[webkit-dev] localStorage quota limit

[Maciej Stachowiak]

On Dec 2, 2009, at 12:06 PM, Michael Nordman wrote:

> Arguably, seems like a bug that invalid string values are let thru  
> the door to start with?

ECMAScript Strings are essentially sequences of arbitrary 16-bit  
values. Sometimes Web apps take advantage of this to use a String as a  
hacky way to represent binary data. I don't think we should reject  
such strings arbitrarily.

> Since users can't effectively store invalid UTF16 character  
> sequences in FF or IE,

I tend to think this is a bug in FF/IE. Nothing in the spec gives  
license to reject particular Strings.

> is there really any downside to using UTF8 text encoding in WebKit?  
> @Jeremy, this isn't a matter of letting users choose the text  
> encoding, this is entirely an implementation detail of WebStorage.

I think it would be fine to use a more compact encoding  
opportunistically, as long as we can still handle an arbitrary  
JavaScript String. Perhaps we should use UTF-8 if and only if the  
conversion succeeds, or perhaps even use Latin1 as the alternative.

>
> Downsides
> * The code change to get UTF8 by default in new databases, tiny.
> * Migrating pre-existing databases to the new encoding. Somewhat of  
> a hassle. But maybe doesn't need to be done, pre-existing files  
> could continue to use UTF16, while newly created dbs could use UTF8  
> (the text encoding is chosen at database creation time and stuck  
> that way forever thereafter).
> * Its possible that some app is already depending on the ability to  
> store invalid character sequences (on the iPhone say), and this  
> would be a breaking change for that app.
>
> The preload everything characteristic is a separate issue altogether.
>
>
>
> On Wed, Dec 2, 2009 at 11:15 AM, Jeremy Orlow <jorlow at chromium.org>  
> wrote:
> IE chokes ("invalid procedure call or argument") and Firefox mangles  
> the data for LocalStorage (but works fine for SessionStorage).
>
> On Wed, Dec 2, 2009 at 10:54 AM, Darin Adler <darin at apple.com> wrote:
> On Dec 2, 2009, at 10:48 AM, Jeremy Orlow wrote:
>
> > How can you construct invalid UTF-16 sequences?
>
> http://unicode.org/faq/utf_bom.html#utf16-7
>
>    -- Darin
>
>
>
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