A virtual filesystem for Rust

The virtual file system abstraction generalizes over file systems and allows using different filesystem implementations (e.g. an in memory implementation for unit tests)

This crate currently has the following implementations:

• PhysicalFS - the actual filesystem of the underlying OS
• MemoryFS - an ephemeral in-memory file system, intended mainly for unit tests
• AltrootFS - a file system with its root in a particular directory of another filesystem
• OverlayFS - an overlay file system combining two filesystems, an upper layer with read/write access and a lower layer with only read access
• EmbeddedFS - a read-only file system embedded in the executable, requires embedded-fs feature

The minimum supported Rust version is 1.40.0.

Comments and pull-requests welcome!

• Fixed a panic when accessing non-existing paths in MemoryFS::append_file() (closes #31)

• Update to EmbeddedFS to rust-embed v6 (closes #29)
• Make OverlayFS and AltrootFS available at the crate root, making it more consistent (PR #30 - thanks @Zyian)

• Activate embedded-fs feature when building on docs.rs to ensure that it actually shows up there (#28 - thanks @Absolucy)

• Added VfsPath::root() method to access the root path of a virtual filesystem (closes #26)
• Added doctests to VfsPath docs to provide usage examples

• Fixed path inconsistency issues in EmbeddedFS (closes #24)
• Added the test macro test_vfs_readonly! which allows verifying read-only filesystem implementations
• Removed dependency on thiserror crate to improve compile times (closes #25)

• Removed potential panic in OverlayFS (closes #23)
• VfsPath::join() now takes AsRef instead of &str to improve ergonomics with crates like camino

• Exported test_vfs macro via the feature flag export-test-macros to allow downstream implementations to verify expected behaviour
• The MSRV is now 1.40 due to requirements in upstream crates
• The embedded implementation was broken by the 0.5.0 API changes, and is now fixed

• Added EmbeddedFS for using filesystems embeded in the binary using rust-embed (PR #12 - thanks @ahouts)
• Changed VfsPath::exists() to return VfsResult<bool> instead of plain bool (closes #17)

• Added OverlayFS union filesystem
• Added VfsPath::read_to_string() convenience method
• Added VfsPath::walk_dir() method for recursive directory traversal
• Added VfsPath::{copy,move}_{file,dir}() methods (closes #9)
• License is now Apache 2.0
• Minimum supported Rust version (MSRV) is 1.32.0

• Refactored to use a trait based design, simplifying usage and testing

• Added AltrootFS (thanks @icefoxen)

• Initial release

• Support for read-only filesystems
• Support for re-mounting filesystems
• Support for virtual filesystem access inside archives (e.g. zip)