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html5/spec Overview.html,1.973,1.974

From: Ian Hickson via cvs-syncmail <cvsmail@w3.org>
Date: Wed, 18 Jun 2008 04:26:10 +0000
To: public-html-commits@w3.org
Message-Id: <E1K8pFK-0008N6-F1@lionel-hutz.w3.org>

Update of /sources/public/html5/spec
In directory hutz:/tmp/cvs-serv32151

Modified Files:
	Overview.html 
Log Message:
Revamp the way that type='' on <link> is defined to actually be accurate. Allow sniffing when the expected type is an image. (whatwg r1784)

Index: Overview.html
===================================================================
RCS file: /sources/public/html5/spec/Overview.html,v
retrieving revision 1.973
retrieving revision 1.974
diff -u -d -r1.973 -r1.974
--- Overview.html	18 Jun 2008 03:37:31 -0000	1.973
+++ Overview.html	18 Jun 2008 04:26:07 -0000	1.974
@@ -7770,7 +7770,8 @@
    then the <code title=attr-link-media><a href="#media0">media</a></code>
    attribute is prescriptive. The user agent must apply the external resource
    to <span>views</span><!-- XXX xref --> while their state match the listed
-   media, and must not apply them otherwise.
+   media and the other relevant conditions apply, and must not apply them
+   otherwise.
 
   <p id=default-media>The default, if the <code title=attr-link-media><a
    href="#media0">media</a></code> attribute is omitted, is <code>all</code>,
@@ -7789,26 +7790,48 @@
    href="#references">[RFC2046]</a>
 
   <p>For <a href="#links1" title="external resource link">external resource
-   links</a>, user agents may use the type given in this attribute to decide
-   whether or not to consider using the resource at all. If the UA does not
-   support the given MIME type for the given link relationship, then the UA
-   may opt not to download and apply the resource.
+   links</a>, the <code title=attr-link-type><a href="#type">type</a></code>
+   attribute is used as a hint to user agents so that they can avoid
+   downloading resources they do not support. If the attribute is present,
+   then the user agent must assume that the resource is of the given type. If
+   the attribute is omitted, but the external resource link type has a
+   default type defined, then the user agent must assume that the resource is
+   of that type. If the UA does not support the given MIME type for the given
+   link relationship, then the UA should not download the resource; if the UA
+   does support the given MIME type for the given link relationship, then the
+   UA should download the resource. If the attribute is omitted, and the
+   external resource link type does not have a default type defined, but the
+   user agent would fetch the resource if the type was known and supported,
+   then the user agent should fetch the resource under the assumption that it
+   will be supported.
 
   <p>User agents must not consider the <code title=attr-link-type><a
    href="#type">type</a></code> attribute authoritative &mdash; upon fetching
-   the resource, user agents must not use metadata included in the link to
-   the resource to determine its type.
+   the resource, user agents must not use the <code title=attr-link-type><a
+   href="#type">type</a></code> attribute to determine its actual type. Only
+   the actual type (as defined in the next paragraph) is used to determine
+   whether to <em>apply</em> the resource, not the aforementioned assumed
+   type.
 
-  <p>If the attribute is omitted, but the user agent would fetch the resource
-   if the type was known and supported, then the user agent must fetch the
-   resource and determine its type <a href="#content-type8"
-   title=Content-Type>from its Content-Type metadata</a> to determine if it
-   supports (and can apply) that external resource. If no type metadata is
-   specified, but the external resource link type has a default type defined,
-   then the user agent must assume that the resource is of that type.
+  <p>If the resource is expected to be an image, user agents may apply the <a
+   href="#content-type6" title="Content-Type sniffing: image">image sniffing
+   rules</a>, with the <var title="">official type</var> being the type
+   determined from the resource's <a href="#content-type8"
+   title=Content-Type>Content-Type metadata</a>, and use the resulting
+   sniffed type of the resource as if it was the actual type. Otherwise, if
+   the resource is not expected to be an image, or if the user agent opts not
+   to apply those rules, then the user agent must use the resource's <a
+   href="#content-type8" title=Content-Type>Content-Type metadata</a> to
+   determine the type of the resource. If there is no type metadata, but the
+   external resource link type has a default type defined, then the user
+   agent must assume that the resource is of that type.
+
+  <p>Once the user agent has established the type of the resource, the user
+   agent must apply the resource if it is of a supported type and the other
+   relevant conditions apply, and must ignore the resource otherwise.
 
   <div class=example>
-   <p>If a document contains four style sheet links labeled as follows:</p>
+   <p>If a document contains style sheet links labeled as follows:</p>
 
    <pre>&lt;link rel="stylesheet" href="A" type="text/plain"&gt;
 &lt;link rel="stylesheet" href="B" type="text/css"&gt;
@@ -34189,8 +34212,8 @@
   <p>User agents must ignore any rows for image types that they do not
    support.
 
-  <p>Otherwise, the <i>sniffed type</i> of the resource is the same as its
-   <var title="">official type</var>.
+  <p>Otherwise, the sniffed type of the resource is the same as its <var
+   title="">official type</var>.
 
   <h4 id=content-type3><span class=secno>4.10.4 </span><dfn
    id=content-type7>Content-Type sniffing: feed or HTML</dfn></h4>
Received on Wednesday, 18 June 2008 04:26:45 GMT

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