llvm-project

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//===--- CommentCommandTraits.cpp - Comment command properties --*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "clang/AST/CommentCommandTraits.h"
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#include "llvm/ADT/STLExtras.h"
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#include <cassert>
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namespace clang {
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namespace comments {
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#include "clang/AST/CommentCommandInfo.inc"
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CommandTraits::CommandTraits(llvm::BumpPtrAllocator &Allocator,
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                             const CommentOptions &CommentOptions)
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    : NextID(std::size(Commands)), Allocator(Allocator) {
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  registerCommentOptions(CommentOptions);
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}
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void CommandTraits::registerCommentOptions(
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    const CommentOptions &CommentOptions) {
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  for (CommentOptions::BlockCommandNamesTy::const_iterator
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           I = CommentOptions.BlockCommandNames.begin(),
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           E = CommentOptions.BlockCommandNames.end();
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       I != E; I++) {
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    registerBlockCommand(*I);
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  }
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}
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const CommandInfo *CommandTraits::getCommandInfoOrNULL(StringRef Name) const {
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  if (const CommandInfo *Info = getBuiltinCommandInfo(Name))
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    return Info;
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  return getRegisteredCommandInfo(Name);
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}
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const CommandInfo *CommandTraits::getCommandInfo(unsigned CommandID) const {
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  if (const CommandInfo *Info = getBuiltinCommandInfo(CommandID))
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    return Info;
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  return getRegisteredCommandInfo(CommandID);
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}
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const CommandInfo *
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CommandTraits::getTypoCorrectCommandInfo(StringRef Typo) const {
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  // Single-character command impostures, such as \t or \n, should not go
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  // through the fixit logic.
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  if (Typo.size() <= 1)
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    return nullptr;
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  // The maximum edit distance we're prepared to accept.
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  const unsigned MaxEditDistance = 1;
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  unsigned BestEditDistance = MaxEditDistance;
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  SmallVector<const CommandInfo *, 2> BestCommand;
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  auto ConsiderCorrection = [&](const CommandInfo *Command) {
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    StringRef Name = Command->Name;
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    unsigned MinPossibleEditDistance = abs((int)Name.size() - (int)Typo.size());
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    if (MinPossibleEditDistance <= BestEditDistance) {
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      unsigned EditDistance = Typo.edit_distance(Name, true, BestEditDistance);
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      if (EditDistance < BestEditDistance) {
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        BestEditDistance = EditDistance;
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        BestCommand.clear();
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      }
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      if (EditDistance == BestEditDistance)
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        BestCommand.push_back(Command);
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    }
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  };
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  for (const auto &Command : Commands)
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    ConsiderCorrection(&Command);
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  for (const auto *Command : RegisteredCommands)
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    if (!Command->IsUnknownCommand)
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      ConsiderCorrection(Command);
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  return BestCommand.size() == 1 ? BestCommand[0] : nullptr;
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}
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CommandInfo *CommandTraits::createCommandInfoWithName(StringRef CommandName) {
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  char *Name = Allocator.Allocate<char>(CommandName.size() + 1);
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  memcpy(Name, CommandName.data(), CommandName.size());
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  Name[CommandName.size()] = '\0';
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  // Value-initialize (=zero-initialize in this case) a new CommandInfo.
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  CommandInfo *Info = new (Allocator) CommandInfo();
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  Info->Name = Name;
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  // We only have a limited number of bits to encode command IDs in the
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  // CommandInfo structure, so the ID numbers can potentially wrap around.
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  assert((NextID < (1 << CommandInfo::NumCommandIDBits))
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         && "Too many commands. We have limited bits for the command ID.");
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  Info->ID = NextID++;
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  RegisteredCommands.push_back(Info);
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  return Info;
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}
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const CommandInfo *CommandTraits::registerUnknownCommand(
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                                                  StringRef CommandName) {
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  CommandInfo *Info = createCommandInfoWithName(CommandName);
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  Info->IsUnknownCommand = true;
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  return Info;
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}
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const CommandInfo *CommandTraits::registerBlockCommand(StringRef CommandName) {
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  CommandInfo *Info = createCommandInfoWithName(CommandName);
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  Info->IsBlockCommand = true;
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  return Info;
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}
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const CommandInfo *CommandTraits::getBuiltinCommandInfo(
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                                                  unsigned CommandID) {
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  if (CommandID < std::size(Commands))
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    return &Commands[CommandID];
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  return nullptr;
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}
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const CommandInfo *CommandTraits::getRegisteredCommandInfo(
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                                                  StringRef Name) const {
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  for (unsigned i = 0, e = RegisteredCommands.size(); i != e; ++i) {
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    if (RegisteredCommands[i]->Name == Name)
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      return RegisteredCommands[i];
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  }
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  return nullptr;
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}
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const CommandInfo *CommandTraits::getRegisteredCommandInfo(
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                                                  unsigned CommandID) const {
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  return RegisteredCommands[CommandID - std::size(Commands)];
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}
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} // end namespace comments
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} // end namespace clang
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