Wentao Liu wtracyliu

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

Shadowsocks Proxy

Server-side setup

apt-get install python-pip
pip install shadowsocks

sudo ssserver -p 443 -k password -m aes-256-cfb --user nobody -d start

编程语言

Swift
Objective-C
C++/C
JavaScript

操作系统

Mac OSX
iOS

Videos

Introduction to Functional Programming Johannes Weiß - https://vimeo.com/100786088
ReactiveCocoa at MobiDevDay Andrew Sardone - https://vimeo.com/65637501
The Future Of ReactiveCocoa Justin Spahr-Summers - https://www.youtube.com/watch?v=ICNjRS2X8WM
Enemy of the State Justin Spahr-Summers - https://www.youtube.com/watch?v=7AqXBuJOJkY
WWDC 2014 Session 229 - Advanced iOS Application Architecture and Patterns Andy Matuschak - https://developer.apple.com/videos/play/wwdc2014/229/
Functioning as a Functionalist Andy Matuschak - https://www.youtube.com/watch?v=rJosPrqBqrA
Controlling Complexity in Swift Andy Matuschak - https://realm.io/news/andy-matuschak-controlling-complexity/

Pull Request Etiquette

Why do we use a Pull Request workflow?

PRs are a great way of sharing information, and can help us be aware of the changes that are occuring in our codebase. They are also an excellent way of getting peer review on the work that we do, without the cost of working in direct pairs.

Ultimately though, the primary reason we use PRs is to encourage quality in the commits that are made to our code repositories

Done well, the commits (and their attached messages) contained within tell a story to people examining the code at a later date. If we are not careful to ensure the quality of these commits, we silently lose this ability.

Whether you're trying to give back to the open source community or collaborating on your own projects, knowing how to properly fork and generate pull requests is essential. Unfortunately, it's quite easy to make mistakes or not know what you should do when you're initially learning the process. I know that I certainly had considerable initial trouble with it, and I found a lot of the information on GitHub and around the internet to be rather piecemeal and incomplete - part of the process described here, another there, common hangups in a different place, and so on.

In an attempt to coallate this information for myself and others, this short tutorial is what I've found to be fairly standard procedure for creating a fork, doing your work, issuing a pull request, and merging that pull request back into the original project.

Creating a Fork

Just head over to the GitHub page and click the "Fork" button. It's just that simple. Once you've done that, you can use your favorite git client to clone your repo or j

	extension Color {
	/// Return a random color
	static var random: Color {
	return Color(
	red: .random(in: 0...1),
	green: .random(in: 0...1),
	blue: .random(in: 0...1)
	)
	}
	}

	from django.db.models import Count, Max

	unique_fields = ['field_1', 'field_2']

	duplicates = (
	MyModel.objects.values(*unique_fields)
	.order_by()
	.annotate(max_id=Max('id'), count_id=Count('id'))
	.filter(count_id__gt=1)
	)

	- Open Automator
	- File -> New -> Service
	- Change "Service Receives" to "files or folders" in "Finder"
	- Add a "Run Shell Script" action
	- Change "Pass input" to "as arguments"
	- Paste the following in the shell script box: open -n -b "com.microsoft.VSCode" --args "$*"
	- Save it as something like "Open in Visual Studio Code"

	import cPickle
	import pickle
	import json
	import random
	from time import time
	from hashlib import md5

	test_runs = 1000

	def float_list():