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