从 XCode 4.2 开始 Objective-C 支持 ARC，对于广大 iPone 开发者来说是巨大的福音，不用面对满屏 [obj release] 和 [pool drain] 这类丑陋不堪的代码了，更重要的是不用整天为对象释放问题搞得寝食难安。但对于许多从 C++ 转到 ObjC 的开发者来说，其实更喜欢 Obj-C++ 混编。Cocoa 负责界面展现，C++ 负责业务逻辑实现，组合起来十分完美。
问题是 Obj-C++ 能否完美支持 ARC 呢，特别是把 ObjcC 对象放入 STL 容器的情形下能否正常工作?
恭喜大家，答案是肯定的!
测试代码一：
#import <vector>
#import <list>
using namespace std;
class Y
{
public:
int value;
public:
Y(int val = 0) : value(val)
{
NSLog(@"Y.Y (%d)", value);
}
~Y()
{
NSLog(@"Y.~Y (%d)", value);
}
};
@interface T : NSObject {
@private
int value;
Y* y;
}
- (id) initWithValue:(int)v;
@end
@implementation T
- (id) init
{
return [self initWithValue:0];
}
- (id) initWithValue:(int)v
{
self = [super init];
self->value = v;
self->y = new Y(v);
NSLog(@"T.init (%d)", self->value);
return self;
}
- (void)dealloc
{
delete self->y;
NSLog(@"T.dealloc (%d)", self->value);
}
@end
class X
{
public:
int value;
T* t;
public:
X(int val = 0) : value(val)
{
NSLog(@"X.X (%d)", value);
}
~X()
{
NSLog(@"X.~X (%d)", value);
}
};
int main(int argc, char *argv[])
{
@autoreleasepool
{
T* t = [[T alloc] initWithValue:1];
{
vector<T*> vt;
vt.push_back(t);
t = nil;
vt.push_back([[T alloc] initWithValue:2]);
vt.push_back([[T alloc] initWithValue:3]);
{
//vt.pop_back();
vt.erase(vt.begin());
NSLog(@"< first element had been dealloc >");
}
{
vt.clear();
NSLog(@"< all other elements had been dealloc >");
}
}
}
}
输出结果：
2012-02-11 19:31:56.256 Switcher[3037:f803] Y.Y (1)
2012-02-11 19:31:56.258 Switcher[3037:f803] T.init (1)
2012-02-11 19:31:57.352 Switcher[3037:f803] Y.Y (2)
2012-02-11 19:31:57.353 Switcher[3037:f803] T.init (2)
2012-02-11 19:31:57.578 Switcher[3037:f803] Y.Y (3)
2012-02-11 19:31:57.579 Switcher[3037:f803] T.init (3)
2012-02-11 19:31:57.786 Switcher[3037:f803] Y.~Y (1)
2012-02-11 19:31:57.787 Switcher[3037:f803] T.dealloc (1)
2012-02-11 19:31:58.894 Switcher[3037:f803] < first element had been dealloc >
2012-02-11 19:32:05.227 Switcher[3037:f803] Y.~Y (2)
2012-02-11 19:32:05.228 Switcher[3037:f803] T.dealloc (2)
2012-02-11 19:32:05.229 Switcher[3037:f803] Y.~Y (3)
2012-02-11 19:32:05.230 Switcher[3037:f803] T.dealloc (3)
2012-02-11 19:32:07.787 Switcher[3037:f803] < other elements had been dealloc >
测试代码二：
int main(int argc, char *argv[])
{
@autoreleasepool
{
X* x = new X(1);
x->t = [[T alloc] initWithValue:1];
{
list<X*> vx;
vx.push_back(x);
vx.push_back(new X(2, [[T alloc] initWithValue:2]));
vx.push_back(new X(3, [[T alloc] initWithValue:3]));
{
X* x2 = vx.front();
vx.pop_front();
delete x2;
NSLog(@"< first element had been dealloc >");
}
{
for(list<X*>::iterator it = vx.begin(); it != vx.end(); ++it)
delete (*it);
NSLog(@"< all other elements had been dealloc >");
}
vx.clear();
}
}
}
输出结果：
2012-02-12 02:34:13.403 Switcher[3142:f803] X.X (1)
2012-02-12 02:34:14.516 Switcher[3142:f803] Y.Y (1)
2012-02-12 02:34:14.517 Switcher[3142:f803] T.init (1)
2012-02-12 02:34:26.171 Switcher[3142:f803] Y.Y (2)
2012-02-12 02:34:26.171 Switcher[3142:f803] T.init (2)
2012-02-12 02:34:26.174 Switcher[3142:f803] X.X (2)
2012-02-12 02:34:42.481 Switcher[3142:f803] Y.Y (3)
2012-02-12 02:34:42.481 Switcher[3142:f803] T.init (3)
2012-02-12 02:34:42.484 Switcher[3142:f803] X.X (3)
2012-02-12 02:34:48.856 Switcher[3142:f803] X.~X (1)
2012-02-12 02:34:48.857 Switcher[3142:f803] Y.~Y (1)
2012-02-12 02:34:48.858 Switcher[3142:f803] T.dealloc (1)
2012-02-12 02:35:02.491 Switcher[3142:f803] < first element had been dealloc >
2012-02-12 02:35:07.303 Switcher[3142:f803] X.~X (2)
2012-02-12 02:35:07.303 Switcher[3142:f803] Y.~Y (2)
2012-02-12 02:35:07.304 Switcher[3142:f803] T.dealloc (2)
2012-02-12 02:35:09.319 Switcher[3142:f803] X.~X (3)
2012-02-12 02:35:09.320 Switcher[3142:f803] Y.~Y (3)
2012-02-12 02:35:09.321 Switcher[3142:f803] T.dealloc (3)
2012-02-12 02:35:11.268 Switcher[3142:f803] < all other elements had been dealloc >
