> On Feb. 10, 2015, 4:08 p.m., Ben Mahler wrote: > > It might be time to introduce os::stat and os::lstat wrappers to avoid > > needing to introduce so many special case functions. > > Bernd Mathiske wrote: > That would reduce portability. > > Ben Mahler wrote: > Oh? Could you elaborate please? :) > > To be specific, I'm referring to `Try<os::Stat> os::stat()` where > `os::Stat` only contains what is specified by > [POSIX](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_stat.h.html) > and uses things like `Bytes`, etc.
1. Not every OS is a POSIX OS. Can we foresee which OSs Mesos will ever run on in its life-time? 2. Do we have any precedent for exposing POSIX APIs this way? Are you sure you want to limit Mesos to POSIX-compliant OSs only? 3. There are always some jitters in APIs across UNIX-like OSs, despite POSIX. Run for example "man -s 2 stat" on Mac OS X. You will find different stat struct definitions depending on whether _DARWIN_FEATURE_64_BIT_INODE is defined. 4. "man -s 2 stat" on Ubuntu. See all the differences between different UNIXes mentioned there. This also illustrates that exposing the full struct parameter implies exposing all the macros and constants that come with it to discern its contents. These are even more vulnerable than the struct itself to changes over time. 5. There are changes in the POSIX specification every few years and parts of stat have been affected at least twice in the past 15 years (2001 and 2008). What if we get caught with some code by the next change? Do you then want to introduce #ifdef at call sites or rather follow the path of hiding any such changes behind a well-defined-*by-us* interface? The latter is what an OS abstraction layer does best and primarily exists for IMHO. :-) - Bernd ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/30609/#review71880 ----------------------------------------------------------- On Feb. 10, 2015, 3:19 a.m., Bernd Mathiske wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/30609/ > ----------------------------------------------------------- > > (Updated Feb. 10, 2015, 3:19 a.m.) > > > Review request for mesos, Adam B, Benjamin Hindman, Till Toenshoff, and > Timothy Chen. > > > Bugs: MESOS-2072 > https://issues.apache.org/jira/browse/MESOS-2072 > > > Repository: mesos > > > Description > ------- > > This returns a file's size as reported by lstat(). (Not stat(). It is desired > that in case of a link, the size of the link, not the size of the referenced > file, is returned.) > > > Diffs > ----- > > 3rdparty/libprocess/3rdparty/stout/include/stout/os.hpp > 8a4fda97ee29c185471a69f60803efc193cbe922 > 3rdparty/libprocess/3rdparty/stout/tests/os_tests.cpp > 8a2d445c2edaa70da0e7b50e14ef88b2d9224a16 > > Diff: https://reviews.apache.org/r/30609/diff/ > > > Testing > ------- > > Wrote a simple test that creates a file and tests its size, and also checks > if a non-existing file yields an error. > > > Thanks, > > Bernd Mathiske > >
