//===- Tree.cpp -----------------------------------------------*- C++ -*-=====//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#include "clang/Tooling/Syntax/Tree.h"

#include "clang/Basic/TokenKinds.h"

#include "clang/Tooling/Syntax/Nodes.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/Support/Casting.h"

#include <cassert>

using namespace clang;

namespace {

static void traverse(const syntax::Node *N,

                     llvm::function_ref<void(const syntax::Node *)> Visit) {

  if (auto *T = dyn_cast<syntax::Tree>(N)) {

    for (const syntax::Node &C : T->getChildren())

      traverse(&C, Visit);

  }

  Visit(N);

}

static void traverse(syntax::Node *N,

                     llvm::function_ref<void(syntax::Node *)> Visit) {

  traverse(static_cast<const syntax::Node *>(N), [&](const syntax::Node *N) {

    Visit(const_cast<syntax::Node *>(N));

  });

}

} // namespace

syntax::Arena::Arena(SourceManager &SourceMgr, const LangOptions &LangOpts,

                     const TokenBuffer &Tokens)

    : SourceMgr(SourceMgr), LangOpts(LangOpts), Tokens(Tokens) {}

const syntax::TokenBuffer &syntax::Arena::getTokenBuffer() const {

  return Tokens;

}

std::pair<FileID, ArrayRef<syntax::Token>>

syntax::Arena::lexBuffer(std::unique_ptr<llvm::MemoryBuffer> Input) {

  auto FID = SourceMgr.createFileID(std::move(Input));

  auto It = ExtraTokens.try_emplace(FID, tokenize(FID, SourceMgr, LangOpts));

  assert(It.second && "duplicate FileID");

  return {FID, It.first->second};

}

syntax::Leaf::Leaf(const syntax::Token *Tok) : Node(NodeKind::Leaf), Tok(Tok) {

  assert(Tok != nullptr);

}

syntax::Node::Node(NodeKind Kind)

    : Parent(nullptr), NextSibling(nullptr), PreviousSibling(nullptr),

      Kind(static_cast<unsigned>(Kind)), Role(0), Original(false),

      CanModify(false) {

  this->setRole(NodeRole::Detached);

}

bool syntax::Node::isDetached() const {

  return getRole() == NodeRole::Detached;

}

void syntax::Node::setRole(NodeRole NR) {

  this->Role = static_cast<unsigned>(NR);

}

void syntax::Tree::appendChildLowLevel(Node *Child, NodeRole Role) {

  assert(Child->getRole() == NodeRole::Detached);

  assert(Role != NodeRole::Detached);

  Child->setRole(Role);

  appendChildLowLevel(Child);

}

void syntax::Tree::appendChildLowLevel(Node *Child) {

  assert(Child->Parent == nullptr);

  assert(Child->NextSibling == nullptr);

  assert(Child->PreviousSibling == nullptr);

  assert(Child->getRole() != NodeRole::Detached);

  Child->Parent = this;

  if (this->LastChild) {

    Child->PreviousSibling = this->LastChild;

    this->LastChild->NextSibling = Child;

  } else

    this->FirstChild = Child;

  this->LastChild = Child;

}

void syntax::Tree::prependChildLowLevel(Node *Child, NodeRole Role) {

  assert(Child->getRole() == NodeRole::Detached);

  assert(Role != NodeRole::Detached);

  Child->setRole(Role);

  prependChildLowLevel(Child);

}

void syntax::Tree::prependChildLowLevel(Node *Child) {

  assert(Child->Parent == nullptr);

  assert(Child->NextSibling == nullptr);

  assert(Child->PreviousSibling == nullptr);

  assert(Child->getRole() != NodeRole::Detached);

  Child->Parent = this;

  if (this->FirstChild) {

    Child->NextSibling = this->FirstChild;

    this->FirstChild->PreviousSibling = Child;

  } else

    this->LastChild = Child;

  this->FirstChild = Child;

}

void syntax::Tree::replaceChildRangeLowLevel(Node *Begin, Node *End,

                                             Node *New) {

  assert((!Begin || Begin->Parent == this) &&

         "`Begin` is not a child of `this`.");

  assert((!End || End->Parent == this) && "`End` is not a child of `this`.");

  assert(canModify() && "Cannot modify `this`.");

#ifndef NDEBUG

  for (auto *N = New; N; 
N = N->NextSibling14
) {

    assert(N->Parent == nullptr);

    assert(N->getRole() != NodeRole::Detached && "Roles must be set");

    // FIXME: sanity-check the role.

  }

  auto Reachable = [](Node *From, Node *N) {

    if (!N)

      return true;

    
for (auto *It = From; 84
It; 
It = It->NextSibling126
)

      if (It == N)

        return true;

    return false;

  };

  assert(Reachable(FirstChild, Begin) && "`Begin` is not reachable.");

  assert(Reachable(Begin, End) && "`End` is not after `Begin`.");

#endif

  if (!New && 
Begin == End28
)

    return;

  // Mark modification.

  
for (auto *T = this; 42
T && 
T->Original140
; 
T = T->Parent140
)

    T->Original = false;

  // Save the node before the range to be removed. Later we insert the `New`

  // range after this node.

  auto *BeforeBegin = Begin ? Begin->PreviousSibling : 
LastChild0
;

  // Detach old nodes.

  for (auto *N = Begin; N != End;) {

    auto *Next = N->NextSibling;

    N->setRole(NodeRole::Detached);

    N->Parent = nullptr;

    N->NextSibling = nullptr;

    N->PreviousSibling = nullptr;

    if (N->Original)

      
traverse(N, [](Node *C) 42
{ C->Original = false; });

    N = Next;

  }

  // Attach new range.

  auto *&NewFirst = BeforeBegin ? BeforeBegin->NextSibling : 
FirstChild0
;

  auto *&NewLast = End ? End->PreviousSibling : 
LastChild0
;

  if (!New) {

    NewFirst = End;

    NewLast = BeforeBegin;

    return;

  }

  New->PreviousSibling = BeforeBegin;

  NewFirst = New;

  Node *LastInNew;

  for (auto *N = New; N != nullptr; 
N = N->NextSibling14
) {

    LastInNew = N;

    N->Parent = this;

  }

  LastInNew->NextSibling = End;

  NewLast = LastInNew;

}

namespace {

static void dumpLeaf(raw_ostream &OS, const syntax::Leaf *L,

                     const SourceManager &SM) {

  assert(L);

  const auto *Token = L->getToken();

  assert(Token);

  // Handle 'eof' separately, calling text() on it produces an empty string.

  if (Token->kind() == tok::eof)

    OS << "<eof>";

  else

    OS << Token->text(SM);

}

static void dumpNode(raw_ostream &OS, const syntax::Node *N,

                     const SourceManager &SM, std::vector<bool> IndentMask) {

  auto DumpExtraInfo = [&OS](const syntax::Node *N) {

    if (N->getRole() != syntax::NodeRole::Unknown)

      OS << " " << N->getRole();

    if (!N->isOriginal())

      OS << " synthesized";

    if (!N->canModify())

      OS << " unmodifiable";

  };

  assert(N);

  if (const auto *L = dyn_cast<syntax::Leaf>(N)) {

    OS << "'";

    dumpLeaf(OS, L, SM);

    OS << "'";

    DumpExtraInfo(N);

    OS << "\n";

    return;

  }

  const auto *T = cast<syntax::Tree>(N);

  OS << T->getKind();

  DumpExtraInfo(N);

  OS << "\n";

  for (const syntax::Node &It : T->getChildren()) {

    for (bool Filled : IndentMask) {

      if (Filled)

        OS << "| ";

      else

        OS << "  ";

    }

    if (!It.getNextSibling()) {

      OS << "`-";

      IndentMask.push_back(false);

    } else {

      OS << "|-";

      IndentMask.push_back(true);

    }

    dumpNode(OS, &It, SM, IndentMask);

    IndentMask.pop_back();

  }

}

} // namespace

std::string syntax::Node::dump(const SourceManager &SM) const {

  std::string Str;

  llvm::raw_string_ostream OS(Str);

  dumpNode(OS, this, SM, /*IndentMask=*/{});

  return std::move(OS.str());

}

std::string syntax::Node::dumpTokens(const SourceManager &SM) const {

  std::string Storage;

  llvm::raw_string_ostream OS(Storage);

  traverse(this, [&](const syntax::Node *N) {

    if (const auto *L = dyn_cast<syntax::Leaf>(N)) {

      dumpLeaf(OS, L, SM);

      OS << " ";

    }

  });

  return OS.str();

}

void syntax::Node::assertInvariants() const {

#ifndef NDEBUG

  if (isDetached())

    assert(getParent() == nullptr);

  else

    assert(getParent() != nullptr);

  const auto *T = dyn_cast<Tree>(this);

  if (!T)

    return;

  
for (const Node &C : T->getChildren())32.3k
 {

    if (T->isOriginal())

      assert(C.isOriginal());

    assert(!C.isDetached());

    assert(C.getParent() == T);

    const auto *Next = C.getNextSibling();

    assert(!Next || &C == Next->getPreviousSibling());

    if (!C.getNextSibling())

      assert(&C == T->getLastChild() &&

             "Last child is reachable by advancing from the first child.");

  }

  const auto *L = dyn_cast<List>(T);

  if (!L)

    return;

  
for (const Node &C : T->getChildren())5.55k
 {

    assert(C.getRole() == NodeRole::ListElement ||

           C.getRole() == NodeRole::ListDelimiter);

    if (C.getRole() == NodeRole::ListDelimiter) {

      assert(isa<Leaf>(C));

      assert(cast<Leaf>(C).getToken()->kind() == L->getDelimiterTokenKind());

    }

  }

#endif

}

void syntax::Node::assertInvariantsRecursive() const {

#ifndef NDEBUG

  traverse(this, [&](const syntax::Node *N) { N->assertInvariants(); });

#endif

}

const syntax::Leaf *syntax::Tree::findFirstLeaf() const {

  for (const Node &C : getChildren()) {

    if (const auto *L = dyn_cast<syntax::Leaf>(&C))

      return L;

    if (const auto *L = cast<syntax::Tree>(C).findFirstLeaf())

      return L;

  }

  return nullptr;

}

const syntax::Leaf *syntax::Tree::findLastLeaf() const {

  for (const auto *C = getLastChild(); C; 
C = C->getPreviousSibling()112
) {

    if (const auto *L = dyn_cast<syntax::Leaf>(C))

      return L;

    if (const auto *L = cast<syntax::Tree>(C)->findLastLeaf())

      return L;

  }

  return nullptr;

}

const syntax::Node *syntax::Tree::findChild(NodeRole R) const {

  for (const Node &C : getChildren()) {

    if (C.getRole() == R)

      return &C;

  }

  return nullptr;

}

std::vector<syntax::List::ElementAndDelimiter<syntax::Node>>

syntax::List::getElementsAsNodesAndDelimiters() {

  if (!getFirstChild())

    return {};

  std::vector<syntax::List::ElementAndDelimiter<Node>> Children;

  syntax::Node *ElementWithoutDelimiter = nullptr;

  for (Node &C : getChildren()) {

    switch (C.getRole()) {

    case syntax::NodeRole::ListElement: {

      if (ElementWithoutDelimiter) {

        Children.push_back({ElementWithoutDelimiter, nullptr});

      }

      ElementWithoutDelimiter = &C;

      break;

    }

    case syntax::NodeRole::ListDelimiter: {

      Children.push_back({ElementWithoutDelimiter, cast<syntax::Leaf>(&C)});

      ElementWithoutDelimiter = nullptr;

      break;

    }

    default:

      llvm_unreachable(

          "A list can have only elements and delimiters as children.");

    }

  }

  switch (getTerminationKind()) {

  case syntax::List::TerminationKind::Separated: {

    Children.push_back({ElementWithoutDelimiter, nullptr});

    break;

  }

  case syntax::List::TerminationKind::Terminated:

  case syntax::List::TerminationKind::MaybeTerminated: {

    if (ElementWithoutDelimiter) {

      Children.push_back({ElementWithoutDelimiter, nullptr});

    }

    break;

  }

  }

  return Children;

}

// Almost the same implementation of `getElementsAsNodesAndDelimiters` but

// ignoring delimiters

std::vector<syntax::Node *> syntax::List::getElementsAsNodes() {

  if (!getFirstChild())

    return {};

  std::vector<syntax::Node *> Children;

  syntax::Node *ElementWithoutDelimiter = nullptr;

  for (Node &C : getChildren()) {

    switch (C.getRole()) {

    case syntax::NodeRole::ListElement: {

      if (ElementWithoutDelimiter) {

        Children.push_back(ElementWithoutDelimiter);

      }

      ElementWithoutDelimiter = &C;

      break;

    }

    case syntax::NodeRole::ListDelimiter: {

      Children.push_back(ElementWithoutDelimiter);

      ElementWithoutDelimiter = nullptr;

      break;

    }

    default:

      llvm_unreachable("A list has only elements or delimiters.");

    }

  }

  switch (getTerminationKind()) {

  case syntax::List::TerminationKind::Separated: {

    Children.push_back(ElementWithoutDelimiter);

    break;

  }

  case syntax::List::TerminationKind::Terminated:

  case syntax::List::TerminationKind::MaybeTerminated: {

    if (ElementWithoutDelimiter) {

      Children.push_back(ElementWithoutDelimiter);

    }

    break;

  }

  }

  return Children;

}

clang::tok::TokenKind syntax::List::getDelimiterTokenKind() const {

  switch (this->getKind()) {

  case NodeKind::NestedNameSpecifier:

    return clang::tok::coloncolon;

  case NodeKind::CallArguments:

  case NodeKind::ParameterDeclarationList:

  case NodeKind::DeclaratorList:

    return clang::tok::comma;

  default:

    llvm_unreachable("This is not a subclass of List, thus "

                     "getDelimiterTokenKind() cannot be called");

  }

}

syntax::List::TerminationKind syntax::List::getTerminationKind() const {

  switch (this->getKind()) {

  case NodeKind::NestedNameSpecifier:

    return TerminationKind::Terminated;

  case NodeKind::CallArguments:

  case NodeKind::ParameterDeclarationList:

  case NodeKind::DeclaratorList:

    return TerminationKind::Separated;

  default:

    llvm_unreachable("This is not a subclass of List, thus "

                     "getTerminationKind() cannot be called");

  }

}

bool syntax::List::canBeEmpty() const {

  switch (this->getKind()) {

  case NodeKind::NestedNameSpecifier:

    return false;

  case NodeKind::CallArguments:

    return true;

  case NodeKind::ParameterDeclarationList:

    return true;

  case NodeKind::DeclaratorList:

    return true;

  default:

    llvm_unreachable("This is not a subclass of List, thus canBeEmpty() "

                     "cannot be called");

  }

}