- From: Michael Smith via cvs-syncmail <cvsmail@w3.org>
 - Date: Thu, 04 Aug 2011 21:46:25 +0000
 - To: public-html-commits@w3.org
 
Update of /sources/public/html5/spec
In directory hutz:/tmp/cvs-serv19444
Modified Files:
	rendering.html spec.html webappapis.html 
Log Message:
Allow UAs to opt out of the storage mutex and corrupt data instead of being slow. (whatwg r6368)
[updated by splitter]
Index: rendering.html
===================================================================
RCS file: /sources/public/html5/spec/rendering.html,v
retrieving revision 1.101
retrieving revision 1.102
diff -u -d -r1.101 -r1.102
--- rendering.html	3 Aug 2011 07:46:23 -0000	1.101
+++ rendering.html	4 Aug 2011 21:46:22 -0000	1.102
@@ -1569,7 +1569,7 @@
       <p>Apply the Unicode Bidirectional Algorithm's Paragraph Level
       steps to <var title="">nodes</var> using the following
       constraints, to determine the <i>paragraph embedding level</i>
-      of the cue: <a href="#BIDI">[BIDI]</a></p>
+      of the cue: <a href="references.html#refsBIDI">[BIDI]</a></p>
 
       <ul><li><var title="">nodes</var> represents a single paragraph.</li>
 
Index: spec.html
===================================================================
RCS file: /sources/public/html5/spec/spec.html,v
retrieving revision 1.1588
retrieving revision 1.1589
diff -u -d -r1.1588 -r1.1589
--- spec.html	4 Aug 2011 06:46:24 -0000	1.1588
+++ spec.html	4 Aug 2011 21:46:22 -0000	1.1589
@@ -349,7 +349,7 @@
     <a href="Overview.html">single page HTML</a>,
     <a href="spec.html">multipage HTML</a>,
     <a href="author/">web developer edition</a>.
-This is revision 1.5086.
+This is revision 1.5088.
    </p> 
      <p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
    © 2011 <a href="http://www.w3.org/"><abbr title="World Wide
Index: webappapis.html
===================================================================
RCS file: /sources/public/html5/spec/webappapis.html,v
retrieving revision 1.185
retrieving revision 1.186
diff -u -d -r1.185 -r1.186
--- webappapis.html	28 Jul 2011 01:46:31 -0000	1.185
+++ webappapis.html	4 Aug 2011 21:46:23 -0000	1.186
@@ -808,11 +808,27 @@
   was queued; if the task was queued by or for a <a href="#concept-script" title="concept-script">script</a> then the document is the
   <a href="#script-s-document">script's document</a>.</p>
 
-  <p>A user agent is required to have one <dfn id="storage-mutex">storage
-  mutex</dfn>. This mutex is used to control access to shared state
-  like cookies. At any one point, the <a href="#storage-mutex">storage mutex</a> is
-  either free, or owned by a particular <a href="#event-loop">event loop</a> or
-  instance of the <a href="fetching-resources.html#fetch" title="fetch">fetching</a> algorithm.</p>
+  <p>A user agent may have one <dfn id="storage-mutex">storage mutex</dfn>. This mutex is
+  used to control access to shared state like cookies. At any one
+  point, the <a href="#storage-mutex">storage mutex</a> is either free, or owned by a
+  particular <a href="#event-loop">event loop</a> or instance of the <a href="fetching-resources.html#fetch" title="fetch">fetching</a> algorithm.</p>
+
+  <p>If a user agent does not implement a <a href="#storage-mutex">storage mutex</a>,
+  it is exempt from implementing the requirements that require it to
+  acquire or release it.</p>
+
+  <p class="note">User agent implementors have to make a choice
+  between two evils. On the one hand, not implementing the storage
+  mutex means that there is a risk of data corruption: a site could,
+  for instance, try to read a cookie, increment its value, then write
+  it back out, using the new value of the cookie as a unique
+  identifier for the session; if the site does this twice in two
+  different browser windows at the same time, it might end up using
+  the same "unique" identifier for both sessions, with potentially
+  disastrous effects. On the other hand, implementing the storage
+  mutex has potentially serious performance implications: whenever a
+  site uses Web Storage or cookies, all other sites that try to use
+  Web Storage or cookies are blocked until the first site finishes.</p>
 
   <p>Whenever a <a href="#concept-script" title="concept-script">script</a> calls into
   a <a href="infrastructure.html#plugin">plugin</a>, and whenever a <a href="infrastructure.html#plugin">plugin</a> calls into
Received on Thursday, 4 August 2011 21:46:31 UTC