//===--- CommentCommandTraits.cpp - Comment command properties --*- 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/AST/CommentCommandTraits.h"

#include "llvm/ADT/STLExtras.h"

#include <cassert>

namespace clang {

namespace comments {

#include "clang/AST/CommentCommandInfo.inc"

CommandTraits::CommandTraits(llvm::BumpPtrAllocator &Allocator,

                             const CommentOptions &CommentOptions)

    : NextID(std::size(Commands)), Allocator(Allocator) {

  registerCommentOptions(CommentOptions);

}

void CommandTraits::registerCommentOptions(

    const CommentOptions &CommentOptions) {

  for (CommentOptions::BlockCommandNamesTy::const_iterator

           I = CommentOptions.BlockCommandNames.begin(),

           E = CommentOptions.BlockCommandNames.end();

       I != E; I++) {

    registerBlockCommand(*I);

  }

}

const CommandInfo *CommandTraits::getCommandInfoOrNULL(StringRef Name) const {

  if (const CommandInfo *Info = getBuiltinCommandInfo(Name))

    return Info;

  return getRegisteredCommandInfo(Name);

}

const CommandInfo *CommandTraits::getCommandInfo(unsigned CommandID) const {

  if (const CommandInfo *Info = getBuiltinCommandInfo(CommandID))

    return Info;

  return getRegisteredCommandInfo(CommandID);

}

const CommandInfo *

CommandTraits::getTypoCorrectCommandInfo(StringRef Typo) const {

  // Single-character command impostures, such as \t or \n, should not go

  // through the fixit logic.

  if (Typo.size() <= 1)

    return nullptr;

  // The maximum edit distance we're prepared to accept.

  const unsigned MaxEditDistance = 1;

  unsigned BestEditDistance = MaxEditDistance;

  SmallVector<const CommandInfo *, 2> BestCommand;

  auto ConsiderCorrection = [&](const CommandInfo *Command) {

    StringRef Name = Command->Name;

    unsigned MinPossibleEditDistance = abs((int)Name.size() - (int)Typo.size());

    if (MinPossibleEditDistance <= BestEditDistance) {

      unsigned EditDistance = Typo.edit_distance(Name, true, BestEditDistance);

      if (EditDistance < BestEditDistance) {

        BestEditDistance = EditDistance;

        BestCommand.clear();

      }

      if (EditDistance == BestEditDistance)

        BestCommand.push_back(Command);

    }

  };

  for (const auto &Command : Commands)

    ConsiderCorrection(&Command);

  for (const auto *Command : RegisteredCommands)

    if (!Command->IsUnknownCommand)

      ConsiderCorrection(Command);

  return BestCommand.size() == 1 ? BestCommand[0] : nullptr;

}

CommandInfo *CommandTraits::createCommandInfoWithName(StringRef CommandName) {

  char *Name = Allocator.Allocate<char>(CommandName.size() + 1);

  memcpy(Name, CommandName.data(), CommandName.size());

  Name[CommandName.size()] = '\0';

  // Value-initialize (=zero-initialize in this case) a new CommandInfo.

  CommandInfo *Info = new (Allocator) CommandInfo();

  Info->Name = Name;

  // We only have a limited number of bits to encode command IDs in the

  // CommandInfo structure, so the ID numbers can potentially wrap around.

  assert((NextID < (1 << CommandInfo::NumCommandIDBits))

         && "Too many commands. We have limited bits for the command ID.");

  Info->ID = NextID++;

  RegisteredCommands.push_back(Info);

  return Info;

}

const CommandInfo *CommandTraits::registerUnknownCommand(

                                                  StringRef CommandName) {

  CommandInfo *Info = createCommandInfoWithName(CommandName);

  Info->IsUnknownCommand = true;

  return Info;

}

const CommandInfo *CommandTraits::registerBlockCommand(StringRef CommandName) {

  CommandInfo *Info = createCommandInfoWithName(CommandName);

  Info->IsBlockCommand = true;

  return Info;

}

const CommandInfo *CommandTraits::getBuiltinCommandInfo(

                                                  unsigned CommandID) {

  if (CommandID < std::size(Commands))

    return &Commands[CommandID];

  return nullptr;

}

const CommandInfo *CommandTraits::getRegisteredCommandInfo(

                                                  StringRef Name) const {

  for (unsigned i = 0, e = RegisteredCommands.size(); i != e; ++i) {

    if (RegisteredCommands[i]->Name == Name)

      return RegisteredCommands[i];

  }

  return nullptr;

}

const CommandInfo *CommandTraits::getRegisteredCommandInfo(

                                                  unsigned CommandID) const {

  return RegisteredCommands[CommandID - std::size(Commands)];

}

} // end namespace comments

} // end namespace clang