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llvm-project/clang/lib/Format/BreakableToken.cpp

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//===--- 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.
///
//===----------------------------------------------------------------------===//
#include "BreakableToken.h"
#include "ContinuationIndenter.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Format/Format.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
#define DEBUG_TYPE "format-token-breaker"
namespace clang {
namespace format {
static const char *const Blanks = " \t\v\f\r";
static bool IsBlank(char C) {
switch (C) {
case ' ':
case '\t':
case '\v':
case '\f':
case '\r':
return true;
default:
return false;
}
}
static StringRef getLineCommentIndentPrefix(StringRef Comment) {
static const char *const KnownPrefixes[] = {"///", "//", "//!"};
StringRef LongestPrefix;
for (StringRef KnownPrefix : KnownPrefixes) {
if (Comment.startswith(KnownPrefix)) {
size_t PrefixLength = KnownPrefix.size();
while (PrefixLength < Comment.size() && Comment[PrefixLength] == ' ')
++PrefixLength;
if (PrefixLength > LongestPrefix.size())
LongestPrefix = Comment.substr(0, PrefixLength);
}
}
return LongestPrefix;
}
static BreakableToken::Split getCommentSplit(StringRef Text,
unsigned ContentStartColumn,
unsigned ColumnLimit,
unsigned TabWidth,
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();) {
unsigned BytesInChar =
encoding::getCodePointNumBytes(Text[MaxSplitBytes], Encoding);
NumChars +=
encoding::columnWidthWithTabs(Text.substr(MaxSplitBytes, BytesInChar),
ContentStartColumn, TabWidth, Encoding);
MaxSplitBytes += BytesInChar;
}
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 UsedColumns, unsigned ColumnLimit,
unsigned TabWidth, encoding::Encoding Encoding) {
// FIXME: Reduce unit test case.
if (Text.empty())
return BreakableToken::Split(StringRef::npos, 0);
if (ColumnLimit <= UsedColumns)
return BreakableToken::Split(StringRef::npos, 0);
unsigned MaxSplit = ColumnLimit - UsedColumns;
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 += encoding::columnWidthWithTabs(
Text.substr(0, Advance), UsedColumns + Chars, TabWidth, Encoding);
}
if (Chars > MaxSplit || Text.size() <= Advance)
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);
}
bool switchesFormatting(const FormatToken &Token) {
assert((Token.is(TT_BlockComment) || Token.is(TT_LineComment)) &&
"formatting regions are switched by comment tokens");
StringRef Content = Token.TokenText.substr(2).ltrim();
return Content.startswith("clang-format on") ||
Content.startswith("clang-format off");
}
unsigned
BreakableToken::getLineLengthAfterCompression(unsigned RemainingTokenColumns,
Split Split) const {
// Example: consider the content
// lala lala
// - RemainingTokenColumns is the original number of columns, 10;
// - Split is (4, 2), denoting the two spaces between the two words;
//
// We compute the number of columns when the split is compressed into a single
// space, like:
// lala lala
return RemainingTokenColumns + 1 - Split.second;
}
unsigned BreakableSingleLineToken::getLineCount() const { return 1; }
unsigned BreakableSingleLineToken::getLineLengthAfterSplit(
unsigned LineIndex, unsigned TailOffset,
StringRef::size_type Length) const {
return StartColumn + Prefix.size() + Postfix.size() +
encoding::columnWidthWithTabs(Line.substr(TailOffset, Length),
StartColumn + Prefix.size(),
Style.TabWidth, Encoding);
}
BreakableSingleLineToken::BreakableSingleLineToken(
const FormatToken &Tok, unsigned StartColumn, StringRef Prefix,
StringRef Postfix, bool InPPDirective, encoding::Encoding Encoding,
const FormatStyle &Style)
: BreakableToken(Tok, InPPDirective, Encoding, Style),
StartColumn(StartColumn), Prefix(Prefix), Postfix(Postfix) {
assert(Tok.TokenText.endswith(Postfix));
Line = Tok.TokenText.substr(
Prefix.size(), Tok.TokenText.size() - Prefix.size() - Postfix.size());
}
BreakableStringLiteral::BreakableStringLiteral(
const FormatToken &Tok, unsigned StartColumn, StringRef Prefix,
StringRef Postfix, bool InPPDirective, encoding::Encoding Encoding,
const FormatStyle &Style)
: BreakableSingleLineToken(Tok, StartColumn, Prefix, Postfix, InPPDirective,
Encoding, Style) {}
BreakableToken::Split
BreakableStringLiteral::getSplit(unsigned LineIndex, unsigned TailOffset,
unsigned ColumnLimit) const {
return getStringSplit(Line.substr(TailOffset),
StartColumn + Prefix.size() + Postfix.size(),
ColumnLimit, Style.TabWidth, Encoding);
}
void BreakableStringLiteral::insertBreak(unsigned LineIndex,
unsigned TailOffset, Split Split,
WhitespaceManager &Whitespaces) {
unsigned LeadingSpaces = StartColumn;
// The '@' of an ObjC string literal (@"Test") does not become part of the
// string token.
// FIXME: It might be a cleaner solution to merge the tokens as a
// precomputation step.
if (Prefix.startswith("@"))
--LeadingSpaces;
Whitespaces.replaceWhitespaceInToken(
Tok, Prefix.size() + TailOffset + Split.first, Split.second, Postfix,
Prefix, InPPDirective, 1, LeadingSpaces);
}
BreakableComment::BreakableComment(const FormatToken &Token,
unsigned StartColumn,
unsigned OriginalStartColumn,
bool FirstInLine, bool InPPDirective,
encoding::Encoding Encoding,
const FormatStyle &Style)
: BreakableToken(Token, InPPDirective, Encoding, Style),
StartColumn(StartColumn), OriginalStartColumn(OriginalStartColumn),
FirstInLine(FirstInLine) {}
unsigned BreakableComment::getLineCount() const { return Lines.size(); }
BreakableToken::Split BreakableComment::getSplit(unsigned LineIndex,
unsigned TailOffset,
unsigned ColumnLimit) const {
return getCommentSplit(Content[LineIndex].substr(TailOffset),
getContentStartColumn(LineIndex, TailOffset),
ColumnLimit, Style.TabWidth, Encoding);
}
void BreakableComment::compressWhitespace(unsigned LineIndex,
unsigned TailOffset, Split Split,
WhitespaceManager &Whitespaces) {
StringRef Text = Content[LineIndex].substr(TailOffset);
// Text is relative to the content line, but Whitespaces operates relative to
// the start of the corresponding token, so compute the start of the Split
// that needs to be compressed into a single space relative to the start of
// its token.
unsigned BreakOffsetInToken =
Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
unsigned CharsToRemove = Split.second;
Whitespaces.replaceWhitespaceInToken(
tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "", "",
/*InPPDirective=*/false, /*Newlines=*/0, /*Spaces=*/1);
}
BreakableToken::Split
BreakableComment::getReflowSplit(StringRef Text, StringRef ReflowPrefix,
unsigned PreviousEndColumn,
unsigned ColumnLimit) const {
unsigned ReflowStartColumn = PreviousEndColumn + ReflowPrefix.size();
StringRef TrimmedText = Text.rtrim(Blanks);
// This is the width of the resulting line in case the full line of Text gets
// reflown up starting at ReflowStartColumn.
unsigned FullWidth = ReflowStartColumn + encoding::columnWidthWithTabs(
TrimmedText, ReflowStartColumn,
Style.TabWidth, Encoding);
// If the full line fits up, we return a reflow split after it,
// otherwise we compute the largest piece of text that fits after
// ReflowStartColumn.
Split ReflowSplit =
FullWidth <= ColumnLimit
? Split(TrimmedText.size(), Text.size() - TrimmedText.size())
: getCommentSplit(Text, ReflowStartColumn, ColumnLimit,
Style.TabWidth, Encoding);
// We need to be extra careful here, because while it's OK to keep a long line
// if it can't be broken into smaller pieces (like when the first word of a
// long line is longer than the column limit), it's not OK to reflow that long
// word up. So we recompute the size of the previous line after reflowing and
// only return the reflow split if that's under the line limit.
if (ReflowSplit.first != StringRef::npos &&
// Check if the width of the newly reflown line is under the limit.
PreviousEndColumn + ReflowPrefix.size() +
encoding::columnWidthWithTabs(Text.substr(0, ReflowSplit.first),
PreviousEndColumn +
ReflowPrefix.size(),
Style.TabWidth, Encoding) <=
ColumnLimit) {
return ReflowSplit;
}
return Split(StringRef::npos, 0);
}
const FormatToken &BreakableComment::tokenAt(unsigned LineIndex) const {
return Tokens[LineIndex] ? *Tokens[LineIndex] : Tok;
}
static bool mayReflowContent(StringRef Content) {
Content = Content.trim(Blanks);
// Lines starting with '@' commonly have special meaning.
static const SmallVector<StringRef, 4> kSpecialMeaningPrefixes = {
"@", "TODO", "FIXME", "XXX"};
bool hasSpecialMeaningPrefix = false;
for (StringRef Prefix : kSpecialMeaningPrefixes) {
if (Content.startswith(Prefix)) {
hasSpecialMeaningPrefix = true;
break;
}
}
// Simple heuristic for what to reflow: content should contain at least two
// characters and either the first or second character must be
// non-punctuation.
return Content.size() >= 2 && !hasSpecialMeaningPrefix &&
!Content.endswith("\\") &&
// Note that this is UTF-8 safe, since if isPunctuation(Content[0]) is
// true, then the first code point must be 1 byte long.
(!isPunctuation(Content[0]) || !isPunctuation(Content[1]));
}
BreakableBlockComment::BreakableBlockComment(
const FormatToken &Token, unsigned StartColumn,
unsigned OriginalStartColumn, bool FirstInLine, bool InPPDirective,
encoding::Encoding Encoding, const FormatStyle &Style)
: BreakableComment(Token, StartColumn, OriginalStartColumn, FirstInLine,
InPPDirective, Encoding, Style) {
assert(Tok.is(TT_BlockComment) &&
"block comment section must start with a block comment");
StringRef TokenText(Tok.TokenText);
assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
TokenText.substr(2, TokenText.size() - 4).split(Lines, "\n");
int IndentDelta = StartColumn - OriginalStartColumn;
Content.resize(Lines.size());
Content[0] = Lines[0];
ContentColumn.resize(Lines.size());
// Account for the initial '/*'.
ContentColumn[0] = StartColumn + 2;
Tokens.resize(Lines.size());
for (size_t i = 1; i < Lines.size(); ++i)
adjustWhitespace(i, IndentDelta);
// Align decorations with the column of the star on the first line,
// that is one column after the start "/*".
DecorationColumn = StartColumn + 1;
// Account for comment decoration patterns like this:
//
// /*
// ** blah blah blah
// */
if (Lines.size() >= 2 && Content[1].startswith("**") &&
static_cast<unsigned>(ContentColumn[1]) == StartColumn) {
DecorationColumn = StartColumn;
}
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 && Content[i].empty())
break;
if (!Content[i].empty() && i + 1 != e &&
Decoration.startswith(Content[i]))
continue;
while (!Content[i].startswith(Decoration))
Decoration = Decoration.substr(0, Decoration.size() - 1);
}
LastLineNeedsDecoration = true;
IndentAtLineBreak = ContentColumn[0] + 1;
for (size_t i = 1, e = Lines.size(); i < e; ++i) {
if (Content[i].empty()) {
if (i + 1 == e) {
// 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;
// Align the star in the last '*/' with the stars on the previous lines.
if (e >= 2 && !Decoration.empty()) {
ContentColumn[i] = DecorationColumn;
}
} 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.
ContentColumn[i] = 0;
}
continue;
}
// The first line already excludes the star.
// The last line excludes the star if LastLineNeedsDecoration is false.
// For all other lines, adjust the line to exclude the star and
// (optionally) the first whitespace.
unsigned DecorationSize = Decoration.startswith(Content[i])
? Content[i].size()
: Decoration.size();
if (DecorationSize) {
ContentColumn[i] = DecorationColumn + DecorationSize;
}
Content[i] = Content[i].substr(DecorationSize);
if (!Decoration.startswith(Content[i]))
IndentAtLineBreak =
std::min<int>(IndentAtLineBreak, std::max(0, ContentColumn[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 << " |" << Content[i] << "| "
<< "CC=" << ContentColumn[i] << "| "
<< "IN=" << (Content[i].data() - Lines[i].data()) << "\n";
}
});
}
void BreakableBlockComment::adjustWhitespace(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].rtrim("\r\n").size();
StringRef Whitespace = Lines[LineIndex].substr(0, StartOfLine);
// Adjust Lines to only contain relevant text.
size_t PreviousContentOffset =
Content[LineIndex - 1].data() - Lines[LineIndex - 1].data();
Content[LineIndex - 1] = Lines[LineIndex - 1].substr(
PreviousContentOffset, EndOfPreviousLine - PreviousContentOffset);
Content[LineIndex] = Lines[LineIndex].substr(StartOfLine);
// Adjust the start column uniformly across all lines.
ContentColumn[LineIndex] =
encoding::columnWidthWithTabs(Whitespace, 0, Style.TabWidth, Encoding) +
IndentDelta;
}
unsigned BreakableBlockComment::getLineLengthAfterSplit(
unsigned LineIndex, unsigned TailOffset,
StringRef::size_type Length) const {
unsigned ContentStartColumn = getContentStartColumn(LineIndex, TailOffset);
unsigned LineLength =
ContentStartColumn + encoding::columnWidthWithTabs(
Content[LineIndex].substr(TailOffset, Length),
ContentStartColumn, Style.TabWidth, Encoding);
// The last line gets a "*/" postfix.
if (LineIndex + 1 == Lines.size()) {
LineLength += 2;
// We never need a decoration when breaking just the trailing "*/" postfix.
// Note that checking that Length == 0 is not enough, since Length could
// also be StringRef::npos.
if (Content[LineIndex].substr(TailOffset, Length).empty()) {
LineLength -= Decoration.size();
}
}
return LineLength;
}
void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
Split Split,
WhitespaceManager &Whitespaces) {
StringRef Text = Content[LineIndex].substr(TailOffset);
StringRef Prefix = Decoration;
// We need this to account for the case when we have a decoration "* " for all
// the lines except for the last one, where the star in "*/" acts as a
// decoration.
unsigned LocalIndentAtLineBreak = IndentAtLineBreak;
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 = "";
if (LocalIndentAtLineBreak >= 2)
LocalIndentAtLineBreak -= 2;
}
// The split offset is from the beginning of the line. Convert it to an offset
// from the beginning of the token text.
unsigned BreakOffsetInToken =
Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
unsigned CharsToRemove = Split.second;
assert(LocalIndentAtLineBreak >= Prefix.size());
Whitespaces.replaceWhitespaceInToken(
tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "", Prefix,
InPPDirective, /*Newlines=*/1,
/*Spaces=*/LocalIndentAtLineBreak - Prefix.size());
}
BreakableToken::Split BreakableBlockComment::getSplitBefore(
unsigned LineIndex,
unsigned PreviousEndColumn,
unsigned ColumnLimit,
llvm::Regex &CommentPragmasRegex) const {
if (!mayReflow(LineIndex, CommentPragmasRegex))
return Split(StringRef::npos, 0);
StringRef TrimmedContent = Content[LineIndex].ltrim(Blanks);
return getReflowSplit(TrimmedContent, ReflowPrefix, PreviousEndColumn,
ColumnLimit);
}
unsigned BreakableBlockComment::getReflownColumn(
StringRef Content,
unsigned LineIndex,
unsigned PreviousEndColumn) const {
unsigned StartColumn = PreviousEndColumn + ReflowPrefix.size();
// If this is the last line, it will carry around its '*/' postfix.
unsigned PostfixLength = (LineIndex + 1 == Lines.size() ? 2 : 0);
// The line is composed of previous text, reflow prefix, reflown text and
// postfix.
unsigned ReflownColumn =
StartColumn + encoding::columnWidthWithTabs(Content, StartColumn,
Style.TabWidth, Encoding) +
PostfixLength;
return ReflownColumn;
}
unsigned BreakableBlockComment::getLineLengthAfterSplitBefore(
unsigned LineIndex, unsigned TailOffset,
unsigned PreviousEndColumn,
unsigned ColumnLimit,
Split SplitBefore) const {
if (SplitBefore.first == StringRef::npos ||
// Block comment line contents contain the trailing whitespace after the
// decoration, so the need of left trim. Note that this behavior is
// consistent with the breaking of block comments where the indentation of
// a broken line is uniform across all the lines of the block comment.
SplitBefore.first + SplitBefore.second <
Content[LineIndex].ltrim().size()) {
// A piece of line, not the whole, gets reflown.
return getLineLengthAfterSplit(LineIndex, TailOffset, StringRef::npos);
} else {
// The whole line gets reflown, need to check if we need to insert a break
// for the postfix or not.
StringRef TrimmedContent = Content[LineIndex].ltrim(Blanks);
unsigned ReflownColumn =
getReflownColumn(TrimmedContent, LineIndex, PreviousEndColumn);
if (ReflownColumn <= ColumnLimit) {
return ReflownColumn;
}
return getLineLengthAfterSplit(LineIndex, TailOffset, StringRef::npos);
}
}
void BreakableBlockComment::replaceWhitespaceBefore(
unsigned LineIndex, unsigned PreviousEndColumn, unsigned ColumnLimit,
Split SplitBefore, WhitespaceManager &Whitespaces) {
if (LineIndex == 0) return;
StringRef TrimmedContent = Content[LineIndex].ltrim(Blanks);
if (SplitBefore.first != StringRef::npos) {
// Here we need to reflow.
assert(Tokens[LineIndex - 1] == Tokens[LineIndex] &&
"Reflowing whitespace within a token");
// This is the offset of the end of the last line relative to the start of
// the token text in the token.
unsigned WhitespaceOffsetInToken = Content[LineIndex - 1].data() +
Content[LineIndex - 1].size() -
tokenAt(LineIndex).TokenText.data();
unsigned WhitespaceLength = TrimmedContent.data() -
tokenAt(LineIndex).TokenText.data() -
WhitespaceOffsetInToken;
Whitespaces.replaceWhitespaceInToken(
tokenAt(LineIndex), WhitespaceOffsetInToken,
/*ReplaceChars=*/WhitespaceLength, /*PreviousPostfix=*/"",
/*CurrentPrefix=*/ReflowPrefix, InPPDirective, /*Newlines=*/0,
/*Spaces=*/0);
// Check if we need to also insert a break at the whitespace range.
// For this we first adapt the reflow split relative to the beginning of the
// content.
// Note that we don't need a penalty for this break, since it doesn't change
// the total number of lines.
Split BreakSplit = SplitBefore;
BreakSplit.first += TrimmedContent.data() - Content[LineIndex].data();
unsigned ReflownColumn =
getReflownColumn(TrimmedContent, LineIndex, PreviousEndColumn);
if (ReflownColumn > ColumnLimit) {
insertBreak(LineIndex, 0, BreakSplit, Whitespaces);
}
return;
}
// Here no reflow with the previous line will happen.
// Fix the decoration of the line at LineIndex.
StringRef Prefix = Decoration;
if (Content[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 (ContentColumn[LineIndex] == 1) {
// This line starts immediately after the decorating *.
Prefix = Prefix.substr(0, 1);
}
}
// This is the offset of the end of the last line relative to the start of the
// token text in the token.
unsigned WhitespaceOffsetInToken = Content[LineIndex - 1].data() +
Content[LineIndex - 1].size() -
tokenAt(LineIndex).TokenText.data();
unsigned WhitespaceLength = Content[LineIndex].data() -
tokenAt(LineIndex).TokenText.data() -
WhitespaceOffsetInToken;
Whitespaces.replaceWhitespaceInToken(
tokenAt(LineIndex), WhitespaceOffsetInToken, WhitespaceLength, "", Prefix,
InPPDirective, /*Newlines=*/1, ContentColumn[LineIndex] - Prefix.size());
}
bool BreakableBlockComment::mayReflow(unsigned LineIndex,
llvm::Regex &CommentPragmasRegex) const {
// Content[LineIndex] may exclude the indent after the '*' decoration. In that
// case, we compute the start of the comment pragma manually.
StringRef IndentContent = Content[LineIndex];
if (Lines[LineIndex].ltrim(Blanks).startswith("*")) {
IndentContent = Lines[LineIndex].ltrim(Blanks).substr(1);
}
return LineIndex > 0 && !CommentPragmasRegex.match(IndentContent) &&
mayReflowContent(Content[LineIndex]) && !Tok.Finalized &&
!switchesFormatting(tokenAt(LineIndex));
}
unsigned
BreakableBlockComment::getContentStartColumn(unsigned LineIndex,
unsigned TailOffset) const {
// If we break, we always break at the predefined indent.
if (TailOffset != 0)
return IndentAtLineBreak;
return std::max(0, ContentColumn[LineIndex]);
}
BreakableLineCommentSection::BreakableLineCommentSection(
const FormatToken &Token, unsigned StartColumn,
unsigned OriginalStartColumn, bool FirstInLine, bool InPPDirective,
encoding::Encoding Encoding, const FormatStyle &Style)
: BreakableComment(Token, StartColumn, OriginalStartColumn, FirstInLine,
InPPDirective, Encoding, Style) {
assert(Tok.is(TT_LineComment) &&
"line comment section must start with a line comment");
FormatToken *LineTok = nullptr;
for (const FormatToken *CurrentTok = &Tok;
CurrentTok && CurrentTok->is(TT_LineComment);
CurrentTok = CurrentTok->Next) {
LastLineTok = LineTok;
StringRef TokenText(CurrentTok->TokenText);
assert(TokenText.startswith("//"));
size_t FirstLineIndex = Lines.size();
TokenText.split(Lines, "\n");
Content.resize(Lines.size());
ContentColumn.resize(Lines.size());
OriginalContentColumn.resize(Lines.size());
Tokens.resize(Lines.size());
Prefix.resize(Lines.size());
OriginalPrefix.resize(Lines.size());
for (size_t i = FirstLineIndex, e = Lines.size(); i < e; ++i) {
// We need to trim the blanks in case this is not the first line in a
// multiline comment. Then the indent is included in Lines[i].
StringRef IndentPrefix =
getLineCommentIndentPrefix(Lines[i].ltrim(Blanks));
assert(IndentPrefix.startswith("//"));
OriginalPrefix[i] = Prefix[i] = IndentPrefix;
if (Lines[i].size() > Prefix[i].size() &&
isAlphanumeric(Lines[i][Prefix[i].size()])) {
if (Prefix[i] == "//")
Prefix[i] = "// ";
else if (Prefix[i] == "///")
Prefix[i] = "/// ";
else if (Prefix[i] == "//!")
Prefix[i] = "//! ";
}
Tokens[i] = LineTok;
Content[i] = Lines[i].substr(IndentPrefix.size());
OriginalContentColumn[i] =
StartColumn +
encoding::columnWidthWithTabs(OriginalPrefix[i],
StartColumn,
Style.TabWidth,
Encoding);
ContentColumn[i] =
StartColumn +
encoding::columnWidthWithTabs(Prefix[i],
StartColumn,
Style.TabWidth,
Encoding);
// Calculate the end of the non-whitespace text in this line.
size_t EndOfLine = Content[i].find_last_not_of(Blanks);
if (EndOfLine == StringRef::npos)
EndOfLine = Content[i].size();
else
++EndOfLine;
Content[i] = Content[i].substr(0, EndOfLine);
}
LineTok = CurrentTok->Next;
if (CurrentTok->Next && !CurrentTok->Next->ContinuesLineCommentSection) {
// A line comment section needs to broken by a line comment that is
// preceded by at least two newlines. Note that we put this break here
// instead of breaking at a previous stage during parsing, since that
// would split the contents of the enum into two unwrapped lines in this
// example, which is undesirable:
// enum A {
// a, // comment about a
//
// // comment about b
// b
// };
//
// FIXME: Consider putting separate line comment sections as children to
// the unwrapped line instead.
break;
}
}
}
unsigned BreakableLineCommentSection::getLineLengthAfterSplit(
unsigned LineIndex, unsigned TailOffset,
StringRef::size_type Length) const {
unsigned ContentStartColumn =
(TailOffset == 0 ? ContentColumn[LineIndex]
: OriginalContentColumn[LineIndex]);
return ContentStartColumn + encoding::columnWidthWithTabs(
Content[LineIndex].substr(TailOffset, Length),
ContentStartColumn, Style.TabWidth, Encoding);
}
void BreakableLineCommentSection::insertBreak(unsigned LineIndex,
unsigned TailOffset, Split Split,
WhitespaceManager &Whitespaces) {
StringRef Text = Content[LineIndex].substr(TailOffset);
// Compute the offset of the split relative to the beginning of the token
// text.
unsigned BreakOffsetInToken =
Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
unsigned CharsToRemove = Split.second;
// Compute the size of the new indent, including the size of the new prefix of
// the newly broken line.
unsigned IndentAtLineBreak = OriginalContentColumn[LineIndex] +
Prefix[LineIndex].size() -
OriginalPrefix[LineIndex].size();
assert(IndentAtLineBreak >= Prefix[LineIndex].size());
Whitespaces.replaceWhitespaceInToken(
tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "",
Prefix[LineIndex], InPPDirective, /*Newlines=*/1,
/*Spaces=*/IndentAtLineBreak - Prefix[LineIndex].size());
}
BreakableComment::Split BreakableLineCommentSection::getSplitBefore(
unsigned LineIndex, unsigned PreviousEndColumn, unsigned ColumnLimit,
llvm::Regex &CommentPragmasRegex) const {
if (!mayReflow(LineIndex, CommentPragmasRegex))
return Split(StringRef::npos, 0);
return getReflowSplit(Content[LineIndex], ReflowPrefix, PreviousEndColumn,
ColumnLimit);
}
unsigned BreakableLineCommentSection::getLineLengthAfterSplitBefore(
unsigned LineIndex, unsigned TailOffset,
unsigned PreviousEndColumn,
unsigned ColumnLimit,
Split SplitBefore) const {
if (SplitBefore.first == StringRef::npos ||
SplitBefore.first + SplitBefore.second < Content[LineIndex].size()) {
// A piece of line, not the whole line, gets reflown.
return getLineLengthAfterSplit(LineIndex, TailOffset, StringRef::npos);
} else {
// The whole line gets reflown.
unsigned StartColumn = PreviousEndColumn + ReflowPrefix.size();
return StartColumn + encoding::columnWidthWithTabs(Content[LineIndex],
StartColumn,
Style.TabWidth,
Encoding);
}
}
void BreakableLineCommentSection::replaceWhitespaceBefore(
unsigned LineIndex, unsigned PreviousEndColumn, unsigned ColumnLimit,
Split SplitBefore, WhitespaceManager &Whitespaces) {
// If this is the first line of a token, we need to inform Whitespace Manager
// about it: either adapt the whitespace range preceding it, or mark it as an
// untouchable token.
// This happens for instance here:
// // line 1 \
// // line 2
if (LineIndex > 0 && Tokens[LineIndex] != Tokens[LineIndex - 1]) {
if (SplitBefore.first != StringRef::npos) {
// Reflow happens between tokens. Replace the whitespace between the
// tokens by the empty string.
Whitespaces.replaceWhitespace(
*Tokens[LineIndex], /*Newlines=*/0, /*Spaces=*/0,
/*StartOfTokenColumn=*/StartColumn, /*InPPDirective=*/false);
// Replace the indent and prefix of the token with the reflow prefix.
unsigned WhitespaceLength =
Content[LineIndex].data() - tokenAt(LineIndex).TokenText.data();
Whitespaces.replaceWhitespaceInToken(*Tokens[LineIndex],
/*Offset=*/0,
/*ReplaceChars=*/WhitespaceLength,
/*PreviousPostfix=*/"",
/*CurrentPrefix=*/ReflowPrefix,
/*InPPDirective=*/false,
/*Newlines=*/0,
/*Spaces=*/0);
} else {
// This is the first line for the current token, but no reflow with the
// previous token is necessary. However, we still may need to adjust the
// start column. Note that ContentColumn[LineIndex] is the expected
// content column after a possible update to the prefix, hence the prefix
// length change is included.
unsigned LineColumn =
ContentColumn[LineIndex] -
(Content[LineIndex].data() - Lines[LineIndex].data()) +
(OriginalPrefix[LineIndex].size() - Prefix[LineIndex].size());
// We always want to create a replacement instead of adding an untouchable
// token, even if LineColumn is the same as the original column of the
// token. This is because WhitespaceManager doesn't align trailing
// comments if they are untouchable.
Whitespaces.replaceWhitespace(*Tokens[LineIndex],
/*Newlines=*/1,
/*Spaces=*/LineColumn,
/*StartOfTokenColumn=*/LineColumn,
/*InPPDirective=*/false);
}
}
if (OriginalPrefix[LineIndex] != Prefix[LineIndex]) {
// Adjust the prefix if necessary.
// Take care of the space possibly introduced after a decoration.
assert(Prefix[LineIndex] == (OriginalPrefix[LineIndex] + " ").str() &&
"Expecting a line comment prefix to differ from original by at most "
"a space");
Whitespaces.replaceWhitespaceInToken(
tokenAt(LineIndex), OriginalPrefix[LineIndex].size(), 0, "", "",
/*InPPDirective=*/false, /*Newlines=*/0, /*Spaces=*/1);
}
// Add a break after a reflow split has been introduced, if necessary.
// Note that this break doesn't need to be penalized, since it doesn't change
// the number of lines.
if (SplitBefore.first != StringRef::npos &&
SplitBefore.first + SplitBefore.second < Content[LineIndex].size()) {
insertBreak(LineIndex, 0, SplitBefore, Whitespaces);
}
}
void BreakableLineCommentSection::updateNextToken(LineState& State) const {
if (LastLineTok) {
State.NextToken = LastLineTok->Next;
}
}
bool BreakableLineCommentSection::mayReflow(
unsigned LineIndex, llvm::Regex &CommentPragmasRegex) const {
// Line comments have the indent as part of the prefix, so we need to
// recompute the start of the line.
StringRef IndentContent = Content[LineIndex];
if (Lines[LineIndex].startswith("//")) {
IndentContent = Lines[LineIndex].substr(2);
}
return LineIndex > 0 && !CommentPragmasRegex.match(IndentContent) &&
mayReflowContent(Content[LineIndex]) && !Tok.Finalized &&
!switchesFormatting(tokenAt(LineIndex)) &&
OriginalPrefix[LineIndex] == OriginalPrefix[LineIndex - 1];
}
unsigned
BreakableLineCommentSection::getContentStartColumn(unsigned LineIndex,
unsigned TailOffset) const {
if (TailOffset != 0) {
return OriginalContentColumn[LineIndex];
}
return ContentColumn[LineIndex];
}
} // namespace format
} // namespace clang
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