//===- Commit.cpp - A unit of edits ---------------------------------------===//

//

// 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/Edit/Commit.h"

#include "clang/Basic/LLVM.h"

#include "clang/Basic/SourceLocation.h"

#include "clang/Basic/SourceManager.h"

#include "clang/Edit/EditedSource.h"

#include "clang/Edit/FileOffset.h"

#include "clang/Lex/Lexer.h"

#include "clang/Lex/PPConditionalDirectiveRecord.h"

#include "llvm/ADT/StringRef.h"

#include <cassert>

#include <utility>

using namespace clang;

using namespace edit;

SourceLocation Commit::Edit::getFileLocation(SourceManager &SM) const {

  SourceLocation Loc = SM.getLocForStartOfFile(Offset.getFID());

  Loc = Loc.getLocWithOffset(Offset.getOffset());

  assert(Loc.isFileID());

  return Loc;

}

CharSourceRange Commit::Edit::getFileRange(SourceManager &SM) const {

  SourceLocation Loc = getFileLocation(SM);

  return CharSourceRange::getCharRange(Loc, Loc.getLocWithOffset(Length));

}

CharSourceRange Commit::Edit::getInsertFromRange(SourceManager &SM) const {

  SourceLocation Loc = SM.getLocForStartOfFile(InsertFromRangeOffs.getFID());

  Loc = Loc.getLocWithOffset(InsertFromRangeOffs.getOffset());

  assert(Loc.isFileID());

  return CharSourceRange::getCharRange(Loc, Loc.getLocWithOffset(Length));

}

Commit::Commit(EditedSource &Editor)

    : SourceMgr(Editor.getSourceManager()), LangOpts(Editor.getLangOpts()),

      PPRec(Editor.getPPCondDirectiveRecord()),

      Editor(&Editor) {}

bool Commit::insert(SourceLocation loc, StringRef text,

                    bool afterToken, bool beforePreviousInsertions) {

  if (text.empty())

    return true;

  FileOffset Offs;

  if ((!afterToken && !canInsert(loc, Offs)) ||

      ( afterToken && !canInsertAfterToken(loc, Offs, loc))) {

    IsCommitable = false;

    return false;

  }

  addInsert(loc, Offs, text, beforePreviousInsertions);

  return true;

}

bool Commit::insertFromRange(SourceLocation loc,

                             CharSourceRange range,

                             bool afterToken, bool beforePreviousInsertions) {

  FileOffset RangeOffs;

  unsigned RangeLen;

  if (!canRemoveRange(range, RangeOffs, RangeLen)) {

    IsCommitable = false;

    return false;

  }

  FileOffset Offs;

  if ((!afterToken && !canInsert(loc, Offs)) ||

      ( afterToken && !canInsertAfterToken(loc, Offs, loc))) {

    IsCommitable = false;

    return false;

  }

  if (PPRec &&

      PPRec->areInDifferentConditionalDirectiveRegion(loc, range.getBegin())) {

    IsCommitable = false;

    return false;

  }

  addInsertFromRange(loc, Offs, RangeOffs, RangeLen, beforePreviousInsertions);

  return true;

}

bool Commit::remove(CharSourceRange range) {

  FileOffset Offs;

  unsigned Len;

  if (!canRemoveRange(range, Offs, Len)) {

    IsCommitable = false;

    return false;

  }

  addRemove(range.getBegin(), Offs, Len);

  return true;

}

bool Commit::insertWrap(StringRef before, CharSourceRange range,

                        StringRef after) {

  bool commitableBefore = insert(range.getBegin(), before, /*afterToken=*/false,

                                 /*beforePreviousInsertions=*/true);

  bool commitableAfter;

  if (range.isTokenRange())

    commitableAfter = insertAfterToken(range.getEnd(), after);

  else

    commitableAfter = insert(range.getEnd(), after);

  return commitableBefore && commitableAfter;

}

bool Commit::replace(CharSourceRange range, StringRef text) {

  if (text.empty())

    return remove(range);

  FileOffset Offs;

  unsigned Len;

  if (!canInsert(range.getBegin(), Offs) || !canRemoveRange(range, Offs, Len)) {

    IsCommitable = false;

    return false;

  }

  addRemove(range.getBegin(), Offs, Len);

  addInsert(range.getBegin(), Offs, text, false);

  return true;

}

bool Commit::replaceWithInner(CharSourceRange range,

                              CharSourceRange replacementRange) {

  FileOffset OuterBegin;

  unsigned OuterLen;

  if (!canRemoveRange(range, OuterBegin, OuterLen)) {

    IsCommitable = false;

    return false;

  }

  FileOffset InnerBegin;

  unsigned InnerLen;

  if (!canRemoveRange(replacementRange, InnerBegin, InnerLen)) {

    IsCommitable = false;

    return false;

  }

  FileOffset OuterEnd = OuterBegin.getWithOffset(OuterLen);

  FileOffset InnerEnd = InnerBegin.getWithOffset(InnerLen);

  if (OuterBegin.getFID() != InnerBegin.getFID() ||

      InnerBegin < OuterBegin ||

      InnerBegin > OuterEnd ||

      InnerEnd > OuterEnd) {

    IsCommitable = false;

    return false;

  }

  addRemove(range.getBegin(),

            OuterBegin, InnerBegin.getOffset() - OuterBegin.getOffset());

  addRemove(replacementRange.getEnd(),

            InnerEnd, OuterEnd.getOffset() - InnerEnd.getOffset());

  return true;

}

bool Commit::replaceText(SourceLocation loc, StringRef text,

                         StringRef replacementText) {

  if (text.empty() || replacementText.empty())

    return true;

  FileOffset Offs;

  unsigned Len;

  if (!canReplaceText(loc, replacementText, Offs, Len)) {

    IsCommitable = false;

    return false;

  }

  addRemove(loc, Offs, Len);

  addInsert(loc, Offs, text, false);

  return true;

}

void Commit::addInsert(SourceLocation OrigLoc, FileOffset Offs, StringRef text,

                       bool beforePreviousInsertions) {

  if (text.empty())

    return;

  Edit data;

  data.Kind = Act_Insert;

  data.OrigLoc = OrigLoc;

  data.Offset = Offs;

  data.Text = text.copy(StrAlloc);

  data.BeforePrev = beforePreviousInsertions;

  CachedEdits.push_back(data);

}

void Commit::addInsertFromRange(SourceLocation OrigLoc, FileOffset Offs,

                                FileOffset RangeOffs, unsigned RangeLen,

                                bool beforePreviousInsertions) {

  if (RangeLen == 0)

    return;

  Edit data;

  data.Kind = Act_InsertFromRange;

  data.OrigLoc = OrigLoc;

  data.Offset = Offs;

  data.InsertFromRangeOffs = RangeOffs;

  data.Length = RangeLen;

  data.BeforePrev = beforePreviousInsertions;

  CachedEdits.push_back(data);

}

void Commit::addRemove(SourceLocation OrigLoc,

                       FileOffset Offs, unsigned Len) {

  if (Len == 0)

    return;

  Edit data;

  data.Kind = Act_Remove;

  data.OrigLoc = OrigLoc;

  data.Offset = Offs;

  data.Length = Len;

  CachedEdits.push_back(data);

}

bool Commit::canInsert(SourceLocation loc, FileOffset &offs) {

  if (loc.isInvalid())

    return false;

  if (loc.isMacroID())

    isAtStartOfMacroExpansion(loc, &loc);

  const SourceManager &SM = SourceMgr;

  loc = SM.getTopMacroCallerLoc(loc);

  if (loc.isMacroID())

    if (!isAtStartOfMacroExpansion(loc, &loc))

      return false;

  if (SM.isInSystemHeader(loc))

    return false;

  std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(loc);

  if (locInfo.first.isInvalid())

    return false;

  offs = FileOffset(locInfo.first, locInfo.second);

  return canInsertInOffset(loc, offs);

}

bool Commit::canInsertAfterToken(SourceLocation loc, FileOffset &offs,

                                 SourceLocation &AfterLoc) {

  if (loc.isInvalid())

    return false;

  SourceLocation spellLoc = SourceMgr.getSpellingLoc(loc);

  unsigned tokLen = Lexer::MeasureTokenLength(spellLoc, SourceMgr, LangOpts);

  AfterLoc = loc.getLocWithOffset(tokLen);

  if (loc.isMacroID())

    isAtEndOfMacroExpansion(loc, &loc);

  const SourceManager &SM = SourceMgr;

  loc = SM.getTopMacroCallerLoc(loc);

  if (loc.isMacroID())

    if (!isAtEndOfMacroExpansion(loc, &loc))

      return false;

  if (SM.isInSystemHeader(loc))

    return false;

  loc = Lexer::getLocForEndOfToken(loc, 0, SourceMgr, LangOpts);

  if (loc.isInvalid())

    return false;

  std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(loc);

  if (locInfo.first.isInvalid())

    return false;

  offs = FileOffset(locInfo.first, locInfo.second);

  return canInsertInOffset(loc, offs);

}

bool Commit::canInsertInOffset(SourceLocation OrigLoc, FileOffset Offs) {

  for (const auto &act : CachedEdits)

    if (act.Kind == Act_Remove) {

      if (act.Offset.getFID() == Offs.getFID() &&

          Offs > act.Offset && Offs < act.Offset.getWithOffset(act.Length))

        return false; // position has been removed.

    }

  if (!Editor)

    return true;

  return Editor->canInsertInOffset(OrigLoc, Offs);

}

bool Commit::canRemoveRange(CharSourceRange range,

                            FileOffset &Offs, unsigned &Len) {

  const SourceManager &SM = SourceMgr;

  range = Lexer::makeFileCharRange(range, SM, LangOpts);

  if (range.isInvalid())

    return false;

  if (range.getBegin().isMacroID() || range.getEnd().isMacroID())

    return false;

  if (SM.isInSystemHeader(range.getBegin()) ||

      SM.isInSystemHeader(range.getEnd()))

    return false;

  if (PPRec && PPRec->rangeIntersectsConditionalDirective(range.getAsRange()))

    return false;

  std::pair<FileID, unsigned> beginInfo = SM.getDecomposedLoc(range.getBegin());

  std::pair<FileID, unsigned> endInfo = SM.getDecomposedLoc(range.getEnd());

  if (beginInfo.first != endInfo.first ||

      beginInfo.second > endInfo.second)

    return false;

  Offs = FileOffset(beginInfo.first, beginInfo.second);

  Len = endInfo.second - beginInfo.second;

  return true;

}

bool Commit::canReplaceText(SourceLocation loc, StringRef text,

                            FileOffset &Offs, unsigned &Len) {

  assert(!text.empty());

  if (!canInsert(loc, Offs))

    return false;

  // Try to load the file buffer.

  bool invalidTemp = false;

  StringRef file = SourceMgr.getBufferData(Offs.getFID(), &invalidTemp);

  if (invalidTemp)

    return false;

  Len = text.size();

  return file.substr(Offs.getOffset()).starts_with(text);

}

bool Commit::isAtStartOfMacroExpansion(SourceLocation loc,

                                       SourceLocation *MacroBegin) const {

  return Lexer::isAtStartOfMacroExpansion(loc, SourceMgr, LangOpts, MacroBegin);

}

bool Commit::isAtEndOfMacroExpansion(SourceLocation loc,

                                     SourceLocation *MacroEnd) const {

  return Lexer::isAtEndOfMacroExpansion(loc, SourceMgr, LangOpts, MacroEnd);

}