不知道我是否碰到了WebKit中的错误，还是我做错了什么，但是我不知道如何使用WKScriptMessageHandler而不会导致WKScriptMessage.body中包含的任何值泄漏。
我能够整理一个最低限度的Mac项目来找出问题所在，但无济于事。
在主 View Controller 中:
class ViewController: NSViewController {
var webView: WKWebView?
override func viewDidLoad() {
super.viewDidLoad()
let userContentController = WKUserContentController()
userContentController.addScriptMessageHandler(self, name: "handler")
let configuration = WKWebViewConfiguration()
configuration.userContentController = userContentController
webView = WKWebView(frame: CGRectZero, configuration: configuration)
view.addSubview(webView!)
let path = NSBundle.mainBundle().pathForResource("index", ofType: "html")
let url = NSURL(fileURLWithPath: path!)!
webView?.loadRequest(NSURLRequest(URL: url))
}
}
extension ViewController: WKScriptMessageHandler {
func userContentController(userContentController: WKUserContentController, didReceiveScriptMessage message: WKScriptMessage) {
print(message.body)
}
}
然后在
index.html文件中:<html>
<head></head>
<body>
<script type="text/javascript">
webkit.messageHandlers.handler.postMessage("Here's a random number for you: " + Math.random() * 10)
</script>
</body>
</html>
当我运行项目然后在Instruments中打开内存调试器时，我看到以下泄漏:
如果我添加了一个按钮来重新加载请求，并且执行了几十次，则该应用程序的内存占用量将继续增长，并在达到某个阈值后崩溃。在这个最小的示例中，崩溃可能需要一段时间，但是在我每秒收到几条消息的应用程序中，崩溃时间不到10秒。
整个项目可以是downloaded here。
知道发生了什么吗？
最佳答案
您看到的是一个WebKit错误:https://bugs.webkit.org/show_bug.cgi?id=136140。它是fixed in WebKit trunk a while ago，但似乎未合并到任何WebKit更新中。
您可以通过在-dealloc中添加WKScriptMessage来弥补过度保留的方法来解决此问题。它可能看起来像这样:
//
// WKScriptMessage+WKScriptMessageLeakFix.m
// TestWebkitMessages
//
// Created by Mark Rowe on 6/27/15.
// Copyright © Mark Rowe.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
// associated documentation files (the "Software"), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial
// portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#import <mach-o/dyld.h>
#import <objc/runtime.h>
#import <WebKit/WebKit.h>
// Work around <https://webkit.org/b/136140> WKScriptMessage leaks its body
@interface WKScriptMessage (WKScriptMessageLeakFix)
@end
@implementation WKScriptMessage (WKScriptMessageLeakFix)
+ (void)load
{
// <https://webkit.org/b/136140> was fixed in WebKit trunk prior to the first v601 build being released.
// Enable the workaround in WebKit versions < 601. In the unlikely event that the fix is backported, this
// version check will need to be updated.
int32_t version = NSVersionOfRunTimeLibrary("WebKit");
int32_t majorVersion = version >> 16;
if (majorVersion > 600)
return;
// Add our -dealloc to WKScriptMessage. If -[WKScriptMessage dealloc] already existed
// we'd need to swap implementations instead.
Method fixedDealloc = class_getInstanceMethod(self, @selector(fixedDealloc));
IMP fixedDeallocIMP = method_getImplementation(fixedDealloc);
class_addMethod(self, @selector(dealloc), fixedDeallocIMP, method_getTypeEncoding(fixedDealloc));
}
- (void)fixedDealloc
{
// Compensate for the over-retain in -[WKScriptMessage _initWithBody:webView:frameInfo:name:].
[self.body release];
// Call our WKScriptMessage's superclass -dealloc implementation.
[super dealloc];
}
@end
将其放入项目的Objective-C文件中，将此文件的编译器标志设置为
-fno-objc-arc，它应该为您解决泄漏问题。关于ios - 使用WKScriptMessageHandler时发生内存泄漏，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/31094110/