代码中的潜在泄漏转换为ARC

Question

我已将一些库的代码翻译成ARC，我怀疑我没有正确地这样做。基本上我已经在代码中添加了som __bridge命令。 Xcode在分析期间抱怨，说存在path中存储的对象可能存在泄漏。代码附在下面。你能帮我解决下一行的潜在泄漏问题：

-(void)drawRect:(CGRect)rect {
    if(self.text.length<=0) {
        self.text = EMPTY;
        return;
    }

    //Prepare View for drawing
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetTextMatrix(context,CGAffineTransformIdentity);
    CGContextTranslateCTM(context,0,([self bounds]).size.height);
    CGContextScaleCTM(context,1.0,-1.0);

    //Get the view frame size
    CGSize size = self.frame.size;

    //Determine default text color
    UIColor* textColor = nil;
    if(!self.highlightColor||!(textColor=[self.highlightColor objectForKey:kRegexHighlightViewTypeText])) {
        if([self.textColor isEqual:[UIColor clearColor]]) {
            if(!(textColor=[[RegexHighlightView highlightTheme:kRegexHighlightViewThemeDefault] objectForKey:kRegexHighlightViewTypeText]))
               textColor = [UIColor blackColor];
        } else textColor = self.textColor;
    }

    //Set line height, font, color and break mode
    CGFloat minimumLineHeight = [self.text sizeWithFont:self.font].height,maximumLineHeight = minimumLineHeight;
    CTFontRef font = CTFontCreateWithName((__bridge CFStringRef)self.font.fontName,self.font.pointSize,NULL);
    CTLineBreakMode lineBreakMode = kCTLineBreakByWordWrapping;

    //Apply paragraph settings
    CTParagraphStyleRef style = CTParagraphStyleCreate((CTParagraphStyleSetting[3]){
        {kCTParagraphStyleSpecifierMinimumLineHeight,sizeof(minimumLineHeight),&minimumLineHeight},
        {kCTParagraphStyleSpecifierMaximumLineHeight,sizeof(maximumLineHeight),&maximumLineHeight},
        {kCTParagraphStyleSpecifierLineBreakMode,sizeof(CTLineBreakMode),&lineBreakMode}
    },3);
    NSDictionary* attributes = [NSDictionary dictionaryWithObjectsAndKeys:(__bridge id)font,(NSString*)kCTFontAttributeName,(__bridge id)textColor.CGColor,(NSString*)kCTForegroundColorAttributeName,(__bridge id)style,(NSString*)kCTParagraphStyleAttributeName,nil];

    //Create path to work with a frame with applied margins
    CGMutablePathRef path = CGPathCreateMutable();
    CGPathAddRect(path,NULL,CGRectMake(MARGIN+0.0,(-self.contentOffset.y+0),(size.width-2*MARGIN),(size.height+self.contentOffset.y-MARGIN)));


    //Create attributed string, with applied syntax highlighting
    CFAttributedStringRef attributedString = (__bridge CFAttributedStringRef)[self highlightText:[[NSAttributedString alloc] initWithString:self.text attributes:attributes]];

    //Draw the frame
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0,CFAttributedStringGetLength(attributedString)),path,NULL);
    CTFrameDraw(frame,context);
}

Answer 1

HaIR的定义有点不完整：编译器只管理Objective-C类型。任何遵循create规则或malloc'd，calloc'或new到堆上的内容都是您的责任。内存泄漏是由4个不同的实例产生的，这些实例没有使用create的函数来平衡函数，并使用正确的前缀...release()调用。

您可以通过调用CGPathRelease()来修正数字1，通过调用-autorelease来获取该属性字符串（假设ARC已关闭，根据具体情况，如果Instruments正在抱怨），数字3和4可以通过两次调用CFRelease()来修复。

Answer 2

在the manual中，它提到编译器不会自动管理CF对象。根据CF内存管理规则，您必须调用CFRetain和CFRelease。

所以你需要CGPathRelease(path);在某些时候。