v0.5.0

This release contains many small changes to the public API. It also introduces the
littlefs2-core crate that can be used for crates that want to access littlefs2
filesystems without depending on a specific implementation version.

Added

• Added object-safe traits DynFile, DynFilesystem and DynStorage for
  accessing Storage, Filesystem and File implementations for any storage.
• Added Filesystem::mount_or_else function (#57)
• Marked Path::is_empty, Path::from_bytes_with_nul, Path::from_cstr, Path::from_cstr_unchecked, Path::as_str_ref_with_trailing_nul, Path::as_str, and PathBuf::new as const.
• Made fs::FileOpenFlags public and added From<fs::FileOpenFlags> for fs::OpenOptions.
• Support platforms where c_int is not i32.

Fixed

• Fixed macro hygiene for path!.
• Fixed build error that would occur on Windows systems.
• Fixed compilation without default features.
• Added path iteration utilities (#47)

Changed

• Enforced const evaluation for path!.
• Removed cstr_core and cty dependencies.
• Updated littlefs2-sys dependency to 0.2.0.
• Replace all panicking Path/PathBuf conversions with fallible alternatives:
  • Return a Result from Path::from_str_with_nul.
  • Replace the From<_> implementations for Path and PathBuf with TryFrom<_>, except for From<&Path> for PathBuf.
• Refactor error types:
  • Change Error enum to a struct with associated constants.
  • Remove Error::Success and enforce negative values for Error.
• Replace Path::exists with Filesystem::exists
• Replace DynFilesystem::open_file_with_options_and_then{,unit} with DynFilesystem::open_file_with_flags_and_then{,unit} using FileOpenFlags instead of OpenOptionsCallback
• Refactor attributes API:
  • Change the set_attribute function in DynFilesystem and Filesystem to accept an ID and a slice instead of an Attribute.
  • Add a buffer argument to the attribute function in DynFilesystem and Filesystem and return a slice of that buffer containing the read data.
  • Change the Attribute struct to store a slice with the read data and the total size of the attribute on the filesystem.
• Introduce object_safe::Vec trait and change DynFile::read_to_end, DynFilesystem::read and DynFilesstem::read_chunk to be generic over a Vec implementation to support multiple heapless versions (disabled by default).

Removed

• Removed Path::from_bytes_with_nul_unchecked. Use CStr::from_bytes_with_nul_unchecked and Path::from_cstr_unchecked instead.
• Removed From<littlefs2::path::Error> for littlefs2::io::Error.
• Removed object_safe::OpenOptionsCallback.
• Removed consts::ATTRBYTES_MAX_TYPE.
• Removed dir-entry-path feature (now always enabled).