##Features
- Simple
Atomicclass for numbers and strings. - Uncomplicated
dispatchkeyword for firing off background routines. - Awesome
Chanfor concurrent communication. - Useful sync APIs.
Mutex,Cond,Once,WaitGroup
Atomic
Types
Int, Int8, Int16, Int32, Int64, UInt, UInt8, UInt16, UInt32, UInt64, Float, Double, Bool, String
Operators
==, !=, &&, ||, <=, >=, >, <, !
+, -, *, /, %, <<, >>, ^, &, &+, &-, &*, ++, --, +=, -=, *=, /=, %=, +=, <<=, >>=, ^=, &=
var anum = IntA(100) // IntA is an alias for Atomic.
anum += 15 // Adds a value atomically.
let res = anum % 4 // Modulo operation atomically.
print("\(anum) \(res)") // prints '115 3'.
Dispatch
Safe adds an uncomplicated method for dispatching routines.
dispatch {
print("Background")
}
print("Foreground")
Channels
A new Chan class provides a clean and simple model for concurrently sharing objects. Chan is modeled after Go channels.
Sharing Memory by Communicating
Example
let jobs = Chan<Int>(5) // buffered channel
let done = Chan<Bool>() // unbuffered channel
dispatch {
for ;; {
if let j = <-jobs {
print("received job \(j)")
} else {
print("received all jobs")
done <- true
return
}
}
}
for var j = 1; j <= 3; j++ {
jobs <- j
print("sent job \(j)")
}
jobs.close()
print("sent all jobs")
<-done
Iterate
A channel can also be iterated through.
while let j = <-jobs {
print("received job \(j)")
}
print("received all jobs")
Select
The _select keyword is a multiway communications multiplexer that works on multiple channels. _select, _case, and _default start with underscores so that they do not conflict with the select, case, and default syscall and keywords. When a _select encounters multiple channels with data, the chosen _case is selected at random
let jobs1 = Chan<Int>()
let jobs2 = Chan<Int>()
dispatch {
for ;; {
_select {
_case(jobs1){ j in
print("received 1: \(j)")
}
_case(jobs2){ j in
print("received 2: \(j)")
}
}
}
}
for var j = 1; ; j++ {
jobs1 <- (j * 1000)
jobs2 <- (j * 2000)
NSThread.sleepForTimeInterval(1)
}
Select with Default
A _select can contain a single _default for non-blocking operations.
_select {
_case(jobs1){ j in
print("received 1: \(j)")
}
_case(jobs2){ j in
print("received 2: \(j)")
}
_default {
print("channels not ready")
}
}
Mutex, Cond, Once, WaitGroup
Incredibly useful sync APIs.
Mutex
let m = Mutex()
m.lock()
m.unlock()
m.lock {
// this block is locked
}
Cond
let c = Cond(Mutex())
c.wait() // wait for signal.
c.wait(0.25) // wait for signal or 250ms to pass.
c.signal() // signal to one wait.
c.broadcast() // signal to all waits.
Once
func f(){
print("hey there")
}
let o = Once()
o.doit(f) // runs once
o.doit(f) // noop: cannot run twice
WaitGroup
let dosomething : (NSTimeInterval, WaitGroup)->() = { (delay, wg) in
NSThread.sleepForTimeInterval(delay)
print("Function in background, duration: \(delay)")
wg.done()
}
let wg = WaitGroup()
wg.add(1)
dispatch { dosomething(0.40, wg) }
wg.add(1)
dispatch { dosomething(0.30, wg) }
wg.add(1)
dispatch { dosomething(0.15, wg) }
wg.add(1)
dispatch { dosomething(0.60, wg) }
wg.wait()
print("done")
##Installation (iOS and OS X)
Carthage
Add the following to your Cartfile:
github "tidwall/Safe"
Then run carthage update.
Follow the current instructions in Carthage's README for up to date installation instructions.
The import Safe directive is required in order to access Safe features.
CocoaPods
Add the following to your Podfile:
use_frameworks!
pod 'Safe'
Then run pod install with CocoaPods 0.36 or newer.
The import Safe directive is required in order to access Safe features.
SPM
Add the following to your Package.swift
dependencies: [
...
.Package(url: "https://github.com/tidwall/Safe", majorVersion: 1, minor: 2)
]
Then run swift build.
The import Safe directive is required in order to access Safe features.
Manually
Copy the Source/*.swift file into your project.
There is no need for import Safe when manually installing.
Contact
Josh Baker @tidwall
License
The Safe source code is available under the MIT License.
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