add NodeCache::with_interner and make it pub

examples/math.rs

@@ -13,10 +13,7 @@
 //!     - "+" Token(Add)
 //!     - "4" Token(Number)
 
-use cstree::{
-    interning::{Reader, Resolver},
-    GreenNodeBuilder, NodeOrToken,
-};
+use cstree::{interning::Resolver, GreenNodeBuilder, NodeOrToken};
 use std::iter::Peekable;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -66,7 +63,7 @@ type SyntaxElement = cstree::NodeOrToken<SyntaxNode, SyntaxToken>;
 type SyntaxElementRef<'a> = cstree::NodeOrToken<&'a SyntaxNode, &'a SyntaxToken>;
 
 struct Parser<'input, I: Iterator<Item = (SyntaxKind, &'input str)>> {
-    builder: GreenNodeBuilder<'static>,
+    builder: GreenNodeBuilder<'static, 'static>,
     iter:    Peekable<I>,
 }
 impl<'input, I: Iterator<Item = (SyntaxKind, &'input str)>> Parser<'input, I> {

examples/s_expressions.rs

@@ -62,10 +62,7 @@ impl cstree::Language for Lang {
 
 /// GreenNode is an immutable tree, which is cheap to change,
 /// but doesn't contain offsets and parent pointers.
-use cstree::{
-    interning::{Reader, Resolver},
-    GreenNode,
-};
+use cstree::{interning::Resolver, GreenNode};
 
 /// You can construct GreenNodes by hand, but a builder
 /// is helpful for top-down parsers: it maintains a stack
@@ -91,7 +88,7 @@ fn parse(text: &str) -> Parse<impl Resolver> {
         /// in *reverse* order.
         tokens:  Vec<(SyntaxKind, &'input str)>,
         /// the in-progress tree.
-        builder: GreenNodeBuilder<'static>,
+        builder: GreenNodeBuilder<'static, 'static>,
         /// the list of syntax errors we've accumulated
         /// so far.
         errors:  Vec<String>,

src/green/builder.rs

@@ -19,29 +19,42 @@ use super::{node::GreenNodeHead, token::GreenTokenData};
 const CHILDREN_CACHE_THRESHOLD: usize = 3;
 
 #[derive(Debug)]
-pub struct NodeCache {
+pub struct NodeCache<'i, I = Rodeo<Spur, FxBuildHasher>> {
     nodes:    FxHashMap<GreenNodeHead, GreenNode>,
     tokens:   FxHashMap<GreenTokenData, GreenToken>,
-    interner: Rodeo<Spur, FxBuildHasher>,
+    interner: MaybeOwned<'i, I>,
 }
 
-impl NodeCache {
+impl NodeCache<'static, Rodeo<Spur, FxBuildHasher>> {
     pub fn new() -> Self {
         Self {
             nodes:    FxHashMap::default(),
             tokens:   FxHashMap::default(),
-            interner: Rodeo::with_capacity_and_hasher(
+            interner: MaybeOwned::Owned(Rodeo::with_capacity_and_hasher(
                 // capacity values suggested by author of `lasso`
                 Capacity::new(512, unsafe { NonZeroUsize::new_unchecked(4096) }),
                 FxBuildHasher::default(),
-            ),
+            )),
+        }
+    }
+}
+
+impl<'i, I> NodeCache<'i, I>
+where
+    I: Interner,
+{
+    pub fn with_interner(interner: &'i mut I) -> Self {
+        Self {
+            nodes:    FxHashMap::default(),
+            tokens:   FxHashMap::default(),
+            interner: MaybeOwned::Borrowed(interner),
         }
     }
 
-    fn node<I>(&mut self, kind: SyntaxKind, children: I) -> GreenNode
+    fn node<It>(&mut self, kind: SyntaxKind, children: It) -> GreenNode
     where
-        I: IntoIterator<Item = GreenElement>,
-        I::IntoIter: ExactSizeIterator,
+        It: IntoIterator<Item = GreenElement>,
+        It::IntoIter: ExactSizeIterator,
     {
         let children = children.into_iter();
 
@@ -61,10 +74,10 @@ impl NodeCache {
 
     /// Creates a [`GreenNode`] by looking inside the cache or inserting
     /// a new node into the cache if it's a cache miss.
-    fn get_cached_node<I>(&mut self, kind: SyntaxKind, children: I) -> GreenNode
+    fn get_cached_node<It>(&mut self, kind: SyntaxKind, children: It) -> GreenNode
     where
-        I: IntoIterator<Item = GreenElement>,
-        I::IntoIter: ExactSizeIterator,
+        It: IntoIterator<Item = GreenElement>,
+        It::IntoIter: ExactSizeIterator,
     {
         #[derive(Clone)]
         struct ChildrenIter {
@@ -132,6 +145,15 @@ enum MaybeOwned<'a, T> {
     Borrowed(&'a mut T),
 }
 
+impl<T> MaybeOwned<'_, T> {
+    fn as_owned(self) -> Option<T> {
+        match self {
+            MaybeOwned::Owned(owned) => Some(owned),
+            MaybeOwned::Borrowed(_) => None,
+        }
+    }
+}
+
 impl<T> std::ops::Deref for MaybeOwned<'_, T> {
     type Target = T;
 
@@ -164,26 +186,31 @@ pub struct Checkpoint(usize);
 
 /// A builder for a green tree.
 #[derive(Debug)]
-pub struct GreenNodeBuilder<'cache> {
-    cache:    MaybeOwned<'cache, NodeCache>,
+pub struct GreenNodeBuilder<'cache, 'interner, I = Rodeo<Spur, FxBuildHasher>> {
+    cache:    MaybeOwned<'cache, NodeCache<'interner, I>>,
     parents:  Vec<(SyntaxKind, usize)>,
     children: Vec<GreenElement>,
 }
 
-impl GreenNodeBuilder<'_> {
+impl GreenNodeBuilder<'static, 'static, Rodeo<Spur, FxBuildHasher>> {
     /// Creates new builder.
-    pub fn new() -> GreenNodeBuilder<'static> {
-        GreenNodeBuilder {
+    pub fn new() -> Self {
+        Self {
             cache:    MaybeOwned::Owned(NodeCache::new()),
             parents:  Vec::with_capacity(8),
             children: Vec::with_capacity(8),
         }
     }
+}
 
+impl<'cache, 'interner, I> GreenNodeBuilder<'cache, 'interner, I>
+where
+    I: Interner,
+{
     /// Reusing `NodeCache` between different `GreenNodeBuilder`s saves memory.
     /// It allows to structurally share underlying trees.
-    pub fn with_cache(cache: &mut NodeCache) -> GreenNodeBuilder<'_> {
-        GreenNodeBuilder {
+    pub fn with_cache(cache: &'cache mut NodeCache<'interner, I>) -> Self {
+        Self {
             cache:    MaybeOwned::Borrowed(cache),
             parents:  Vec::with_capacity(8),
             children: Vec::with_capacity(8),
@@ -268,15 +295,12 @@ impl GreenNodeBuilder<'_> {
     /// `start_node_at` and `finish_node` calls
     /// are paired!
     #[inline]
-    pub fn finish(mut self) -> (GreenNode, Option<impl Interner<Spur>>) {
+    pub fn finish(mut self) -> (GreenNode, Option<I>) {
         assert_eq!(self.children.len(), 1);
-        let resolver = match self.cache {
-            MaybeOwned::Owned(cache) => Some(cache.interner),
-            MaybeOwned::Borrowed(_) => None,
-        };
+        let resolver = self.cache.as_owned().and_then(|cache| cache.interner.as_owned());
         match self.children.pop().unwrap() {
             NodeOrToken::Node(node) => (node, resolver),
-            NodeOrToken::Token(_) => panic!(),
+            NodeOrToken::Token(_) => panic!("called `finish` on a `GreenNodeBuilder` which only contained a token"),
         }
     }
 }

src/lib.rs

@@ -53,7 +53,7 @@ use std::fmt;
 pub use text_size::{TextLen, TextRange, TextSize};
 
 pub use crate::{
-    green::{Checkpoint, Children, GreenNode, GreenNodeBuilder, GreenToken, SyntaxKind},
+    green::{Checkpoint, Children, GreenNode, GreenNodeBuilder, GreenToken, NodeCache, SyntaxKind},
     syntax::{SyntaxElement, SyntaxElementChildren, SyntaxElementRef, SyntaxNode, SyntaxNodeChildren, SyntaxToken},
     syntax_text::SyntaxText,
     utility_types::{Direction, NodeOrToken, TokenAtOffset, WalkEvent},

tests/basic.rs

@@ -1,8 +1,8 @@
 mod common;
 
 use common::TestLang;
-use cstree::{GreenNodeBuilder, SyntaxKind, SyntaxNode, TextRange};
-use lasso::Resolver;
+use cstree::{GreenNodeBuilder, NodeCache, SyntaxKind, SyntaxNode, TextRange};
+use lasso::{Interner, Resolver, Rodeo};
 
 #[derive(Debug)]
 enum Element<'s> {
@@ -26,7 +26,21 @@ fn build_tree<D>(root: &Element<'_>) -> (SyntaxNode<TestLang, D>, impl Resolver)
     (SyntaxNode::new_root(node), interner.unwrap())
 }
 
-fn build_recursive(root: &Element<'_>, builder: &mut GreenNodeBuilder, mut from: u16) -> u16 {
+fn build_tree_with_cache<'c, 'i, D, I>(root: &Element<'_>, cache: &'c mut NodeCache<'i, I>) -> SyntaxNode<TestLang, D>
+where
+    I: Interner,
+{
+    let mut builder = GreenNodeBuilder::with_cache(cache);
+    build_recursive(root, &mut builder, 0);
+    let (node, interner) = builder.finish();
+    assert!(interner.is_none());
+    SyntaxNode::new_root(node)
+}
+
+fn build_recursive<'c, 'i, I>(root: &Element<'_>, builder: &mut GreenNodeBuilder<'c, 'i, I>, mut from: u16) -> u16
+where
+    I: Interner,
+{
     match root {
         Element::Node(children) => {
             builder.start_node(SyntaxKind(from));
@@ -98,3 +112,30 @@ fn data() {
         assert_eq!(node2.get_data(), None);
     }
 }
+
+#[test]
+fn with_interner() {
+    let mut interner = Rodeo::new();
+    let mut cache = NodeCache::with_interner(&mut interner);
+    let tree = two_level_tree();
+    let tree = build_tree_with_cache::<(), _>(&tree, &mut cache);
+    let resolver = interner;
+
+    assert_eq!(tree.syntax_kind(), SyntaxKind(0));
+    assert_eq!(tree.kind(), SyntaxKind(0));
+    {
+        let leaf1_0 = tree.children().nth(1).unwrap().children_with_tokens().nth(0).unwrap();
+        let leaf1_0 = leaf1_0.into_token().unwrap();
+        assert_eq!(leaf1_0.syntax_kind(), SyntaxKind(5));
+        assert_eq!(leaf1_0.kind(), SyntaxKind(5));
+        assert_eq!(leaf1_0.text(&resolver), "1.0");
+        assert_eq!(leaf1_0.text_range(), TextRange::at(6.into(), 3.into()));
+    }
+    {
+        let node2 = tree.children().nth(2).unwrap();
+        assert_eq!(node2.syntax_kind(), SyntaxKind(6));
+        assert_eq!(node2.kind(), SyntaxKind(6));
+        assert_eq!(node2.children_with_tokens().count(), 3);
+        assert_eq!(node2.text(&resolver), "2.02.12.2");
+    }
+}