From 94921c0b7448c982448cfc8308f9a12732c3c8af Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <jolesen@mozilla.com>
Date: Tue, 24 Oct 2017 09:09:02 -0700
Subject: [PATCH] Remove the dead B-Tree interface.

We're starting over from scratch.
---
 lib/cretonne/src/btree.rs | 112 --------------------------------------
 1 file changed, 112 deletions(-)
 delete mode 100644 lib/cretonne/src/btree.rs

diff --git a/lib/cretonne/src/btree.rs b/lib/cretonne/src/btree.rs
deleted file mode 100644
index e625b6108e..0000000000
--- a/lib/cretonne/src/btree.rs
+++ /dev/null
@@ -1,112 +0,0 @@
-//! Generic B-Tree implementation.
-//!
-//! This module defines a `Btree<K, V>` type which provides similar functionality to
-//! `BtreeMap<K, V>`, but with some important differences in the implementation:
-//!
-//! 1. Memory is allocated from a `NodePool<K, V>` instead of the global heap.
-//! 2. The footprint of a BTree is only 4 bytes.
-//! 3. A BTree doesn't implement `Drop`, leaving it to the pool to manage memory.
-//!
-//! The node pool is intended to be used as a LIFO allocator. After building up a larger data
-//! structure with many list references, the whole thing can be discarded quickly by clearing the
-//! pool.
-
-use std::marker::PhantomData;
-
-// A Node reference is a direct index to an element of the pool.
-type NodeRef = u32;
-
-/// A B-tree data structure which nodes are allocated from a pool.
-pub struct BTree<K, V> {
-    index: NodeRef,
-    unused1: PhantomData<K>,
-    unused2: PhantomData<V>,
-}
-
-/// An enum representing a B-tree node.
-/// Keys and values are required to implement Default.
-enum Node<K, V> {
-    Inner {
-        size: u8,
-        keys: [K; 7],
-        nodes: [NodeRef; 8],
-    },
-    Leaf {
-        size: u8,
-        keys: [K; 7],
-        values: [V; 7],
-    },
-}
-
-/// Memory pool for nodes.
-struct NodePool<K, V> {
-    // The array containing the nodes.
-    data: Vec<Node<K, V>>,
-
-    // A free list
-    freelist: Vec<NodeRef>,
-}
-
-impl<K: Default, V: Default> NodePool<K, V> {
-    /// Create a new NodePool.
-    pub fn new() -> NodePool<K, V> {
-        NodePool {
-            data: Vec::new(),
-            freelist: Vec::new(),
-        }
-    }
-
-    /// Get a B-tree node.
-    pub fn get(&self, index: u32) -> Option<&Node<K, V>> {
-        unimplemented!()
-    }
-}
-
-impl<K: Default, V: Default> BTree<K, V> {
-    /// Search for `key` and return a `Cursor` that either points at `key` or the position
-    /// where it would be inserted.
-    pub fn search(&mut self, key: K) -> Cursor<K, V> {
-        unimplemented!()
-    }
-}
-
-pub struct Cursor<'a, K: 'a, V: 'a> {
-    pool: &'a mut NodePool<K, V>,
-    height: usize,
-    path: [(NodeRef, u8); 16],
-}
-
-impl<'a, K: Default, V: Default> Cursor<'a, K, V> {
-    /// The key at the cursor position. Returns `None` when the cursor points off the end.
-    pub fn key(&self) -> Option<K> {
-        unimplemented!()
-    }
-
-    /// The value at the cursor position. Returns `None` when the cursor points off the end.
-    pub fn value(&self) -> Option<&V> {
-        unimplemented!()
-    }
-
-    /// Move to the next element.
-    /// Returns `false` if that moves the cursor off the end.
-    pub fn next(&mut self) -> bool {
-        unimplemented!()
-    }
-
-    /// Move to the previous element.
-    /// Returns `false` if this moves the cursor before the beginning.
-    pub fn prev(&mut self) -> bool {
-        unimplemented!()
-    }
-
-    /// Insert a `(key, value)` pair at the cursor position.
-    /// It is an error to insert a key that would be out of order at this position.
-    pub fn insert(&mut self, key: K, value: V) {
-        unimplemented!()
-    }
-
-    /// Remove the current element.
-    pub fn remove(&mut self) {
-        unimplemented!()
-    }
-}