text: //===- Archive.h - ar archive file format -----------------------*- 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
  //
  //===----------------------------------------------------------------------===//
  //
  // This file declares the ar archive file format class.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_OBJECT_ARCHIVE_H
  #define LLVM_OBJECT_ARCHIVE_H
  
  #include "llvm/ADT/Optional.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/ADT/fallible_iterator.h"
  #include "llvm/ADT/iterator_range.h"
  #include "llvm/Object/Binary.h"
  #include "llvm/Support/Chrono.h"
  #include "llvm/Support/Error.h"
  #include "llvm/Support/FileSystem.h"
  #include "llvm/Support/MemoryBuffer.h"
  #include <algorithm>
  #include <cassert>
  #include <cstdint>
  #include <memory>
  #include <string>
  #include <vector>
  
  namespace llvm {
  namespace object {
  
  const char ArchiveMagic[] = "!<arch>\n";
  const char ThinArchiveMagic[] = "!<thin>\n";
  const char BigArchiveMagic[] = "<bigaf>\n";
  
  class Archive;
  
  class AbstractArchiveMemberHeader {
  protected:
    AbstractArchiveMemberHeader(const Archive *Parent) : Parent(Parent){};
  
  public:
    friend class Archive;
    virtual std::unique_ptr<AbstractArchiveMemberHeader> clone() const = 0;
    virtual ~AbstractArchiveMemberHeader() = default;
  
    /// Get the name without looking up long names.
    virtual Expected<StringRef> getRawName() const = 0;
    virtual StringRef getRawAccessMode() const = 0;
    virtual StringRef getRawLastModified() const = 0;
    virtual StringRef getRawUID() const = 0;
    virtual StringRef getRawGID() const = 0;
  
    /// Get the name looking up long names.
    virtual Expected<StringRef> getName(uint64_t Size) const = 0;
    virtual Expected<uint64_t> getSize() const = 0;
    virtual uint64_t getOffset() const = 0;
  
    /// Get next file member location.
    virtual Expected<const char *> getNextChildLoc() const = 0;
    virtual Expected<bool> isThin() const = 0;
  
    Expected<sys::fs::perms> getAccessMode() const;
    Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const;
    Expected<unsigned> getUID() const;
    Expected<unsigned> getGID() const;
  
    /// Returns the size in bytes of the format-defined member header of the
    /// concrete archive type.
    virtual uint64_t getSizeOf() const = 0;
  
    const Archive *Parent;
  };
  
  template <typename T>
  class CommonArchiveMemberHeader : public AbstractArchiveMemberHeader {
  public:
    CommonArchiveMemberHeader(const Archive *Parent, const T *RawHeaderPtr)
        : AbstractArchiveMemberHeader(Parent), ArMemHdr(RawHeaderPtr){};
    StringRef getRawAccessMode() const override;
    StringRef getRawLastModified() const override;
    StringRef getRawUID() const override;
    StringRef getRawGID() const override;
  
    uint64_t getOffset() const override;
    uint64_t getSizeOf() const override { return sizeof(T); }
  
    T const *ArMemHdr;
  };
  
  struct UnixArMemHdrType {
    char Name[16];
    char LastModified[12];
    char UID[6];
    char GID[6];
    char AccessMode[8];
    char Size[10]; ///< Size of data, not including header or padding.
    char Terminator[2];
  };
  
  class ArchiveMemberHeader : public CommonArchiveMemberHeader<UnixArMemHdrType> {
  public:
    ArchiveMemberHeader(const Archive *Parent, const char *RawHeaderPtr,
                        uint64_t Size, Error *Err);
  
    std::unique_ptr<AbstractArchiveMemberHeader> clone() const override {
      return std::make_unique<ArchiveMemberHeader>(*this);
    }
  
    Expected<StringRef> getRawName() const override;
  
    Expected<StringRef> getName(uint64_t Size) const override;
    Expected<uint64_t> getSize() const override;
    Expected<const char *> getNextChildLoc() const override;
    Expected<bool> isThin() const override;
  };
  
  // File Member Header
  struct BigArMemHdrType {
    char Size[20];       // File member size in decimal
    char NextOffset[20]; // Next member offset in decimal
    char PrevOffset[20]; // Previous member offset in decimal
    char LastModified[12];
    char UID[12];
    char GID[12];
    char AccessMode[12];
    char NameLen[4]; // File member name length in decimal
    union {
      char Name[2]; // Start of member name
      char Terminator[2];
    };
  };
  
  // Define file member header of AIX big archive.
  class BigArchiveMemberHeader
      : public CommonArchiveMemberHeader<BigArMemHdrType> {
  
  public:
    BigArchiveMemberHeader(Archive const *Parent, const char *RawHeaderPtr,
                           uint64_t Size, Error *Err);
    std::unique_ptr<AbstractArchiveMemberHeader> clone() const override {
      return std::make_unique<BigArchiveMemberHeader>(*this);
    }
  
    Expected<StringRef> getRawName() const override;
    Expected<uint64_t> getRawNameSize() const;
  
    Expected<StringRef> getName(uint64_t Size) const override;
    Expected<uint64_t> getSize() const override;
    Expected<const char *> getNextChildLoc() const override;
    Expected<uint64_t> getNextOffset() const;
    Expected<bool> isThin() const override { return false; }
  };
  
  class Archive : public Binary {
    virtual void anchor();
  
  public:
    class Child {
      friend Archive;
      friend AbstractArchiveMemberHeader;
  
      const Archive *Parent;
      std::unique_ptr<AbstractArchiveMemberHeader> Header;
      /// Includes header but not padding byte.
      StringRef Data;
      /// Offset from Data to the start of the file.
      uint16_t StartOfFile;
  
      Expected<bool> isThinMember() const;
  
    public:
      Child(const Archive *Parent, const char *Start, Error *Err);
      Child(const Archive *Parent, StringRef Data, uint16_t StartOfFile);
  
      Child(const Child &C)
          : Parent(C.Parent), Data(C.Data), StartOfFile(C.StartOfFile) {
        if (C.Header)
          Header = C.Header->clone();
      }
  
      Child(Child &&C) {
        Parent = std::move(C.Parent);
        Header = std::move(C.Header);
        Data = C.Data;
        StartOfFile = C.StartOfFile;
      }
  
      Child &operator=(Child &&C) noexcept {
        if (&C == this)
          return *this;
  
        Parent = std::move(C.Parent);
        Header = std::move(C.Header);
        Data = C.Data;
        StartOfFile = C.StartOfFile;
  
        return *this;
      }
  
      Child &operator=(const Child &C) {
        if (&C == this)
          return *this;
  
        Parent = C.Parent;
        if (C.Header)
          Header = C.Header->clone();
        Data = C.Data;
        StartOfFile = C.StartOfFile;
  
        return *this;
      }
  
      bool operator==(const Child &other) const {
        assert(!Parent || !other.Parent || Parent == other.Parent);
        return Data.begin() == other.Data.begin();
      }
  
      const Archive *getParent() const { return Parent; }
      Expected<Child> getNext() const;
  
      Expected<StringRef> getName() const;
      Expected<std::string> getFullName() const;
      Expected<StringRef> getRawName() const { return Header->getRawName(); }
  
      Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const {
        return Header->getLastModified();
      }
  
      StringRef getRawLastModified() const {
        return Header->getRawLastModified();
      }
  
      Expected<unsigned> getUID() const { return Header->getUID(); }
      Expected<unsigned> getGID() const { return Header->getGID(); }
  
      Expected<sys::fs::perms> getAccessMode() const {
        return Header->getAccessMode();
      }
  
      /// \return the size of the archive member without the header or padding.
      Expected<uint64_t> getSize() const;
      /// \return the size in the archive header for this member.
      Expected<uint64_t> getRawSize() const;
  
      Expected<StringRef> getBuffer() const;
      uint64_t getChildOffset() const;
      uint64_t getDataOffset() const { return getChildOffset() + StartOfFile; }
  
      Expected<MemoryBufferRef> getMemoryBufferRef() const;
  
      Expected<std::unique_ptr<Binary>>
      getAsBinary(LLVMContext *Context = nullptr) const;
    };
  
    class ChildFallibleIterator {
      Child C;
  
    public:
      ChildFallibleIterator() : C(Child(nullptr, nullptr, nullptr)) {}
      ChildFallibleIterator(const Child &C) : C(C) {}
  
      const Child *operator->() const { return &C; }
      const Child &operator*() const { return C; }
  
      bool operator==(const ChildFallibleIterator &other) const {
        // Ignore errors here: If an error occurred during increment then getNext
        // will have been set to child_end(), and the following comparison should
        // do the right thing.
        return C == other.C;
      }
  
      bool operator!=(const ChildFallibleIterator &other) const {
        return !(*this == other);
      }
  
      Error inc() {
        auto NextChild = C.getNext();
        if (!NextChild)
          return NextChild.takeError();
        C = std::move(*NextChild);
        return Error::success();
      }
    };
  
    using child_iterator = fallible_iterator<ChildFallibleIterator>;
  
    class Symbol {
      const Archive *Parent;
      uint32_t SymbolIndex;
      uint32_t StringIndex; // Extra index to the string.
  
    public:
      Symbol(const Archive *p, uint32_t symi, uint32_t stri)
          : Parent(p), SymbolIndex(symi), StringIndex(stri) {}
  
      bool operator==(const Symbol &other) const {
        return (Parent == other.Parent) && (SymbolIndex == other.SymbolIndex);
      }
  
      StringRef getName() const;
      Expected<Child> getMember() const;
      Symbol getNext() const;
    };
  
    class symbol_iterator {
      Symbol symbol;
  
    public:
      symbol_iterator(const Symbol &s) : symbol(s) {}
  
      const Symbol *operator->() const { return &symbol; }
      const Symbol &operator*() const { return symbol; }
  
      bool operator==(const symbol_iterator &other) const {
        return symbol == other.symbol;
      }
  
      bool operator!=(const symbol_iterator &other) const {
        return !(*this == other);
      }
  
      symbol_iterator &operator++() { // Preincrement
        symbol = symbol.getNext();
        return *this;
      }
    };
  
    Archive(MemoryBufferRef Source, Error &Err);
    static Expected<std::unique_ptr<Archive>> create(MemoryBufferRef Source);
  
    /// Size field is 10 decimal digits long
    static const uint64_t MaxMemberSize = 9999999999;
  
    enum Kind { K_GNU, K_GNU64, K_BSD, K_DARWIN, K_DARWIN64, K_COFF, K_AIXBIG };
  
    Kind kind() const { return (Kind)Format; }
    bool isThin() const { return IsThin; }
  
    child_iterator child_begin(Error &Err, bool SkipInternal = true) const;
    child_iterator child_end() const;
    iterator_range<child_iterator> children(Error &Err,
                                            bool SkipInternal = true) const {
      return make_range(child_begin(Err, SkipInternal), child_end());
    }
  
    symbol_iterator symbol_begin() const;
    symbol_iterator symbol_end() const;
    iterator_range<symbol_iterator> symbols() const {
      return make_range(symbol_begin(), symbol_end());
    }
  
    static bool classof(Binary const *v) { return v->isArchive(); }
  
    // check if a symbol is in the archive
    Expected<Optional<Child>> findSym(StringRef name) const;
  
    bool isEmpty() const;
    bool hasSymbolTable() const;
    StringRef getSymbolTable() const { return SymbolTable; }
    StringRef getStringTable() const { return StringTable; }
    uint32_t getNumberOfSymbols() const;
    virtual uint64_t getFirstChildOffset() const { return getArchiveMagicLen(); }
  
    std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {
      return std::move(ThinBuffers);
    }
  
    std::unique_ptr<AbstractArchiveMemberHeader>
    createArchiveMemberHeader(const char *RawHeaderPtr, uint64_t Size,
                              Error *Err) const;
  
  protected:
    uint64_t getArchiveMagicLen() const;
    void setFirstRegular(const Child &C);
  
  private:
    StringRef SymbolTable;
    StringRef StringTable;
  
    StringRef FirstRegularData;
    uint16_t FirstRegularStartOfFile = -1;
  
    unsigned Format : 3;
    unsigned IsThin : 1;
    mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
  };
  
  class BigArchive : public Archive {
    /// Fixed-Length Header.
    struct FixLenHdr {
      char Magic[sizeof(BigArchiveMagic) - 1]; ///< Big archive magic string.
      char MemOffset[20];                      ///< Offset to member table.
      char GlobSymOffset[20];                  ///< Offset to global symbol table.
      char
          GlobSym64Offset[20]; ///< Offset global symbol table for 64-bit objects.
      char FirstChildOffset[20]; ///< Offset to first archive member.
      char LastChildOffset[20];  ///< Offset to last archive member.
      char FreeOffset[20];       ///< Offset to first mem on free list.
    };
  
    const FixLenHdr *ArFixLenHdr;
    uint64_t FirstChildOffset = 0;
    uint64_t LastChildOffset = 0;
  
  public:
    BigArchive(MemoryBufferRef Source, Error &Err);
    uint64_t getFirstChildOffset() const override { return FirstChildOffset; }
    uint64_t getLastChildOffset() const { return LastChildOffset; }
  };
  
  } // end namespace object
  } // end namespace llvm
  
  #endif // LLVM_OBJECT_ARCHIVE_H
  