Bug 15640 – REGRESSION (r17701): Favicons should be viewable as image documents

• Status: RESOLVED
• Resolution: FIXED
• Component: Images

[David Kilzer (:ddkilzer)]

* SUMMARY
Viewing a favicon in WebKit (Safari) always causes the image to be downloaded.

* STEPS TO REPRODUCE
1. Launch Safari/WebKit.
2. Open a URL to a favicon:  http://webkit.org/favicon.ico

* EXPECTED RESULTS
The favicon should be rendered as an image document in the browser.

* ACTUAL RESULTS
The favicon is downloaded.

* REGRESSION
This is a regression from Safari 2.0.4 (419.3) with original WebKit on Mac OS X 10.4.10 (8R218).  Tested with a local debug build of WebKit r26851 with Safari 3 Public Beta v. 3.0.3 (522.12.1) on Mac OS X 10.4.10 (8R218).

* NOTES
The official IANA-registered MIME type for these icons is image/vnd.microsoft.icon according to Wikipedia:

http://en.wikipedia.org/wiki/ICO_(icon_image_file_format)

The historical MIME type used was image/x-icon.  We should probably support both.

[David Kilzer (:ddkilzer)]

The bisect-builds script says:

Works: r17700  Fails: r17701

I'm guessing that CoreGraphics (CG) on Tiger doesn't automatically include image/x-icon in its list of supported MIME types in initialiseSupportedImageMIMETypes() in WebCore/platform/MIMETypeRegistry.cpp.

[David Kilzer (:ddkilzer)]

Can't view favicons in Safari for Windows either.  Have not tested Leopard yet.

[David Kilzer (:ddkilzer)]

Mac OS X 10.5 (9A581) adds these MIME types in WebCore::initialiseSupportedImageMIMETypes():

>>> Adding CG MIME Type: image/png
>>> Adding CG MIME Type: image/jpeg
>>> Adding CG MIME Type: image/gif
>>> Adding CG MIME Type: image/jp2
>>> Adding CG MIME Type: image/tiff
>>> Adding CG MIME Type: image/x-canon-crw
>>> Adding CG MIME Type: image/vnd.adobe.photoshop
>>> Adding CG MIME Type: application/pdf
>>> Adding CG MIME Type: image/x-xbitmap
>>> Adding CG MIME Type: image/pict
>>> Adding CG MIME Type: image/targa
>>> Adding CG MIME Type: image/sgi
>>> Adding CG MIME Type: image/x-quicktime
>>> Adding CG MIME Type: image/fpx

[David Kilzer (:ddkilzer)]

Mac OS X 10.4.10 (8R218) adds these MIME types in
WebCore::initialiseSupportedImageMIMETypes():

>>> Adding CG MIME Type: image/jpeg
>>> Adding CG MIME Type: image/gif
>>> Adding CG MIME Type: image/png
>>> Adding CG MIME Type: image/jp2
>>> Adding CG MIME Type: image/tiff
>>> Adding CG MIME Type: image/photoshop
>>> Adding CG MIME Type: application/pdf
>>> Adding CG MIME Type: image/targa
>>> Adding CG MIME Type: image/sgi
>>> Adding CG MIME Type: image/x-quicktime
>>> Adding CG MIME Type: image/pict
>>> Adding CG MIME Type: image/fpx
>>> Adding CG MIME Type: image/x-quicktime

[David Kilzer (:ddkilzer)]

Created attachment 16930 [details]
Patch v1

Patch with ChangeLog and layout test.

(In reply to comment #0)
> * NOTES
> The official IANA-registered MIME type for these icons is
> image/vnd.microsoft.icon according to Wikipedia:
> 
> http://en.wikipedia.org/wiki/ICO_(icon_image_file_format)
> 
> The historical MIME type used was image/x-icon.  We should probably support
> both.

Until we have evidence of real web sites returning favicon.ico files with a MIME type of image/vnd.microsoft.icon, I don't think it's necessary to add this type.

$ curl --head http://www.microsoft.com/favicon.ico
HTTP/1.1 200 OK
Content-Length: 3638
Content-Type: image/x-icon
Last-Modified: Wed, 11 Oct 2006 22:18:37 GMT
Accept-Ranges: bytes
ETag: "3a71c93283edc61:0"
Server: Microsoft-IIS/7.0
P3P: CP="ALL IND DSP COR ADM CONo CUR CUSo IVAo IVDo PSA PSD TAI TELo OUR SAMo CNT COM INT NAV ONL PHY PRE PUR UNI"
X-Powered-By: ASP.NET
Date: Mon, 29 Oct 2007 04:10:34 GMT

[David Kilzer (:ddkilzer)]

Hixie, do you have any numbers on how many web sites return favicons with MIME type image/vnd.microsoft.icon?

[Darin Adler]

Comment on attachment 16930 [details]
Patch v1

r=me

[David Kilzer (:ddkilzer)]

Committed r27223

[Ian 'Hixie' Hickson]

I don't have any data, but, HTML5 suggests treating all image/* types as equivalent and using magic bytes to distinguish them.