//===--- UnwrappedLineParser.h - Format C++ code ----------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

///

/// \file

/// This file contains the declaration of the UnwrappedLineParser,

/// which turns a stream of tokens into UnwrappedLines.

///

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEPARSER_H

#define LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEPARSER_H

#include "FormatToken.h"

#include "clang/Basic/IdentifierTable.h"

#include "clang/Format/Format.h"

#include "llvm/ADT/BitVector.h"

#include "llvm/Support/Regex.h"

#include <stack>

#include <vector>

namespace clang {

namespace format {

struct UnwrappedLineNode;

/// An unwrapped line is a sequence of \c Token, that we would like to

/// put on a single line if there was no column limit.

///

/// This is used as a main interface between the \c UnwrappedLineParser and the

/// \c UnwrappedLineFormatter. The key property is that changing the formatting

/// within an unwrapped line does not affect any other unwrapped lines.

struct UnwrappedLine {

  UnwrappedLine();

  /// The \c Tokens comprising this \c UnwrappedLine.

  std::vector<UnwrappedLineNode> Tokens;

  /// The indent level of the \c UnwrappedLine.

  unsigned Level;

  /// Whether this \c UnwrappedLine is part of a preprocessor directive.

  bool InPPDirective;

  bool MustBeDeclaration;

  /// If this \c UnwrappedLine closes a block in a sequence of lines,

  /// \c MatchingOpeningBlockLineIndex stores the index of the corresponding

  /// opening line. Otherwise, \c MatchingOpeningBlockLineIndex must be

  /// \c kInvalidIndex.

  size_t MatchingOpeningBlockLineIndex = kInvalidIndex;

  /// If this \c UnwrappedLine opens a block, stores the index of the

  /// line with the corresponding closing brace.

  size_t MatchingClosingBlockLineIndex = kInvalidIndex;

  static const size_t kInvalidIndex = -1;

  unsigned FirstStartColumn = 0;

};

class UnwrappedLineConsumer {

public:

  virtual ~UnwrappedLineConsumer() {}

  virtual void consumeUnwrappedLine(const UnwrappedLine &Line) = 0;

  virtual void finishRun() = 0;

};

class FormatTokenSource;

class UnwrappedLineParser {

public:

  UnwrappedLineParser(const FormatStyle &Style,

                      const AdditionalKeywords &Keywords,

                      unsigned FirstStartColumn, ArrayRef<FormatToken *> Tokens,

                      UnwrappedLineConsumer &Callback);

  void parse();

private:

  enum class IfStmtKind {

    NotIf,   // Not an if statement.

    IfOnly,  // An if statement without the else clause.

    IfElse,  // An if statement followed by else but not else if.

    IfElseIf // An if statement followed by else if.

  };

  void reset();

  void parseFile();

  bool precededByCommentOrPPDirective() const;

  bool mightFitOnOneLine() const;

  bool parseLevel(bool HasOpeningBrace, IfStmtKind *IfKind = nullptr);

  IfStmtKind parseBlock(bool MustBeDeclaration = false, unsigned AddLevels = 1u,

                        bool MunchSemi = true,

                        bool UnindentWhitesmithsBraces = false);

  void parseChildBlock();

  void parsePPDirective();

  void parsePPDefine();

  void parsePPIf(bool IfDef);

  void parsePPElIf();

  void parsePPElse();

  void parsePPEndIf();

  void parsePPUnknown();

  void readTokenWithJavaScriptASI();

  void parseStructuralElement(IfStmtKind *IfKind = nullptr,

                              bool IsTopLevel = false);

  bool tryToParseBracedList();

  bool parseBracedList(bool ContinueOnSemicolons = false, bool IsEnum = false,

                       tok::TokenKind ClosingBraceKind = tok::r_brace);

  void parseParens();

  void parseSquare(bool LambdaIntroducer = false);

  void keepAncestorBraces();

  FormatToken *parseIfThenElse(IfStmtKind *IfKind, bool KeepBraces = false);

  void parseTryCatch();

  void parseForOrWhileLoop();

  void parseDoWhile();

  void parseLabel(bool LeftAlignLabel = false);

  void parseCaseLabel();

  void parseSwitch();

  void parseNamespace();

  void parseModuleImport();

  void parseNew();

  void parseAccessSpecifier();

  bool parseEnum();

  bool parseStructLike();

  void parseConcept();

  void parseRequires();

  void parseRequiresExpression(unsigned int OriginalLevel);

  void parseConstraintExpression(unsigned int OriginalLevel);

  void parseJavaEnumBody();

  // Parses a record (aka class) as a top level element. If ParseAsExpr is true,

  // parses the record as a child block, i.e. if the class declaration is an

  // expression.

  void parseRecord(bool ParseAsExpr = false);

  void parseObjCLightweightGenerics();

  void parseObjCMethod();

  void parseObjCProtocolList();

  void parseObjCUntilAtEnd();

  void parseObjCInterfaceOrImplementation();

  bool parseObjCProtocol();

  void parseJavaScriptEs6ImportExport();

  void parseStatementMacro();

  void parseCSharpAttribute();

  // Parse a C# generic type constraint: `where T : IComparable<T>`.

  // See:

  // https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/where-generic-type-constraint

  void parseCSharpGenericTypeConstraint();

  bool tryToParseLambda();

  bool tryToParseChildBlock();

  bool tryToParseLambdaIntroducer();

  bool tryToParsePropertyAccessor();

  void tryToParseJSFunction();

  bool tryToParseSimpleAttribute();

  // Used by addUnwrappedLine to denote whether to keep or remove a level

  // when resetting the line state.

  enum class LineLevel { Remove, Keep };

  void addUnwrappedLine(LineLevel AdjustLevel = LineLevel::Remove);

  bool eof() const;

  // LevelDifference is the difference of levels after and before the current

  // token. For example:

  // - if the token is '{' and opens a block, LevelDifference is 1.

  // - if the token is '}' and closes a block, LevelDifference is -1.

  void nextToken(int LevelDifference = 0);

  void readToken(int LevelDifference = 0);

  // Decides which comment tokens should be added to the current line and which

  // should be added as comments before the next token.

  //

  // Comments specifies the sequence of comment tokens to analyze. They get

  // either pushed to the current line or added to the comments before the next

  // token.

  //

  // NextTok specifies the next token. A null pointer NextTok is supported, and

  // signifies either the absence of a next token, or that the next token

  // shouldn't be taken into accunt for the analysis.

  void distributeComments(const SmallVectorImpl<FormatToken *> &Comments,

                          const FormatToken *NextTok);

  // Adds the comment preceding the next token to unwrapped lines.

  void flushComments(bool NewlineBeforeNext);

  void pushToken(FormatToken *Tok);

  void calculateBraceTypes(bool ExpectClassBody = false);

  // Marks a conditional compilation edge (for example, an '#if', '#ifdef',

  // '#else' or merge conflict marker). If 'Unreachable' is true, assumes

  // this branch either cannot be taken (for example '#if false'), or should

  // not be taken in this round.

  void conditionalCompilationCondition(bool Unreachable);

  void conditionalCompilationStart(bool Unreachable);

  void conditionalCompilationAlternative();

  void conditionalCompilationEnd();

  bool isOnNewLine(const FormatToken &FormatTok);

  // Compute hash of the current preprocessor branch.

  // This is used to identify the different branches, and thus track if block

  // open and close in the same branch.

  size_t computePPHash() const;

  // FIXME: We are constantly running into bugs where Line.Level is incorrectly

  // subtracted from beyond 0. Introduce a method to subtract from Line.Level

  // and use that everywhere in the Parser.

  std::unique_ptr<UnwrappedLine> Line;

  // Comments are sorted into unwrapped lines by whether they are in the same

  // line as the previous token, or not. If not, they belong to the next token.

  // Since the next token might already be in a new unwrapped line, we need to

  // store the comments belonging to that token.

  SmallVector<FormatToken *, 1> CommentsBeforeNextToken;

  FormatToken *FormatTok;

  bool MustBreakBeforeNextToken;

  // The parsed lines. Only added to through \c CurrentLines.

  SmallVector<UnwrappedLine, 8> Lines;

  // Preprocessor directives are parsed out-of-order from other unwrapped lines.

  // Thus, we need to keep a list of preprocessor directives to be reported

  // after an unwrapped line that has been started was finished.

  SmallVector<UnwrappedLine, 4> PreprocessorDirectives;

  // New unwrapped lines are added via CurrentLines.

  // Usually points to \c &Lines. While parsing a preprocessor directive when

  // there is an unfinished previous unwrapped line, will point to

  // \c &PreprocessorDirectives.

  SmallVectorImpl<UnwrappedLine> *CurrentLines;

  // We store for each line whether it must be a declaration depending on

  // whether we are in a compound statement or not.

  llvm::BitVector DeclarationScopeStack;

  const FormatStyle &Style;

  const AdditionalKeywords &Keywords;

  llvm::Regex CommentPragmasRegex;

  FormatTokenSource *Tokens;

  UnwrappedLineConsumer &Callback;

  // FIXME: This is a temporary measure until we have reworked the ownership

  // of the format tokens. The goal is to have the actual tokens created and

  // owned outside of and handed into the UnwrappedLineParser.

  ArrayRef<FormatToken *> AllTokens;

  // Keeps a stack of the states of nested control statements (true if the

  // statement contains more than some predefined number of nested statements).

  SmallVector<bool, 8> NestedTooDeep;

  // Represents preprocessor branch type, so we can find matching

  // #if/#else/#endif directives.

  enum PPBranchKind {

    PP_Conditional, // Any #if, #ifdef, #ifndef, #elif, block outside #if 0

    PP_Unreachable  // #if 0 or a conditional preprocessor block inside #if 0

  };

  struct PPBranch {

    PPBranch(PPBranchKind Kind, size_t Line) : Kind(Kind), Line(Line) {}

    PPBranchKind Kind;

    size_t Line;

  };

  // Keeps a stack of currently active preprocessor branching directives.

  SmallVector<PPBranch, 16> PPStack;

  // The \c UnwrappedLineParser re-parses the code for each combination

  // of preprocessor branches that can be taken.

  // To that end, we take the same branch (#if, #else, or one of the #elif

  // branches) for each nesting level of preprocessor branches.

  // \c PPBranchLevel stores the current nesting level of preprocessor

  // branches during one pass over the code.

  int PPBranchLevel;

  // Contains the current branch (#if, #else or one of the #elif branches)

  // for each nesting level.

  SmallVector<int, 8> PPLevelBranchIndex;

  // Contains the maximum number of branches at each nesting level.

  SmallVector<int, 8> PPLevelBranchCount;

  // Contains the number of branches per nesting level we are currently

  // in while parsing a preprocessor branch sequence.

  // This is used to update PPLevelBranchCount at the end of a branch

  // sequence.

  std::stack<int> PPChainBranchIndex;

  // Include guard search state. Used to fixup preprocessor indent levels

  // so that include guards do not participate in indentation.

  enum IncludeGuardState {

    IG_Inited,   // Search started, looking for #ifndef.

    IG_IfNdefed, // #ifndef found, IncludeGuardToken points to condition.

    IG_Defined,  // Matching #define found, checking other requirements.

    IG_Found,    // All requirements met, need to fix indents.

    IG_Rejected, // Search failed or never started.

  };

  // Current state of include guard search.

  IncludeGuardState IncludeGuard;

  // Points to the #ifndef condition for a potential include guard. Null unless

  // IncludeGuardState == IG_IfNdefed.

  FormatToken *IncludeGuardToken;

  // Contains the first start column where the source begins. This is zero for

  // normal source code and may be nonzero when formatting a code fragment that

  // does not start at the beginning of the file.

  unsigned FirstStartColumn;

  friend class ScopedLineState;

  friend class CompoundStatementIndenter;

};

struct UnwrappedLineNode {

  UnwrappedLineNode() : Tok(nullptr) {}

  UnwrappedLineNode(FormatToken *Tok) : Tok(Tok) {}

  FormatToken *Tok;

  SmallVector<UnwrappedLine, 0> Children;

};

inline UnwrappedLine::UnwrappedLine()

    : Level(0), InPPDirective(false), MustBeDeclaration(false),

      MatchingOpeningBlockLineIndex(kInvalidIndex) {}

} // end namespace format

} // end namespace clang

#endif