将 Objective-C 代码转换为 Swift：可以省略发布调用吗？

Question

我们需要将下面的代码从 Objective-C 转换为 Swift。

问题：

有几个函数调用可以释放对象，例如 CGImageRelease(newImage)。假设 Swift 版本不需要模拟是否安全，因为所有内存管理都是自动的，或者您是否还需要释放 Swift 中的内存？

Objective-C代码：

CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(imageSampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer,0);
uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef newContext = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
CGImageRef newImage = CGBitmapContextCreateImage(newContext); CGContextRelease(newContext);
CGColorSpaceRelease(colorSpace);
UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0 orientation:orientation];
CGImageRelease(newImage);

Swift 到目前为止的版本：

private func turnBufferToPNGImage(imageSampleBuffer: CMSampleBufferRef, scale: CGFloat) -> UIImage {
    let imageBuffer = CMSampleBufferGetImageBuffer(imageSampleBuffer)

    // Lock base address
    CVPixelBufferLockBaseAddress(imageBuffer, 0)

    // Set properties for CGBitmapContext
    let pixelData = CVPixelBufferGetBaseAddress(imageBuffer)
    let width = CVPixelBufferGetWidth(imageBuffer)
    let height = CVPixelBufferGetHeight(imageBuffer)
    let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
    let colorSpace = CGColorSpaceCreateDeviceRGB()

    // Create CGBitmapContext
    let newContext = CGBitmapContextCreate(pixelData, width, height, 8, bytesPerRow, colorSpace, CGImageAlphaInfo.PremultipliedFirst.rawValue)

    // Create image from context
    let rawImage = CGBitmapContextCreateImage(newContext)!
    let newImage = UIImage(CGImage: rawImage, scale: scale, orientation: .Up)

    // Unlock base address
    CVPixelBufferUnlockBaseAddress(imageBuffer,0)

    // Return image
    return newImage
}

Answer 1

根据文档：

Core Foundation types are automatically imported as full-fledged Swift classes. Wherever memory management annotations have been provided, Swift automatically manages the memory of Core Foundation objects, including Core Foundation objects that you instantiate yourself

所以你可以省略电话。

Answer 2

否你不需要释放 Core Foundation 对象，因为苹果说：

The Core Foundation CFTypeRef type completely remaps to the AnyObject type.

和

Core Foundation objects returned from annotated APIs are automatically memory managed in Swift—you do not need to invoke the CFRetain, CFRelease, or CFAutorelease functions yourself.

文档here

将 Objective-C 代码转换为 Swift：可以省略发布调用吗？

Converting Objective-C code to Swift: okay to omit release calls?

core-graphics

objective-c

core-media

ios

swift