ios - 使用 CGPathCreateCopyByTransforming 和 CGPathCreateCopy 导致的挤压内存泄漏
<p><p>我正在使用 ARC 和 while 循环来调整几个 CGPathRef，直到它们符合我的某些约束条件，并且一旦满足 while 循环的条件，我就需要访问路径。</p>
<p>谁能解释我的代码是如何泄漏的？ </p>
<p>CGCreateCopy... 函数的文档说它们会创建一个新副本，您负责发布该副本。所以我相信我的代码路径(while 循环的结尾)确实释放了 Instruments 正在捕获并将泄漏对象归因于的路径引用。</p>
<p>Instrument 调用在下面的代码中表示，并在 Instruments 突出显示的位置下方带有注释。</p>
<p>这个例程被赋予一个 GCSize 大小，它是一个矩形的大小和一个 int 值，它是一个最终将在此处创建的形状中显示的数值(形状的尺寸在某种程度上取决于字符串的大小这个值的表示)</p>
<p>我应该注意，代码确实会生成我想要的所需路径——我不是要求任何人调试这个 block !但它泄漏了，我不明白为什么。</p>
<pre><code>float lineThickness = size.width;
float perimeterStrokeWidth = lineThickness * 2;
CGSize shadowOffset = CGSizeMake( perimeterStrokeWidth / 1.5, perimeterStrokeWidth * 1.25 );
float shadowBlur = perimeterStrokeWidth * 2.0;
NSString *edgeSymbol = @"°";
CGPathRef rightEdgePath = NULL;
CGPathRef leftEdgePath = NULL;
CGPathRef valueStringPath = NULL;
CGAffineTransform adjust, flip;
float pointsize, deltaX, deltaY, inset, pointSizeThatFits;
CGRect valueRect, edgeRect, leftEdgeRect, rectForValue;
CGSize trialSize = size;
pointsize = size.height;
CGPoint tdc; // top dead center
CGPoint bdc; // bottom dead center
NSLog(@"\n\n");
BOOL done = false;
int attempts = 0;
int attemptsRemaining = 11; // ensure no infinite looping
while ( ! done ) {
done = YES; // presumptive close!tests below will reset if they fail
--attemptsRemaining;
trialSize = CGSizeMake(trialSize.width, trialSize.height - attempts);
++attempts;
lineThickness = trialSize.height / 60;
perimeterStrokeWidth = lineThickness * 2;
shadowOffset = CGSizeMake( perimeterStrokeWidth / 1.5, perimeterStrokeWidth * 1.0 );
shadowBlur = perimeterStrokeWidth * 2.0;
pointsize = [UIFont sizeFont:[UIFont fontWithName:@"Alameda"
size:pointsize]
toFitText:edgeSymbol
withinRect:CGRectMake(0,
0,
trialSize.width,
trialSize.height)];
// sizeFont:toFitText:withinRect: is a custom addition to UIFont that
// recursively tries smaller and smaller pointsize values until the
// text fits within the rectangle provided.
CGPathRef tmpRightEdgePath = ];
// newPathWithFont: is a custom addition to NSString that returns a
// CGPathRef representing the glyphs that make up the string, rendered in
// the font (and size) specified
flip = CGAffineTransformMakeScale(-1.0, 1.0);
CGPathRef tmpLeftEdgePath = CGPathCreateCopyByTransformingPath(tmpRightEdgePath, &flip);
edgeRect = CGPathGetBoundingBox(tmpRightEdgePath);
// Center the symbol vertically in the size we were given (maybe up a little because of the shadow below?)
deltaY = ( (size.height / 2) - (edgeRect.size.height / 2) - edgeRect.origin.y);
// Slide it over to the right edge, inset slightly for the shadow
inset = shadowOffset.width + shadowBlur;
deltaX = ( trialSize.width - edgeRect.origin.x - edgeRect.size.width - inset);
adjust = CGAffineTransformMakeTranslation(deltaX, deltaY);
CGPathRef tmpRightEdgePath1 = CGPathCreateCopyByTransformingPath(tmpRightEdgePath, &adjust);
CGPathRelease(tmpRightEdgePath);
tmpRightEdgePath = NULL;
edgeRect = CGPathGetBoundingBox(tmpRightEdgePath1);
leftEdgeRect = CGPathGetBoundingBox(tmpLeftEdgePath);
deltaX = inset - leftEdgeRect.origin.x;
adjust = CGAffineTransformMakeTranslation(deltaX, deltaY);
CGPathRef tmpLeftEdgePath1 = CGPathCreateCopyByTransformingPath(tmpLeftEdgePath, &adjust);
CGPathRelease(tmpLeftEdgePath);
tmpLeftEdgePath = NULL;
leftEdgeRect = CGPathGetBoundingBox(tmpLeftEdgePath1);
rectForValue = CGRectMake(leftEdgeRect.origin.x + leftEdgeRect.size.width,
leftEdgeRect.origin.y,
edgeRect.origin.x - leftEdgeRect.origin.x - leftEdgeRect.size.width,
leftEdgeRect.size.height);
NSString *valueString = ;
pointSizeThatFits =
toFitText:valueString
withinRect:rectForValue];
valueStringPath = ];
valueRect = CGPathGetBoundingBox(valueStringPath);
deltaY = ( (size.height / 2) - (valueRect.size.height / 2) - valueRect.origin.y);
deltaX = ( (trialSize.width / 2)- (valueRect.size.width / 2)- valueRect.origin.x);
adjust = CGAffineTransformMakeTranslation(deltaX, deltaY);
CGPathRef tmpValueStringPath1 = CGPathCreateCopyByTransformingPath(valueStringPath, &adjust);
CGPathRelease(valueStringPath);
valueStringPath = NULL;
valueRect = CGPathGetBoundingBox(tmpValueStringPath1);
CGPathRef tmpRightEdgePath2;
CGPathRef tmpLeftEdgePath2;
if ((valueRect.origin.x + valueRect.size.width) < edgeRect.origin.x) {
float gapToClose = edgeRect.origin.x - (valueRect.origin.x + valueRect.size.width);
adjust = CGAffineTransformMakeTranslation(- gapToClose, 0);
{
tmpRightEdgePath2 = CGPathCreateCopyByTransformingPath(tmpRightEdgePath1, &adjust);
// ^^^^ Instruments reports 5.9% of leaks here
CGPathRelease(tmpRightEdgePath1);
tmpRightEdgePath1 = NULL;
}
adjust = CGAffineTransformMakeTranslation(gapToClose, 0);
{
tmpLeftEdgePath2 = CGPathCreateCopyByTransformingPath(tmpLeftEdgePath1, &adjust);
// ^^^^ Instruments reports 23.5% of leaks here
CGPathRelease(tmpLeftEdgePath1);
tmpLeftEdgePath1 = NULL;
}
leftEdgeRect = CGPathGetBoundingBox(tmpLeftEdgePath2);
} else {
{
tmpRightEdgePath2 = CGPathCreateCopy(tmpRightEdgePath1);
CGPathRelease(tmpRightEdgePath1);
tmpRightEdgePath1 = NULL;
}
{
tmpLeftEdgePath2= CGPathCreateCopy(tmpLeftEdgePath1);
CGPathRelease(tmpLeftEdgePath1);
tmpLeftEdgePath1 = NULL;
}
leftEdgeRect = CGPathGetBoundingBox(tmpLeftEdgePath2);
}
tdc.x = CGRectGetMidX(rectForValue);
bdc.x = tdc.x;
tdc.y = leftEdgeRect.origin.y - (tdc.x - leftEdgeRect.origin.x) * 0.08; // SWAG on the 10% of width
if ((tdc.y - lineThickness/2.0) < 0) {
done = NO;
}
bdc.y = leftEdgeRect.origin.y + leftEdgeRect.size.height + (leftEdgeRect.origin.y - tdc.y);
float shadowness = shadowOffset.height;
if ((bdc.y + shadowness) > size.height) {
done = NO;
}
if (attemptsRemaining <= 0) {
done = YES;
}
// And finally, assign them out if DONE!
if (done) {
leftEdgePath = CGPathCreateCopy(tmpLeftEdgePath2);
// ^^^^ Instruments reports 35.3% of leaks here
rightEdgePath = CGPathCreateCopy(tmpRightEdgePath2);
// ^^^^ Instruments reports 35.3% of leaks here
valueStringPath = CGPathCreateCopy(tmpValueStringPath1);
}
CGPathRelease(tmpLeftEdgePath2);
tmpLeftEdgePath2 = NULL;
CGPathRelease(tmpRightEdgePath2);
tmpRightEdgePath2 = NULL;
CGPathRelease(tmpValueStringPath1);
tmpValueStringPath1 = NULL;
}
// what follows is the application of those paths within CGContext drawing calls.
</code></pre>
<p>我从关于仪器和泄漏的其他有用答案中了解到，标记的行通常是创建即将泄漏的对象的位置。考虑到这一点，我向下看我可能会在没有首先释放先前路径的情况下分配新路径，但没有任何(我可以看到 - 但我承认我有点睡眼惺忪看着这个)。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>为了其他发现自己被内存泄漏问题困扰的人的利益，我将在此处提供我的问题的答案，因为侦查过程可能会对您有所帮助。</p>
<p>在代码 list 的中间，您可以看到我在哪里通知编译器我将很快使用两个 CGPathRef，最初在 if/then/else 的范围内，所以我需要在该 block 之外分配(？)所以它们在我的日常生活中是本地的。</p>
<pre><code>CGPathRef tmpRightEdgePath2;
CGPathRef tmpLeftEdgePath2;
</code></pre>
<p>通过将它们更改为:</p>
<pre><code>CGPathRef tmpRightEdgePath2 = NULL;
CGPathRef tmpLeftEdgePath2 = NULL;
</code></pre>
<p>这清除了在 if/then/else 语句期间报告的两个泄漏。</p>
<p>所以现在我剩下的两个泄漏报告在 if (done) {}block 内。</p>
<p>在 Instruments 中，查看 Leaks 工具，Cycles & Roots -> Leak Cycles -> foo History 我看到 10 个内存事件以 RefCt 为 1 结束，因此很明显是泄漏:</p>
<pre><code>#Category Event Type RefCtResponsibleLibraryResponsible Caller
0NSMutableRLEArrayMalloc 1 Foundation -
1NSMutableRLEArrayRelease 0 Foundation -
2NSMutableRLEArrayFree 0 Foundation -
3CGPath Malloc 1 CoreGraphics CGTypeCreateInstance
4CGPath CFRelease 0 my app my routine
5CGPath Free 0 my app my routine
6CGPath Malloc 1 CoreGraphics CGTypeCreateInstance
7CGPath CFRelease 0 my app my routine
8CGPath Free 0 my app my routine
9CGPath Malloc 1 CoreGraphics CGTypeCreateInstance
</code></pre>
<p>所以在我认为我已经完成了路径操作之后的某个时刻，必须发生另一个 CGCreateCopy... 样式调用，因为在我发布所有内容之后，<em></em> 调用了 Malloc。因此，通过使用搜索/查找，我通过绘图代码继续前进，并找到了最后一个 CGPathCreateCopyByTransforming:</p>
<pre><code>CGAffineTransform slightUp = CGAffineTransformMakeTranslation(0, - lineThickness * 2 );
leftEdgePath = CGPathCreateMutableCopyByTransformingPath(leftEdgePath, &slightUp);
rightEdgePath = CGPathCreateMutableCopyByTransformingPath(rightEdgePath, &slightUp);
</code></pre>
<p>由于保留计数在该复制期间增加了 1，因此可以保证泄漏。所以我把它们改成了:</p>
<pre><code>CGAffineTransform slightUp = CGAffineTransformMakeTranslation(0, - lineThickness * 2 );
CGMutablePathRef finalLeftEdgePath = CGPathCreateMutableCopyByTransformingPath(leftEdgePath, &slightUp);
CGPathRelease(leftEdgePath);
CGMutablePathRef finalRightEdgePath = CGPathCreateMutableCopyByTransformingPath(rightEdgePath, &slightUp);
CGPathRelease(rightEdgePath);
</code></pre>
<p>然后我更改了我的 CGContextAddPath() 以匹配新的“最终”路径，以及最终发布调用以发布“最终”版本并且我没有泄漏!</p></p>
<p style="font-size: 20px;">关于ios - 使用 CGPathCreateCopyByTransforming 和 CGPathCreateCopy 导致的挤压内存泄漏，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/13601239/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/13601239/
</a>
</p>
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