//===--- SerializationTest.cpp - Experimental Object Serialization --------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements prototype code for serialization of objects in clang.
//  It is not intended yet for public use, but simply is a placeholder to
//  experiment with new serialization features.  Serialization will eventually
//  be integrated as a proper component of the clang libraries.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/ASTConsumer.h"
#include "clang/AST/CFG.h"
#include "clang.h"
#include "ASTConsumers.h"
#include "clang/AST/TranslationUnit.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Support/Streams.h"
#include <fstream>

using namespace clang;

//===----------------------------------------------------------------------===//
// Driver code.
//===----------------------------------------------------------------------===//

namespace {
  
class SerializationTest : public ASTConsumer {
  TranslationUnit TU;
  Diagnostic &Diags;
  FileManager &FMgr;  
public:  
  SerializationTest(Diagnostic &d, FileManager& fmgr, const LangOptions& LOpts)
                    : TU(LOpts), Diags(d), FMgr(fmgr) {}
  
  ~SerializationTest();

  virtual void Initialize(ASTContext& context) {
    TU.setContext(&context);
  }  

  virtual void HandleTopLevelDecl(Decl *D) {
    TU.AddTopLevelDecl(D);
  }
  
private:
  bool Serialize(llvm::sys::Path& Filename, llvm::sys::Path& FNameDeclPrint);
  bool Deserialize(llvm::sys::Path& Filename, llvm::sys::Path& FNameDeclPrint);
};
  
} // end anonymous namespace

ASTConsumer*
clang::CreateSerializationTest(Diagnostic &Diags, FileManager& FMgr,
                               const LangOptions &LOpts) {
  
  return new SerializationTest(Diags,FMgr,LOpts);
}


bool SerializationTest::Serialize(llvm::sys::Path& Filename,
                                  llvm::sys::Path& FNameDeclPrint) {
  { 
    // Pretty-print the decls to a temp file.
    std::ofstream DeclPP(FNameDeclPrint.c_str());
    assert (DeclPP && "Could not open file for printing out decls.");
    llvm::OwningPtr<ASTConsumer> FilePrinter(CreateASTPrinter(&DeclPP));
    
    for (TranslationUnit::iterator I=TU.begin(), E=TU.end(); I!=E; ++I)
      FilePrinter->HandleTopLevelDecl(*I);
  }
  
  // Serialize the translation unit.
  return EmitASTBitcodeFile(TU,Filename);
}

bool SerializationTest::Deserialize(llvm::sys::Path& Filename,
                                    llvm::sys::Path& FNameDeclPrint) {
  
  // Deserialize the translation unit.
  TranslationUnit* NewTU = ReadASTBitcodeFile(Filename,FMgr);

  if (!NewTU)
    return false;
  
  { 
    // Pretty-print the deserialized decls to a temp file.
    std::ofstream DeclPP(FNameDeclPrint.c_str());
    assert (DeclPP && "Could not open file for printing out decls.");
    llvm::OwningPtr<ASTConsumer> FilePrinter(CreateASTPrinter(&DeclPP));
    
    for (TranslationUnit::iterator I=NewTU->begin(), E=NewTU->end(); I!=E; ++I)
      FilePrinter->HandleTopLevelDecl(*I);
  }
  
  return true;
}
  
namespace {
  class TmpDirJanitor {
    llvm::sys::Path& Dir;
  public:
    explicit TmpDirJanitor(llvm::sys::Path& dir) : Dir(dir) {}

    ~TmpDirJanitor() { 
      llvm::cerr << "Removing: " << Dir.c_str() << '\n';
      Dir.eraseFromDisk(true); 
    }
  };
}

SerializationTest::~SerializationTest() {

  std::string ErrMsg;
  llvm::sys::Path Dir = llvm::sys::Path::GetTemporaryDirectory(&ErrMsg);
  
  if (Dir.isEmpty()) {
    llvm::cerr << "Error: " << ErrMsg << "\n";
    return;
  }
  
  TmpDirJanitor RemoveTmpOnExit(Dir);
    
  llvm::sys::Path FNameDeclBefore = Dir;
  FNameDeclBefore.appendComponent("test.decl_before.txt");

  if (FNameDeclBefore.makeUnique(true,&ErrMsg)) {
    llvm::cerr << "Error: " << ErrMsg << "\n";
    return;
  }
  
  llvm::sys::Path FNameDeclAfter = Dir;
  FNameDeclAfter.appendComponent("test.decl_after.txt");
  
  if (FNameDeclAfter.makeUnique(true,&ErrMsg)) {
    llvm::cerr << "Error: " << ErrMsg << "\n";
    return;
  }

  llvm::sys::Path ASTFilename = Dir;
  ASTFilename.appendComponent("test.ast");
  
  if (ASTFilename.makeUnique(true,&ErrMsg)) {
    llvm::cerr << "Error: " << ErrMsg << "\n";
    return;
  }
  
  // Serialize and then deserialize the ASTs.
  bool status = Serialize(ASTFilename, FNameDeclBefore);
  assert (status && "Serialization failed.");  
  status = Deserialize(ASTFilename, FNameDeclAfter);
  assert (status && "Deserialization failed.");
  
  // Read both pretty-printed files and compare them.
  
  using llvm::MemoryBuffer;
  
  llvm::OwningPtr<MemoryBuffer>
    MBufferSer(MemoryBuffer::getFile(FNameDeclBefore.c_str(),
                                     strlen(FNameDeclBefore.c_str())));
  
  if(!MBufferSer) {
    llvm::cerr << "ERROR: Cannot read pretty-printed file (pre-pickle).\n";
    return;
  }
  
  llvm::OwningPtr<MemoryBuffer>
    MBufferDSer(MemoryBuffer::getFile(FNameDeclAfter.c_str(),
                                      strlen(FNameDeclAfter.c_str())));
  
  if(!MBufferDSer) {
    llvm::cerr << "ERROR: Cannot read pretty-printed file (post-pickle).\n";
    return;
  }
  
  const char *p1 = MBufferSer->getBufferStart();
  const char *e1 = MBufferSer->getBufferEnd();
  const char *p2 = MBufferDSer->getBufferStart();
  const char *e2 = MBufferDSer->getBufferEnd();

  if (MBufferSer->getBufferSize() == MBufferDSer->getBufferSize())
    for ( ; p1 != e1 ; ++p1, ++p2  )
      if (*p1 != *p2) break;
  
  if (p1 != e1 || p2 != e2 )
    llvm::cerr << "ERROR: Pretty-printed files are not the same.\n";
  else
    llvm::cerr << "SUCCESS: Pretty-printed files are the same.\n";
}