//===--- 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 "Encoding.h"

#include "FormatToken.h"

#include "Macros.h"

#include "clang/Basic/IdentifierTable.h"

#include "clang/Format/Format.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/BitVector.h"

#include "llvm/Support/Regex.h"

#include <list>

#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() = default;

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

  std::list<UnwrappedLineNode> Tokens;

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

  unsigned Level = 0;

  /// The \c PPBranchLevel (adjusted for header guards) if this line is a

  /// \c InMacroBody line, and 0 otherwise.

  unsigned PPLevel = 0;

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

  bool InPPDirective = false;

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

  bool InPragmaDirective = false;

  /// Whether it is part of a macro body.

  bool InMacroBody = false;

  bool MustBeDeclaration = false;

  /// Whether the parser has seen \c decltype(auto) in this line.

  bool SeenDecltypeAuto = false;

  /// \c True if this line should be indented by ContinuationIndent in

  /// addition to the normal indention level.

  bool IsContinuation = false;

  /// 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;

};

/// Interface for users of the UnwrappedLineParser to receive the parsed lines.

/// Parsing a single snippet of code can lead to multiple runs, where each

/// run is a coherent view of the file.

///

/// For example, different runs are generated:

/// - for different combinations of #if blocks

/// - when macros are involved, for the expanded code and the as-written code

///

/// Some tokens will only be visible in a subset of the runs.

/// For each run, \c UnwrappedLineParser will call \c consumeUnwrappedLine

/// for each parsed unwrapped line, and then \c finishRun to indicate

/// that the set of unwrapped lines before is one coherent view of the

/// code snippet to be formatted.

class UnwrappedLineConsumer {

public:

  virtual ~UnwrappedLineConsumer() {}

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

  virtual void finishRun() = 0;

};

class FormatTokenSource;

class UnwrappedLineParser {

public:

  UnwrappedLineParser(SourceManager &SourceMgr, const FormatStyle &Style,

                      const AdditionalKeywords &Keywords,

                      unsigned FirstStartColumn, ArrayRef<FormatToken *> Tokens,

                      UnwrappedLineConsumer &Callback,

                      llvm::SpecificBumpPtrAllocator<FormatToken> &Allocator,

                      IdentifierTable &IdentTable);

  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 parseLevel(const FormatToken *OpeningBrace = nullptr,

                  IfStmtKind *IfKind = nullptr,

                  FormatToken **IfLeftBrace = nullptr);

  bool mightFitOnOneLine(UnwrappedLine &Line,

                         const FormatToken *OpeningBrace = nullptr) const;

  FormatToken *parseBlock(bool MustBeDeclaration = false,

                          unsigned AddLevels = 1u, bool MunchSemi = true,

                          bool KeepBraces = true, IfStmtKind *IfKind = nullptr,

                          bool UnindentWhitesmithsBraces = false);

  void parseChildBlock();

  void parsePPDirective();

  void parsePPDefine();

  void parsePPIf(bool IfDef);

  void parsePPElse();

  void parsePPEndIf();

  void parsePPPragma();

  void parsePPUnknown();

  void readTokenWithJavaScriptASI();

  void parseStructuralElement(const FormatToken *OpeningBrace = nullptr,

                              IfStmtKind *IfKind = nullptr,

                              FormatToken **IfLeftBrace = nullptr,

                              bool *HasDoWhile = nullptr,

                              bool *HasLabel = nullptr);

  bool tryToParseBracedList();

  bool parseBracedList(bool IsAngleBracket = false, bool IsEnum = false);

  bool parseParens(TokenType AmpAmpTokenType = TT_Unknown);

  void parseSquare(bool LambdaIntroducer = false);

  void keepAncestorBraces();

  void parseUnbracedBody(bool CheckEOF = false);

  void handleAttributes();

  bool handleCppAttributes();

  bool isBlockBegin(const FormatToken &Tok) const;

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

                               bool IsVerilogAssert = false);

  void parseTryCatch();

  void parseLoopBody(bool KeepBraces, bool WrapRightBrace);

  void parseForOrWhileLoop(bool HasParens = true);

  void parseDoWhile();

  void parseLabel(bool LeftAlignLabel = false);

  void parseCaseLabel();

  void parseSwitch();

  void parseNamespace();

  bool parseModuleImport();

  void parseNew();

  void parseAccessSpecifier();

  bool parseEnum();

  bool parseStructLike();

  bool parseRequires();

  void parseRequiresClause(FormatToken *RequiresToken);

  void parseRequiresExpression(FormatToken *RequiresToken);

  void parseConstraintExpression();

  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();

  void parseVerilogHierarchyIdentifier();

  void parseVerilogSensitivityList();

  // Returns the number of levels of indentation in addition to the normal 1

  // level for a block, used for indenting case labels.

  unsigned parseVerilogHierarchyHeader();

  void parseVerilogTable();

  void parseVerilogCaseLabel();

  std::optional<llvm::SmallVector<llvm::SmallVector<FormatToken *, 8>, 1>>

  parseMacroCall();

  // 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 account 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);

  void setPreviousRBraceType(TokenType Type);

  // 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);

  // Returns whether there is a macro expansion in the line, i.e. a token that

  // was expanded from a macro call.

  bool containsExpansion(const UnwrappedLine &Line) const;

  // 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;

  bool parsingPPDirective() const { return CurrentLines != &Lines; }

  // 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;

  // Lines that are created by macro expansion.

  // When formatting code containing macro calls, we first format the expanded

  // lines to set the token types correctly. Afterwards, we format the

  // reconstructed macro calls, re-using the token types determined in the first

  // step.

  // ExpandedLines will be reset every time we create a new LineAndExpansion

  // instance once a line containing macro calls has been parsed.

  SmallVector<UnwrappedLine, 8> CurrentExpandedLines;

  // Maps from the first token of a top-level UnwrappedLine that contains

  // a macro call to the replacement UnwrappedLines expanded from the macro

  // call.

  llvm::DenseMap<FormatToken *, SmallVector<UnwrappedLine, 8>> ExpandedLines;

  // Map from the macro identifier to a line containing the full unexpanded

  // macro call.

  llvm::DenseMap<FormatToken *, std::unique_ptr<UnwrappedLine>> Unexpanded;

  // For recursive macro expansions, trigger reconstruction only on the

  // outermost expansion.

  bool InExpansion = false;

  // Set while we reconstruct a macro call.

  // For reconstruction, we feed the expanded lines into the reconstructor

  // until it is finished.

  std::optional<MacroCallReconstructor> Reconstruct;

  // 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 = nullptr;

  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;

  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;

  // Keeps a stack of the states of nested lambdas (true if the return type of

  // the lambda is `decltype(auto)`).

  SmallVector<bool, 4> NestedLambdas;

  // Whether the parser is parsing the body of a function whose return type is

  // `decltype(auto)`.

  bool IsDecltypeAutoFunction = false;

  // 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;

  MacroExpander Macros;

  friend class ScopedLineState;

  friend class CompoundStatementIndenter;

};

struct UnwrappedLineNode {

  UnwrappedLineNode() : Tok(nullptr) {}

  UnwrappedLineNode(FormatToken *Tok,

                    llvm::ArrayRef<UnwrappedLine> Children = {})

      : Tok(Tok), Children(Children.begin(), Children.end()) {}

  FormatToken *Tok;

  SmallVector<UnwrappedLine, 0> Children;

};

} // end namespace format

} // end namespace clang

#endif