////////////////////////////////////////////////////////////////////////////////
/// @brief Aql, v8 context executor
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#include "Aql/V8Executor.h"
#include "Aql/AstNode.h"
#include "Basics/StringBuffer.h"
#include "Utils/Exception.h"
#include "V8/v8-conv.h"
#include "V8/v8-globals.h"

using namespace triagens::aql;

// -----------------------------------------------------------------------------
// --SECTION--                                        constructors / destructors
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief creates an executor
////////////////////////////////////////////////////////////////////////////////

V8Executor::V8Executor () :
  _buffer(nullptr) {
}

////////////////////////////////////////////////////////////////////////////////
/// @brief destroys an executor
////////////////////////////////////////////////////////////////////////////////

V8Executor::~V8Executor () {
  if (_buffer != nullptr) {
    delete _buffer;
    _buffer = nullptr;
  }
}

// -----------------------------------------------------------------------------
// --SECTION--                                                    public methods
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief executes a comparison operation using V8
////////////////////////////////////////////////////////////////////////////////

TRI_json_t* V8Executor::executeComparison (std::string const& func,
                                           AstNode const* lhs,
                                           AstNode const* rhs) {

  triagens::basics::StringBuffer* buffer = getBuffer();
  TRI_ASSERT(buffer != nullptr);

  _buffer->appendText("(function(){ var aql = require(\"org/arangodb/ahuacatl\"); return aql.RELATIONAL_");
  _buffer->appendText(func);
  _buffer->appendText("(");

  lhs->append(buffer);
  
  _buffer->appendText(", ");
  
  rhs->append(buffer);

  _buffer->appendText("); })");

  return execute();
}

// -----------------------------------------------------------------------------
// --SECTION--                                                   private methods
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief create the string buffer
////////////////////////////////////////////////////////////////////////////////

triagens::basics::StringBuffer* V8Executor::getBuffer () {
  if (_buffer == nullptr) {
    _buffer = new triagens::basics::StringBuffer(TRI_UNKNOWN_MEM_ZONE);

    if (_buffer == nullptr) {
      THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
    }

    _buffer->reserve(256);
  }
  else {
    _buffer->clear();
  }

  return _buffer;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief executes the contents of the string buffer
////////////////////////////////////////////////////////////////////////////////

TRI_json_t* V8Executor::execute () {
  TRI_ASSERT(_buffer != nullptr);

  v8::Handle<v8::Script> compiled = v8::Script::Compile(v8::String::New(_buffer->c_str(), (int) _buffer->length()),
                                                        v8::String::New("--script--"));
  
  if (compiled.IsEmpty()) {
    THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
  }
  
  v8::TryCatch tryCatch;
  v8::Handle<v8::Value> func = compiled->Run();
  
  if (tryCatch.HasCaught()) {
    if (tryCatch.CanContinue()) {
      THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
    }
    else {
      TRI_v8_global_t* v8g = static_cast<TRI_v8_global_t*>(v8::Isolate::GetCurrent()->GetData());
      v8g->_canceled = true;

      THROW_ARANGO_EXCEPTION(TRI_ERROR_REQUEST_CANCELED);
    }
  }

  if (func.IsEmpty() || ! func->IsFunction()) {
    THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
  }

  // execute the function
  v8::Handle<v8::Value> args[] = { };
  v8::Handle<v8::Value> result = v8::Handle<v8::Function>::Cast(func)->Call(v8::Object::New(), 0, args);
  
  if (tryCatch.HasCaught()) {
    if (tryCatch.CanContinue()) {
      THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
    }
    else {
      TRI_v8_global_t* v8g = static_cast<TRI_v8_global_t*>(v8::Isolate::GetCurrent()->GetData());
      v8g->_canceled = true;

      THROW_ARANGO_EXCEPTION(TRI_ERROR_REQUEST_CANCELED);
    }
  }

  if (result.IsEmpty()) {
    THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
  }

  return TRI_ObjectToJson(result);
}

// -----------------------------------------------------------------------------
// --SECTION--                                                       END-OF-FILE
// -----------------------------------------------------------------------------

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