text: //===--- NestedNameSpecifier.h - C++ nested name specifiers -----*- C++ -*-===//
  //
  //                     The LLVM37 Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  //  This file defines the NestedNameSpecifier class, which represents
  //  a C++ nested-name-specifier.
  //
  //===----------------------------------------------------------------------===//
  #ifndef LLVM37_CLANG_AST_NESTEDNAMESPECIFIER_H
  #define LLVM37_CLANG_AST_NESTEDNAMESPECIFIER_H
  
  #include "clang/Basic/Diagnostic.h"
  #include "llvm37/ADT/FoldingSet.h"
  #include "llvm37/ADT/PointerIntPair.h"
  #include "llvm37/Support/Compiler.h"
  
  namespace clang {
  
  class ASTContext;
  class CXXRecordDecl;
  class NamespaceAliasDecl;
  class NamespaceDecl;
  class IdentifierInfo;
  struct PrintingPolicy;
  class Type;
  class TypeLoc;
  class LangOptions;
  
  /// \brief Represents a C++ nested name specifier, such as
  /// "\::std::vector<int>::".
  ///
  /// C++ nested name specifiers are the prefixes to qualified
  /// namespaces. For example, "foo::" in "foo::x" is a nested name
  /// specifier. Nested name specifiers are made up of a sequence of
  /// specifiers, each of which can be a namespace, type, identifier
  /// (for dependent names), decltype specifier, or the global specifier ('::').
  /// The last two specifiers can only appear at the start of a 
  /// nested-namespace-specifier.
  class NestedNameSpecifier : public llvm37::FoldingSetNode {
  
    /// \brief Enumeration describing
    enum StoredSpecifierKind {
      StoredIdentifier = 0,
      StoredDecl = 1,
      StoredTypeSpec = 2,
      StoredTypeSpecWithTemplate = 3
    };
  
    /// \brief The nested name specifier that precedes this nested name
    /// specifier.
    ///
    /// The pointer is the nested-name-specifier that precedes this
    /// one. The integer stores one of the first four values of type
    /// SpecifierKind.
    llvm37::PointerIntPair<NestedNameSpecifier *, 2, StoredSpecifierKind> Prefix;
  
    /// \brief The last component in the nested name specifier, which
    /// can be an identifier, a declaration, or a type.
    ///
    /// When the pointer is NULL, this specifier represents the global
    /// specifier '::'. Otherwise, the pointer is one of
    /// IdentifierInfo*, Namespace*, or Type*, depending on the kind of
    /// specifier as encoded within the prefix.
    void* Specifier;
  
  public:
    /// \brief The kind of specifier that completes this nested name
    /// specifier.
    enum SpecifierKind {
      /// \brief An identifier, stored as an IdentifierInfo*.
      Identifier,
      /// \brief A namespace, stored as a NamespaceDecl*.
      Namespace,
      /// \brief A namespace alias, stored as a NamespaceAliasDecl*.
      NamespaceAlias,
      /// \brief A type, stored as a Type*.
      TypeSpec,
      /// \brief A type that was preceded by the 'template' keyword,
      /// stored as a Type*.
      TypeSpecWithTemplate,
      /// \brief The global specifier '::'. There is no stored value.
      Global,
      /// \brief Microsoft's '__super' specifier, stored as a CXXRecordDecl* of
      /// the class it appeared in.
      Super
    };
  
  private:
    /// \brief Builds the global specifier.
    NestedNameSpecifier()
      : Prefix(nullptr, StoredIdentifier), Specifier(nullptr) {}
  
    /// \brief Copy constructor used internally to clone nested name
    /// specifiers.
    NestedNameSpecifier(const NestedNameSpecifier &Other)
      : llvm37::FoldingSetNode(Other), Prefix(Other.Prefix),
        Specifier(Other.Specifier) {
    }
  
    void operator=(const NestedNameSpecifier &) = delete;
  
    /// \brief Either find or insert the given nested name specifier
    /// mockup in the given context.
    static NestedNameSpecifier *FindOrInsert(const ASTContext &Context,
                                             const NestedNameSpecifier &Mockup);
  
  public:
    /// \brief Builds a specifier combining a prefix and an identifier.
    ///
    /// The prefix must be dependent, since nested name specifiers
    /// referencing an identifier are only permitted when the identifier
    /// cannot be resolved.
    static NestedNameSpecifier *Create(const ASTContext &Context,
                                       NestedNameSpecifier *Prefix,
                                       IdentifierInfo *II);
  
    /// \brief Builds a nested name specifier that names a namespace.
    static NestedNameSpecifier *Create(const ASTContext &Context,
                                       NestedNameSpecifier *Prefix,
                                       const NamespaceDecl *NS);
  
    /// \brief Builds a nested name specifier that names a namespace alias.
    static NestedNameSpecifier *Create(const ASTContext &Context,
                                       NestedNameSpecifier *Prefix,
                                       NamespaceAliasDecl *Alias);
  
    /// \brief Builds a nested name specifier that names a type.
    static NestedNameSpecifier *Create(const ASTContext &Context,
                                       NestedNameSpecifier *Prefix,
                                       bool Template, const Type *T);
  
    /// \brief Builds a specifier that consists of just an identifier.
    ///
    /// The nested-name-specifier is assumed to be dependent, but has no
    /// prefix because the prefix is implied by something outside of the
    /// nested name specifier, e.g., in "x->Base::f", the "x" has a dependent
    /// type.
    static NestedNameSpecifier *Create(const ASTContext &Context,
                                       IdentifierInfo *II);
  
    /// \brief Returns the nested name specifier representing the global
    /// scope.
    static NestedNameSpecifier *GlobalSpecifier(const ASTContext &Context);
  
    /// \brief Returns the nested name specifier representing the __super scope
    /// for the given CXXRecordDecl.
    static NestedNameSpecifier *SuperSpecifier(const ASTContext &Context,
                                               CXXRecordDecl *RD);
  
    /// \brief Return the prefix of this nested name specifier.
    ///
    /// The prefix contains all of the parts of the nested name
    /// specifier that preced this current specifier. For example, for a
    /// nested name specifier that represents "foo::bar::", the current
    /// specifier will contain "bar::" and the prefix will contain
    /// "foo::".
    NestedNameSpecifier *getPrefix() const { return Prefix.getPointer(); }
  
    /// \brief Determine what kind of nested name specifier is stored.
    SpecifierKind getKind() const;
  
    /// \brief Retrieve the identifier stored in this nested name
    /// specifier.
    IdentifierInfo *getAsIdentifier() const {
      if (Prefix.getInt() == StoredIdentifier)
        return (IdentifierInfo *)Specifier;
  
      return nullptr;
    }
  
    /// \brief Retrieve the namespace stored in this nested name
    /// specifier.
    NamespaceDecl *getAsNamespace() const;
  
    /// \brief Retrieve the namespace alias stored in this nested name
    /// specifier.
    NamespaceAliasDecl *getAsNamespaceAlias() const;
  
    /// \brief Retrieve the record declaration stored in this nested name
    /// specifier.
    CXXRecordDecl *getAsRecordDecl() const;
  
    /// \brief Retrieve the type stored in this nested name specifier.
    const Type *getAsType() const {
      if (Prefix.getInt() == StoredTypeSpec ||
          Prefix.getInt() == StoredTypeSpecWithTemplate)
        return (const Type *)Specifier;
  
      return nullptr;
    }
  
    /// \brief Whether this nested name specifier refers to a dependent
    /// type or not.
    bool isDependent() const;
  
    /// \brief Whether this nested name specifier involves a template
    /// parameter.
    bool isInstantiationDependent() const;
  
    /// \brief Whether this nested-name-specifier contains an unexpanded
    /// parameter pack (for C++11 variadic templates).
    bool containsUnexpandedParameterPack() const;
  
    /// \brief Print this nested name specifier to the given output
    /// stream.
    void print(raw_ostream &OS, const PrintingPolicy &Policy) const;
  
    void Profile(llvm37::FoldingSetNodeID &ID) const {
      ID.AddPointer(Prefix.getOpaqueValue());
      ID.AddPointer(Specifier);
    }
  
    /// \brief Dump the nested name specifier to standard output to aid
    /// in debugging.
    void dump(const LangOptions &LO);
  };
  
  /// \brief A C++ nested-name-specifier augmented with source location
  /// information.
  class NestedNameSpecifierLoc {
    NestedNameSpecifier *Qualifier;
    void *Data;
  
    /// \brief Determines the data length for the last component in the
    /// given nested-name-specifier.
    static unsigned getLocalDataLength(NestedNameSpecifier *Qualifier);
  
    /// \brief Determines the data length for the entire
    /// nested-name-specifier.
    static unsigned getDataLength(NestedNameSpecifier *Qualifier);
  
  public:
    /// \brief Construct an empty nested-name-specifier.
    NestedNameSpecifierLoc() : Qualifier(nullptr), Data(nullptr) { }
  
    /// \brief Construct a nested-name-specifier with source location information
    /// from
    NestedNameSpecifierLoc(NestedNameSpecifier *Qualifier, void *Data)
      : Qualifier(Qualifier), Data(Data) { }
  
    /// \brief Evalutes true when this nested-name-specifier location is
    /// non-empty.
    explicit operator bool() const { return Qualifier; }
  
    /// \brief Evalutes true when this nested-name-specifier location is
    /// empty.
    bool hasQualifier() const { return Qualifier; }
  
    /// \brief Retrieve the nested-name-specifier to which this instance
    /// refers.
    NestedNameSpecifier *getNestedNameSpecifier() const {
      return Qualifier;
    }
  
    /// \brief Retrieve the opaque pointer that refers to source-location data.
    void *getOpaqueData() const { return Data; }
  
    /// \brief Retrieve the source range covering the entirety of this
    /// nested-name-specifier.
    ///
    /// For example, if this instance refers to a nested-name-specifier
    /// \c \::std::vector<int>::, the returned source range would cover
    /// from the initial '::' to the last '::'.
    SourceRange getSourceRange() const LLVM37_READONLY;
  
    /// \brief Retrieve the source range covering just the last part of
    /// this nested-name-specifier, not including the prefix.
    ///
    /// For example, if this instance refers to a nested-name-specifier
    /// \c \::std::vector<int>::, the returned source range would cover
    /// from "vector" to the last '::'.
    SourceRange getLocalSourceRange() const;
  
    /// \brief Retrieve the location of the beginning of this
    /// nested-name-specifier.
    SourceLocation getBeginLoc() const {
      return getSourceRange().getBegin();
    }
  
    /// \brief Retrieve the location of the end of this
    /// nested-name-specifier.
    SourceLocation getEndLoc() const {
      return getSourceRange().getEnd();
    }
  
    /// \brief Retrieve the location of the beginning of this
    /// component of the nested-name-specifier.
    SourceLocation getLocalBeginLoc() const {
      return getLocalSourceRange().getBegin();
    }
  
    /// \brief Retrieve the location of the end of this component of the
    /// nested-name-specifier.
    SourceLocation getLocalEndLoc() const {
      return getLocalSourceRange().getEnd();
    }
  
    /// \brief Return the prefix of this nested-name-specifier.
    ///
    /// For example, if this instance refers to a nested-name-specifier
    /// \c \::std::vector<int>::, the prefix is \c \::std::. Note that the
    /// returned prefix may be empty, if this is the first component of
    /// the nested-name-specifier.
    NestedNameSpecifierLoc getPrefix() const {
      if (!Qualifier)
        return *this;
  
      return NestedNameSpecifierLoc(Qualifier->getPrefix(), Data);
    }
  
    /// \brief For a nested-name-specifier that refers to a type,
    /// retrieve the type with source-location information.
    TypeLoc getTypeLoc() const;
  
    /// \brief Determines the data length for the entire
    /// nested-name-specifier.
    unsigned getDataLength() const { return getDataLength(Qualifier); }
  
    friend bool operator==(NestedNameSpecifierLoc X,
                           NestedNameSpecifierLoc Y) {
      return X.Qualifier == Y.Qualifier && X.Data == Y.Data;
    }
  
    friend bool operator!=(NestedNameSpecifierLoc X,
                           NestedNameSpecifierLoc Y) {
      return !(X == Y);
    }
  };
  
  /// \brief Class that aids in the construction of nested-name-specifiers along
  /// with source-location information for all of the components of the
  /// nested-name-specifier.
  class NestedNameSpecifierLocBuilder {
    /// \brief The current representation of the nested-name-specifier we're
    /// building.
    NestedNameSpecifier *Representation;
  
    /// \brief Buffer used to store source-location information for the
    /// nested-name-specifier.
    ///
    /// Note that we explicitly manage the buffer (rather than using a
    /// SmallVector) because \c Declarator expects it to be possible to memcpy()
    /// a \c CXXScopeSpec, and CXXScopeSpec uses a NestedNameSpecifierLocBuilder.
    char *Buffer;
  
    /// \brief The size of the buffer used to store source-location information
    /// for the nested-name-specifier.
    unsigned BufferSize;
  
    /// \brief The capacity of the buffer used to store source-location
    /// information for the nested-name-specifier.
    unsigned BufferCapacity;
  
  public:
    NestedNameSpecifierLocBuilder()
      : Representation(nullptr), Buffer(nullptr), BufferSize(0),
        BufferCapacity(0) {}
  
    NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other);
  
    NestedNameSpecifierLocBuilder &
    operator=(const NestedNameSpecifierLocBuilder &Other);
  
    ~NestedNameSpecifierLocBuilder() {
      if (BufferCapacity)
        delete[] Buffer;
    }
  
    /// \brief Retrieve the representation of the nested-name-specifier.
    NestedNameSpecifier *getRepresentation() const { return Representation; }
  
    /// \brief Extend the current nested-name-specifier by another
    /// nested-name-specifier component of the form 'type::'.
    ///
    /// \param Context The AST context in which this nested-name-specifier
    /// resides.
    ///
    /// \param TemplateKWLoc The location of the 'template' keyword, if present.
    ///
    /// \param TL The TypeLoc that describes the type preceding the '::'.
    ///
    /// \param ColonColonLoc The location of the trailing '::'.
    void Extend(ASTContext &Context, SourceLocation TemplateKWLoc, TypeLoc TL,
                SourceLocation ColonColonLoc);
  
    /// \brief Extend the current nested-name-specifier by another
    /// nested-name-specifier component of the form 'identifier::'.
    ///
    /// \param Context The AST context in which this nested-name-specifier
    /// resides.
    ///
    /// \param Identifier The identifier.
    ///
    /// \param IdentifierLoc The location of the identifier.
    ///
    /// \param ColonColonLoc The location of the trailing '::'.
    void Extend(ASTContext &Context, IdentifierInfo *Identifier,
                SourceLocation IdentifierLoc, SourceLocation ColonColonLoc);
  
    /// \brief Extend the current nested-name-specifier by another
    /// nested-name-specifier component of the form 'namespace::'.
    ///
    /// \param Context The AST context in which this nested-name-specifier
    /// resides.
    ///
    /// \param Namespace The namespace.
    ///
    /// \param NamespaceLoc The location of the namespace name.
    ///
    /// \param ColonColonLoc The location of the trailing '::'.
    void Extend(ASTContext &Context, NamespaceDecl *Namespace,
                SourceLocation NamespaceLoc, SourceLocation ColonColonLoc);
  
    /// \brief Extend the current nested-name-specifier by another
    /// nested-name-specifier component of the form 'namespace-alias::'.
    ///
    /// \param Context The AST context in which this nested-name-specifier
    /// resides.
    ///
    /// \param Alias The namespace alias.
    ///
    /// \param AliasLoc The location of the namespace alias
    /// name.
    ///
    /// \param ColonColonLoc The location of the trailing '::'.
    void Extend(ASTContext &Context, NamespaceAliasDecl *Alias,
                SourceLocation AliasLoc, SourceLocation ColonColonLoc);
  
    /// \brief Turn this (empty) nested-name-specifier into the global
    /// nested-name-specifier '::'.
    void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);
    
    /// \brief Turns this (empty) nested-name-specifier into '__super'
    /// nested-name-specifier.
    ///
    /// \param Context The AST context in which this nested-name-specifier
    /// resides.
    ///
    /// \param RD The declaration of the class in which nested-name-specifier
    /// appeared.
    ///
    /// \param SuperLoc The location of the '__super' keyword.
    /// name.
    ///
    /// \param ColonColonLoc The location of the trailing '::'.
    void MakeSuper(ASTContext &Context, CXXRecordDecl *RD, 
                   SourceLocation SuperLoc, SourceLocation ColonColonLoc);
    /// \brief Make a new nested-name-specifier from incomplete source-location
    /// information.
    ///
    /// This routine should be used very, very rarely, in cases where we
    /// need to synthesize a nested-name-specifier. Most code should instead use
    /// \c Adopt() with a proper \c NestedNameSpecifierLoc.
    void MakeTrivial(ASTContext &Context, NestedNameSpecifier *Qualifier,
                     SourceRange R);
  
    /// \brief Adopt an existing nested-name-specifier (with source-range
    /// information).
    void Adopt(NestedNameSpecifierLoc Other);
  
    /// \brief Retrieve the source range covered by this nested-name-specifier.
    SourceRange getSourceRange() const LLVM37_READONLY {
      return NestedNameSpecifierLoc(Representation, Buffer).getSourceRange();
    }
  
    /// \brief Retrieve a nested-name-specifier with location information,
    /// copied into the given AST context.
    ///
    /// \param Context The context into which this nested-name-specifier will be
    /// copied.
    NestedNameSpecifierLoc getWithLocInContext(ASTContext &Context) const;
  
    /// \brief Retrieve a nested-name-specifier with location
    /// information based on the information in this builder.
    ///
    /// This loc will contain references to the builder's internal data and may
    /// be invalidated by any change to the builder.
    NestedNameSpecifierLoc getTemporary() const {
      return NestedNameSpecifierLoc(Representation, Buffer);
    }
  
    /// \brief Clear out this builder, and prepare it to build another
    /// nested-name-specifier with source-location information.
    void Clear() {
      Representation = nullptr;
      BufferSize = 0;
    }
  
    /// \brief Retrieve the underlying buffer.
    ///
    /// \returns A pair containing a pointer to the buffer of source-location
    /// data and the size of the source-location data that resides in that
    /// buffer.
    std::pair<char *, unsigned> getBuffer() const {
      return std::make_pair(Buffer, BufferSize);
    }
  };
  
  /// Insertion operator for diagnostics.  This allows sending
  /// NestedNameSpecifiers into a diagnostic with <<.
  inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
                                             NestedNameSpecifier *NNS) {
    DB.AddTaggedVal(reinterpret_cast<intptr_t>(NNS),
                    DiagnosticsEngine::ak_nestednamespec);
    return DB;
  }
  
  }
  
  #endif
  