1 files changed, 215 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/yellow/syntax.rs b/crates/ra_syntax/src/yellow/syntax.rs
new file mode 100644
index 000000000..1d99cab4a
--- /dev/null
+++ b/crates/ra_syntax/src/yellow/syntax.rs
@@ -0,0 +1,215 @@
+use std::{
+    fmt, sync::Arc,
+    hash::{Hasher, Hash},
+    ops::Range,
+};
+
+use smol_str::SmolStr;
+
+use {
+    yellow::{GreenNode, RedNode, TreeRoot, SyntaxRoot, RedPtr, RefRoot, OwnedRoot, SyntaxText},
+    SyntaxKind::{self, *},
+    TextRange, TextUnit,
+};
+
+
+#[derive(Clone, Copy)]
+pub struct SyntaxNode<R: TreeRoot = OwnedRoot> {
+    pub(crate) root: R,
+    // Guaranteed to not dangle, because `root` holds a
+    // strong reference to red's ancestor
+    red: RedPtr,
+}
+
+unsafe impl<R: TreeRoot> Send for SyntaxNode<R> {}
+unsafe impl<R: TreeRoot> Sync for SyntaxNode<R> {}
+
+impl<R1: TreeRoot, R2: TreeRoot> PartialEq<SyntaxNode<R1>> for SyntaxNode<R2> {
+    fn eq(&self, other: &SyntaxNode<R1>) -> bool {
+        self.red == other.red
+    }
+}
+
+impl<R: TreeRoot> Eq for SyntaxNode<R> {}
+impl<R: TreeRoot> Hash for SyntaxNode<R> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.red.hash(state)
+    }
+}
+
+pub type SyntaxNodeRef<'a> = SyntaxNode<RefRoot<'a>>;
+
+#[test]
+fn syntax_node_ref_is_copy() {
+    fn assert_copy<T: Copy>(){}
+    assert_copy::<SyntaxNodeRef>()
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub struct SyntaxError {
+    pub msg: String,
+    pub offset: TextUnit,
+}
+
+impl SyntaxNode<OwnedRoot> {
+    pub(crate) fn new_owned(root: SyntaxRoot) -> Self {
+        let root = OwnedRoot(Arc::new(root));
+        let red = RedPtr::new(&root.syntax_root().red);
+        SyntaxNode { root, red }
+    }
+}
+
+impl<'a> SyntaxNode<RefRoot<'a>> {
+    pub(crate) fn leaf_text_ref(self) -> Option<&'a SmolStr> {
+        let red = unsafe { self.red.get(self.root.syntax_root()) };
+        red.green().leaf_text_ref()
+    }
+}
+
+impl<R: TreeRoot> SyntaxNode<R> {
+    pub fn borrowed<'a>(&'a self) -> SyntaxNodeRef<'a> {
+        SyntaxNode {
+            root: self.root.borrowed(),
+            red: self.red,
+        }
+    }
+
+    pub fn owned(&self) -> SyntaxNode {
+        SyntaxNode {
+            root: self.root.owned(),
+            red: self.red,
+        }
+    }
+
+    pub fn kind(&self) -> SyntaxKind {
+        self.red().green().kind()
+    }
+
+    pub fn range(&self) -> TextRange {
+        let red = self.red();
+        TextRange::offset_len(red.start_offset(), red.green().text_len())
+    }
+
+    pub fn text(&self) -> SyntaxText {
+        SyntaxText::new(self.borrowed())
+    }
+
+    pub fn children(&self) -> SyntaxNodeChildren<R> {
+        SyntaxNodeChildren {
+            parent: self.clone(),
+            iter: (0..self.red().n_children())
+        }
+    }
+
+    pub fn parent(&self) -> Option<SyntaxNode<R>> {
+        let parent = self.red().parent()?;
+        Some(SyntaxNode {
+            root: self.root.clone(),
+            red: parent,
+        })
+    }
+
+    pub fn first_child(&self) -> Option<SyntaxNode<R>> {
+        let red = self.red().get_child(0)?;
+        Some(SyntaxNode { root: self.root.clone(), red })
+    }
+
+    pub fn last_child(&self) -> Option<SyntaxNode<R>> {
+        let n = self.red().n_children();
+        let n = n.checked_sub(1)?;
+        let red = self.red().get_child(n)?;
+        Some(SyntaxNode { root: self.root.clone(), red })
+    }
+
+    pub fn next_sibling(&self) -> Option<SyntaxNode<R>> {
+        let red = self.red();
+        let parent = self.parent()?;
+        let next_sibling_idx = red.index_in_parent()? + 1;
+        let sibling_red = parent.red().get_child(next_sibling_idx)?;
+        Some(SyntaxNode {
+            root: self.root.clone(),
+            red: sibling_red,
+        })
+    }
+
+    pub fn prev_sibling(&self) -> Option<SyntaxNode<R>> {
+        let red = self.red();
+        let parent = self.parent()?;
+        let prev_sibling_idx = red.index_in_parent()?.checked_sub(1)?;
+        let sibling_red = parent.red().get_child(prev_sibling_idx)?;
+        Some(SyntaxNode {
+            root: self.root.clone(),
+            red: sibling_red,
+        })
+    }
+
+    pub fn is_leaf(&self) -> bool {
+        self.first_child().is_none()
+    }
+
+    pub fn leaf_text(&self) -> Option<SmolStr> {
+        self.borrowed().leaf_text_ref().map(|it| it.clone())
+    }
+
+    pub(crate) fn replace_with(&self, green: GreenNode) -> GreenNode {
+        assert_eq!(self.kind(), green.kind());
+        match self.parent() {
+            None => green,
+            Some(parent) => {
+                let children: Vec<_> = parent.children().map(|child| {
+                    if child == *self {
+                        green.clone()
+                    } else {
+                        child.red().green().clone()
+                    }
+                }).collect();
+                let new_parent = GreenNode::new_branch(
+                    parent.kind(),
+                    children.into_boxed_slice(),
+                );
+                parent.replace_with(new_parent)
+            },
+        }
+    }
+
+    fn red(&self) -> &RedNode {
+        unsafe { self.red.get(self.root.syntax_root()) }
+    }
+}
+
+impl<R: TreeRoot> fmt::Debug for SyntaxNode<R> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{:?}@{:?}", self.kind(), self.range())?;
+        if has_short_text(self.kind()) {
+            write!(fmt, " \"{}\"", self.text())?;
+        }
+        Ok(())
+    }
+}
+
+#[derive(Debug)]
+pub struct SyntaxNodeChildren<R: TreeRoot> {
+    parent: SyntaxNode<R>,
+    iter: Range<usize>,
+}
+
+impl<R: TreeRoot> Iterator for SyntaxNodeChildren<R> {
+    type Item = SyntaxNode<R>;
+
+    fn next(&mut self) -> Option<SyntaxNode<R>> {
+        self.iter.next().map(|i| {
+            let red = self.parent.red();
+            SyntaxNode {
+                root: self.parent.root.clone(),
+                red: red.get_child(i).unwrap(),
+            }
+        })
+    }
+}
+
+fn has_short_text(kind: SyntaxKind) -> bool {
+    match kind {
+        IDENT | LIFETIME | INT_NUMBER | FLOAT_NUMBER => true,
+        _ => false,
+    }
+}