nullptr was being returned in the error case, which, at a glance may
seem perfectly OK... until you realize that std::string has the
invariant that it may not be constructed from a null pointer. This
means that if this error case was ever hit, then the application would
most likely crash from a thrown exception in std::string's constructor.
Instead, we can change the function to return an optional value,
indicating if a failure occurred.
Makes the parameter ordering consistent, and also makes the filename
parameter a std::string. A std::string would be constructed anyways with
the previous code, as IOFile's only constructor with a filepath is one
taking a std::string.
We can also make WriteStringToFile's string parameter utilize a
std::string_view for the string, making use of our previous changes to
IOFile.
We can just leverage std::unique_ptr to automatically close these for us
in error cases instead of jumping to the end of the function to call
fclose on them.
Instead of using an unsigned int as a parameter and expecting a user to
always pass in the correct values, we can just convert the enum into an
enum class and use that type as the parameter type instead, which makes
the interface more type safe.
We also get rid of the bookkeeping "NUM_" element in the enum by just
using an unordered map. This function is generally low-frequency in
terms of calls (and I'd hope so, considering otherwise would mean we're
slamming the disk with IO all the time) so I'd consider this acceptable
in this case.
* Add VfsFile and VfsDirectory classes
* Finish abstract Vfs classes
* Implement RealVfsFile (computer fs backend)
* Finish RealVfsFile and RealVfsDirectory
* Finished OffsetVfsFile
* More changes
* Fix import paths
* Major refactor
* Remove double const
* Use experimental/filesystem or filesystem depending on compiler
* Port partition_filesystem
* More changes
* More Overhaul
* FSP_SRV fixes
* Fixes and testing
* Try to get filesystem to compile
* Filesystem on linux
* Remove std::filesystem and document/test
* Compile fixes
* Missing include
* Bug fixes
* Fixes
* Rename v_file and v_dir
* clang-format fix
* Rename NGLOG_* to LOG_*
* Most review changes
* Fix TODO
* Guess 'main' to be Directory by filename
Without this, it's possible to get compilation failures in the (rare) scenario where
a container is used to store a bunch of live IOFile instances, as they may be using
std::move_if_noexcept under the hood. Given these definitely don't throw exceptions
this is also not incorrect to add either.
Most modern Unix environments use 64-bit off_t by default: OpenBSD,
FreeBSD, OS X, and Linux libc implementations such as Musl.
glibc is the lone exception; it can default to 32 bits but this is
configurable by setting _FILE_OFFSET_BITS.
Avoiding the stat64()/fstat64() interfaces is desirable because they
are nonstandard and not implemented on many systems (including
OpenBSD and FreeBSD), and using 64 bits for stat()/fstat() is either
the default or trivial to set up.
Lioncash