1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

//! # 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 `FileId`s -- 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`.
//! `FileSet`s 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.
mod vfs_path;
mod path_interner;
pub mod file_set;
pub mod loader;

use std::{fmt, mem};

use crate::path_interner::PathInterner;

pub use crate::vfs_path::VfsPath;
pub use paths::{AbsPath, AbsPathBuf};

#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Hash)]
pub struct FileId(pub u32);

#[derive(Default)]
pub struct Vfs {
    interner: PathInterner,
    data: Vec<Option<Vec<u8>>>,
    changes: Vec<ChangedFile>,
}

pub struct ChangedFile {
    pub file_id: FileId,
    pub change_kind: ChangeKind,
}

impl ChangedFile {
    pub fn exists(&self) -> bool {
        self.change_kind != ChangeKind::Delete
    }
    pub fn is_created_or_deleted(&self) -> bool {
        matches!(self.change_kind, ChangeKind::Create | ChangeKind::Delete)
    }
}

#[derive(Eq, PartialEq, Copy, Clone, Debug)]
pub enum ChangeKind {
    Create,
    Modify,
    Delete,
}

impl Vfs {
    pub fn len(&self) -> usize {
        self.data.len()
    }
    pub fn file_id(&self, path: &VfsPath) -> Option<FileId> {
        self.interner.get(path).filter(|&it| self.get(it).is_some())
    }
    pub fn file_path(&self, file_id: FileId) -> VfsPath {
        self.interner.lookup(file_id).clone()
    }
    pub fn file_contents(&self, file_id: FileId) -> &[u8] {
        self.get(file_id).as_deref().unwrap()
    }
    pub fn iter(&self) -> impl Iterator<Item = (FileId, &VfsPath)> + '_ {
        (0..self.data.len())
            .map(|it| FileId(it as u32))
            .filter(move |&file_id| self.get(file_id).is_some())
            .map(move |file_id| {
                let path = self.interner.lookup(file_id);
                (file_id, path)
            })
    }
    pub fn set_file_contents(&mut self, path: VfsPath, contents: Option<Vec<u8>>) {
        let file_id = self.alloc_file_id(path);
        let change_kind = match (&self.get(file_id), &contents) {
            (None, None) => return,
            (None, Some(_)) => ChangeKind::Create,
            (Some(_), None) => ChangeKind::Delete,
            (Some(old), Some(new)) if old == new => return,
            (Some(_), Some(_)) => ChangeKind::Modify,
        };

        *self.get_mut(file_id) = contents;
        self.changes.push(ChangedFile { file_id, change_kind })
    }
    pub fn has_changes(&self) -> bool {
        !self.changes.is_empty()
    }
    pub fn take_changes(&mut self) -> Vec<ChangedFile> {
        mem::take(&mut self.changes)
    }
    fn alloc_file_id(&mut self, path: VfsPath) -> FileId {
        let file_id = self.interner.intern(path);
        let idx = file_id.0 as usize;
        let len = self.data.len().max(idx + 1);
        self.data.resize_with(len, || None);
        file_id
    }
    fn get(&self, file_id: FileId) -> &Option<Vec<u8>> {
        &self.data[file_id.0 as usize]
    }
    fn get_mut(&mut self, file_id: FileId) -> &mut Option<Vec<u8>> {
        &mut self.data[file_id.0 as usize]
    }
}

impl fmt::Debug for Vfs {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Vfs").field("n_files", &self.data.len()).finish()
    }
}