// Copyright (c) 2017 Google Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef SOURCE_OPT_INSTRUCTION_LIST_H_

#define SOURCE_OPT_INSTRUCTION_LIST_H_

#include <cassert>

#include <functional>

#include <memory>

#include <utility>

#include <vector>

#include "source/latest_version_spirv_header.h"

#include "source/operand.h"

#include "source/opt/instruction.h"

#include "source/util/ilist.h"

#include "spirv-tools/libspirv.h"

namespace spvtools {

namespace opt {

// This class is intended to be the container for Instructions.  This container

// owns the instructions that are in it.  When removing an Instruction from the

// list, the caller is assuming responsibility for deleting the storage.

//

// TODO: Because there are a number of other data structures that will want

// pointers to instruction, ownership should probably be moved to the module.

// Because of that I have not made the ownership passing in this class fully

// explicit.  For example, RemoveFromList takes ownership from the list, but

// does not return an std::unique_ptr to signal that.  When we fully decide on

// ownership, this will have to be fixed up one way or the other.

class InstructionList : public utils::IntrusiveList<Instruction> {

 public:

  InstructionList() = default;

  InstructionList(InstructionList&& that)

      : utils::IntrusiveList<Instruction>(std::move(that)) {}

  InstructionList& operator=(InstructionList&& that) {

    auto p = static_cast<utils::IntrusiveList<Instruction>*>(this);

    *p = std::move(that);

    return *this;

  }

  // Destroy this list and any instructions in the list.

  inline ~InstructionList() override;

  class iterator : public utils::IntrusiveList<Instruction>::iterator {

   public:

    iterator(const utils::IntrusiveList<Instruction>::iterator& i)

        : utils::IntrusiveList<Instruction>::iterator(i) {}

    iterator(Instruction* i) : utils::IntrusiveList<Instruction>::iterator(i) {}

    iterator& operator++() {

      utils::IntrusiveList<Instruction>::iterator::operator++();

      return *this;

    }

    iterator& operator--() {

      utils::IntrusiveList<Instruction>::iterator::operator--();

      return *this;

    }

    // DEPRECATED: Please use MoveBefore with an InstructionList instead.

    //

    // Moves the nodes in |list| to the list that |this| points to.  The

    // positions of the nodes will be immediately before the element pointed to

    // by the iterator.  The return value will be an iterator pointing to the

    // first of the newly inserted elements.  Ownership of the elements in

    // |list| is now passed on to |*this|.

    iterator InsertBefore(std::vector<std::unique_ptr<Instruction>>&& list);

    // The node |i| will be inserted immediately before |this|. The return value

    // will be an iterator pointing to the newly inserted node.  The owner of

    // |*i| becomes |*this|

    iterator InsertBefore(std::unique_ptr<Instruction>&& i);

    // Removes the node from the list, and deletes the storage.  Returns a valid

    // iterator to the next node.

    iterator Erase() {

      iterator_template next_node = *this;

      ++next_node;

      node_->RemoveFromList();

      delete node_;

      return next_node;

    }

  };

  iterator begin() { return utils::IntrusiveList<Instruction>::begin(); }

  iterator end() { return utils::IntrusiveList<Instruction>::end(); }

  const_iterator begin() const {

    return utils::IntrusiveList<Instruction>::begin();

  }

  const_iterator end() const {

    return utils::IntrusiveList<Instruction>::end();

  }

  void push_back(std::unique_ptr<Instruction>&& inst) {

    utils::IntrusiveList<Instruction>::push_back(inst.release());

  }

  // Same as in the base class, except it will delete the data as well.

  inline void clear();

  // Runs the given function |f| on the instructions in the list and optionally

  // on the preceding debug line instructions.

  inline void ForEachInst(const std::function<void(Instruction*)>& f,

                          bool run_on_debug_line_insts) {

    auto next = begin();

    for (auto i = next; i != end(); i = next) {

      ++next;

      i->ForEachInst(f, run_on_debug_line_insts);

    }

  }

};

InstructionList::~InstructionList() { clear(); }

void InstructionList::clear() {

  while (!empty()) {

    Instruction* inst = &front();

    inst->RemoveFromList();

    delete inst;

  }

}

}  // namespace opt

}  // namespace spvtools

#endif  // SOURCE_OPT_INSTRUCTION_LIST_H_