From 4e79073e3872df718eb189dd5301ffc000f87d58 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Mon, 30 Jul 2018 02:23:01 +0300
Subject: Use raw pointers

---
 src/yellow/mod.rs    | 31 -------------------------------
 src/yellow/red.rs    | 10 +++++-----
 src/yellow/syntax.rs | 19 ++++++++++---------
 3 files changed, 15 insertions(+), 45 deletions(-)

diff --git a/src/yellow/mod.rs b/src/yellow/mod.rs
index 9a6203cc1..4fd0d24d7 100644
--- a/src/yellow/mod.rs
+++ b/src/yellow/mod.rs
@@ -3,10 +3,6 @@ mod red;
 mod syntax;
 mod builder;
 
-use std::{
-    sync::{Arc, Weak},
-    mem
-};
 pub(crate) use self::{
     green::{GreenNode, GreenNodeBuilder},
     red::RedNode,
@@ -14,30 +10,3 @@ pub(crate) use self::{
     builder::GreenBuilder,
 };
 pub use self::syntax::SyntaxNode;
-
-// This could be just `*const T`, but we use `Weak` for additional checks
-#[derive(Debug)]
-pub(crate) struct Ptr<T>(Weak<T>);
-
-impl<T> Clone for Ptr<T> {
-    fn clone(&self) -> Self {
-        Ptr(self.0.clone())
-    }
-}
-
-impl<T> Ptr<T> {
-    fn clone(self_: &Ptr<T>) -> Ptr<T> {
-        Ptr(Weak::clone(&self_.0))
-    }
-
-    fn new(arc: &Arc<T>) -> Ptr<T> {
-        Ptr(Arc::downgrade(arc))
-    }
-
-    unsafe fn get(&self) -> &T {
-        let t = self.0.upgrade()
-            .expect("caller must guarantee that Ptr is not null");
-        let t: &T = &*t;
-        mem::transmute(t)
-    }
-}
diff --git a/src/yellow/red.rs b/src/yellow/red.rs
index e2dbceeae..3fdbfe0c5 100644
--- a/src/yellow/red.rs
+++ b/src/yellow/red.rs
@@ -1,7 +1,7 @@
 use std::sync::{Arc, RwLock};
 use {
     TextUnit,
-    yellow::{Ptr, GreenNode},
+    yellow::GreenNode,
 };
 
 #[derive(Debug)]
@@ -13,7 +13,7 @@ pub(crate) struct RedNode {
 
 #[derive(Debug)]
 struct ParentData {
-    parent: Ptr<RedNode>,
+    parent: *const RedNode,
     start_offset: TextUnit,
     index_in_parent: usize,
 }
@@ -27,7 +27,7 @@ impl RedNode {
 
     fn new_child(
         green: GreenNode,
-        parent: Ptr<RedNode>,
+        parent: *const RedNode,
         start_offset: TextUnit,
         index_in_parent: usize,
     ) -> RedNode {
@@ -62,7 +62,7 @@ impl RedNode {
         self.green.children().len()
     }
 
-    pub(crate) fn nth_child(&self, me: Ptr<RedNode>, idx: usize) -> Arc<RedNode> {
+    pub(crate) fn nth_child(&self, idx: usize) -> Arc<RedNode> {
         match &self.children.read().unwrap()[idx] {
             Some(child) => return child.clone(),
             None => (),
@@ -72,7 +72,7 @@ impl RedNode {
             let green_children = self.green.children();
             let start_offset = self.start_offset()
                 + green_children[..idx].iter().map(|x| x.text_len()).sum::<TextUnit>();
-            let child = RedNode::new_child(green_children[idx].clone(), me, start_offset, idx);
+            let child = RedNode::new_child(green_children[idx].clone(), self, start_offset, idx);
             children[idx] = Some(Arc::new(child))
         }
         children[idx].as_ref().unwrap().clone()
diff --git a/src/yellow/syntax.rs b/src/yellow/syntax.rs
index 53d8c82b9..fa51e8d13 100644
--- a/src/yellow/syntax.rs
+++ b/src/yellow/syntax.rs
@@ -1,18 +1,20 @@
 use std::{
     fmt,
     sync::Arc,
+    ptr
 };
 
 use {
     TextRange, TextUnit,
     SyntaxKind::{self, *},
-    yellow::{Ptr, RedNode, GreenNode},
+    yellow::{RedNode, GreenNode},
 };
 
 #[derive(Clone)]
 pub struct SyntaxNode {
     pub(crate) root: SyntaxRoot,
-    red: Ptr<RedNode>,
+    // guaranteed to be alive bc SyntaxRoot holds a strong ref
+    red: ptr::NonNull<RedNode>,
 }
 
 #[derive(Clone)]
@@ -29,10 +31,10 @@ pub(crate) struct SyntaxError {
 
 impl SyntaxNode {
     pub(crate) fn new(root: GreenNode, errors: Vec<SyntaxError>) -> SyntaxNode {
-        let root = Arc::new(RedNode::new_root(root));
-        let red = Ptr::new(&root);
-        let root = SyntaxRoot { red: root, errors: Arc::new(errors) };
-        SyntaxNode { root, red }
+        let red = Arc::new(RedNode::new_root(root));
+        let red_weak: ptr::NonNull<RedNode> = (&*red).into();
+        let root = SyntaxRoot { red, errors: Arc::new(errors) };
+        SyntaxNode { root, red: red_weak }
     }
 
     pub fn kind(&self) -> SyntaxKind {
@@ -58,15 +60,14 @@ impl SyntaxNode {
         for i in 0..n_children {
             res.push(SyntaxNode {
                 root: self.root.clone(),
-                red: Ptr::new(&red.nth_child(Ptr::clone(&self.red), i)),
+                red: (&*red.nth_child(i)).into(),
             });
         }
         res
     }
 
     fn red(&self) -> &RedNode {
-        // Safe b/c root ptr keeps red alive
-        unsafe { self.red.get() }
+        unsafe { self.red.as_ref() }
     }
 }
 
-- 
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