objective-c中线程编程一例

/*
    print with threads :
    print every file's first n char contents under the path that pass to this program,
    format like : pwt [-h n] /some/path
*/

#import <Foundation/Foundation.h>

#define DEFAULT_N_SIZE 32
//#define MIN(x,y) (x<=y?x:y)

@class Main;

@interface OperationReadFile:NSOperation{
    NSString *path;
}
@property(copy) NSString *path;
-(id)initWithPath:(NSString*)path;
@end

@interface Main:NSObject{
    NSString *path;
    NSOperationQueue *queue;
}

@property (copy) NSString *path;
+(id)shared;
-(void)start;
-(id)initWithPath:(NSString *)path;
-(void)print:(NSString *)str;

@end

@implementation OperationReadFile
@synthesize path;
-(id)initWithPath:(NSString*)path_v{
    self = [super init];
    if(self){
        self.path = path_v;
    }
    return self;
}

NSString *head_n(NSString *str,NSUInteger n){
    return [str substringToIndex:MIN(n,[str length])];
}

-(void)main{
    //NSLog(@"path is %@",path);
    NSString *content = [NSString stringWithContentsOfFile:path
        encoding:NSASCIIStringEncoding error:NULL];
    content = head_n(content,DEFAULT_N_SIZE);
    NSLog(@"content:%@",content);
    [[Main shared] performSelectorOnMainThread:@selector(print:)
        withObject:content waitUntilDone:NO];
}
@end

@implementation Main{
    NSMutableArray *files;
}
static Main *shared;

@synthesize path;

+(id)shared{
    if(!shared){
        NSLog(@"ERR:shared is not inited!");
    }
    return shared;

}

-(void)start{
    for(NSString *file in files){
        OperationReadFile *orf = [[OperationReadFile alloc] initWithPath:file];
        [queue addOperation:orf];
    }
}

-(void)print:(NSString *)str{
    NSLog(@"file contents : %@",str);
}

-(id)initWithPath:(NSString *)path_v{
    if(shared) return shared;
    self = [super init];
    if(self){
        self.path = [path_v stringByExpandingTildeInPath];
        NSLog(@"full path is %@",path);
        NSFileManager *fm = [NSFileManager defaultManager];
        files = [NSMutableArray array];
        NSDirectoryEnumerator *enum_dir = [fm enumeratorAtPath:path];
        NSString *file;
        BOOL flag = false;
        while(file = [enum_dir nextObject]){
            //NSLog(@"file is %@",file);
            [fm fileExistsAtPath:[path stringByAppendingPathComponent:file] isDirectory:&flag];
            if(flag)
                [enum_dir skipDescendents];
            else
                [files addObject:[path stringByAppendingPathComponent:file]];
        }
        NSLog(@"files is : %@",files);
        queue = [[NSOperationQueue alloc] init];
        shared = self;
    }
    return self;
}

-(id)init{
    return [self initWithPath:@"."];
}

@end

int main(void){
    @autoreleasepool{
        NSProcessInfo *pi = [NSProcessInfo processInfo];
        NSArray *args = [pi arguments];
        NSLog(@"args : %@",args);

        //NSString *path = @".";
        Main *main = [[Main alloc] init];
        //NSLog(@"%@",[@"~/src" stringByAppendingPathComponent:@"asm_src"]);
        //Main *main = [[Main alloc]initWithPath:@"~/src/asm_src/nasm_src/linux"];
        [main start];
        //NSString *content = [[NSString alloc] initWithContentsOfFile:@"./9.m"
            //encoding:NSUTF8StringEncoding error:NULL];
        //NSLog(@"%@",[NSString stringWithContentsOfFile:@"./9.m"
            //encoding:NSASCIIStringEncoding error:NULL]);
        //NSLog(@"%@",content);
        NSRunLoop *loop = [NSRunLoop currentRunLoop];
        [loop run];
    }
    return 0;
}