//===- 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 {

class Archive;

class ArchiveMemberHeader {

public:

  friend class Archive;

  ArchiveMemberHeader(Archive const *Parent, const char *RawHeaderPtr,

                      uint64_t Size, Error *Err);

  // ArchiveMemberHeader() = default;

  /// Get the name without looking up long names.

  Expected<StringRef> getRawName() const;

  /// Get the name looking up long names.

  Expected<StringRef> getName(uint64_t Size) const;

  /// Members are not larger than 4GB.

  Expected<uint32_t> getSize() const;

  Expected<sys::fs::perms> getAccessMode() const;

  Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const;

  StringRef getRawLastModified() const {

    return StringRef(ArMemHdr->LastModified,

                     sizeof(ArMemHdr->LastModified)).rtrim(' ');

  }

  Expected<unsigned> getUID() const;

  Expected<unsigned> getGID() const;

  // This returns the size of the private struct ArMemHdrType

  uint64_t getSizeOf() const {

    return sizeof(ArMemHdrType);

  }

private:

  struct ArMemHdrType {

    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];

  };

  Archive const *Parent;

  ArMemHdrType const *ArMemHdr;

};

class Archive : public Binary {

  virtual void anchor();

public:

  class Child {

    friend Archive;

    friend ArchiveMemberHeader;

    const Archive *Parent;

    ArchiveMemberHeader 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);

    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;

    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);

  enum Kind {

    K_GNU,

    K_GNU64,

    K_BSD,

    K_DARWIN,

    K_DARWIN64,

    K_COFF

  };

  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());

  }

  // Cast methods.

  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;

  std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {

    return std::move(ThinBuffers);

  }

private:

  StringRef SymbolTable;

  StringRef StringTable;

  StringRef FirstRegularData;

  uint16_t FirstRegularStartOfFile = -1;

  void setFirstRegular(const Child &C);

  unsigned Format : 3;

  unsigned IsThin : 1;

  mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;

};

} // end namespace object

} // end namespace llvm

#endif // LLVM_OBJECT_ARCHIVE_H