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Diffstat (limited to 'contrib/llvm/tools/clang/lib/Format/UnwrappedLineFormatter.h')
-rw-r--r-- | contrib/llvm/tools/clang/lib/Format/UnwrappedLineFormatter.h | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Format/UnwrappedLineFormatter.h b/contrib/llvm/tools/clang/lib/Format/UnwrappedLineFormatter.h new file mode 100644 index 0000000..3ae6dbc --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Format/UnwrappedLineFormatter.h @@ -0,0 +1,168 @@ +//===--- UnwrappedLineFormatter.h - Format C++ code -------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// \brief Implements a combinartorial exploration of all the different +/// linebreaks unwrapped lines can be formatted in. +/// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEFORMATTER_H +#define LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEFORMATTER_H + +#include "ContinuationIndenter.h" +#include "clang/Format/Format.h" +#include <map> +#include <queue> +#include <string> + +namespace clang { +namespace format { + +class ContinuationIndenter; +class WhitespaceManager; + +class UnwrappedLineFormatter { +public: + UnwrappedLineFormatter(ContinuationIndenter *Indenter, + WhitespaceManager *Whitespaces, + const FormatStyle &Style) + : Indenter(Indenter), Whitespaces(Whitespaces), Style(Style) {} + + unsigned format(const SmallVectorImpl<AnnotatedLine *> &Lines, bool DryRun, + int AdditionalIndent = 0, bool FixBadIndentation = false); + +private: + /// \brief Formats an \c AnnotatedLine and returns the penalty. + /// + /// If \p DryRun is \c false, directly applies the changes. + unsigned format(const AnnotatedLine &Line, unsigned FirstIndent, + bool DryRun); + + /// \brief An edge in the solution space from \c Previous->State to \c State, + /// inserting a newline dependent on the \c NewLine. + struct StateNode { + StateNode(const LineState &State, bool NewLine, StateNode *Previous) + : State(State), NewLine(NewLine), Previous(Previous) {} + LineState State; + bool NewLine; + StateNode *Previous; + }; + + /// \brief A pair of <penalty, count> that is used to prioritize the BFS on. + /// + /// In case of equal penalties, we want to prefer states that were inserted + /// first. During state generation we make sure that we insert states first + /// that break the line as late as possible. + typedef std::pair<unsigned, unsigned> OrderedPenalty; + + /// \brief An item in the prioritized BFS search queue. The \c StateNode's + /// \c State has the given \c OrderedPenalty. + typedef std::pair<OrderedPenalty, StateNode *> QueueItem; + + /// \brief The BFS queue type. + typedef std::priority_queue<QueueItem, std::vector<QueueItem>, + std::greater<QueueItem> > QueueType; + + /// \brief Get the offset of the line relatively to the level. + /// + /// For example, 'public:' labels in classes are offset by 1 or 2 + /// characters to the left from their level. + int getIndentOffset(const FormatToken &RootToken) { + if (Style.Language == FormatStyle::LK_Java) + return 0; + if (RootToken.isAccessSpecifier(false) || RootToken.isObjCAccessSpecifier()) + return Style.AccessModifierOffset; + return 0; + } + + /// \brief Add a new line and the required indent before the first Token + /// of the \c UnwrappedLine if there was no structural parsing error. + void formatFirstToken(FormatToken &RootToken, + const AnnotatedLine *PreviousLine, unsigned IndentLevel, + unsigned Indent, bool InPPDirective); + + /// \brief Get the indent of \p Level from \p IndentForLevel. + /// + /// \p IndentForLevel must contain the indent for the level \c l + /// at \p IndentForLevel[l], or a value < 0 if the indent for + /// that level is unknown. + unsigned getIndent(ArrayRef<int> IndentForLevel, unsigned Level); + + void join(AnnotatedLine &A, const AnnotatedLine &B); + + unsigned getColumnLimit(bool InPPDirective) const { + // In preprocessor directives reserve two chars for trailing " \" + return Style.ColumnLimit - (InPPDirective ? 2 : 0); + } + + struct CompareLineStatePointers { + bool operator()(LineState *obj1, LineState *obj2) const { + return *obj1 < *obj2; + } + }; + + /// \brief Analyze the entire solution space starting from \p InitialState. + /// + /// This implements a variant of Dijkstra's algorithm on the graph that spans + /// the solution space (\c LineStates are the nodes). The algorithm tries to + /// find the shortest path (the one with lowest penalty) from \p InitialState + /// to a state where all tokens are placed. Returns the penalty. + /// + /// If \p DryRun is \c false, directly applies the changes. + unsigned analyzeSolutionSpace(LineState &InitialState, bool DryRun = false); + + void reconstructPath(LineState &State, StateNode *Current); + + /// \brief Add the following state to the analysis queue \c Queue. + /// + /// Assume the current state is \p PreviousNode and has been reached with a + /// penalty of \p Penalty. Insert a line break if \p NewLine is \c true. + void addNextStateToQueue(unsigned Penalty, StateNode *PreviousNode, + bool NewLine, unsigned *Count, QueueType *Queue); + + /// \brief If the \p State's next token is an r_brace closing a nested block, + /// format the nested block before it. + /// + /// Returns \c true if all children could be placed successfully and adapts + /// \p Penalty as well as \p State. If \p DryRun is false, also directly + /// creates changes using \c Whitespaces. + /// + /// The crucial idea here is that children always get formatted upon + /// encountering the closing brace right after the nested block. Now, if we + /// are currently trying to keep the "}" on the same line (i.e. \p NewLine is + /// \c false), the entire block has to be kept on the same line (which is only + /// possible if it fits on the line, only contains a single statement, etc. + /// + /// If \p NewLine is true, we format the nested block on separate lines, i.e. + /// break after the "{", format all lines with correct indentation and the put + /// the closing "}" on yet another new line. + /// + /// This enables us to keep the simple structure of the + /// \c UnwrappedLineFormatter, where we only have two options for each token: + /// break or don't break. + bool formatChildren(LineState &State, bool NewLine, bool DryRun, + unsigned &Penalty); + + ContinuationIndenter *Indenter; + WhitespaceManager *Whitespaces; + FormatStyle Style; + + llvm::SpecificBumpPtrAllocator<StateNode> Allocator; + + // Cache to store the penalty of formatting a vector of AnnotatedLines + // starting from a specific additional offset. Improves performance if there + // are many nested blocks. + std::map<std::pair<const SmallVectorImpl<AnnotatedLine *> *, unsigned>, + unsigned> PenaltyCache; +}; +} // end namespace format +} // end namespace clang + +#endif // LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEFORMATTER_H |