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The Metro Developer Show

2012 Apr 20, 9:15

The Metro Developer Show is the first podcast exclusively for Metro developers and enthusiasts.

Each week Ryan and Travis Lowdermilk traverse the exciting world of Metro (phone, tablet, desktop and Xbox); covering the latest news and exploring what it means for the developer community and everyday users.

PermalinkCommentsaudio technical podcast metro windows programming win8

JavaScript in JavaScript (js.js): smaller, faster, and with demos (princeton.edu)

2012 Apr 19, 3:36

Unlike Inception, running a JS engine in a JS engine does not make the inner JS engine go faster.

PermalinkCommentstechnical javascript programming interpretter

Why Did This Work?

2012 Mar 23, 7:05

Do we have a word or phrase to describe the following situation: You code up something complicated and it compiles and works on the first try. You then spend the next ten minutes trying to figure out what's actually broken because it shouldn't be this easy.

Or in meme form:

PermalinkCommentstechnical humor programming futurama

Changing System Environment Variables on Windows

2012 Mar 16, 3:13

Is this really the right way to do this? Feels icky:

To programmatically add or modify system environment variables, add them to the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the string “Environment”.

PermalinkCommentsprogramming techncial registry environment-variable windows

How to collect JavaScript performance data for Windows Metro apps on a device that does not have Visual Studio installed

2012 Mar 16, 2:27

Documentation for the VS JS profiler for Win8 HTML Metro Apps on profiling apps running on remote machines. 

PermalinkCommentswin8 programming technical js vs

Dave Weston on security best practices in Win8 HTML Metro Apps.

2012 Mar 14, 9:29PermalinkCommentssecurity technical video david-weston wwa win8 programming html javascript

Alternate IPv4 Forms - URI Host Syntax Notes

2012 Mar 14, 4:30

By the URI RFC there is only one way to represent a particular IPv4 address in the host of a URI. This is the standard dotted decimal notation of four bytes in decimal with no leading zeroes delimited by periods. And no leading zeros are allowed which means there's only one textual representation of a particular IPv4 address.

However as discussed in the URI RFC, there are other forms of IPv4 addresses that although not officially allowed are generally accepted. Many implementations used inet_aton to parse the address from the URI which accepts more than just dotted decimal. Instead of dotted decimal, each dot delimited part can be in decimal, octal (if preceded by a '0') or hex (if preceded by '0x' or '0X'). And that's each section individually - they don't have to match. And there need not be 4 parts: there can be between 1 and 4 (inclusive). In case of less than 4, the last part in the string represents all of the left over bytes, not just one.

For example the following are all equivalent:

192.168.1.1
Standard dotted decimal form
0300.0250.01.01
Octal
0xC0.0XA8.0x1.0X1
Hex
192.168.257
Fewer parts
0300.0XA8.257
All of the above

The bread and butter of URI related security issues is when one part of the system disagrees with another about the interpretation of the URI. So this non-standard, non-normal form syntax has been been a great source of security issues in the past. Its mostly well known now (CreateUri normalizes these non-normal forms to dotted decimal), but occasionally a good tool for bypassing naive URI blocking systems.

PermalinkCommentsurl inet_aton uri technical host programming ipv4

Dark Patterns are UI patterns used to trick users into doing...

2012 Mar 12, 7:05


Dark Patterns are UI patterns used to trick users into doing things they’d otherwise rather not: buy traveler’s insurance, click on ads, etc.  Covers the anti-patterns and how we as technical folk can help stop this.

PermalinkCommentstechnical ui programming dark-pattern

A Dad’s Plea To Developers Of iPad Apps For Children (smashingmagazine.com)

2012 Mar 12, 7:02

Set of issues run into by children using iPad apps.  Should be generally appropriate though:

Designing apps for children is extremely hard. Not only is quality, age-appropriate content hard to create, but designing the flow and interaction of these apps is made more difficult because designers must refrain from implementing advanced gestures, which would only confuse and frustrate kids (and, by extension, their parents). Yet all apps can and should adhere to certain basics. Hopefully, the four guidelines discussed here can become fixtures of all children’s apps.

PermalinkCommentstechnical ui ipad design children programming

Sometimes the bug isn't in your code, it's in the CPU (dragonflybsd.org)

2012 Mar 7, 8:00

Fascinating, but really most of the time it is in your code.  Really you should look there first.  Usually not the compiler’s fault, or the OS’s fault, or a loose wire in the CPU…

PermalinkCommentstechnical programming cpu

Web Worker Initialization Race

2012 Feb 24, 1:44

Elaborating on a previous brief post on the topic of Web Worker initialization race conditions, there's two important points to avoid a race condition when setting up a Worker:

  1. The parent starts the communication posting to the worker.
  2. The worker sets up its message handler in its first synchronous block of execution.

For example the following has no race becaues the spec guarentees that messages posted to a worker during its first synchronous block of execution will be queued and handled after that block. So the worker gets a chance to setup its onmessage handler. No race:

'parent.js':
var worker = new Worker();
worker.postMessage("initialize");

'worker.js':
onmessage = function(e) {
// ...
}

The following has a race because there's no guarentee that the parent's onmessage handler is setup before the worker executes postMessage. Race (violates 1):

'parent.js':
var worker = new Worker();
worker.onmessage = function(e) {
// ...
};

'worker.js':
postMessage("initialize");

The following has a race because the worker has no onmessage handler set in its first synchronous execution block and so the parent's postMessage may be sent before the worker sets its onmessage handler. Race (violates 2):

'parent.js':
var worker = new Worker();
worker.postMessage("initialize");

'worker.js':
setTimeout(
function() {
onmessage = function(e) {
// ...
}
},
0);
PermalinkCommentstechnical programming worker web-worker html script

Learn from Haskell - Functional, Reusable JavaScript (github.com)

2012 Feb 21, 3:32PermalinkCommentstechnical programming functional haskell javascript

MapReduce Patterns, Algorithms, and Use Cases

2012 Feb 10, 3:42PermalinkCommentstechnical map-reduce programming howto

JavaScript Array methods in the latest browsers

2011 Dec 3, 6:46

Cool and (relatively) new methods on the JavaScript Array object are here in the most recent versions of your favorite browser! More about them on ECMAScript5, MSDN, the IE blog, or Mozilla's documentation. Here's the list that's got me excited:

some & every
Does your callback function return true for any (some) or all (every) of the array's elements?
filter
Filters out elements for which your callback function returns false (in a new copy of the Array).
map
Each element is replaced with the result of it run through your callback function (in a new copy of the Array).
reduce & reduceRight
Your callback is called on each element in the array in sequence (from start to finish in reduce and from finish to start in reduceRight) with the result of the previous callback call passed to the next. Reduce your array to a single value aggregated in any manner you like via your callback function.
forEach
Simply calls your callback passing in each element of your array in turn. I have vague performance concerns as compared to using a normal for loop.
indexOf & lastIndexOf
Finds the first or last (respectively) element in the array that matches the provided value via strict equality operator and returns the index of that element or -1 if there is no such element. Surprisingly, no custom comparison callback method mechanism is provided.
PermalinkCommentsjavascript array technical programming

Bug Spotting: Ctors with default parameters

2011 Dec 1, 4:59

The following code compiled just fine but did not at all act in the manner I expected:

BOOL CheckForThing(__in CObj *pObj, __in IFigMgr* pFigMgr, __in_opt LPCWSTR url)
{
BOOL fCheck = FALSE;
if (SubCheck(pObj))
{
...
I’m calling SubCheck which looks like:
bool SubCheck(const CObj& obj);

Did you spot the bug? As you can see I should be passing in *pObj not pObj since the method takes a const CObj& not a CObj*. But then why does it compile?

It works because CObj has a constructor with all but one param with default values and CObj is derived from IUnknown:

CObj(__in_opt IUnknown * pUnkOuter, __in_opt LPCWSTR pszUrl = NULL);
Accordingly C++ uses this constructor as an implicit conversion operator. So instead of passing in my CObj, I end up creating a new CObj on the stack passing in the CObj I wanted as the outer object which has a number of issues.

The lesson is unless you really want this behavior, don't make constructors with all but 1 or 0 default parameters. If you need to do that consider using the 'explicit' keyword on the constructor.

More info about forcing single argument constructors to be explicit is available on stack overflow.

PermalinkCommentsc++ technical bug programming

Evolving ECMAScript

2011 Nov 24, 4:44PermalinkCommentstechnical javascript programming

Elements of Modern C++ Style (herbsutter.com)

2011 Nov 15, 11:59

Summary of some of the new C++ features with comments and suggested usage.  Not sure I agree with the take on auto.

‘“C++11 feels like a new language.” – Bjarne Stroustrup’

PermalinkCommentstechnical c++ programming

Things That Turbo Pascal is Smaller Than (dadgum.com)

2011 Nov 14, 7:52PermalinkCommentstechnical humor programming

Bug Spotting: Smart pointers and parameter evaluation order

2011 Oct 19, 5:58PermalinkCommentsc++ technical bug programming smart-pointer cpp

[html5] Web Workers: Race-Condition setting onmessage handler?

2011 Sep 20, 7:17There's no race between posting to a web worker and the web worker setting up its message handler as long as the web worker sets its message handler in the first sync. block of code that runs in the web worker: "Basically, once the initial worker script returns, the worker's port is enabled and the normal message port event delivery mechanism kicks in (including dropping unhandled messages on the floor)."PermalinkCommentstechnical web-worker webbrowser programming postMessage
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