Rollup merge of #41249 - GuillaumeGomez:rustdoc-render, r=steveklabnik,frewsxcv

[rust.git] / src / librustc_data_structures / transitive_relation.rs

diff --git a/src/librustc_data_structures/transitive_relation.rs b/src/librustc_data_structures/transitive_relation.rs
index e09e260afc8d99c0e0fddc6d0c3b6a85f26deb49..2631108aeb5fa3563c6f004d791927b8a2d080c5 100644 (file)
--- a/src/librustc_data_structures/transitive_relation.rs
+++ b/src/librustc_data_structures/transitive_relation.rs
@@ -9,10 +9,14 @@
 // except according to those terms.
 
 use bitvec::BitMatrix;
+use stable_hasher::{HashStable, StableHasher, StableHasherResult};
+use rustc_serialize::{Encodable, Encoder, Decodable, Decoder};
 use std::cell::RefCell;
 use std::fmt::Debug;
 use std::mem;
 
+
+
 #[derive(Clone)]
 pub struct TransitiveRelation<T: Debug + PartialEq> {
     // List of elements. This is used to map from a T to a usize.  We
@@ -36,10 +40,10 @@ pub struct TransitiveRelation<T: Debug + PartialEq> {
     closure: RefCell<Option<BitMatrix>>,
 }
 
-#[derive(Clone, PartialEq, PartialOrd)]
+#[derive(Clone, PartialEq, PartialOrd, RustcEncodable, RustcDecodable)]
 struct Index(usize);
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
 struct Edge {
     source: Index,
     target: Index,
@@ -54,6 +58,10 @@ pub fn new() -> TransitiveRelation<T> {
         }
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.edges.is_empty()
+    }
+
     fn index(&self, a: &T) -> Option<Index> {
         self.elements.iter().position(|e| *e == *a).map(Index)
     }
@@ -305,6 +313,73 @@ fn pare_down(candidates: &mut Vec<usize>, closure: &BitMatrix) {
     }
 }
 
+impl<T> Encodable for TransitiveRelation<T>
+    where T: Encodable + Debug + PartialEq
+{
+    fn encode<E: Encoder>(&self, s: &mut E) -> Result<(), E::Error> {
+        s.emit_struct("TransitiveRelation", 2, |s| {
+            s.emit_struct_field("elements", 0, |s| self.elements.encode(s))?;
+            s.emit_struct_field("edges", 1, |s| self.edges.encode(s))?;
+            Ok(())
+        })
+    }
+}
+
+impl<T> Decodable for TransitiveRelation<T>
+    where T: Decodable + Debug + PartialEq
+{
+    fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error> {
+        d.read_struct("TransitiveRelation", 2, |d| {
+            let elements = d.read_struct_field("elements", 0, |d| Decodable::decode(d))?;
+            let edges = d.read_struct_field("edges", 1, |d| Decodable::decode(d))?;
+            Ok(TransitiveRelation { elements, edges, closure: RefCell::new(None) })
+        })
+    }
+}
+
+impl<CTX, T> HashStable<CTX> for TransitiveRelation<T>
+    where T: HashStable<CTX> + PartialEq + Debug
+{
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut CTX,
+                                          hasher: &mut StableHasher<W>) {
+        // We are assuming here that the relation graph has been built in a
+        // deterministic way and we can just hash it the way it is.
+        let TransitiveRelation {
+            ref elements,
+            ref edges,
+            // "closure" is just a copy of the data above
+            closure: _
+        } = *self;
+
+        elements.hash_stable(hcx, hasher);
+        edges.hash_stable(hcx, hasher);
+    }
+}
+
+impl<CTX> HashStable<CTX> for Edge {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut CTX,
+                                          hasher: &mut StableHasher<W>) {
+        let Edge {
+            ref source,
+            ref target,
+        } = *self;
+
+        source.hash_stable(hcx, hasher);
+        target.hash_stable(hcx, hasher);
+    }
+}
+
+impl<CTX> HashStable<CTX> for Index {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut CTX,
+                                          hasher: &mut StableHasher<W>) {
+        let Index(idx) = *self;
+        idx.hash_stable(hcx, hasher);
+    }
+}
+
 #[test]
 fn test_one_step() {
     let mut relation = TransitiveRelation::new();