forked from OSchip/llvm-project
352 lines
14 KiB
C++
352 lines
14 KiB
C++
//===--- BreakableToken.cpp - Format C++ code -----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief Contains implementation of BreakableToken class and classes derived
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/// from it.
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///
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "format-token-breaker"
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#include "BreakableToken.h"
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#include "clang/Format/Format.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Support/Debug.h"
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#include <algorithm>
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namespace clang {
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namespace format {
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namespace {
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BreakableToken::Split getCommentSplit(StringRef Text,
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unsigned ContentStartColumn,
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unsigned ColumnLimit,
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encoding::Encoding Encoding) {
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if (ColumnLimit <= ContentStartColumn + 1)
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return BreakableToken::Split(StringRef::npos, 0);
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unsigned MaxSplit = ColumnLimit - ContentStartColumn + 1;
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unsigned MaxSplitBytes = 0;
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for (unsigned NumChars = 0;
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NumChars < MaxSplit && MaxSplitBytes < Text.size(); ++NumChars)
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MaxSplitBytes +=
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encoding::getCodePointNumBytes(Text[MaxSplitBytes], Encoding);
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StringRef::size_type SpaceOffset = Text.rfind(' ', MaxSplitBytes);
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if (SpaceOffset == StringRef::npos ||
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// Don't break at leading whitespace.
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Text.find_last_not_of(' ', SpaceOffset) == StringRef::npos) {
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// Make sure that we don't break at leading whitespace that
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// reaches past MaxSplit.
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StringRef::size_type FirstNonWhitespace = Text.find_first_not_of(" ");
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if (FirstNonWhitespace == StringRef::npos)
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// If the comment is only whitespace, we cannot split.
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return BreakableToken::Split(StringRef::npos, 0);
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SpaceOffset =
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Text.find(' ', std::max<unsigned>(MaxSplitBytes, FirstNonWhitespace));
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}
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if (SpaceOffset != StringRef::npos && SpaceOffset != 0) {
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StringRef BeforeCut = Text.substr(0, SpaceOffset).rtrim();
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StringRef AfterCut = Text.substr(SpaceOffset).ltrim();
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return BreakableToken::Split(BeforeCut.size(),
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AfterCut.begin() - BeforeCut.end());
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}
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return BreakableToken::Split(StringRef::npos, 0);
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}
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BreakableToken::Split getStringSplit(StringRef Text,
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unsigned ContentStartColumn,
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unsigned ColumnLimit,
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encoding::Encoding Encoding) {
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// FIXME: Reduce unit test case.
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if (Text.empty())
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return BreakableToken::Split(StringRef::npos, 0);
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if (ColumnLimit <= ContentStartColumn)
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return BreakableToken::Split(StringRef::npos, 0);
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unsigned MaxSplit =
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std::min<unsigned>(ColumnLimit - ContentStartColumn,
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encoding::getCodePointCount(Text, Encoding) - 1);
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StringRef::size_type SpaceOffset = 0;
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StringRef::size_type SlashOffset = 0;
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StringRef::size_type SplitPoint = 0;
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for (unsigned Chars = 0;;) {
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unsigned Advance;
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if (Text[0] == '\\') {
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Advance = encoding::getEscapeSequenceLength(Text);
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Chars += Advance;
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} else {
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Advance = encoding::getCodePointNumBytes(Text[0], Encoding);
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Chars += 1;
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}
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if (Chars > MaxSplit)
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break;
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if (Text[0] == ' ')
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SpaceOffset = SplitPoint;
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if (Text[0] == '/')
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SlashOffset = SplitPoint;
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SplitPoint += Advance;
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Text = Text.substr(Advance);
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}
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if (SpaceOffset != 0)
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return BreakableToken::Split(SpaceOffset + 1, 0);
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if (SlashOffset != 0)
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return BreakableToken::Split(SlashOffset + 1, 0);
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if (SplitPoint != 0)
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return BreakableToken::Split(SplitPoint, 0);
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return BreakableToken::Split(StringRef::npos, 0);
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}
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} // namespace
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unsigned BreakableSingleLineToken::getLineCount() const { return 1; }
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unsigned
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BreakableSingleLineToken::getLineLengthAfterSplit(unsigned LineIndex,
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unsigned TailOffset) const {
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return StartColumn + Prefix.size() + Postfix.size() +
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encoding::getCodePointCount(Line.substr(TailOffset), Encoding);
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}
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void BreakableSingleLineToken::insertBreak(unsigned LineIndex,
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unsigned TailOffset, Split Split,
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bool InPPDirective,
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WhitespaceManager &Whitespaces) {
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Whitespaces.breakToken(Tok, Prefix.size() + TailOffset + Split.first,
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Split.second, Postfix, Prefix, InPPDirective,
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StartColumn);
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}
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BreakableSingleLineToken::BreakableSingleLineToken(const FormatToken &Tok,
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unsigned StartColumn,
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StringRef Prefix,
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StringRef Postfix,
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encoding::Encoding Encoding)
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: BreakableToken(Tok, Encoding), StartColumn(StartColumn), Prefix(Prefix),
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Postfix(Postfix) {
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assert(Tok.TokenText.startswith(Prefix) && Tok.TokenText.endswith(Postfix));
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Line = Tok.TokenText.substr(
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Prefix.size(), Tok.TokenText.size() - Prefix.size() - Postfix.size());
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}
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BreakableStringLiteral::BreakableStringLiteral(const FormatToken &Tok,
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unsigned StartColumn,
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encoding::Encoding Encoding)
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: BreakableSingleLineToken(Tok, StartColumn, "\"", "\"", Encoding) {}
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BreakableToken::Split
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BreakableStringLiteral::getSplit(unsigned LineIndex, unsigned TailOffset,
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unsigned ColumnLimit) const {
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return getStringSplit(Line.substr(TailOffset), StartColumn + 2, ColumnLimit,
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Encoding);
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}
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static StringRef getLineCommentPrefix(StringRef Comment) {
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const char *KnownPrefixes[] = { "/// ", "///", "// ", "//" };
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for (size_t i = 0, e = llvm::array_lengthof(KnownPrefixes); i != e; ++i)
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if (Comment.startswith(KnownPrefixes[i]))
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return KnownPrefixes[i];
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return "";
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}
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BreakableLineComment::BreakableLineComment(const FormatToken &Token,
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unsigned StartColumn,
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encoding::Encoding Encoding)
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: BreakableSingleLineToken(Token, StartColumn,
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getLineCommentPrefix(Token.TokenText), "",
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Encoding) {}
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BreakableToken::Split
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BreakableLineComment::getSplit(unsigned LineIndex, unsigned TailOffset,
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unsigned ColumnLimit) const {
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return getCommentSplit(Line.substr(TailOffset), StartColumn + Prefix.size(),
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ColumnLimit, Encoding);
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}
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BreakableBlockComment::BreakableBlockComment(
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const FormatStyle &Style, const FormatToken &Token, unsigned StartColumn,
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unsigned OriginalStartColumn, bool FirstInLine, encoding::Encoding Encoding)
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: BreakableToken(Token, Encoding) {
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StringRef TokenText(Token.TokenText);
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assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
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TokenText.substr(2, TokenText.size() - 4).split(Lines, "\n");
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int IndentDelta = StartColumn - OriginalStartColumn;
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bool NeedsStar = true;
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LeadingWhitespace.resize(Lines.size());
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StartOfLineColumn.resize(Lines.size());
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if (Lines.size() == 1 && !FirstInLine) {
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// Comments for which FirstInLine is false can start on arbitrary column,
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// and available horizontal space can be too small to align consecutive
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// lines with the first one.
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// FIXME: We could, probably, align them to current indentation level, but
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// now we just wrap them without stars.
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NeedsStar = false;
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}
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StartOfLineColumn[0] = StartColumn + 2;
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for (size_t i = 1; i < Lines.size(); ++i) {
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adjustWhitespace(Style, i, IndentDelta);
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if (Lines[i].empty())
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// If the last line is empty, the closing "*/" will have a star.
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NeedsStar = NeedsStar && i + 1 == Lines.size();
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else
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NeedsStar = NeedsStar && Lines[i][0] == '*';
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}
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Decoration = NeedsStar ? "* " : "";
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IndentAtLineBreak = StartOfLineColumn[0] + 1;
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for (size_t i = 1; i < Lines.size(); ++i) {
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if (Lines[i].empty()) {
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if (!NeedsStar && i + 1 != Lines.size())
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// For all but the last line (which always ends in */), set the
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// start column to 0 if they're empty, so we do not insert
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// trailing whitespace anywhere.
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StartOfLineColumn[i] = 0;
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continue;
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}
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if (NeedsStar) {
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// The first line already excludes the star.
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// For all other lines, adjust the line to exclude the star and
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// (optionally) the first whitespace.
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int Offset = Lines[i].startswith("* ") ? 2 : 1;
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StartOfLineColumn[i] += Offset;
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Lines[i] = Lines[i].substr(Offset);
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LeadingWhitespace[i] += Offset;
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}
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IndentAtLineBreak = std::min<int>(IndentAtLineBreak, StartOfLineColumn[i]);
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}
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IndentAtLineBreak = std::max<unsigned>(IndentAtLineBreak, Decoration.size());
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DEBUG({
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for (size_t i = 0; i < Lines.size(); ++i) {
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llvm::dbgs() << i << " |" << Lines[i] << "| " << LeadingWhitespace[i]
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<< "\n";
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}
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});
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}
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void BreakableBlockComment::adjustWhitespace(const FormatStyle &Style,
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unsigned LineIndex,
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int IndentDelta) {
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// Calculate the end of the non-whitespace text in the previous line.
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size_t EndOfPreviousLine = Lines[LineIndex - 1].find_last_not_of(" \\\t");
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if (EndOfPreviousLine == StringRef::npos)
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EndOfPreviousLine = 0;
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else
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++EndOfPreviousLine;
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// Calculate the start of the non-whitespace text in the current line.
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size_t StartOfLine = Lines[LineIndex].find_first_not_of(" \t");
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if (StartOfLine == StringRef::npos)
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StartOfLine = Lines[LineIndex].size();
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// Adjust Lines to only contain relevant text.
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Lines[LineIndex - 1] = Lines[LineIndex - 1].substr(0, EndOfPreviousLine);
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Lines[LineIndex] = Lines[LineIndex].substr(StartOfLine);
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// Adjust LeadingWhitespace to account all whitespace between the lines
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// to the current line.
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LeadingWhitespace[LineIndex] =
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Lines[LineIndex].begin() - Lines[LineIndex - 1].end();
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// FIXME: We currently count tabs as 1 character. To solve this, we need to
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// get the correct indentation width of the start of the comment, which
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// requires correct counting of the tab expansions before the comment, and
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// a configurable tab width. Since the current implementation only breaks
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// if leading tabs are intermixed with spaces, that is not a high priority.
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// Adjust the start column uniformly accross all lines.
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StartOfLineColumn[LineIndex] = std::max<int>(0, StartOfLine + IndentDelta);
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}
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unsigned BreakableBlockComment::getLineCount() const { return Lines.size(); }
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unsigned
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BreakableBlockComment::getLineLengthAfterSplit(unsigned LineIndex,
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unsigned TailOffset) const {
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return getContentStartColumn(LineIndex, TailOffset) +
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encoding::getCodePointCount(Lines[LineIndex].substr(TailOffset),
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Encoding) +
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// The last line gets a "*/" postfix.
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(LineIndex + 1 == Lines.size() ? 2 : 0);
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}
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BreakableToken::Split
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BreakableBlockComment::getSplit(unsigned LineIndex, unsigned TailOffset,
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unsigned ColumnLimit) const {
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return getCommentSplit(Lines[LineIndex].substr(TailOffset),
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getContentStartColumn(LineIndex, TailOffset),
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ColumnLimit, Encoding);
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}
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void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
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Split Split, bool InPPDirective,
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WhitespaceManager &Whitespaces) {
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StringRef Text = Lines[LineIndex].substr(TailOffset);
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StringRef Prefix = Decoration;
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if (LineIndex + 1 == Lines.size() &&
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Text.size() == Split.first + Split.second) {
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// For the last line we need to break before "*/", but not to add "* ".
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Prefix = "";
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}
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unsigned BreakOffsetInToken =
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Text.data() - Tok.TokenText.data() + Split.first;
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unsigned CharsToRemove = Split.second;
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assert(IndentAtLineBreak >= Decoration.size());
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Whitespaces.breakToken(Tok, BreakOffsetInToken, CharsToRemove, "", Prefix,
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InPPDirective, IndentAtLineBreak - Decoration.size());
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}
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void
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BreakableBlockComment::replaceWhitespaceBefore(unsigned LineIndex,
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unsigned InPPDirective,
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WhitespaceManager &Whitespaces) {
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if (LineIndex == 0)
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return;
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StringRef Prefix = Decoration;
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if (Lines[LineIndex].empty()) {
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if (LineIndex + 1 == Lines.size()) {
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// If the last line is empty, we don't need a prefix, as the */ will line
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// up with the decoration (if it exists).
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Prefix = "";
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} else if (!Decoration.empty()) {
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// For other empty lines, if we do have a decoration, adapt it to not
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// contain a trailing whitespace.
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Prefix = Prefix.substr(0, 1);
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}
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} else {
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if (StartOfLineColumn[LineIndex] == 1) {
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// This lines starts immediately after the decorating *.
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Prefix = Prefix.substr(0, 1);
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}
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}
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unsigned WhitespaceOffsetInToken =
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Lines[LineIndex].data() - Tok.TokenText.data() -
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LeadingWhitespace[LineIndex];
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assert(StartOfLineColumn[LineIndex] >= Prefix.size());
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Whitespaces.breakToken(
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Tok, WhitespaceOffsetInToken, LeadingWhitespace[LineIndex], "", Prefix,
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InPPDirective, StartOfLineColumn[LineIndex] - Prefix.size());
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}
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unsigned
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BreakableBlockComment::getContentStartColumn(unsigned LineIndex,
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unsigned TailOffset) const {
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// If we break, we always break at the predefined indent.
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if (TailOffset != 0)
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return IndentAtLineBreak;
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return StartOfLineColumn[LineIndex];
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}
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} // namespace format
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} // namespace clang
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