Here are the overall shares for March 2010 to June 2011:

• 45% MSIE
• 24% Firefox
• 13% Chrome (WebKit)
• 13% Safari (WebKit)
• 5% Others (1% Opera)

So for the past year, MSIE usage fell significantly (from 64%!), Firefox and Safari rose slightly, and Chrome rose significantly (out of the “Other” category). Since both Safari and Chrome use WebKit, WebKit has now passed Firefox's Gecko engine to become the second most widely used browser engine.

The Internet Explorer breakdown:

• 50% MSIE 8.0
• 31% MSIE 7.0
• 18% MSIE 6.0
• 2% MSIE 9.0

Firefox:

• 68% Firefox 3.6
• 18% Firefox 3.5
• 6% Firefox 4.0
• 5% Firefox 3.0
• 2% Firefox 2.0
• 2% Firefox 5.0

Firefox 2.0 and 3.0 have now all but disappeared. Both 4.0 and 5.0 are simply too new to have garnered much share. It remains to be seen if 4.0 ever garners much share, or if users got directly to 5.0 (or 6.0, or…).

Safari:

• 40% Safari 5.0
• 18% Safari 4.0
• 17% Safari 4.0 Mobile
• 12% Safari 5.0 Mobile
• 5% Safari 4.1
• 4% Safari 5.1
• 5% Safari 3.0–3.2

The total mobile share has jumped from 20% last year to 29% this year. Safari 5.0 did not appear on last year's chart at all.

I did not include a by-version breakdown of Chrome share this year; maybe next year. Because Chrome self-updates in the background, I would expect that the latest couple of versions to dominate.

Unique Xcode object IDs using Ruby

The “UUIDs” used in project files are shorter than true UUIDs (only 12 bytes/16 characters), and have no punctuation. We can’t just use system UUID services to generate new ones, then. In practice, our UUIDs usually do not need to be universally unique; they must be unique within a project file, and ideally would be unique across all projects built or opened on a given machine. Here, nonetheless, is a quickie ruby class that generates Xcode project UUIDs:

class XcodeUUIDGenerator

    def initialize
        @num = [Time.now.to_i, Process.pid, getMAC]
    end

    # Get the ethernet hardware address ("MAC"). This version
    # works on Mac OS X 10.6 (Snow Leopard); it has not been tested
    # on other versions.

    def getMAC(interface='en0')
        addrMAC = `ifconfig #{interface} ether`.split("\n")[1]
        addrMAC ? addrMAC.strip.split[1].gsub(':','').to_i(16) : 0
    end

    def generate
        @num[0] += 1
        self
    end

    def to_s
        "%08X%04X%012X" % @num
    end
end

Usage is simple:

    gen = XcodeUUIDGenerator.new
    id1 = gen.generate.to_s
    id2 = gen.generate.to_s
    id3 = gen.generate.to_s

PBXFileReference

A PBXFileReference is used to track every external file referenced by the project: source files, resource files, libraries, generated application files, and so on. A source file might look like this:

 29B97316FDCFA39411CA2CEA /* main.m */ = {
	isa = PBXFileReference;
	fileEncoding = 4;
	lastKnownFileType = sourcecode.c.objc;
	path = main.m;
	sourceTree = "";
 };

The values for lastKnownFileType may be found within Xcode itself, by selecting the file and choosing “Get Info”. A sourceTree of “” corresponds to “Relative to Enclosing Group”. A fileEncoding value of “4″ is UTF-8. Here, the path is only a file name, however it can be a (longer) relative path or an absolute path (sourceTree = ““). Relative paths may also be relative to the chosen SDK, the Xcode application (rare), the project file (that is, the .xcodeproj bundle), or the built product.

 1058C7A1FEA54F0111CA2CBB /* Cocoa.framework */ = {
	isa = PBXFileReference;
	lastKnownFileType = wrapper.framework;
	name = Cocoa.framework;
	path = /System/Library/Frameworks/Cocoa.framework;
	sourceTree = "";
 };

Some Xcode templates contain absolute paths to some frameworks (as in the above example), however this is, arguably, “wrong”—SDK files should always use SDK-relative paths (as, indeed, Xcode 3.2.x will do if you add a framework to a project manually):

 2D04AF89126B8A7A00073224 /* AppleScriptObjC.framework */ = {
	isa = PBXFileReference;
	lastKnownFileType = wrapper.framework;
	name = AppleScriptObjC.framework;
	path = System/Library/Frameworks/AppleScriptObjC.framework;
	sourceTree = SDKROOT;
 };

Finally, the final output of your target also has a PBXFileReference. It looks slightly different:

 8D1107320486CEB800E47090 /* MyProject.app */ = {
	isa = PBXFileReference;
	explicitFileType = wrapper.application;
	includeInIndex = 0;
	path = MyProject.app;
	sourceTree = BUILT_PRODUCTS_DIR;
 };

Instead of lastKnownFileType, it has an explicitFileType; it also has a property includeInIndex, set to 0 (FALSE).

You can add comment to files; these are stored as a comments property on the PBXFileReference.

PBXBuildFile

Files that need to be processed in the build (for example compiled, linked, or copied) also have a PBXBuildFile. These are very simple:

 8D11072D0486CEB800E47090 /* main.m in Sources */ = {
	isa = PBXBuildFile;
	fileRef = 29B97316FDCFA39411CA2CEA /* main.m */;
	settings = {ATTRIBUTES = (); };
};

The fileRef is the id of the PBXFileReference. The settings property is usually omitted entirely. If you specify per-file compiler flags, they will be stored in the COMPILER_FLAGS property of the settings property.

PBXSourcesBuildPhase

Projects commonly have several build phases: compiling, linking, copying resources, copying other files, and perhaps running shell scripts. PBXSourcesBuildPhase describes the compiling phase for a target.

 8D11072C0486CEB800E47090 /* Sources */ = {
    isa = PBXSourcesBuildPhase;
    buildActionMask = 2147483647;
    files = (
      8D11072D0486CEB800E47090 /* main.m in Sources */,
      256AC3DA0F4B6AC300CF3369 /* MyProjectAppDelegate.m in Sources */,
    );
    runOnlyForDeploymentPostprocessing = 0;
 };

The files property contains an array of PBXBuildFile references. buildActionMask is usually 2147483647 (that’s 0x7FFFFFFF in hexadecimal). The runOnlyForDeploymentPostprocessing property is normally 0 (FALSE).

Until next time…

That’s it for this week! Next time, we’ll look at the other build phases.

¶

Last week we looked at the overall format of Xcode project files. Here’s an easy parser written in Ruby; this one will only run on Mac OS X, because it uses Foundation from Ruby:

#!/usr/bin/ruby
# http://danwright.info/blog/xcode-pbxproject-files-2

require 'osx/cocoa'

xcodeproj = "/Users/danwr/Documents/MyProject/MyProject.xcodeproj"

projectpbxproj = "#{xcodeproj}/project.pbxproj"
data = OSX::NSData.dataWithContentsOfFile(projectpbxproj)
plist = OSX::NSPropertyListSerialization.propertyListFromData_mutabilityOption_format_errorDescription(data, 0, nil, nil)

rootObject = plist['rootObject']
objects    = plist['objects']

if ARGV.length == 0
	puts "rootObject = #{objects[rootObject]}"
else
	what = ARGV.shift
	if /^[0-9a-fA-F]{24}$/ =~ what
		puts "object #{what} = #{objects[what]}"
	else
		results = objects.keys.find_all {|key| objects[key]['isa'] == what }
		puts "isa '#{what}': #{results}"
	end
end

If you run this command without any arguments, it will show you the root object (PBXProject). If you run it with a UUID, it will display the corresponding object; if you provide it with an object class (‘isa’), it will display the UUIDs for all matching objects. For purposes of this article, I’ve hard-coded the path to a project; you can edit that to point to your own project, or modify the script to allow a path to be specified as an argument.

Wow, that’s silly-easy. If you want your script to run on another platform—Windows or Linux—you would need another solution (but it isn’t exactly difficult to write a custom parser in a modern scripting language such as Ruby, Python, or even Old Man Perl.

XCConfigurationList

An XCConfigurationList is simply a list of configurations. A configuration refers to a group of settings, and commonly we have at least two: Debug and Release, the former for debugging the project, the latter optimized for customers.

C01FCF4E08A954540054247B = {
    buildConfigurations =     (
        C01FCF4F08A954540054247B,
        C01FCF5008A954540054247B
    );
    defaultConfigurationIsVisible = 0;
    defaultConfigurationName = Release;
    isa = XCConfigurationList;
}

The defaultConfigurationName and defaultConfigurationIsVisible properties indicate which configuration is the default when building with the xcodebuild tool, as well as whether this information should be exposed in the Xcode user interface. The buildConfigurations array contains references to objects of type XCBuildConfiguration.

XCBuildConfiguration

An XCBuildConfiguration is a collection of build settings, like so:

C01FCF4F08A954540054247B = {
    buildSettings =     {
        ARCHS = "$(ARCHS_STANDARD_32_64_BIT)";
        "GCC_C_LANGUAGE_STANDARD" = gnu99;
        "GCC_OPTIMIZATION_LEVEL" = 0;
        "GCC_WARN_ABOUT_RETURN_TYPE" = YES;
        "GCC_WARN_UNUSED_VARIABLE" = YES;
        "ONLY_ACTIVE_ARCH" = YES;
        PREBINDING = NO;
        SDKROOT = "macosx10.6";
    };
    isa = XCBuildConfiguration;
    name = Debug;
}

The buildSettings property is the heart of an XCBuildConfiguration. Each build setting should look familiar: these are the same names and settings you would use in an .xcconfig file. Of course, buildSettings can be empty, as it often will be when you have an .xcconfig file specified instead.

PBXVariantGroup

A PBXVariantGroup describes a group of files that act like one; this is used to described localized files (strings and xibs).

1DDD58140DA1D0A300B32029 = {
    children =     (
        1DDD58150DA1D0A300B32029
    );
    isa = PBXVariantGroup;
    name = "MainMenu.xib";
    sourceTree = "";
}

This one describes the application’s main xib (describing the menu bar and main window). The name is the name of the file. The children contains a list of localizations; here, there is just one, for the English version. Let’s look at that child:

1DDD58150DA1D0A300B32029 = {
    isa = PBXFileReference;
    lastKnownFileType = "file.xib";
    name = English;
    path = "English.lproj/MainMenu.xib";
    sourceTree = "";
}

The path is the path of the actual .xib file (relative to the encoding group). lastKnownFileType indicates the file type.

Next time…

Next time, a look at PBXFileReference, PBXBuildFile, and PBXSourcesBuildPhase.

¶

“One melancholy thought occurs as my fingers glide and flow over the surface of this astonishing object: Douglas Adams is not alive to see the closest thing to his Hitchhiker’s Guide [to the Galaxy] that humankind has yet devised.”
– Stephen Fry

Read more

Take Internet Explorer 6 users (please!), for instance. Surely their numbers have fallen?

Here are my overall numbers for March 2009 to March 2010:

• 64% MSIE
• 20% Firefox
• 10% Safari
• 6% Others (3% Chrome, 2% Opera)

So for the past year, MSIE usage actually increased, Firefox and Safari fell; Others held their own.

The Internet Explorer breakdown:

• 38% MSIE 6.0
• 36% MSIE 7.0
• 26% MSIE 8.0

MSIE 8 has now been released for just over 12 months; and yet, it is only the third most popular version of Internet Explorer. Internet Explorer is the only browser with an upside-down adoption rate. Last year, MSIE 7 was the most popular version; this year, perversely, it is MSIE 6. MSIE 6 went up six points compared to last year.

Sigh.

Firefox:

• 42% Firefox 3.5
• 42% Firefox 3.0
• 8% Firefox 2.0
• 7% Firefox 3.6

Firefox 3.6 has only been out for about two months, so it’s on track for a 42% share of the Firefox segment. Firefox 2.0 had the most share last year, at 48%. Quite a contrast with MSIE.

Safari:

• 57% Safari 4.0
• 15% Safari 4.0 (mobile – iPhone/iPod Touch)
• 10% Safari 3.2
• 6% Safari 3.1
• 5% Safari 3.1 (mobile)
• 7% Safari 3.0, 4.1, and 2.x

iPhone/iPod share has increased slightly, from 15 to 20%. A year ago, 3.2 was new, and version 3.1 had the largest share.

This problem is caused by a WebKit bug, triggered when files are taken from the browser’s cache rather than from your server. The simple workaround is to force WebKit not to cache your javascript files while you’re debugging them. This is easy if you server supports PHP (it almost certainly does). Create a php file to serve your javascript, and have your test page include that instead of your javascript:

Before:
<script src="testing.js" type="text/javascript"></script>

After:
<script src="debug.php/testing.js" type="text/javascript"></script>

Where debug.php has:


<?php
header('Content-Type: application/x-javascript');
header('Expires: ' . gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-cache, must-revalidate, max-age=0');
header('Pragma: no-cache');
readfile(dirname(__FILE__).'/testing.js');
?>


Or, more generally:


<?php
header('Content-Type: application/x-javascript');
header('Expires: ' . gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-cache, must-revalidate, max-age=0');
header('Pragma: no-cache');
$file = isset($_SERVER['PATH_INFO']) ? $_SERVER['PATH_INFO'] : '/testing.js';
readfile(dirname(__FILE__).$file);
?>


If you use the general version, you may wish to include some security checks on the input (PATH_INFO) to protect against potential exploits. That is left as an exercise for the reader.

Of course, before you deploy, remember to change the script include back to the original form!

Regrettably, I’ve been a bit behind the curve updating the Photoluna web site; most of the screen shots are from version 1.0. I was off on a two-week stint of jury duty just as 1.1 hit the store, followed by a bad cold that led straight into the holidays! The page should be updated soon.

“But how much will the upgrade cost,” you ask? Nothing! This upgrade will be free to all current customers.

“What’s in the upgrade?” Ah, for that, you’ll have to wait a little longer…