On 19/09/2018 19:48, Joe Wang wrote:
Hi,
After much discussion and 10 iterations of reviews, this proposal has evolved from what was the original isSameContent method to a mismatch method. API-wise, a compare method was also considered as it looked like just a short step forward from mismatch, however, it was eventually dropped since there is no convincing use case comparing files lexicographically by contents. Impl-wise, extensive performance benchmarking has been done to compare a buffered reading vs memory mapping, the result was that a simple buffered reading performed better among small files, and those with the mismatched byte closer to the beginning of files. Since the proposed method's targeted files are small ones, the impl currently does a buffered reading only.
Please review.
JBS: https://bugs.openjdk.java.net/browse/JDK-8202285
specdiff: http://cr.openjdk.java.net/~joehw/jdk12/8202285/specdiff/java/nio/file/Files...
webrev: http://cr.openjdk.java.net/~joehw/jdk12/8202285/webrev/ Starting out using buffered I/O is probably okay but I assume we will want to change this in the future to having it use memory mapped I/O beyond a certain threshold.
Can you explain the use of toRealPath and comparing the names? That shouldn't be needed. Also the catching of ProviderMismatchExcepiton seems a bit strange too. Can you replace mismatchByAttrs with isSameFile? You could call this from Files.mismatch and then use the supporting implementation for the case that the files are not the same. -Alan