poi page 5 - Dave's Blog

Internet Explorer 8 Released

IE8, the software I've been working on for some time now, has finally been released at MIX09.

• Download IE8.
• Dean's MIX09 Keynote releasing IE8 is viewable here.
• Louis pointed me to this humorous IE8 advertising that doesn't make me cringe. On the contrary it has Ask a Ninja, Janeane Garofalo, and several comedians I recall collectively from either 'I Love the [decade]' or 'Best Week Ever'.
• It seems like only a year ago that IE8 Beta was released.
• IE Blog: IE8 Released.

Notes on Creating Internet Explorer Extensions in C++ and COM

Working on Internet Explorer extensions in C++ & COM, I had to relearn or rediscover how to do several totally basic and important things. To save myself and possibly others trouble in the future, here's some pertinent links and tips.

First you must choose your IE extensibility point. Here's a very short list of the few I've used:

• Explorer Bars and IE Toolbars
• IE Tools, IE Help, and IE Context Menu menu items
• IE Toolbar Buttons

Once you've created your COM object that implements IObjectWithSite and whatever other interfaces your extensibility point requires as described in the above links you'll see your SetSite method get called by IE. You might want to know how to get the top level browser object from the IUnknown site object passed in via that method.

After that you may also want to listen for some events from the browser. To do this you'll need to:

1. Implement the dispinterface that has the event you want. For instance DWebBrowserEvents2, or HTMLDocumentEvents, or HTMLWindowEvents2. You'll have to search around in that area of the documentation to find the event you're looking for.
2. Register for events using AtlAdvise. The object you need to subscribe to depends on the events you want. For example, DWebBrowserEvents2 come from the webbrowser object, HTMLDocumentEvents come from the document object assuming its an HTML document (I obtained via get_Document method on the webbrowser), and HTMLWindowEvents2 come from the window object (which oddly I obtained via calling the get_script method on the document object). Note that depending on when your SetSite method is called the document may not exist yet. For my extension I signed up for browser events immediately and then listened for events like NavigateComplete before signing up for document and window events.
3. Implement IDispatch. The Invoke method will get called with event notifications from the dispinterfaces you sign up for in AtlAdvise. Implementing Invoke manually is a slight pain as all the parameters come in as VARIANTs and are in reverse order. There's some ATL macros that may make this easier but I didn't bother.
4. Call AtlUnadvise at some point -- at the latest when SetSite is called again and your site object changes.

If you want to check if an IHTMLElement is not visible on screen due how the page is scrolled, try comparing the Body or Document Element's client height and width, which appears to be the dimensions of the visible document area, to the element's bounding client rect which appears to be its position relative to the upper left corner of the visible document area. I've found this to be working for me so far, but I'm not positive that frames, iframes, zooming, editable document areas, etc won't mess this up.

Be sure to use pointers you get from the IWebBrowser/IHTMLDocument/etc. only on the thread on which you obtained the pointer or correctly marshal the pointers to other threads to avoid weird crashes and hangs.

Obtaining the HTML document of a subframe is slightly more complicated then you might hope. On the other hand this might be resolved by the new to IE8 method IHTMLFrameElement3::get_contentDocument

Check out Eric's IE blog post on IE extensibility which has some great links on this topic as well.

The 'Is It UTF-8?' Quick and Dirty Test

I've found while debugging networking in IE its often useful to quickly tell if a string is encoded in UTF-8. You can check for the Byte Order Mark (EF BB BF in UTF-8) but, I rarely see the BOM on UTF-8 strings. Instead I apply a quick and dirty UTF-8 test that takes advantage of the well-formed UTF-8 restrictions.

Unlike other multibyte character encoding forms (see Windows supported character sets or IANA's list of character sets), for example Big5, where sticking together any two bytes is more likely than not to give a valid byte sequence, UTF-8 is more restrictive. And unlike other multibyte character encodings, UTF-8 bytes may be taken out of context and one can still know that its a single byte character, the starting byte of a three byte sequence, etc.

The full rules for well-formed UTF-8 are a little too complicated for me to commit to memory. Instead I've got my own simpler (this is the quick part) set of rules that will be mostly correct (this is the dirty part). For as many bytes in the string as you care to examine, check the most significant digit of the byte:

F:

This is byte 1 of a 4 byte encoded codepoint and must be followed by 3 trail bytes.

E:

This is byte 1 of a 3 byte encoded codepoint and must be followed by 2 trail bytes.

C..D:

This is byte 1 of a 2 byte encoded codepoint and must be followed by 1 trail byte.

8..B:

This is a trail byte.

0..7:

This is a single byte encoded codepoint.

Sarah and I Are Engaged

Over the previous weekend Sarah and I got engaged. I had a limo pick us up and take us to a park that has a beautiful view of the Seattle skyline where I proposed, then out for dinner and drinks including a bottle of wine for the ride back. What's the point of a limo ride if you don't drink while being driven around? It was a nice night and only had a hint of rain when we came home. We don't yet have a date set.

Text/Plain Fragment Bookmarklet

The text/plain fragment documented in RFC 5147 and described on Erik Wilde's blog struck my interest and, like the XML fragment, I wanted to see if I could implement this in IE. In this case there's no XSLT for me to edit so, like my plain/text word wrap bookmarklet I've implemented it as a bookmarklet. This is only a partial implementation as it doesn't implement the integrity checks.

Check out my text/plain fragment bookmarklet.

Investigation of a Few Application Protocols (Updated)

Windows allows for application protocols in which, through the registry, you specify a URL scheme and a command line to have that URL passed to your application. Its an easy way to hook a webbrowser up to your application. Anyone can read the doc above and then walk through the registry and pick out the application protocols but just from that info you can't tell what the application expects these URLs to look like. I did a bit of research on some of the application protocols I've seen which is listed below. Good places to look for information on URI schemes: Wikipedia URI scheme, and ESW Wiki UriSchemes.

Anecdotes from Work

The names in the following anecdote have been changed. Except for my name (I'm Dave).

I got a new laptop a while back. I had it in my office and Tim came in to ask me something but paused when he saw my laptop. "Oh, is this one of those new touch screen laptops?" he asked, the whole time moving his hand towards my laptop and punctuating his sentence by pressing his finger to the screen. "No" I responded.

Walking down a hallway I heard Winston, one of our managers, say, "Hey Tim!" Winston catches up to me and asks, "Are you almost done with the XYZ bug?" I realized Winston was talking to me and got my name wrong but I figured I'll ignore it and perhaps he'll realize his mistake. Winston continued "I just talked with some people who say they're blocked and waiting for Tim to finish the XYZ bug." "Dave" I said helpfully attempting to diplomatically correct Winston since he apparently hadn't realized his error. "No, it was Jeremy and Bill." Winston said naming the people he had talked to who were waiting for me to fix the XYZ bug. At this point I decided it would be easier to just answer his question and end the conversation than to get into this whole thing. As far as I know, Winston has not gotten my name wrong at any other time.

Braid Recommendation

I recently finished Braid, the Xbox Live game, and a comparison with Portal is helpful. From a screen shot Braid looks like a normal 2D platformer, but that's like looking at a screen shot of Portal and saying its a first person shooter. While the scaffolding of the game-play may sort of fall into that category, the games are actually about exploring the character's ability and solving puzzles. In Portal the ability is bending space and in Braid its bending time. However, whereas in Portal there is one space bending mechanism, the portal gun, Braid's protagonist explores several different time bending techniques including, most prominently, reversing time, but also time dilation, multiple time-lines, and other odd things.

Similar to the difference in game-play, while Portal has a strict simplicity to its visual style, Braid is much more ornate, like you're playing in an oil painting. Without seeing video of the game, or playing the demo (which is available for free on Xbox Live) its difficult to convey, but it is quite lovely and the animation adds quite a bit. Both games too are rather short leaving you just a bit hungry for more and have an interesting plot and an ending that I'd hate to spoil although Braid replaces Portal's humor with melancholy. If you enjoyed Portal and Twelve Monkeys then I'd recommend Braid.

Dr. Horrible Link Roundup

Doctor Horrible's Sing Along Blog is an Internet only show you may have already watched and heard everything about. If you missed this somehow, its a musical by Joss Whedon (Buffy the Vampire Slayer, Firefly) staring Neil Patrick Harris as an aspiring super villian who can't get up the courage to talk to his laundromat crush. Its very funny, fairly geeky, and on the Internet so of course I've enjoyed it thoroughly and have some links to share. It surprised me how many blogs that I don't usually see posting the same things telling me about it: first on Eric's blog, then The Old New Thing, and even Penny-Arcade.

Dr. Horrible's again available online via Hulu with commercial interruption.

Check out the official fan site. They link to such things as the owner of Dr. Horrible's house. He had appeared on Monster House, a reality show about remaking people's homes like Monster Car or Pimp My Ride is about remaking folk's cars, and had his house turned into a evil scientist's lab. Consequently its a perfect fit for Dr. Horrible and in return the owner appears in one of the final scenes and in the credits as the 'Purple Pimp'. Apparently the purple suit is his. Also on his blog you can find out what's happened on that big chair that appears in the show. All I'll say about that is, good thing Neil Patrick Harris wears a lab coat while sitting on it.

At the recent Comic Con some attendees took video of the Dr. Horrible Comic Con panel (video clips contain spoilers) some of which I've grouped together. Besides the videos containing the creators and stars of the musical who are all hilarious (see Felicia Day's comment on twittering) there's also some excellent bits about a possible second installment and information on the impending DVD. To finish off this series of Dr. Horrible links check out this Venn Diagram of Felicia Day's work.