Crate ra_ap_vfs

Virtual File System

VFS stores all files read by rust-analyzer. Reading file contents from VFS always returns the same contents, unless VFS was explicitly modified with set_file_contents. All changes to VFS are logged, and can be retrieved via take_changes method. The pack of changes is then pushed to salsa and triggers incremental recomputation.

Files in VFS are identified with FileIds -- interned paths. The notion of the path, VfsPath is somewhat abstract: at the moment, it is represented as an std::path::PathBuf internally, but this is an implementation detail.

VFS doesn't do IO or file watching itself. For that, see the loader module. loader::Handle is an object-safe trait which abstracts both file loading and file watching. Handle is dynamically configured with a set of directory entries which should be scanned and watched. Handle then asynchronously pushes file changes. Directory entries are configured in free-form via list of globs, it's up to the Handle to interpret the globs in any specific way.

A simple WalkdirLoaderHandle is provided, which doesn't implement watching and just scans the directory using walkdir.

VFS stores a flat list of files. FileSet can partition this list of files into disjoint sets of files. Traversal-like operations (including getting the neighbor file by the relative path) are handled by the FileSet. FileSets are also pushed to salsa and cause it to re-check mod foo; declarations when files are created or deleted.

file_set::FileSet and loader::Entry play similar, but different roles. Both specify the "set of paths/files", one is geared towards file watching, the other towards salsa changes. In particular, single file_set::FileSet may correspond to several loader::Entry. For example, a crate from crates.io which uses code generation would have two Entries -- for sources in ~/.cargo, and for generated code in ./target/debug/build. It will have a single FileSet which unions the two sources.

Modules

file_set	Partitions a list of files into disjoint subsets.
loader	Object safe interface for file watching and reading.

Structs

AbsPath
AbsPathBuf
ChangedFile
FileId
Vfs
VfsPath	Long-term, we want to support files which do not reside in the file-system, so we treat VfsPaths as opaque identifiers.

Enums

ChangeKind