Remove unused `Backtracker` (#7115)

backtrackable.h was defining a datastructure Backtracker, which was
a member in ArrayInfo and Info but it was not doing anything.

2 files changed, 0 insertions, 222 deletions

diff --git a/src/context/CMakeLists.txt b/src/context/CMakeLists.txt
index 73166462c..6cc066235 100644
--- a/src/context/CMakeLists.txt
+++ b/src/context/CMakeLists.txt
@@ -14,7 +14,6 @@
 ##
 
 set(LIBCONTEXT_SOURCES
-  backtrackable.h
   cddense_set.h
   cdhashmap.h
   cdhashmap_forward.h
diff --git a/src/context/backtrackable.h b/src/context/backtrackable.h
deleted file mode 100644
index 28654dbdf..000000000
--- a/src/context/backtrackable.h
+++ /dev/null
@@ -1,221 +0,0 @@
-/******************************************************************************
- * Top contributors (to current version):
- *   Morgan Deters, Mathias Preiner
- *
- * This file is part of the cvc5 project.
- *
- * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
- * in the top-level source directory and their institutional affiliations.
- * All rights reserved.  See the file COPYING in the top-level source
- * directory for licensing information.
- * ****************************************************************************
- *
- * Contains a backtrackable list.
- */
-
-#include "cvc5_private.h"
-
-#ifndef CVC5__UTIL__BACKTRACKABLE_H
-#define CVC5__UTIL__BACKTRACKABLE_H
-
-#include <cstdlib>
-#include <vector>
-#include "context/cdo.h"
-
-namespace cvc5 {
-
-template <class T> class List;
-template <class T> class List_iterator;
-template <class T> class Backtracker;
-
-template <class T>
-class ListNode {
-private:
-  T data;
-  ListNode<T>* next;
-
-  bool empty;
-  ListNode(const T& t, ListNode<T>* n, bool e = false) : data(t), next(n), empty(e) {}
-  ~ListNode() {
-    // maybe set to NULL
-    delete next;
-  }
-
-  friend class List<T>;
-  friend class List_iterator<T>;
-};/* class ListNode<T> */
-
-template <class T>
-class List_iterator : public std::iterator <std::forward_iterator_tag, T> {
-  friend class List<T>;
-
-public:
-  const T& operator*();
-  List_iterator<T>& operator++();
-  List_iterator<T> operator++(int);
-  bool operator!=(const List_iterator<T> & other) const;
-
-private:
-  const ListNode<T>* pointee;
-  List_iterator(const ListNode<T>* p) : pointee(p) {}
-
-};/* class List_iterator<T> */
-
-template <class T>
-const T& List_iterator<T>::operator*() {
-  return pointee->data;
-}
-
-template <class T>
-List_iterator<T>& List_iterator<T>::operator++() {
-  Assert(pointee != NULL);
-  pointee = pointee->next;
-  while(pointee != NULL && pointee->empty ) {
-    pointee = pointee->next;
-  }
-  return *this;
-}
-
-template <class T>
-List_iterator<T> List_iterator<T>::operator++(int) {
-  List_iterator<T> it = *this;
-  ++*this;
-  return it;
-}
-
-template <class T>
-bool List_iterator<T>::operator!=(const List_iterator<T>& other) const {
-  return (this->pointee != other.pointee);
-}
-
-// !! for the backtracking to work the lists must be allocated on the heap
-// therefore the hashmap from TNode to List<TNode> should store pointers!
-template <class T>
-class List {
-  ListNode<T>* head;
-  ListNode<T>* tail;
-  ListNode<T>* ptr_to_head;
-  bool uninitialized;
-  Backtracker<T>* bck;
-  List (const List&) {}
-public:
-  List(Backtracker<T>* b) : ptr_to_head(NULL), uninitialized(true), bck(b) {
-    head = tail = (ListNode<T>*)calloc(1,sizeof(ListNode<T>));
-    head->next = NULL;
-    head->empty = true;
-  }
-  ~List() {delete head;}
-  bool empty() {
-    bck->checkConsistency();
-    return head == NULL;
-  }
-  void append(const T& d);
-  //typedef List_iterator<T> iterator;
-  typedef List_iterator<T> const_iterator;
-
-  const_iterator begin() {
-    bck->checkConsistency();
-    if(head->empty) {
-      ListNode<T>* temp = head;
-      // if the head is empty return the first non-empty element or NULL
-      while(temp != NULL && temp->empty ) {
-        temp = temp->next;
-      }
-      return List_iterator<T>(temp);
-    }
-    return List_iterator<T>(head);
-  }
-
-  const_iterator end() {
-    bck->checkConsistency();
-    return List_iterator<T>(NULL);
-  }
-  void concat(List<T>* other);
-  void unconcat(List<T>* other);
-};/* class List */
-
-template <class T>
-void List<T>::append (const T& d) {
-  bck->checkConsistency();
-
-  if(uninitialized) {
-    new(head)ListNode<T> (d, head->next);
-    //head->data = d;
-    head->empty = false;
-    //Assert(tail == head); FIXME: do I need this because this list might be empty but append to another one
-    uninitialized = false;
-
-  } else {
-    ListNode<T>* new_node = new ListNode<T>(d, head);
-    head = new_node;
-  }
-
-  if(ptr_to_head != NULL) {
-    ptr_to_head->next = head;
-  }
-}
-
-template <class T>
-void List<T>::concat (List<T>* other) {
-  bck->checkConsistency();
-  bck->notifyConcat(this, other);
-  Assert(tail->next == NULL);
-  tail->next = other->head;
-  Assert(other->ptr_to_head == NULL);
-  other->ptr_to_head = tail;
-  tail = other->tail;
-}
-
-template <class T>
-void List<T>::unconcat(List<T>* other) {
-  // we do not need to check consistency since this is only called by the
-  // Backtracker when we are inconsistent
-  Assert(other->ptr_to_head != NULL);
-  other->ptr_to_head->next = NULL;
-  tail = other->ptr_to_head;
-  other->ptr_to_head = NULL;
-}
-
-/* Backtrackable Table */
-
-template <class T>
-class Backtracker {
-  friend class List<T>;
-  std::vector<std::pair<List<T>*,List<T>*> > undo_stack;
-
-  int curr_level;
-  context::CDO<int> pop_level;
-
-  void checkConsistency();
-  void notifyConcat(List<T>* a, List<T>* b);
-public:
-  Backtracker(context::Context* c) : undo_stack(), curr_level(0), pop_level(c, 0) {}
-  ~Backtracker() {}
-
-};/* class Backtrackable */
-
-template <class T>  void Backtracker<T>::notifyConcat(List<T>* a, List<T>* b) {
-  curr_level++;
-  pop_level.set(pop_level.get()+1);
-  undo_stack.push_back( std::make_pair(a, b));
-}
-
-template <class T> void Backtracker<T>::checkConsistency() {
-  if( curr_level == pop_level || pop_level == -1) {
-    return;
-  }
-  Assert(curr_level > pop_level);
-
-  while (curr_level > pop_level) {
-    curr_level--;
-    List<T>* l1 = undo_stack[curr_level].first;
-    List<T>* l2 = undo_stack[curr_level].second;
-    l1->unconcat(l2);
-    undo_stack.pop_back();
-  }
-  Assert(curr_level == pop_level);
-}
-
-}  // namespace cvc5
-
-#endif /* CVC5__UTIL__BACKTRACKABLE_H */