From 9be24db05187dfcfbca459a5387ed13fef29e8a2 Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Thu, 16 Nov 2023 07:59:46 -0800
Subject: [PATCH] tree: make TreeEntriesDirItem not self-referential

This removes the last use of `ouroboros`. Since `TreeEntriesDirItem`
is only used in "legacy trees" (before tree-level conflicts), I didn't
bother to check the performance impact. I also didn't bother to check
the matcher before adding the entries to the list, instead leaving
that where it is in `Iterator::next()`.
---
 Cargo.lock      | 38 --------------------------------------
 lib/Cargo.toml  |  1 -
 lib/src/tree.rs | 21 +++++++++++----------
 3 files changed, 11 insertions(+), 49 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 14d0eb339..36823dd54 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -26,12 +26,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "aliasable"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "250f629c0161ad8107cf89319e990051fae62832fd343083bea452d93e2205fd"
-
 [[package]]
 name = "android-tzdata"
 version = "0.1.1"
@@ -1679,7 +1673,6 @@ dependencies = [
  "maplit",
  "num_cpus",
  "once_cell",
- "ouroboros",
  "pest",
  "pest_derive",
  "pollster",
@@ -1989,31 +1982,6 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
 
-[[package]]
-name = "ouroboros"
-version = "0.18.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1c86de06555b970aec45229b27291b53154f21a5743a163419f4e4c0b065dcde"
-dependencies = [
- "aliasable",
- "ouroboros_macro",
- "static_assertions",
-]
-
-[[package]]
-name = "ouroboros_macro"
-version = "0.18.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8cad0c4b129e9696e37cb712b243777b90ef489a0bfaa0ac34e7d9b860e4f134"
-dependencies = [
- "heck",
- "itertools 0.11.0",
- "proc-macro-error",
- "proc-macro2",
- "quote",
- "syn 2.0.37",
-]
-
 [[package]]
 name = "overload"
 version = "0.1.1"
@@ -2701,12 +2669,6 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
-[[package]]
-name = "static_assertions"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
-
 [[package]]
 name = "strsim"
 version = "0.10.0"
diff --git a/lib/Cargo.toml b/lib/Cargo.toml
index 2bd52db76..a9f719b74 100644
--- a/lib/Cargo.toml
+++ b/lib/Cargo.toml
@@ -36,7 +36,6 @@ hex = { workspace = true }
 itertools = { workspace = true }
 maplit = { workspace = true }
 once_cell = { workspace = true }
-ouroboros = { workspace = true }
 pest = { workspace = true }
 pest_derive = { workspace = true }
 pollster = { workspace = true }
diff --git a/lib/src/tree.rs b/lib/src/tree.rs
index 804080c0f..bc6443329 100644
--- a/lib/src/tree.rs
+++ b/lib/src/tree.rs
@@ -196,17 +196,19 @@ pub struct TreeEntriesIterator<'matcher> {
     matcher: &'matcher dyn Matcher,
 }
 
-#[ouroboros::self_referencing]
 struct TreeEntriesDirItem {
     tree: Tree,
-    #[borrows(tree)]
-    #[not_covariant]
-    entry_iterator: TreeEntriesNonRecursiveIterator<'this>,
+    entries: Vec<(RepoPath, TreeValue)>,
 }
 
 impl From<Tree> for TreeEntriesDirItem {
     fn from(tree: Tree) -> Self {
-        Self::new(tree, |tree| tree.entries_non_recursive())
+        let mut entries = tree
+            .entries_non_recursive()
+            .map(|entry| (tree.dir().join(entry.name()), entry.value().clone()))
+            .collect_vec();
+        entries.reverse();
+        Self { tree, entries }
     }
 }
 
@@ -225,20 +227,19 @@ impl Iterator for TreeEntriesIterator<'_> {
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(top) = self.stack.last_mut() {
-            if let (tree, Some(entry)) = top.with_mut(|x| (x.tree, x.entry_iterator.next())) {
-                let path = tree.dir().join(entry.name());
-                match entry.value() {
+            if let Some((path, value)) = top.entries.pop() {
+                match value {
                     TreeValue::Tree(id) => {
                         // TODO: Handle the other cases (specific files and trees)
                         if self.matcher.visit(&path).is_nothing() {
                             continue;
                         }
-                        let subtree = tree.known_sub_tree(&path, id);
+                        let subtree = top.tree.known_sub_tree(&path, &id);
                         self.stack.push(TreeEntriesDirItem::from(subtree));
                     }
                     value => {
                         if self.matcher.matches(&path) {
-                            return Some((path, value.clone()));
+                            return Some((path, value));
                         }
                     }
                 };