nswrap/examples/gc/main.go

167 lines
3.8 KiB
Go
Raw Normal View History

package main
import "C"
import (
"fmt"
"runtime"
"time"
"git.wow.st/gmp/nswrap/examples/gc/ns"
)
func releaseX(x int) func (ns.MyClassSupermethods) {
return func(super ns.MyClassSupermethods) {
//fmt.Printf("--release %d\n", x)
super.Release() // comment out for leak
}
}
func memtest1() {
fmt.Println("memtest1 started")
for {
arr := make([]*ns.MyClass,1000)
for i := 0; i < 1000; i++ {
// Alloc methods set a finalizer that causes the Go GC to
// Release these objects.
arr[i] = ns.MyClassAlloc()
arr[i].ReleaseCallback(releaseX(i))
// You can still manually retain objects, but that will cause
// them to stick around after their Go pointers are collected.
//arr[i].Retain() // uncomment for leak
}
// Manually run the Go GC at every loop iteration. May not be needed
// in a real program.
runtime.GC()
time.Sleep(time.Second/50)
//fmt.Printf("Loop complete\n")
}
}
func memtest2() {
fmt.Println("memtest2 started")
i := 0
for {
o1 := ns.NSStringAlloc().InitWithGoString(fmt.Sprintf("two string %d",i))
o2 := ns.NSStringWithGoString(fmt.Sprintf("two string %d",i))
// NSWrap runs object constructors inside an @autoreleasepool block,
// and then calls "retain" on them before returning to Go. A Go
// finalizer is set allowing the Go GC to call Release().
o3 := ns.NSStringWithString(o1)
o4 := ns.NSStringAlloc()
_ = o4
a1 := ns.NSArrayAlloc()
// init methods in Objective-C always return a retained object.
// init may or may not return the same object that was sent in.
a1 = a1.InitWithObjects(o1,o2,o3,o4)
a2 := ns.NSArrayWithObjects(o1,o2,o3,o4)
// you can always nest alloc and init.
a3 := ns.NSMutableArrayAlloc().Init()
a3.AddObject(o1)
a3.AddObject(o2)
a3.AddObject(o3)
a3.AddObject(o4)
_ = a1
_ = a2
_ = a3
runtime.GC()
time.Sleep(time.Second/50)
}
}
func addStr(arr *ns.NSMutableArray) {
// temporary strings made by the 'WithGoString' methods should be released
// automatically by the GC.
s1 := ns.NSStringAlloc().InitWithGoString("a string")
arr.AddObject(s1)
// s1 should be eligible for Go garbage collection here, but is still referenced
// on the Objective-C side. By adding s1 to an array, the array automatically
// calls 'retain' on the underlying Objective-C string.
}
func memtest3() {
fmt.Println("memtest3 started")
for {
// arr will be garbage collected by Go
arr := ns.NSMutableArrayAlloc().Init()
addStr(arr)
runtime.GC()
time.Sleep(time.Second)
// check that our string was retained.
s1 := arr.ObjectAtIndex(0)
gstr := s1.NSString().UTF8String().String()
_ = gstr
}
}
func memtest4() {
fmt.Println("memtest4 started")
for {
o1 := ns.NSStringAlloc().InitWithGoString("red string")
// conversions to UTF8String internally create autoreleased strings
// in the Objective-C runtime. NSWrap runs these in a mini-
// @autoreleasepool block.
c1 := o1.UTF8String()
_ = o1
_ = c1
runtime.GC()
time.Sleep(time.Second/50)
}
}
func memtest5() {
fmt.Println("memtest5 started")
i := 0
for {
// by incrementing i we can ensure that Objective-C needs to create
// a new NSString object at each loop iteration and cannot be reusing
// the same string object.
str := ns.NSStringWithGoString(fmt.Sprintf("blue string %d",i))
// SubstringFromIndex should be returning a newly allocated NSString,
// which is getting retained by NSWrap and released by a Go GC
// finalizer.
sub := str.SubstringFromIndex(5)
_ = sub
u := sub.UTF8String()
_ = u
time.Sleep(time.Second/50)
runtime.GC()
i++
}
}
func main() {
go memtest1()
go memtest2()
go memtest3()
go memtest4()
go memtest5()
go func() {
for {
// print a progress indicator
fmt.Printf("t = %s\n",time.Now())
time.Sleep(time.Second * 10)
}
}()
select {}
}