 @@ takes no arguments:
<li><p>Let <var>deferredRecord</var> be a new <a>deferred fetch record</a> whose
<a for="deferred fetch record">request</a> is <var>request</var>.

<li><p>Let <var>topMostDirectSameOriginAncestor</var> be <var>request</var>'s
<a for=request>client</a>.

<li><p>While <var>topMostDirectSameOriginAncestor</var>'s <a>node navigable</a>'s
<a>container document</a> is a {{Document}} whose <a for=Document>origin</a> is <a>same origin</a>
with <var>request</var>'s <a for=request>client</a>'s <a for=Document>origin</a>, set
<var>topMostDirectSameOriginAncestor</var> to <var>topMostDirectSameOriginAncestor</var>'s
<a>node navigable</a>'s <a>container document</a>.

<li>
<p><a for=list>Append</a> <var>deferredRecord</var> to
<var>topMostDirectSameOriginAncestor</var>'s <a>active document</a>'s
<a for=fetch>fetch group</a>'s <a for="fetch group">deferred fetch records</a>.
<p><a for=list>Append</a> <var>deferredRecord</var> to <var>fetchGroup</var>'s
<a for="fetch group">deferred fetch records</a>.

<p class=note>This prevents a case where eagerly creating and destroying nested documents would
circumvent the keepalive quota.
Expand Down Expand Up @@ -6873,15 +6861,15 @@ takes no arguments:

<!-- non-normative -->
<p>The deferred-fetch quota is allocated to a <a for=/>top-level traversable</a> (a "tab"),
amounting to 640 kibibytes. The top-level {{Document}} and its same-origin nested documents can
use this quota to queue deferred fetches, or delegate some of it to cross-origin nested documents,
using permissions policy.
amounting to 640 kibibytes. The top-level {{Document}} and its same-origin directly nested documents
can use this quota to queue deferred fetches, or delegate some of it to cross-origin nested
documents, using permissions policy.

<p>By default, 128 kibibytes out of these 640 kibibytes are allocated to delegating the quota to
cross-origin nested documents, each reserving 8 kibibytes.

<p>The top-level {{Document}}, and subsequently its nested documents, can control how much of their quota
is delegates to cross-origin/cross-agent nested documents, by using permissions policy.
<p>The top-level {{Document}}, and subsequently its nested documents, can control how much of their
quota is delegates to cross-origin/cross-agent nested documents, by using permissions policy.
By default, "{{PermissionsPolicy/deferred-fetch-minimal}}" is enabled for any origin, while
"{{PermissionsPolicy/deferred-fetch}}" is enabled for the top-level document's origin only.
By relaxing the "{{PermissionsPolicy/deferred-fetch}}" policy for particular origins and nested
Expand Down Expand Up @@ -6940,9 +6928,8 @@ calls would succeed and the last one would throw.
to <code>https://frame.example.com</code>, for example by serving the following header:
<pre><code class=lang-http>Permissions-Policy: deferred-fetch=(self "https://frame.example.com")</code></pre>

<p>Each nested document reserves its own quota, and all the same-origin documents in the tree share
quota with each other. So the following would work, because each frame reserve 8 kibibytes and they
share the accumulated 16 kibibytes:
<p>Each nested document reserves its own quota. So the following would work, because each frame
reserve 8 kibibytes:
<pre><code class=lang-javascript>
// In cross-origin nested document at https://frame.example.com/frame-1
fetchLater("https://a.example.com", {body: a_6kb_body});
Expand All @@ -6961,11 +6948,15 @@ share the accumulated 16 kibibytes:
| | Shares quota with the <a for=/>top-level traversable</a>, as they're same origin.
| |
| + ---- + https://x.example.com
| Shares 16 kibibytes together with one other cross-origin nested document of the same origin.
| 8 kibibytes.
|
|
+ ---- + https://x.example.com
| Shares 16 kibibytes together with one other cross-origin nested document of the same origin.
| 8 kibibytes.
| |
| + https://me.example.com
| 0. Even though it's same origin with the <a for=/>top-level traversable</a>, it does not
| automatically share its quota as they are separated by a cross-origin intermediary.
|
+ ---- + https://ok.example.com/good
| | 64 kibibytes, granted via the "{{PermissionsPolicy/deferred-fetch}}" policy.
Expand All @@ -6986,10 +6977,12 @@ descendants share a quota of 384 kibibytes. That value is computed as such:
<ul>
<li><p>640 kibibytes are initially granted to the <a for=/>top-level traversable</a>.
<li><p>128 kibibytes are reserved for the "{{PermissionsPolicy/deferred-fetch-minimal}}" policy.
<li><p>64 kibibytes are reserved for the container navigating to <code>https://ok.example/good</code>.
<li><p>64 kibibytes are reserved for the container navigating to <code>https://ok.example/redirect</code>, and lost when it navigates away.
<li><code>https://ok.example.com/back</code> did not reserve 64 kibibytes, because it navigated back to <a for=/>top-level traversable</a>'s origin.
<li><p>640 - 128 - 64 - 64 = 384 kibibytes.
<li><p>64 kibibytes are reserved for the container navigating to
<code>https://ok.example/good</code>.
<li><p>64 kibibytes are reserved for the container navigating to
<code>https://ok.example/redirect</code>, and lost when it navigates away.
<li><code>https://ok.example.com/back</code> did not reserve 64 kibibytes, because it navigated
back to <a for=/>top-level traversable</a>'s origin. <li><p>640 - 128 - 64 - 64 = 384 kibibytes.
</ul>
</div>

Expand All @@ -7002,105 +6995,75 @@ descendants share a quota of 384 kibibytes. That value is computed as such:
"<dfn for=PermissionsPolicy enum-value>deferred-fetch-minimal</dfn>". Its
<a for="policy-controlled feature">default allowlist</a> is "<code>*</code>".

<p>The <dfn>optional nested document deferred-fetch quota</dfn> is 64 kibibytes.
<p>The <dfn>minimal nested document deferred-fetch quota</dfn> is 8 kibibytes.
<p>The <dfn>max containers with minimal quota</dfn> is 16.


<div algorithm>
<p>To get the <dfn>available deferred-fetch quota</dfn> given a {{Document}}
<var>requestClientDocument</var> and an <a for=/>origin</a>-or-null <var>origin</var>:
<var>controlDocument</var> and an <a for=/>origin</a>-or-null <var>origin</var>:

<ol>
<li><p>Let <var>quota</var> be 0.

<li><p>Let <var>quotaForOrigin</var> be 64 kibibytes.

<li>
<p>For each <var>otherNavigable</var> of <var>requestClientDocument</var>'s <a>node navigable</a>'s
<a for=navigable>top-level traversable</a>'s <a>inclusive descendant navigables</a>:

<p class=note>This algorithm iterates over the entire navigable tree. It accumulates quota from
the <a for=/>top-level traversable</a>, and from nested documents who inherit quota. Subsequently,
it subtracts the quota delegated to cross-origin nested documents, as well as quota
spent on pending deferred fetch requests.
<p>If <var>controlDocument</var>'s <a>node navigable</a> is a
<a for=/>top-level traversable</a>, then:

<ol>
<li><p>Let <var>otherDocument</var> be <var>otherNavigable</var>'s <a>active document</a>.
<li><p>Let <var>otherContainer</var> be <var>otherNavigable</var>'s <a>navigable container</a>.
<li><p>If <var>controlDocument</var> is not <a>allowed to use</a> the
<a>policy-controlled feature</a> "{{PermissionsPolicy/deferred-fetch}}", then return 0.

<li>
<p>If <var>requestClientDocument</var>'s <a for=Document>origin</a> is <a>same origin</a> with
<var>otherDocument</var>'s <a for=Document>origin</a>, then:
<ol>
<li>
<p>If <var>otherContainer</var> is null, then:

<p class=note>Accumulate the <a for=/>top-level traversable</a>'s initial quota.

<ol>
<li><p>If <var>otherDocument</var> is not <a>allowed to use</a> the
<a>policy-controlled feature</a> "{{PermissionsPolicy/deferred-fetch}}", then return 0.

<li><p>Assert: <var>quota</var> is 0.

<li>
<p>Set <var>quota</var> be 640 kibibytes.
<p class="note allow-2119">640kb should be enough for everyone.

<li><p>If <var>otherDocument</var> is <a>allowed to use</a> the
<a>policy-controlled feature</a> "{{PermissionsPolicy/deferred-fetch-minimal}}", then
decrement <var>quota</var> by <a>max containers with minimal quota</a>, multiplied by
<a for="reserved deferred-fetch quota">minimal quota</a>.
</ol>
<p>Set <var>quota</var> be 640 kibibytes.
<p class="note allow-2119">640kb should be enough for everyone.

<li>
<p>Otherwise, if any of the following conditions is true:

<ul class=brief>
<li><p><var>otherContainer</var>'s <a>reserved deferred-fetch quota</a> is
<a for="reserved deferred-fetch quota">normal quota</a>, and <var>otherDocument</var> is
<a>allowed to use</a> the <a>policy-controlled feature</a>
"{{PermissionsPolicy/deferred-fetch}}"

<li><p><var>otherContainer</var>'s <a>reserved deferred-fetch quota</a> is
<a for="reserved deferred-fetch quota">minimal quota</a>, and <var>otherDocument</var> is
<a>allowed to use</a> the <a>policy-controlled feature</a>
"{{PermissionsPolicy/deferred-fetch-minimal}}"
</ul>

<p>then increment <var>quota</var> by <var>otherContainer</var>'s
<a>reserved deferred-fetch quota</a>.
<p class=note>Accumulate quota granted by parent documents.

<li>
<p><a for=list>For each</a> <a>deferred fetch record</a> <var>deferredRecord</var> of
<var>otherDocument</var>'s <a for=fetch>fetch group</a>'s
<a for="fetch group">deferred fetch records</a>:</p>
<li><p>If <var>controlDocument</var> is <a>allowed to use</a> the
<a>policy-controlled feature</a> "{{PermissionsPolicy/deferred-fetch-minimal}}", then
decrement <var>quota</var> by <a>max containers with minimal quota</a>, multiplied by
<a for="reserved deferred-fetch quota">minimal quota</a>.
</ol>

<p class=note>Account for quota on deferred fetches performed by <a>same origin</a> clients.
<p>Otherwise:

<ol>
<li><p>Let <var>requestLength</var> be the <a>total request length</a> of
<var>deferredRecord</var>'s <a for="deferred fetch record">request</a>.
<ol>
<li><p>Let <var>container</var> be <var>controlDocument</var>'s <a>node navigable</a>'s
<a>navigable container</a>.

<li><p>If <var>container</var>'s <a>reserved deferred-fetch quota</a> is
<a for="reserved deferred-fetch quota">normal quota</a>, and <var>controlDocument</var> is
<a>allowed to use</a> the <a>policy-controlled feature</a>
"{{PermissionsPolicy/deferred-fetch}}", then set <var>quota</var> to
<a for="reserved deferred-fetch quota">normal quota</a>.

<li><p>Otherwise, if <var>container</var>'s <a>reserved deferred-fetch quota</a> is
<a for="reserved deferred-fetch quota">minimal quota</a>, and <var>controlDocument</var> is
<a>allowed to use</a> the <a>policy-controlled feature</a>
"{{PermissionsPolicy/deferred-fetch-minimal}}", then set <var>quota</var> to
<a for="reserved deferred-fetch quota">minimal quota</a>.
</ol>

<li><p>Decrement <var>quota</var> by <var>requestLength</var>.
<li>
<p><a for=list>For each</a> <a>deferred fetch record</a> <var>deferredRecord</var> of
<var>controlDocument</var>'s <a>fetch group</a>'s
<a for="fetch group">deferred fetch records</a>:</p>

<li><p>If <var>deferredRecord</var>'s <a for="deferred fetch record">request</a>'s
<a for=request>URL</a>'s <a for=url>origin</a> is <a>same origin</a> with <var>origin</var>,
then decrement <var>quotaForOrigin</var> by <var>requestLength</var>.
</ol>
</ol>
<ol>
<li><p>Let <var>requestLength</var> be the <a>total request length</a> of
<var>deferredRecord</var>'s <a for="deferred fetch record">request</a>.

<li>
<p>If <var>otherDocument</var>'s <a>container document</a> is a {{Document}} whose
<a for=Document>origin</a> is <a>same origin</a> with <var>requestClientDocument</var>'s
<a for=Document>origin</a>, then decrement <var>quota</var> by <var>otherContainer</var>'s
<a>reserved deferred-fetch quota</a>.
<li><p>Decrement <var>quota</var> by <var>requestLength</var>.

<p class=note>Account for quota granted to child documents.
<li><p>If <var>deferredRecord</var>'s <a for="deferred fetch record">request</a>'s
<a for=request>URL</a>'s <a for=url>origin</a> is <a>same origin</a> with <var>origin</var>,
then decrement <var>quotaForOrigin</var> by <var>requestLength</var>.
</ol>

<li><p><a for=list>For each</a> <var>navigable</var> in <var>controlDocument</var>'s
<a>node navigable</a>'s <a>descendant navigables</a> whose <a>container document</a>'s
<a>deferred-fetch control document</a> is <var>controlDocument</var>, decrement <var>quota</var> by
<var>navigable</var>'s <a>navigable container</a>'s <a>reserved deferred-fetch quota</a>.

<li><p>If <var>quota</var> is less than 0, then return 0.
<li><p>If <var>quota</var> is less than <var>quotaForOrigin</var>, then return <var>quota</var>.
<li><p>Return <var>quotaForOrigin</var>.
Expand All @@ -7123,32 +7086,36 @@ shared.
<ol>
<li><p>Set <var>container</var>'s <a>reserved deferred-fetch quota</a> to 0.

<li><p>Let <var>controlDocument</var> be <var>container</var>'s <a>node document</a>'s
<a>deferred-fetch control document</a>.

<li><p>If the <a data-lt="define an inherited policy for feature in container">inherited policy</a>
for "{{PermissionsPolicy/deferred-fetch}}", <var>container</var> and <var>originToNavigateTo</var>
is <code>Enabled</code>, and the <a>available deferred-fetch quota</a> for
<var>container</var>'s <a>container document</a> is equal or greater than
<var>controlDocument</var> is equal or greater than
<a for="reserved deferred-fetch quota">normal quota</a>, then set <var>container</var>'s
<a>reserved deferred-fetch quota</a> to <a for="reserved deferred-fetch quota">normal quota</a> and
return.

<li><p>If the <a data-lt="define an inherited policy for feature in container">inherited policy</a>
for "{{PermissionsPolicy/deferred-fetch-minimal}}", <var>container</var> and
<var>originToNavigateTo</var> is <code>Disabled</code>, then return.

<li><p>If <var>container</var>'s <a>node document</a>'s <a for=Document>origin</a> is not
<a>same origin</a> with <var>container</var>'s <a>node navigable</a>'s
<a for=navigable>top-level traversable</a>'s <a>active document</a>'s <a for=Document>origin</a>,
then return.

<li><p>Let <var>containersWithReservedMinimalQuota</var> be <var>container</var>'s
<a>node navigable</a>'s <a for=navigable>top-level traversable</a>'s
<a>descendant navigables</a>, <a for=list data-lt=remove>removing</a> any <a for=/>navigable</a>
whose <a>navigable container</a>'s <a>reserved deferred-fetch quota</a> is not
<a for="reserved deferred-fetch quota">minimal quota</a> .

<li><p>If <var>containersWithReservedMinimalQuota</var>'s <a for=list>size</a> is less
than <a>max containers with minimal quota</a>, then set <var>container</var>'s
<a>reserved deferred-fetch quota</a> to <a for="reserved deferred-fetch quota">minimal quota</a>.
<li>
<p>If all of the following conditions are true:

<ul class=brief>
<li><p><var>controlDocument</var>'s <a>node navigable</a> is a <a for=/>top-level traversable</a>

<li><p>The <a data-lt="define an inherited policy for feature in container">inherited policy</a>
for "{{PermissionsPolicy/deferred-fetch-minimal}}", <var>container</var> and
<var>originToNavigateTo</var> is <code>Enabled</code>

<li><p>The <a for=list>size</a> of <var>controlDocument</var>'s <a>node navigable</a>'s
<a>descendant navigables</a>, <a for=list data-lt=remove>removing</a> any <a for=/>navigable</a>
whose <a>navigable container</a>'s <a>reserved deferred-fetch quota</a> is not
<a for="reserved deferred-fetch quota">minimal quota</a>, is less than
<a>max containers with minimal quota</a>
</ul>

<p>then set <var>container</var>'s <a>reserved deferred-fetch quota</a> to
<a for="reserved deferred-fetch quota">minimal quota</a>.
</ol>
</div>

Expand All @@ -7165,6 +7132,17 @@ document creation, as the <a for=Document>origin</a> of the {{Document}} is only
redirects are handled.
</div>

<div algorithm>
<p>To get the <dfn>deferred-fetch control document</dfn> of a {{Document}} <var>document</var>:

<ol>
<li><p>If <var>document</var>' <a>node navigable</a>'s <a>container document</a> is null or a
{{Document}} whose <a for=Document>origin</a> is not <a>same origin</a> with <var>document</var>,
return <var>document</var>; Otherwise return the <a>deferred-fetch control document</a> given
<var>document</var>' <a>node navigable</a>'s <a>container document</a>.
</ol>
</div>


<h2 id=fetch-api>Fetch API</h2>

Expand Down Expand Up @@ -9084,22 +9062,24 @@ method steps are:
then throw a {{TypeError}}.

<li>
<p>If <var>request</var>'s
<a for=request>body</a> is not null, and <var>request</var>'s <a for=request>body</a>
<a for=body>length</a> is null, then throw a {{TypeError}}.
<p>If <var>request</var>'s <a for=request>body</a> is not null, and <var>request</var>'s
<a for=request>body</a> <a for=body>length</a> is null, then throw a {{TypeError}}.

<p class=note>Requests whose <a for=request>body</a> is a {{ReadableStream}} cannot be deferred.

<li><p>If the <a>available deferred-fetch quota</a> given <var>request</var>'s
<a for=request>client</a> and <var>request</var>'s <a for=request>URL</a>'s <a for=url>origin</a>
is less than <var>request</var>'s <a>total request length</a>, then throw a
"{{QuotaExceededError}}" {{DOMException}}.
<li><p>Let <var>controlDocument</var> be <var>request</var>'s <a for=request>client</var>'s
<a>deferred-fetch control document</a>.

<li><p>If the <a>available deferred-fetch quota</a> given <var>controlDocument</var> and
<var>request</var>'s <a for=request>URL</a>'s <a for=url>origin</a> is less than
<var>request</var>'s <a>total request length</a>, then throw a "{{QuotaExceededError}}"
{{DOMException}}.

<li><p>Let <var>activated</var> be false.

<li><p>Let <var>deferredRecord</var> be the result of calling
<a>queue a deferred fetch</a> given <var>request</var>, <var>activateAfter</var>, and the
following step: set <var>activated</var> to true.
<li><p>Let <var>deferredRecord</var> be the result of calling <a>queue a deferred fetch</a> given
<var>request</var>, <var>controlDocument</var>'s <a>fetch group</a>, <var>activateAfter</var>, and
the following step: set <var>activated</var> to true.

<li>
<p><a for=AbortSignal lt=add>Add the following abort steps</a> to <var>requestObject</var>'s
Expand All @@ -9108,9 +9088,8 @@ method steps are:
<ol>
<li><p>Set <var>deferredRecord</var>'s <a for="deferred fetch record">done</a> to true.

<li><p><a for=list>Remove</a> <var>deferredRecord</var> from
<var>request</var>'s <a for=request>client</a>'s <a for=fetch>fetch group</a>'s
<a for="fetch group">deferred fetch records</a>.
<li><p><a for=list>Remove</a> <var>deferredRecord</var> from <var>controlDocument</var>'s
<a for=fetch>fetch group</a>'s <a for="fetch group">deferred fetch records</a>.
</ol>

<li><p>Return a new {{FetchLaterResult}} whose
Expand Down

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