Closed
Bug 906413
Opened 11 years ago
Closed 9 years ago
Blob slice method can not support relativeEnd is Number.MAX_VALUE
Categories
(Core :: DOM: Core & HTML, defect)
Tracking
()
RESOLVED
FIXED
People
(Reporter: 418716640, Assigned: arun)
References
Details
Attachments
(1 file)
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1521.3 Safari/537.36
Steps to reproduce:
<meta charset="UTF-8">
<title>FileAPI Test: Blob slice()</title>
<link rel="author" title="zhongquansun" href="mailto:418716640@qq.com" />
<link rel="help" href="http://www.w3.org/TR/FileAPI/#slide-method-algo" />
<meta name="flags" content="dom"/>
<meta name="assert" content="test blob constructor methed , type property ,size property ,slice method , all of success is pass" />
<link rel="stylesheet" href="/resources/testharness.css" />
<script type="text/javascript" src="/resources/testharness.js"></script>
<script type="text/javascript" src="/resources/testharnessreport.js"></script>
<body>
<div id="log"></div>
<script type="text/javascript">
test(function() {
var blob = new Blob(['ttwf']);
var bl = blob.slice(0,Number.MAX_VALUE);
assert_equals( bl.size, 4);
}, 'test blob slice for Number.MAX_VALUE');
test(function() {
var blob = new Blob(['ttwf']);
var bl = blob.slice(Number.MIN_VALUE,Number.MAX_VALUE);
assert_equals( bl.size, 4);
}, 'test blob slice for Number.MIN_VALUE and Number.MAX_VALUE -2');
</script>
</body>
</html>
Actual results:
2 Fail
Expected results:
2 PASS
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Updated•11 years ago
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Component: Untriaged → DOM
Product: Firefox → Core
Attachment #791802 -
Attachment mime type: text/plain → text/html
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Comment 1•11 years ago
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Per spec, slice() is defined as:
Blob slice(optional long long start,
optional long long end,
optional DOMString contentType);
WebIDL defines conversion to long long at http://dev.w3.org/2006/webapi/WebIDL/#es-long-long as follows:
Set x to sign(x) * floor(abs(x)).
Set x to x modulo 2^64.
If x is greater than or equal to 2^63, then set x to x − 2^64.
Number.MAX_VALUE is the largest positive finite value of the Number type. For an IEEE double, that's some 53-digit binary mantissa times 2^1023 or so. In particular, it's evenly divisibly by 2^64, so when converting it to IDL long long you get 0.
So what we implement is exactly what the spec says to do, as far as I can tell: slice(0,0) should be returning a Blob of size 0.
Now maybe the spec should be using [Clamp] here? But note that even then the subtractions the spec defines can overflow.
Flags: needinfo?(arun)
Whiteboard: invalid?
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Updated•11 years ago
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Summary: Blob sclice method can not support relativeEnd is Number.MAX_VALUE → Blob slice method can not support relativeEnd is Number.MAX_VALUE
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Assignee | |
Comment 2•11 years ago
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Fx is doing the right thing here. Furthermore, outside of what 'long long' can contain, I think that slice(0, Number.MAX_VALUE) called on a Blob of size 4 should be illegal. I've logged a bug for further boundary checks on start and end:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23140
Flags: needinfo?(arun)
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Comment 3•11 years ago
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Arun, thanks.
Status: UNCONFIRMED → RESOLVED
Closed: 11 years ago
Resolution: --- → INVALID
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Comment 4•11 years ago
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Actually, per discussion with Arun, reopening. Spec is being changed to [Clamp]. Once we fix bug 827823 this will be fixed automagically.
Status: RESOLVED → REOPENED
Depends on: 827823
Ever confirmed: true
Resolution: INVALID → ---
Whiteboard: invalid?
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Assignee | |
Comment 5•11 years ago
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W3C bug https://www.w3.org/Bugs/Public/show_bug.cgi?id=23140 is resolved | fixed and the "spec fix" using [Clamp] is in the editor's draft:
http://dev.w3.org/2006/webapi/FileAPI/#blob
WebIDL tweak is sufficient here; further spec prose is not necessary.
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Assignee | |
Comment 6•9 years ago
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(Fixed in spec.; closing.)
Assignee: nobody → arun
Status: REOPENED → RESOLVED
Closed: 11 years ago → 9 years ago
QA Contact: arun
Resolution: --- → FIXED
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Updated•6 years ago
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Component: DOM → DOM: Core & HTML
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Description
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