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492 lines
22 KiB
492 lines
22 KiB
//===--- BreakableToken.h - Format C++ code ---------------------*- 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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///
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/// \file
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/// Declares BreakableToken, BreakableStringLiteral, BreakableComment,
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/// BreakableBlockComment and BreakableLineCommentSection classes, that contain
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/// token type-specific logic to break long lines in tokens and reflow content
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/// between tokens.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LIB_FORMAT_BREAKABLETOKEN_H
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#define LLVM_CLANG_LIB_FORMAT_BREAKABLETOKEN_H
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#include "Encoding.h"
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#include "TokenAnnotator.h"
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#include "WhitespaceManager.h"
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#include "llvm/ADT/StringSet.h"
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#include "llvm/Support/Regex.h"
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#include <utility>
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namespace clang {
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namespace format {
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/// Checks if \p Token switches formatting, like /* clang-format off */.
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/// \p Token must be a comment.
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bool switchesFormatting(const FormatToken &Token);
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struct FormatStyle;
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/// Base class for tokens / ranges of tokens that can allow breaking
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/// within the tokens - for example, to avoid whitespace beyond the column
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/// limit, or to reflow text.
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///
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/// Generally, a breakable token consists of logical lines, addressed by a line
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/// index. For example, in a sequence of line comments, each line comment is its
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/// own logical line; similarly, for a block comment, each line in the block
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/// comment is on its own logical line.
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///
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/// There are two methods to compute the layout of the token:
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/// - getRangeLength measures the number of columns needed for a range of text
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/// within a logical line, and
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/// - getContentStartColumn returns the start column at which we want the
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/// content of a logical line to start (potentially after introducing a line
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/// break).
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///
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/// The mechanism to adapt the layout of the breakable token is organised
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/// around the concept of a \c Split, which is a whitespace range that signifies
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/// a position of the content of a token where a reformatting might be done.
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///
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/// Operating with splits is divided into two operations:
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/// - getSplit, for finding a split starting at a position,
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/// - insertBreak, for executing the split using a whitespace manager.
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///
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/// There is a pair of operations that are used to compress a long whitespace
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/// range with a single space if that will bring the line length under the
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/// column limit:
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/// - getLineLengthAfterCompression, for calculating the size in columns of the
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/// line after a whitespace range has been compressed, and
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/// - compressWhitespace, for executing the whitespace compression using a
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/// whitespace manager; note that the compressed whitespace may be in the
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/// middle of the original line and of the reformatted line.
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///
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/// For tokens where the whitespace before each line needs to be also
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/// reformatted, for example for tokens supporting reflow, there are analogous
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/// operations that might be executed before the main line breaking occurs:
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/// - getReflowSplit, for finding a split such that the content preceding it
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/// needs to be specially reflown,
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/// - reflow, for executing the split using a whitespace manager,
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/// - introducesBreakBefore, for checking if reformatting the beginning
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/// of the content introduces a line break before it,
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/// - adaptStartOfLine, for executing the reflow using a whitespace
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/// manager.
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///
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/// For tokens that require the whitespace after the last line to be
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/// reformatted, for example in multiline jsdoc comments that require the
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/// trailing '*/' to be on a line of itself, there are analogous operations
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/// that might be executed after the last line has been reformatted:
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/// - getSplitAfterLastLine, for finding a split after the last line that needs
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/// to be reflown,
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/// - replaceWhitespaceAfterLastLine, for executing the reflow using a
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/// whitespace manager.
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///
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class BreakableToken {
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public:
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/// Contains starting character index and length of split.
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typedef std::pair<StringRef::size_type, unsigned> Split;
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virtual ~BreakableToken() {}
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/// Returns the number of lines in this token in the original code.
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virtual unsigned getLineCount() const = 0;
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/// Returns the number of columns required to format the text in the
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/// byte range [\p Offset, \p Offset \c + \p Length).
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///
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/// \p Offset is the byte offset from the start of the content of the line
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/// at \p LineIndex.
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///
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/// \p StartColumn is the column at which the text starts in the formatted
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/// file, needed to compute tab stops correctly.
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virtual unsigned getRangeLength(unsigned LineIndex, unsigned Offset,
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StringRef::size_type Length,
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unsigned StartColumn) const = 0;
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/// Returns the number of columns required to format the text following
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/// the byte \p Offset in the line \p LineIndex, including potentially
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/// unbreakable sequences of tokens following after the end of the token.
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///
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/// \p Offset is the byte offset from the start of the content of the line
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/// at \p LineIndex.
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///
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/// \p StartColumn is the column at which the text starts in the formatted
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/// file, needed to compute tab stops correctly.
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///
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/// For breakable tokens that never use extra space at the end of a line, this
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/// is equivalent to getRangeLength with a Length of StringRef::npos.
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virtual unsigned getRemainingLength(unsigned LineIndex, unsigned Offset,
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unsigned StartColumn) const {
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return getRangeLength(LineIndex, Offset, StringRef::npos, StartColumn);
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}
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/// Returns the column at which content in line \p LineIndex starts,
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/// assuming no reflow.
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///
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/// If \p Break is true, returns the column at which the line should start
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/// after the line break.
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/// If \p Break is false, returns the column at which the line itself will
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/// start.
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virtual unsigned getContentStartColumn(unsigned LineIndex,
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bool Break) const = 0;
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/// Returns additional content indent required for the second line after the
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/// content at line \p LineIndex is broken.
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///
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// (Next lines do not start with `///` since otherwise -Wdocumentation picks
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// up the example annotations and generates warnings for them)
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// For example, Javadoc @param annotations require and indent of 4 spaces and
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// in this example getContentIndex(1) returns 4.
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// /**
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// * @param loooooooooooooong line
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// * continuation
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// */
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virtual unsigned getContentIndent(unsigned LineIndex) const { return 0; }
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/// Returns a range (offset, length) at which to break the line at
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/// \p LineIndex, if previously broken at \p TailOffset. If possible, do not
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/// violate \p ColumnLimit, assuming the text starting at \p TailOffset in
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/// the token is formatted starting at ContentStartColumn in the reformatted
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/// file.
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virtual Split getSplit(unsigned LineIndex, unsigned TailOffset,
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unsigned ColumnLimit, unsigned ContentStartColumn,
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const llvm::Regex &CommentPragmasRegex) const = 0;
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/// Emits the previously retrieved \p Split via \p Whitespaces.
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virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
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unsigned ContentIndent,
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WhitespaceManager &Whitespaces) const = 0;
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/// Returns the number of columns needed to format
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/// \p RemainingTokenColumns, assuming that Split is within the range measured
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/// by \p RemainingTokenColumns, and that the whitespace in Split is reduced
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/// to a single space.
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unsigned getLengthAfterCompression(unsigned RemainingTokenColumns,
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Split Split) const;
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/// Replaces the whitespace range described by \p Split with a single
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/// space.
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virtual void compressWhitespace(unsigned LineIndex, unsigned TailOffset,
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Split Split,
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WhitespaceManager &Whitespaces) const = 0;
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/// Returns whether the token supports reflowing text.
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virtual bool supportsReflow() const { return false; }
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/// Returns a whitespace range (offset, length) of the content at \p
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/// LineIndex such that the content of that line is reflown to the end of the
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/// previous one.
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///
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/// Returning (StringRef::npos, 0) indicates reflowing is not possible.
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///
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/// The range will include any whitespace preceding the specified line's
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/// content.
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///
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/// If the split is not contained within one token, for example when reflowing
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/// line comments, returns (0, <length>).
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virtual Split getReflowSplit(unsigned LineIndex,
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const llvm::Regex &CommentPragmasRegex) const {
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return Split(StringRef::npos, 0);
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}
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/// Reflows the current line into the end of the previous one.
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virtual void reflow(unsigned LineIndex,
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WhitespaceManager &Whitespaces) const {}
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/// Returns whether there will be a line break at the start of the
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/// token.
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virtual bool introducesBreakBeforeToken() const { return false; }
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/// Replaces the whitespace between \p LineIndex-1 and \p LineIndex.
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virtual void adaptStartOfLine(unsigned LineIndex,
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WhitespaceManager &Whitespaces) const {}
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/// Returns a whitespace range (offset, length) of the content at
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/// the last line that needs to be reformatted after the last line has been
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/// reformatted.
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///
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/// A result having offset == StringRef::npos means that no reformat is
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/// necessary.
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virtual Split getSplitAfterLastLine(unsigned TailOffset) const {
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return Split(StringRef::npos, 0);
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}
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/// Replaces the whitespace from \p SplitAfterLastLine on the last line
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/// after the last line has been formatted by performing a reformatting.
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void replaceWhitespaceAfterLastLine(unsigned TailOffset,
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Split SplitAfterLastLine,
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WhitespaceManager &Whitespaces) const {
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insertBreak(getLineCount() - 1, TailOffset, SplitAfterLastLine,
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/*ContentIndent=*/0, Whitespaces);
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}
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/// Updates the next token of \p State to the next token after this
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/// one. This can be used when this token manages a set of underlying tokens
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/// as a unit and is responsible for the formatting of the them.
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virtual void updateNextToken(LineState &State) const {}
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protected:
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BreakableToken(const FormatToken &Tok, bool InPPDirective,
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encoding::Encoding Encoding, const FormatStyle &Style)
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: Tok(Tok), InPPDirective(InPPDirective), Encoding(Encoding),
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Style(Style) {}
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const FormatToken &Tok;
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const bool InPPDirective;
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const encoding::Encoding Encoding;
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const FormatStyle &Style;
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};
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class BreakableStringLiteral : public BreakableToken {
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public:
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/// Creates a breakable token for a single line string literal.
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///
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/// \p StartColumn specifies the column in which the token will start
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/// after formatting.
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BreakableStringLiteral(const FormatToken &Tok, unsigned StartColumn,
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StringRef Prefix, StringRef Postfix,
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unsigned UnbreakableTailLength, bool InPPDirective,
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encoding::Encoding Encoding, const FormatStyle &Style);
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Split getSplit(unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
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unsigned ContentStartColumn,
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const llvm::Regex &CommentPragmasRegex) const override;
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void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
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unsigned ContentIndent,
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WhitespaceManager &Whitespaces) const override;
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void compressWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
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WhitespaceManager &Whitespaces) const override {}
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unsigned getLineCount() const override;
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unsigned getRangeLength(unsigned LineIndex, unsigned Offset,
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StringRef::size_type Length,
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unsigned StartColumn) const override;
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unsigned getRemainingLength(unsigned LineIndex, unsigned Offset,
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unsigned StartColumn) const override;
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unsigned getContentStartColumn(unsigned LineIndex, bool Break) const override;
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protected:
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// The column in which the token starts.
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unsigned StartColumn;
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// The prefix a line needs after a break in the token.
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StringRef Prefix;
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// The postfix a line needs before introducing a break.
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StringRef Postfix;
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// The token text excluding the prefix and postfix.
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StringRef Line;
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// Length of the sequence of tokens after this string literal that cannot
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// contain line breaks.
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unsigned UnbreakableTailLength;
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};
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class BreakableComment : public BreakableToken {
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protected:
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/// Creates a breakable token for a comment.
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///
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/// \p StartColumn specifies the column in which the comment will start after
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/// formatting.
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BreakableComment(const FormatToken &Token, unsigned StartColumn,
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bool InPPDirective, encoding::Encoding Encoding,
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const FormatStyle &Style);
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public:
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bool supportsReflow() const override { return true; }
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unsigned getLineCount() const override;
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Split getSplit(unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
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unsigned ContentStartColumn,
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const llvm::Regex &CommentPragmasRegex) const override;
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void compressWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
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WhitespaceManager &Whitespaces) const override;
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protected:
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// Returns the token containing the line at LineIndex.
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const FormatToken &tokenAt(unsigned LineIndex) const;
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// Checks if the content of line LineIndex may be reflown with the previous
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// line.
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virtual bool mayReflow(unsigned LineIndex,
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const llvm::Regex &CommentPragmasRegex) const = 0;
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// Contains the original text of the lines of the block comment.
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//
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// In case of a block comments, excludes the leading /* in the first line and
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// trailing */ in the last line. In case of line comments, excludes the
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// leading // and spaces.
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SmallVector<StringRef, 16> Lines;
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// Contains the text of the lines excluding all leading and trailing
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// whitespace between the lines. Note that the decoration (if present) is also
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// not considered part of the text.
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SmallVector<StringRef, 16> Content;
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// Tokens[i] contains a reference to the token containing Lines[i] if the
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// whitespace range before that token is managed by this block.
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// Otherwise, Tokens[i] is a null pointer.
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SmallVector<FormatToken *, 16> Tokens;
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// ContentColumn[i] is the target column at which Content[i] should be.
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// Note that this excludes a leading "* " or "*" in case of block comments
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// where all lines have a "*" prefix, or the leading "// " or "//" in case of
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// line comments.
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//
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// In block comments, the first line's target column is always positive. The
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// remaining lines' target columns are relative to the first line to allow
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// correct indentation of comments in \c WhitespaceManager. Thus they can be
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// negative as well (in case the first line needs to be unindented more than
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// there's actual whitespace in another line).
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SmallVector<int, 16> ContentColumn;
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// The intended start column of the first line of text from this section.
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unsigned StartColumn;
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// The prefix to use in front a line that has been reflown up.
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// For example, when reflowing the second line after the first here:
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// // comment 1
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// // comment 2
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// we expect:
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// // comment 1 comment 2
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// and not:
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// // comment 1comment 2
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StringRef ReflowPrefix = " ";
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};
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class BreakableBlockComment : public BreakableComment {
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public:
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BreakableBlockComment(const FormatToken &Token, unsigned StartColumn,
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unsigned OriginalStartColumn, bool FirstInLine,
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bool InPPDirective, encoding::Encoding Encoding,
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const FormatStyle &Style, bool UseCRLF);
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Split getSplit(unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
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unsigned ContentStartColumn,
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const llvm::Regex &CommentPragmasRegex) const override;
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unsigned getRangeLength(unsigned LineIndex, unsigned Offset,
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StringRef::size_type Length,
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unsigned StartColumn) const override;
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unsigned getRemainingLength(unsigned LineIndex, unsigned Offset,
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unsigned StartColumn) const override;
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unsigned getContentStartColumn(unsigned LineIndex, bool Break) const override;
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unsigned getContentIndent(unsigned LineIndex) const override;
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void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
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unsigned ContentIndent,
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WhitespaceManager &Whitespaces) const override;
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Split getReflowSplit(unsigned LineIndex,
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const llvm::Regex &CommentPragmasRegex) const override;
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void reflow(unsigned LineIndex,
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WhitespaceManager &Whitespaces) const override;
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bool introducesBreakBeforeToken() const override;
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void adaptStartOfLine(unsigned LineIndex,
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WhitespaceManager &Whitespaces) const override;
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Split getSplitAfterLastLine(unsigned TailOffset) const override;
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bool mayReflow(unsigned LineIndex,
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const llvm::Regex &CommentPragmasRegex) const override;
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// Contains Javadoc annotations that require additional indent when continued
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// on multiple lines.
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static const llvm::StringSet<> ContentIndentingJavadocAnnotations;
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private:
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// Rearranges the whitespace between Lines[LineIndex-1] and Lines[LineIndex].
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//
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// Updates Content[LineIndex-1] and Content[LineIndex] by stripping off
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// leading and trailing whitespace.
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//
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// Sets ContentColumn to the intended column in which the text at
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// Lines[LineIndex] starts (note that the decoration, if present, is not
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// considered part of the text).
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void adjustWhitespace(unsigned LineIndex, int IndentDelta);
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// The column at which the text of a broken line should start.
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// Note that an optional decoration would go before that column.
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// IndentAtLineBreak is a uniform position for all lines in a block comment,
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// regardless of their relative position.
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// FIXME: Revisit the decision to do this; the main reason was to support
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// patterns like
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// /**************//**
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// * Comment
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// We could also support such patterns by special casing the first line
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// instead.
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unsigned IndentAtLineBreak;
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// This is to distinguish between the case when the last line was empty and
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// the case when it started with a decoration ("*" or "* ").
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bool LastLineNeedsDecoration;
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// Either "* " if all lines begin with a "*", or empty.
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StringRef Decoration;
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// If this block comment has decorations, this is the column of the start of
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// the decorations.
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unsigned DecorationColumn;
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// If true, make sure that the opening '/**' and the closing '*/' ends on a
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// line of itself. Styles like jsdoc require this for multiline comments.
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bool DelimitersOnNewline;
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// Length of the sequence of tokens after this string literal that cannot
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// contain line breaks.
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unsigned UnbreakableTailLength;
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};
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class BreakableLineCommentSection : public BreakableComment {
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public:
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BreakableLineCommentSection(const FormatToken &Token, unsigned StartColumn,
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unsigned OriginalStartColumn, bool FirstInLine,
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bool InPPDirective, encoding::Encoding Encoding,
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const FormatStyle &Style);
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unsigned getRangeLength(unsigned LineIndex, unsigned Offset,
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StringRef::size_type Length,
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unsigned StartColumn) const override;
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unsigned getContentStartColumn(unsigned LineIndex, bool Break) const override;
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void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
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unsigned ContentIndent,
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WhitespaceManager &Whitespaces) const override;
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Split getReflowSplit(unsigned LineIndex,
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const llvm::Regex &CommentPragmasRegex) const override;
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void reflow(unsigned LineIndex,
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WhitespaceManager &Whitespaces) const override;
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void adaptStartOfLine(unsigned LineIndex,
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WhitespaceManager &Whitespaces) const override;
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void updateNextToken(LineState &State) const override;
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bool mayReflow(unsigned LineIndex,
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const llvm::Regex &CommentPragmasRegex) const override;
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private:
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// OriginalPrefix[i] contains the original prefix of line i, including
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// trailing whitespace before the start of the content. The indentation
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// preceding the prefix is not included.
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// For example, if the line is:
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// // content
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// then the original prefix is "// ".
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SmallVector<StringRef, 16> OriginalPrefix;
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// Prefix[i] contains the intended leading "//" with trailing spaces to
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// account for the indentation of content within the comment at line i after
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// formatting. It can be different than the original prefix when the original
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// line starts like this:
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// //content
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// Then the original prefix is "//", but the prefix is "// ".
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SmallVector<StringRef, 16> Prefix;
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SmallVector<unsigned, 16> OriginalContentColumn;
|
|
|
|
/// The token to which the last line of this breakable token belongs
|
|
/// to; nullptr if that token is the initial token.
|
|
///
|
|
/// The distinction is because if the token of the last line of this breakable
|
|
/// token is distinct from the initial token, this breakable token owns the
|
|
/// whitespace before the token of the last line, and the whitespace manager
|
|
/// must be able to modify it.
|
|
FormatToken *LastLineTok = nullptr;
|
|
};
|
|
} // namespace format
|
|
} // namespace clang
|
|
|
|
#endif
|