From dafe747dcc069084fc8bc771c5dcf72e7cb9ec23 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 6 Nov 2018 20:56:32 +0300
Subject: upstream basic tree algorithms to rowan

---
 crates/ra_syntax/src/algo/mod.rs | 113 +++------------------------------------
 1 file changed, 8 insertions(+), 105 deletions(-)

(limited to 'crates/ra_syntax/src/algo')

diff --git a/crates/ra_syntax/src/algo/mod.rs b/crates/ra_syntax/src/algo/mod.rs
index faf5a6211..4b3548ea9 100644
--- a/crates/ra_syntax/src/algo/mod.rs
+++ b/crates/ra_syntax/src/algo/mod.rs
@@ -1,116 +1,19 @@
 pub mod visit;
-// pub mod walk;
 
-use crate::{text_utils::contains_offset_nonstrict, SyntaxNodeRef, TextRange, TextUnit};
+use crate::{SyntaxNode, SyntaxNodeRef, TextRange, TextUnit};
 
-pub fn find_leaf_at_offset(node: SyntaxNodeRef, offset: TextUnit) -> LeafAtOffset {
-    let range = node.range();
-    assert!(
-        contains_offset_nonstrict(range, offset),
-        "Bad offset: range {:?} offset {:?}",
-        range,
-        offset
-    );
-    if range.is_empty() {
-        return LeafAtOffset::None;
-    }
-
-    if node.is_leaf() {
-        return LeafAtOffset::Single(node);
-    }
-
-    let mut children = node.children().filter(|child| {
-        let child_range = child.range();
-        !child_range.is_empty() && contains_offset_nonstrict(child_range, offset)
-    });
-
-    let left = children.next().unwrap();
-    let right = children.next();
-    assert!(children.next().is_none());
-
-    if let Some(right) = right {
-        match (
-            find_leaf_at_offset(left, offset),
-            find_leaf_at_offset(right, offset),
-        ) {
-            (LeafAtOffset::Single(left), LeafAtOffset::Single(right)) => {
-                LeafAtOffset::Between(left, right)
-            }
-            _ => unreachable!(),
-        }
-    } else {
-        find_leaf_at_offset(left, offset)
-    }
-}
-
-#[derive(Clone, Debug)]
-pub enum LeafAtOffset<'a> {
-    None,
-    Single(SyntaxNodeRef<'a>),
-    Between(SyntaxNodeRef<'a>, SyntaxNodeRef<'a>),
-}
+pub use rowan::LeafAtOffset;
 
-impl<'a> LeafAtOffset<'a> {
-    pub fn right_biased(self) -> Option<SyntaxNodeRef<'a>> {
-        match self {
-            LeafAtOffset::None => None,
-            LeafAtOffset::Single(node) => Some(node),
-            LeafAtOffset::Between(_, right) => Some(right),
-        }
-    }
-
-    pub fn left_biased(self) -> Option<SyntaxNodeRef<'a>> {
-        match self {
-            LeafAtOffset::None => None,
-            LeafAtOffset::Single(node) => Some(node),
-            LeafAtOffset::Between(left, _) => Some(left),
-        }
-    }
-}
-
-impl<'f> Iterator for LeafAtOffset<'f> {
-    type Item = SyntaxNodeRef<'f>;
-
-    fn next(&mut self) -> Option<SyntaxNodeRef<'f>> {
-        match *self {
-            LeafAtOffset::None => None,
-            LeafAtOffset::Single(node) => {
-                *self = LeafAtOffset::None;
-                Some(node)
-            }
-            LeafAtOffset::Between(left, right) => {
-                *self = LeafAtOffset::Single(right);
-                Some(left)
-            }
-        }
+pub fn find_leaf_at_offset(node: SyntaxNodeRef, offset: TextUnit) -> LeafAtOffset<SyntaxNodeRef> {
+    match node.0.leaf_at_offset(offset) {
+        LeafAtOffset::None => LeafAtOffset::None,
+        LeafAtOffset::Single(n) => LeafAtOffset::Single(SyntaxNode(n)),
+        LeafAtOffset::Between(l, r) => LeafAtOffset::Between(SyntaxNode(l), SyntaxNode(r)),
     }
 }
 
 pub fn find_covering_node(root: SyntaxNodeRef, range: TextRange) -> SyntaxNodeRef {
-    assert!(
-        range.is_subrange(&root.range()),
-        "node range: {:?}, target range: {:?}",
-        root.range(),
-        range,
-    );
-    let (left, right) = match (
-        find_leaf_at_offset(root, range.start()).right_biased(),
-        find_leaf_at_offset(root, range.end()).left_biased(),
-    ) {
-        (Some(l), Some(r)) => (l, r),
-        _ => return root,
-    };
-
-    common_ancestor(left, right)
-}
-
-fn common_ancestor<'a>(n1: SyntaxNodeRef<'a>, n2: SyntaxNodeRef<'a>) -> SyntaxNodeRef<'a> {
-    for p in n1.ancestors() {
-        if n2.ancestors().any(|a| a == p) {
-            return p;
-        }
-    }
-    panic!("Can't find common ancestor of {:?} and {:?}", n1, n2)
+    SyntaxNode(root.0.covering_node(range))
 }
 
 pub fn generate<T>(seed: Option<T>, step: impl Fn(&T) -> Option<T>) -> impl Iterator<Item = T> {
-- 
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