问题
I am developing folder watcher application for MAC in XCode using Foundation framework and FSEvents API. I need to know whether the file has been completely copied to the destination before I open the file for other operation. Is there any way of knowing it? please advice
回答1:
From simply studying the FSEvents API I would say that what you want is not possible. I could be mistaken, though, I have never used FSEvents myself. The asker of this question has solved the problem by separately monitoring the new file with lsof.
回答2:
I noticed that FSEvents API sends "create" event at beginning and "create-and-modify" at the end. On my project I used FSEventsStream with zero latency, and "NoDefer" flag on creation. Watching for "Modify" only events may give you information that file copy is completed.
回答3:
you can check that whether the file you want to open is exist or not? and act accordingly.
来源：https://stackoverflow.com/questions/9139445/how-to-determine-if-a-file-copy-is-completed-using-cocoa