// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#include "rustllvm.h"

#include "llvm/Object/Archive.h"
#include "llvm/Object/ArchiveWriter.h"

using namespace llvm;
using namespace llvm::object;

struct RustArchiveMember {
  const char *filename;
  const char *name;
  Archive::Child child;

  RustArchiveMember()
      : filename(nullptr), name(nullptr),
#if LLVM_VERSION_GE(3, 8)
        child(nullptr, nullptr, nullptr)
#else
        child(nullptr, nullptr)
#endif
  {
  }
  ~RustArchiveMember() {}
};

struct RustArchiveIterator {
  bool first;
  Archive::child_iterator cur;
  Archive::child_iterator end;
#if LLVM_VERSION_GE(3, 9)
  Error err;

  RustArchiveIterator() : first(true), err(Error::success()) {}
#else
  RustArchiveIterator() : first(true) {}
#endif
};

enum class LLVMRustArchiveKind {
  Other,
  GNU,
  MIPS64,
  BSD,
  COFF,
};

static Archive::Kind from_rust(LLVMRustArchiveKind kind) {
  switch (kind) {
  case LLVMRustArchiveKind::GNU:
    return Archive::K_GNU;
  case LLVMRustArchiveKind::MIPS64:
    return Archive::K_MIPS64;
  case LLVMRustArchiveKind::BSD:
    return Archive::K_BSD;
  case LLVMRustArchiveKind::COFF:
    return Archive::K_COFF;
  default:
    llvm_unreachable("Bad ArchiveKind.");
  }
}

typedef OwningBinary<Archive> *LLVMRustArchiveRef;
typedef RustArchiveMember *LLVMRustArchiveMemberRef;
typedef Archive::Child *LLVMRustArchiveChildRef;
typedef Archive::Child const *LLVMRustArchiveChildConstRef;
typedef RustArchiveIterator *LLVMRustArchiveIteratorRef;

extern "C" LLVMRustArchiveRef LLVMRustOpenArchive(char *path) {
  ErrorOr<std::unique_ptr<MemoryBuffer>> buf_or =
      MemoryBuffer::getFile(path, -1, false);
  if (!buf_or) {
    LLVMRustSetLastError(buf_or.getError().message().c_str());
    return nullptr;
  }

#if LLVM_VERSION_LE(3, 8)
  ErrorOr<std::unique_ptr<Archive>> archive_or =
#else
  Expected<std::unique_ptr<Archive>> archive_or =
#endif
      Archive::create(buf_or.get()->getMemBufferRef());

  if (!archive_or) {
#if LLVM_VERSION_LE(3, 8)
    LLVMRustSetLastError(archive_or.getError().message().c_str());
#else
    LLVMRustSetLastError(toString(archive_or.takeError()).c_str());
#endif
    return nullptr;
  }

  OwningBinary<Archive> *ret = new OwningBinary<Archive>(
      std::move(archive_or.get()), std::move(buf_or.get()));

  return ret;
}

extern "C" void LLVMRustDestroyArchive(LLVMRustArchiveRef ar) { delete ar; }

extern "C" LLVMRustArchiveIteratorRef
LLVMRustArchiveIteratorNew(LLVMRustArchiveRef ra) {
  Archive *ar = ra->getBinary();
  RustArchiveIterator *rai = new RustArchiveIterator();
#if LLVM_VERSION_LE(3, 8)
  rai->cur = ar->child_begin();
#else
  rai->cur = ar->child_begin(rai->err);
  if (rai->err) {
    LLVMRustSetLastError(toString(std::move(rai->err)).c_str());
    delete rai;
    return nullptr;
  }
#endif
  rai->end = ar->child_end();
  return rai;
}

extern "C" LLVMRustArchiveChildConstRef
LLVMRustArchiveIteratorNext(LLVMRustArchiveIteratorRef rai) {
  if (rai->cur == rai->end)
    return nullptr;

  // Advancing the iterator validates the next child, and this can
  // uncover an error. LLVM requires that we check all Errors,
  // so we only advance the iterator if we actually need to fetch
  // the next child.
  // This means we must not advance the iterator in the *first* call,
  // but instead advance it *before* fetching the child in all later calls.
  if (!rai->first) {
    ++rai->cur;
#if LLVM_VERSION_GE(3, 9)
    if (rai->err) {
      LLVMRustSetLastError(toString(std::move(rai->err)).c_str());
      return nullptr;
    }
#endif
  } else {
    rai->first = false;
  }

  if (rai->cur == rai->end)
    return nullptr;

#if LLVM_VERSION_EQ(3, 8)
  const ErrorOr<Archive::Child> *cur = rai->cur.operator->();
  if (!*cur) {
    LLVMRustSetLastError(cur->getError().message().c_str());
    return nullptr;
  }
  const Archive::Child &child = cur->get();
#else
  const Archive::Child &child = *rai->cur.operator->();
#endif
  Archive::Child *ret = new Archive::Child(child);

  return ret;
}

extern "C" void LLVMRustArchiveChildFree(LLVMRustArchiveChildRef child) {
  delete child;
}

extern "C" void LLVMRustArchiveIteratorFree(LLVMRustArchiveIteratorRef rai) {
  delete rai;
}

extern "C" const char *
LLVMRustArchiveChildName(LLVMRustArchiveChildConstRef child, size_t *size) {
#if LLVM_VERSION_GE(4, 0)
  Expected<StringRef> name_or_err = child->getName();
  if (!name_or_err) {
    // rustc_llvm currently doesn't use this error string, but it might be useful
    // in the future, and in the mean time this tells LLVM that the error was
    // not ignored and that it shouldn't abort the process.
    LLVMRustSetLastError(toString(name_or_err.takeError()).c_str());
    return nullptr;
  }
#else
  ErrorOr<StringRef> name_or_err = child->getName();
  if (name_or_err.getError())
    return nullptr;
#endif
  StringRef name = name_or_err.get();
  *size = name.size();
  return name.data();
}

extern "C" const char *LLVMRustArchiveChildData(LLVMRustArchiveChildRef child,
                                                size_t *size) {
  StringRef buf;
#if LLVM_VERSION_GE(4, 0)
  Expected<StringRef> buf_or_err = child->getBuffer();
  if (!buf_or_err) {
    LLVMRustSetLastError(toString(buf_or_err.takeError()).c_str());
    return nullptr;
  }
#else
  ErrorOr<StringRef> buf_or_err = child->getBuffer();
  if (buf_or_err.getError()) {
    LLVMRustSetLastError(buf_or_err.getError().message().c_str());
    return nullptr;
  }
#endif
  buf = buf_or_err.get();
  *size = buf.size();
  return buf.data();
}

extern "C" LLVMRustArchiveMemberRef
LLVMRustArchiveMemberNew(char *Filename, char *Name,
                         LLVMRustArchiveChildRef child) {
  RustArchiveMember *Member = new RustArchiveMember;
  Member->filename = Filename;
  Member->name = Name;
  if (child)
    Member->child = *child;
  return Member;
}

extern "C" void LLVMRustArchiveMemberFree(LLVMRustArchiveMemberRef Member) {
  delete Member;
}

extern "C" LLVMRustResult
LLVMRustWriteArchive(char *Dst, size_t NumMembers,
                     const LLVMRustArchiveMemberRef *NewMembers,
                     bool WriteSymbtab, LLVMRustArchiveKind rust_kind) {

#if LLVM_VERSION_LE(3, 8)
  std::vector<NewArchiveIterator> Members;
#else
  std::vector<NewArchiveMember> Members;
#endif
  auto Kind = from_rust(rust_kind);

  for (size_t i = 0; i < NumMembers; i++) {
    auto Member = NewMembers[i];
    assert(Member->name);
    if (Member->filename) {
#if LLVM_VERSION_GE(3, 9)
      Expected<NewArchiveMember> MOrErr =
          NewArchiveMember::getFile(Member->filename, true);
      if (!MOrErr) {
        LLVMRustSetLastError(toString(MOrErr.takeError()).c_str());
        return LLVMRustResult::Failure;
      }
      Members.push_back(std::move(*MOrErr));
#elif LLVM_VERSION_EQ(3, 8)
      Members.push_back(NewArchiveIterator(Member->filename));
#else
      Members.push_back(NewArchiveIterator(Member->filename, Member->name));
#endif
    } else {
#if LLVM_VERSION_LE(3, 8)
      Members.push_back(NewArchiveIterator(Member->child, Member->name));
#else
      Expected<NewArchiveMember> MOrErr =
          NewArchiveMember::getOldMember(Member->child, true);
      if (!MOrErr) {
        LLVMRustSetLastError(toString(MOrErr.takeError()).c_str());
        return LLVMRustResult::Failure;
      }
      Members.push_back(std::move(*MOrErr));
#endif
    }
  }
#if LLVM_VERSION_GE(3, 8)
  auto pair = writeArchive(Dst, Members, WriteSymbtab, Kind, true, false);
#else
  auto pair = writeArchive(Dst, Members, WriteSymbtab, Kind, true);
#endif
  if (!pair.second)
    return LLVMRustResult::Success;
  LLVMRustSetLastError(pair.second.message().c_str());
  return LLVMRustResult::Failure;
}