Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/base-db/src/span.rs')
| -rw-r--r-- | crates/base-db/src/span.rs | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/crates/base-db/src/span.rs b/crates/base-db/src/span.rs new file mode 100644 index 0000000000..1072d937a3 --- /dev/null +++ b/crates/base-db/src/span.rs @@ -0,0 +1,166 @@ +use std::fmt; + +use salsa::InternId; +use vfs::FileId; + +pub type ErasedFileAstId = la_arena::Idx<syntax::SyntaxNodePtr>; + +// The first inde is always the root node's AstId +pub const ROOT_ERASED_FILE_AST_ID: ErasedFileAstId = + la_arena::Idx::from_raw(la_arena::RawIdx::from_u32(0)); + +#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)] +pub struct SyntaxContext; + +pub type SpanData = tt::SpanData<SpanAnchor>; + +#[derive(Copy, Clone, PartialEq, Eq, Hash)] +pub struct SpanAnchor { + pub file_id: HirFileId, + pub ast_id: ErasedFileAstId, +} + +impl fmt::Debug for SpanAnchor { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("SpanAnchor").field(&self.file_id).field(&self.ast_id.into_raw()).finish() + } +} + +impl tt::Span for SpanAnchor { + const DUMMY: Self = SpanAnchor { file_id: HirFileId(0), ast_id: ROOT_ERASED_FILE_AST_ID }; +} + +/// Input to the analyzer is a set of files, where each file is identified by +/// `FileId` and contains source code. However, another source of source code in +/// Rust are macros: each macro can be thought of as producing a "temporary +/// file". To assign an id to such a file, we use the id of the macro call that +/// produced the file. So, a `HirFileId` is either a `FileId` (source code +/// written by user), or a `MacroCallId` (source code produced by macro). +/// +/// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file +/// containing the call plus the offset of the macro call in the file. Note that +/// this is a recursive definition! However, the size_of of `HirFileId` is +/// finite (because everything bottoms out at the real `FileId`) and small +/// (`MacroCallId` uses the location interning. You can check details here: +/// <https://en.wikipedia.org/wiki/String_interning>). +/// +/// The two variants are encoded in a single u32 which are differentiated by the MSB. +/// If the MSB is 0, the value represents a `FileId`, otherwise the remaining 31 bits represent a +/// `MacroCallId`. +#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)] +pub struct HirFileId(u32); + +impl From<HirFileId> for u32 { + fn from(value: HirFileId) -> Self { + value.0 + } +} + +impl From<u32> for HirFileId { + fn from(value: u32) -> Self { + HirFileId(value) + } +} + +impl From<MacroCallId> for HirFileId { + fn from(value: MacroCallId) -> Self { + value.as_file() + } +} + +impl fmt::Debug for HirFileId { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.repr().fmt(f) + } +} + +#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] +pub struct MacroFile { + pub macro_call_id: MacroCallId, +} + +/// `MacroCallId` identifies a particular macro invocation, like +/// `println!("Hello, {}", world)`. +#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] +pub struct MacroCallId(salsa::InternId); +crate::impl_intern_key!(MacroCallId); + +impl MacroCallId { + pub fn as_file(self) -> HirFileId { + MacroFile { macro_call_id: self }.into() + } + + pub fn as_macro_file(self) -> MacroFile { + MacroFile { macro_call_id: self } + } +} + +#[derive(Clone, Copy, PartialEq, Eq, Hash)] +pub enum HirFileIdRepr { + FileId(FileId), + MacroFile(MacroFile), +} + +impl fmt::Debug for HirFileIdRepr { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + Self::FileId(arg0) => f.debug_tuple("FileId").field(&arg0.0).finish(), + Self::MacroFile(arg0) => { + f.debug_tuple("MacroFile").field(&arg0.macro_call_id.0).finish() + } + } + } +} + +impl From<FileId> for HirFileId { + fn from(FileId(id): FileId) -> Self { + assert!(id < Self::MAX_FILE_ID); + HirFileId(id) + } +} + +impl From<MacroFile> for HirFileId { + fn from(MacroFile { macro_call_id: MacroCallId(id) }: MacroFile) -> Self { + let id = id.as_u32(); + assert!(id < Self::MAX_FILE_ID); + HirFileId(id | Self::MACRO_FILE_TAG_MASK) + } +} + +impl HirFileId { + const MAX_FILE_ID: u32 = u32::MAX ^ Self::MACRO_FILE_TAG_MASK; + const MACRO_FILE_TAG_MASK: u32 = 1 << 31; + + #[inline] + pub fn is_macro(self) -> bool { + self.0 & Self::MACRO_FILE_TAG_MASK != 0 + } + + #[inline] + pub fn macro_file(self) -> Option<MacroFile> { + match self.0 & Self::MACRO_FILE_TAG_MASK { + 0 => None, + _ => Some(MacroFile { + macro_call_id: MacroCallId(InternId::from(self.0 ^ Self::MACRO_FILE_TAG_MASK)), + }), + } + } + + #[inline] + pub fn file_id(self) -> Option<FileId> { + match self.0 & Self::MACRO_FILE_TAG_MASK { + 0 => Some(FileId(self.0)), + _ => None, + } + } + + #[inline] + pub fn repr(self) -> HirFileIdRepr { + match self.0 & Self::MACRO_FILE_TAG_MASK { + 0 => HirFileIdRepr::FileId(FileId(self.0)), + _ => HirFileIdRepr::MacroFile(MacroFile { + macro_call_id: MacroCallId(InternId::from(self.0 ^ Self::MACRO_FILE_TAG_MASK)), + }), + } + } +} |