//===--- Serialization.cpp - Read and write Swift modules -----------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

#include "swift/Serialization/Serialization.h"
#include "swift/AST/AST.h"
#include "swift/AST/Diagnostics.h"
#include "swift/Serialization/BCRecordLayout.h"
#include "swift/Subsystems.h"
#include "llvm/Bitcode/BitstreamWriter.h"
#include "llvm/Config/Config.h"
#include "llvm/Support/raw_ostream.h"

using namespace swift;
using namespace swift::serialization;

namespace {
  class Serializer {
    SmallVector<char, 0> Buffer;
    llvm::BitstreamWriter Out;

    /// A reusable buffer for emitting records.
    SmallVector<uint64_t, 64> ScratchRecord;

    /// Writes the Swift module file header and BLOCKINFO block.
    void writeHeader();

    /// Top-level entry point for serializing a translation unit module.
    void writeTranslationUnit(const TranslationUnit *TU);

  public:
    Serializer() : Out(Buffer) {}

    /// Serialize a translation unit to the given stream.
    void writeToStream(const TranslationUnit *TU, raw_ostream &os);
  };
} // end anonymous namespace

void Serializer::writeHeader() {
  // Swift module file type: 'SMod'.
  Out.Emit((unsigned)'S', 8);
  Out.Emit((unsigned)'M', 8);
  Out.Emit((unsigned)'o', 8);
  Out.Emit((unsigned)'d', 8);

  {
    BCBlockRAII restoreBlock(Out, llvm::bitc::BLOCKINFO_BLOCK_ID, 2);
  }

  {
    BCBlockRAII restoreBlock(Out, CONTROL_BLOCK_ID, 3);

    BCRecordLayout<
      BCLiteral<METADATA>, // ID
      BCFixed<16>, // Module format major version
      BCFixed<16>, // Module format minor version
      BCBlob // misc. version information
    > Metadata(Out);

    // FIXME: put a real version in here.
#ifdef LLVM_VERSION_INFO
# define EXTRA_VERSION_STRING PACKAGE_STRING LLVM_VERSION_INFO
#else
# define EXTRA_VERSION_STRING PACKAGE_STRING
#endif
    Metadata.emit(ScratchRecord,
                  METADATA, VERSION_MAJOR, VERSION_MINOR, EXTRA_VERSION_STRING);
#undef EXTRA_VERSION_STRING
  }
}

void Serializer::writeTranslationUnit(const TranslationUnit *TU) {
  (void)TU;
}

void Serializer::writeToStream(const TranslationUnit *TU, raw_ostream &os) {
  writeHeader();
  writeTranslationUnit(TU);

  os.write(Buffer.data(), Buffer.size());
  os.flush();
  Buffer.clear();
}

void swift::serialize(const TranslationUnit *TU, const char *outputPath) {
  std::string errorInfo;
  llvm::raw_fd_ostream out(outputPath, errorInfo,
                           llvm::raw_fd_ostream::F_Binary);

  if (out.has_error() || !errorInfo.empty()) {
    TU->Ctx.Diags.diagnose(SourceLoc(), diag::error_opening_output, outputPath,
                           errorInfo);
    out.clear_error();
    return;
  }

  Serializer S;
  S.writeToStream(TU, out);
}