Bug 148810 – Document.characterSet should return "UTF-8" instead of null by default

• Component: New Bugs
• Status: RESOLVED FIXED

Set default encoding of document to be 'UTF-8'.

Created attachment 260607 [details]
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> Source/WebCore/ChangeLog:14
> +

Is it ok to have 2 separate change logs?

[Chris Dumez]

Comment on attachment 260607 [details]
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> Source/WebCore/ChangeLog:11
> +

Please indicate in the Change Log that this behavior is consistent with Firefox.

> Source/WebCore/dom/Document.cpp:-1255
> -    return String();

We should also update Document.idl to drop the [TreatReturnedNullStringAs=Null] IDL extended attribute from the following attributes: inputEncoding, charset, characterSet. The spec says that these attributes are not nullable and we no longer return a null string.

> Source/WebCore/dom/Document.cpp:1255
> +    return String(UTF8Encoding().domName());

I don't believe we need the String()

> LayoutTests/ChangeLog:3
> +        Update the tests which test the default encoding of document.

Please use bug title here: "Set 'UTF-8' to be the default of document encoding." and move "Update the tests which test the default encoding of document." to the description under the Reviewed By line.

> LayoutTests/fast/dom/document-attribute-js-null-expected.txt:5
> +TEST FAILED: The value should have been undefined but was the string 'UTF-8'. [tested Document.charset]

You need to update this test instead of simply rebaselining it. This is not an imported test.

[Chris Dumez]

Comment on attachment 260607 [details]
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> Source/WebCore/ChangeLog:5
> +        <rdar://problem/22549736>

Wrong radar?

> Source/WebCore/ChangeLog:10
> +        https://dom.spec.whatwg.org/#concept-document-url.

Wrong URL?

[Chris Dumez]

Comment on attachment 260607 [details]
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> Source/WebCore/ChangeLog:3
> +        Set 'UTF-8' to be the default of document encoding.

I would prefer "document.characterSet should return "UTF-8" instead of null by default"

[Chris Dumez]

Comment on attachment 260607 [details]
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>> Source/WebCore/ChangeLog:14
>> +
> 
> Is it ok to have 2 separate change logs?

Yes.

Created attachment 260611 [details]
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[Chris Dumez]

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> Source/WebCore/dom/Document.cpp:1255
> +    return UTF8Encoding().domName();

What about the IDL changes I suggested?

Created attachment 260620 [details]
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> Source/WebCore/dom/Document.idl:178
> +             [TreatNullAs=NullString] attribute DOMString charset;

Can we also drop [TreatNullAs=NullString] as well?

[Chris Dumez]

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> Source/WebCore/ChangeLog:11
> +        is consistent with Firefox.

Chrome also follows the spec.

>> Source/WebCore/dom/Document.idl:178
>> +             [TreatNullAs=NullString] attribute DOMString charset;
> 
> Can we also drop [TreatNullAs=NullString] as well?

It is non-standard so I wouldn't touch it.

[Chris Dumez]

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> Source/WebCore/dom/Document.cpp:1255
> +    return UTF8Encoding().domName();

As per Alexey's feedback, let's check that this doesn't impact Document::encoding() call sites in native code.

[Chris Dumez]

Comment on attachment 260620 [details]
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>> Source/WebCore/dom/Document.cpp:1255
>> +    return UTF8Encoding().domName();
> 
> As per Alexey's feedback, let's check that this doesn't impact Document::encoding() call sites in native code.

I see one call site in FrameLoader::addExtraFieldsToRequest():
        // Always try UTF-8. If that fails, try frame encoding (if any) and then the default.
        request.setResponseContentDispositionEncodingFallbackArray("UTF-8", m_frame.document()->encoding(), m_frame.settings().defaultTextEncodingName());

This already tries UTF-8 first and the implementation ignores null-string encodings so I think this is fine.

[Chris Dumez]

Comment on attachment 260620 [details]
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View in context: https://bugs.webkit.org/attachment.cgi?id=260620&action=review

>>> Source/WebCore/dom/Document.cpp:1255
>>> +    return UTF8Encoding().domName();
>> 
>> As per Alexey's feedback, let's check that this doesn't impact Document::encoding() call sites in native code.
> 
> I see one call site in FrameLoader::addExtraFieldsToRequest():
>         // Always try UTF-8. If that fails, try frame encoding (if any) and then the default.
>         request.setResponseContentDispositionEncodingFallbackArray("UTF-8", m_frame.document()->encoding(), m_frame.settings().defaultTextEncodingName());
> 
> This already tries UTF-8 first and the implementation ignores null-string encodings so I think this is fine.

charset() / inputEncoding() are used a lot more internally and they all call Document::encoding() so we need to double check those.

Created attachment 260639 [details]
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[Chris Dumez]

Comment on attachment 260639 [details]
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View in context: https://bugs.webkit.org/attachment.cgi?id=260639&action=review

> Source/WebCore/dom/Document.cpp:1258
> +String Document::characterSet() const

Please do not duplicate code. Have this call document::encoding().

> Source/WebCore/dom/Document.h:403
>      String charset() const { return Document::encoding(); }

Please add a comment explaining this may return a null String.

> Source/WebCore/dom/Document.h:404
> +    String characterSet() const;

Please add a comment explaining this returns "UTF-8" by default.

> LayoutTests/ChangeLog:9
> +        Update the tests which test the default encoding of document.

Please add a blank line after this.

> LayoutTests/ChangeLog:11
> +        * fast/dom/document-attribute-js-null-expected.txt: Obsolete test.

Not obsolete.

> LayoutTests/fast/dom/document-attribute-js-null-expected.txt:-5
> -TEST SUCCEEDED: The value was undefined. [tested Document.charset]

Do not remove.

> LayoutTests/fast/dom/document-attribute-js-null.html:-69
> -                        {name: 'charset', expectedNull: undefined},

Do not remove

Created attachment 260653 [details]
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[WebKit Commit Bot]

Attachment 260653 [details] did not pass style-queue:


ERROR: Source/WebCore/dom/Document.cpp:1261:  Missing space before ( in if(  [whitespace/parens] [5]
Total errors found: 1 in 15 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Chris Dumez]

Comment on attachment 260653 [details]
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r=me with changes.

> Source/WebCore/dom/Document.cpp:1255
>      return String();

nullAtom

> Source/WebCore/dom/Document.cpp:1260
> +    String name = encoding();

AtomicString

> Source/WebCore/dom/Document.cpp:1261
> +    if(!name.isEmpty())

missing space between if and (

isNull() not isEmpty()

> Source/WebCore/dom/Document.h:403
> +    String charset() const { return Document::encoding(); } // may return a null String

Comments need to end with a dot and start with a capital letter.

> Source/WebCore/dom/Document.h:404
> +    String characterSet() const; // returns "UTF-8" by default

Ditto

> Source/WebCore/dom/InlineStyleSheetOwner.cpp:144
> +    m_sheet = CSSStyleSheet::createInline(element, URL(), m_startTextPosition, document.charset());

Let's use encoding() for these as they wanted an encoding. Ditto below.

Created attachment 260889 [details]
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[Chris Dumez]

Comment on attachment 260889 [details]
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r=me

[Ryosuke Niwa]

Comment on attachment 260889 [details]
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> Source/WebCore/ChangeLog:15
> +        * dom/Document.cpp:
> +        (WebCore::Document::encoding):
> +        (WebCore::Document::characterSet):

You should add comments as to what you're modifying in each function.

> Source/WebCore/dom/Document.h:404
> +    String charset() const { return Document::encoding(); } // May return a null String.
> +    String characterSet() const; // Returns "UTF-8" by default.

We don't normally add comments like this. Instead, we rename functions to reflect these semantics.
Can we call the latter bindingCharacterSet instead?

[Chris Dumez]

Comment on attachment 260889 [details]
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>> Source/WebCore/dom/Document.h:404
>> +    String characterSet() const; // Returns "UTF-8" by default.
> 
> We don't normally add comments like this. Instead, we rename functions to reflect these semantics.
> Can we call the latter bindingCharacterSet instead?

Hmm, OK, how about characterSetForBindings() then. I think we usually use such naming.

> Source/WebCore/dom/Document.idl:67
> +    [ImplementedAs=characterSet] readonly attribute DOMString inputEncoding;

characterSetForBindings

> Source/WebCore/dom/Document.idl:191
> +    readonly attribute DOMString characterSet;

[ImplementedAs=characterSetForBindings]

Created attachment 260893 [details]
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[Ryosuke Niwa]

Comment on attachment 260893 [details]
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> Source/WebCore/dom/Document.h:404
> +    String charset() const { return Document::encoding(); } // May return a null String.
> +    String characterSetForBindings() const; // Returns "UTF-8" by default.

I don't think we want these comments.

[Ryosuke Niwa]

These are "what" comments that repeat the code.  We only want "why" comments.

Created attachment 260896 [details]
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[WebKit Commit Bot]

Comment on attachment 260896 [details]
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Clearing flags on attachment: 260896

Committed r189564: <http://trac.webkit.org/changeset/189564>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Alexey Proskuryakov]

This broke imported/w3c/web-platform-tests/html/dom/interfaces.html on Windows. Could you please update the results?

(In reply to comment #30)
> This broke imported/w3c/web-platform-tests/html/dom/interfaces.html on
> Windows. Could you please update the results?
Of course. I'll do it right now.

(In reply to comment #30)
> This broke imported/w3c/web-platform-tests/html/dom/interfaces.html on
> Windows. Could you please update the results?

Updated. https://bugs.webkit.org/show_bug.cgi?id=149038

[Darin Adler]

Comment on attachment 260896 [details]
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I think it’s worthwhile to return at some point and do additional cleanup.

> Source/WebCore/dom/Document.h:404
>      String charset() const { return Document::encoding(); }
> -    String characterSet() const { return Document::encoding(); }
> +    String characterSetForBindings() const;

I know we made an effort at clarity here, but I still find the naming confusing. There’s charset, used for the DOM binding attribute "charset", and also characterSetForBindings, used for two other DOM binding attributes "inputEncoding" and "characterSet".

Now how do those names make it clear why we wouldn’t want to use characterSetForBindings for "charset"? There’s a reason, presumably charset is supposed to return null rather than "UTF-8", but I think that reason needs to be expressed in these function names.

> Source/WebCore/loader/DocumentWriter.cpp:192
> +                m_decoder->setEncoding(TextEncoding(parentFrame->document()->encoding()), TextResourceDecoder::EncodingFromParentFrame);

This seems inefficient. Why convert from a TextEncoding to a string and then back to a TextEncoding?

> Source/WebCore/loader/FormSubmission.cpp:154
> +    return TextEncoding(document.encoding());

This seems inefficient. Why convert from a TextEncoding to a string and then back to a TextEncoding?

Polished in bug 149131.
(In reply to comment #33)
> Comment on attachment 260896 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=260896&action=review
> 
> I think it’s worthwhile to return at some point and do additional cleanup.
> 
> > Source/WebCore/dom/Document.h:404
> >      String charset() const { return Document::encoding(); }
> > -    String characterSet() const { return Document::encoding(); }
> > +    String characterSetForBindings() const;
> 
> I know we made an effort at clarity here, but I still find the naming
> confusing. There’s charset, used for the DOM binding attribute "charset",
> and also characterSetForBindings, used for two other DOM binding attributes
> "inputEncoding" and "characterSet".
> 
> Now how do those names make it clear why we wouldn’t want to use
> characterSetForBindings for "charset"? There’s a reason, presumably charset
> is supposed to return null rather than "UTF-8", but I think that reason
> needs to be expressed in these function names.
> 
> > Source/WebCore/loader/DocumentWriter.cpp:192
> > +                m_decoder->setEncoding(TextEncoding(parentFrame->document()->encoding()), TextResourceDecoder::EncodingFromParentFrame);
> 
> This seems inefficient. Why convert from a TextEncoding to a string and then
> back to a TextEncoding?
> 
> > Source/WebCore/loader/FormSubmission.cpp:154
> > +    return TextEncoding(document.encoding());
> 
> This seems inefficient. Why convert from a TextEncoding to a string and then
> back to a TextEncoding?