57 lines
2 KiB
Rust
57 lines
2 KiB
Rust
//! The `DepGraphSafe` trait
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use crate::ty::TyCtxt;
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use rustc_hir::def_id::DefId;
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use rustc_hir::BodyId;
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use syntax::ast::NodeId;
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/// The `DepGraphSafe` trait is used to specify what kinds of values
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/// are safe to "leak" into a task. The idea is that this should be
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/// only be implemented for things like the tcx as well as various id
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/// types, which will create reads in the dep-graph whenever the trait
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/// loads anything that might depend on the input program.
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pub trait DepGraphSafe {}
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/// A `BodyId` on its own doesn't give access to any particular state.
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/// You must fetch the state from the various maps or generate
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/// on-demand queries, all of which create reads.
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impl DepGraphSafe for BodyId {}
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/// A `NodeId` on its own doesn't give access to any particular state.
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/// You must fetch the state from the various maps or generate
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/// on-demand queries, all of which create reads.
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impl DepGraphSafe for NodeId {}
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/// A `DefId` on its own doesn't give access to any particular state.
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/// You must fetch the state from the various maps or generate
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/// on-demand queries, all of which create reads.
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impl DepGraphSafe for DefId {}
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/// The type context itself can be used to access all kinds of tracked
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/// state, but those accesses should always generate read events.
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impl<'tcx> DepGraphSafe for TyCtxt<'tcx> {}
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/// Tuples make it easy to build up state.
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impl<A, B> DepGraphSafe for (A, B)
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where
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A: DepGraphSafe,
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B: DepGraphSafe,
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{
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}
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/// Shared ref to dep-graph-safe stuff should still be dep-graph-safe.
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impl<'a, A> DepGraphSafe for &'a A where A: DepGraphSafe {}
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/// Mut ref to dep-graph-safe stuff should still be dep-graph-safe.
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impl<'a, A> DepGraphSafe for &'a mut A where A: DepGraphSafe {}
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/// No data here! :)
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impl DepGraphSafe for () {}
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/// A convenient override that lets you pass arbitrary state into a
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/// task. Every use should be accompanied by a comment explaining why
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/// it makes sense (or how it could be refactored away in the future).
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pub struct AssertDepGraphSafe<T>(pub T);
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impl<T> DepGraphSafe for AssertDepGraphSafe<T> {}
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