X-Git-Url: https://git.ralfj.de/rust-101.git/blobdiff_plain/2d40516a8393db1f27bb822ff95c71a1a9c82537..ab7f9b241429bd675b437d2437799de75d2f409b:/workspace/src/part16.rs

diff --git a/workspace/src/part16.rs b/workspace/src/part16.rs
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--- a/workspace/src/part16.rs
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@@ -1,115 +0,0 @@
-// Rust-101, Part 16: Unsafe Rust, Drop
-// ====================================
-
-use std::ptr;
-use std::mem;
-use std::marker::PhantomData;
-
-
-// A node of the list consists of the data, and two node pointers for the predecessor and successor.
-struct Node<T> {
-    next: NodePtr<T>,
-    prev: NodePtr<T>,
-    data: T,
-}
-// A node pointer is a *mutable raw pointer* to a node.
-type NodePtr<T> = *mut Node<T>;
-
-// The linked list itself stores pointers to the first and the last node. In addition, we tell Rust that this type
-// will own data of type `T`.
-pub struct LinkedList<T> {
-    first: NodePtr<T>,
-    last:  NodePtr<T>,
-    _marker: PhantomData<T>,
-}
-
-
-unsafe fn raw_into_box<T>(r: *mut T) -> Box<T> {
-    mem::transmute(r)
-}
-fn box_into_raw<T>(b: Box<T>) -> *mut T {
-    unsafe { mem::transmute(b) }
-}
-
-impl<T> LinkedList<T> {
-    // A new linked list just contains null pointers. `PhantomData` is how we construct any `PhantomData<T>`.
-    pub fn new() -> Self {
-        LinkedList { first: ptr::null_mut(), last: ptr::null_mut(), _marker: PhantomData }
-    }
-
-    // This function adds a new node to the end of the list.
-    pub fn push_back(&mut self, t: T) {
-        // Create the new node, and make it a raw pointer.
-        let new = Box::new( Node { data: t, next: ptr::null_mut(), prev: self.last } );
-        let new = box_into_raw(new);
-        // Update other pointers to this node.
-        if self.last.is_null() {
-            debug_assert!(self.first.is_null());
-            // The list is currently empty, so we have to update the head pointer.
-            unimplemented!()
-        } else {
-            debug_assert!(!self.first.is_null());
-            // We have to update the `next` pointer of the tail node.
-            unimplemented!()
-        }
-        // Make this the last node.
-        self.last = new;
-    }
-
-    // **Exercise 16.1**: Add some more operations to `LinkedList`: `pop_back`, `push_front` and `pop_front`.
-    // Add testcases for `push_back` and all of your functions. The `pop` functions should take `&mut self`
-    // and return `Option<T>`.
-
-    // Next, we are going to provide an iterator.
-    pub fn iter_mut(&mut self) -> IterMut<T> {
-        IterMut { next: self.first, _marker: PhantomData  }
-    }
-}
-
-
-pub struct IterMut<'a, T> where T: 'a {
-    next: NodePtr<T>,
-    _marker: PhantomData<&'a mut LinkedList<T>>,
-}
-
-impl<'a, T> Iterator for IterMut<'a, T> {
-    type Item = &'a mut T;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        // The actual iteration is straight-forward: Once we reached a null pointer, we are done.
-        if self.next.is_null() {
-            None
-        } else {
-            // Otherwise, we can convert the next pointer to a reference, get a reference to the data
-            // and update the iterator.
-            let next = unsafe { &mut *self.next };
-            let ret = &mut next.data;
-            unimplemented!()
-        }
-    }
-}
-
-
-// **Exercise 16.2**: Add a method `iter` and a type `Iter` providing iteration for shared references.
-// Add testcases for both kinds of iterators.
-
-// ## `Drop`
-
-impl<T> Drop for LinkedList<T> {
-    // The destructor itself is a method which takes `self` in mutably borrowed form. It cannot own `self`, because then
-    // the destructor of `self` would be called at the end of the function, resulting in endless recursion.
-    fn drop(&mut self) {
-        let mut cur_ptr = self.first;
-        while !cur_ptr.is_null() {
-            // In the destructor, we just iterate over the entire list, successively obtaining ownership
-            // (`Box`) of every node. When the box is dropped, it will call the destructor on `data` if
-            // necessary, and subsequently free the node on the heap.
-            let cur = unsafe { raw_into_box(cur_ptr) };
-            cur_ptr = cur.next;
-            drop(cur);
-        }
-    }
-}
-
-// ## The End
-