chaiscript_engine.hpp

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// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
// Copyright 2009-2017, Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com
 
// This is an open source non-commercial project. Dear PVS-Studio, please check it.
// PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
 
#ifndef CHAISCRIPT_ENGINE_HPP_
#define CHAISCRIPT_ENGINE_HPP_
 
#include <cassert>
#include <exception>
#include <fstream>
#include <functional>
#include <map>
#include <memory>
#include <mutex>
#include <set>
#include <stdexcept>
#include <vector>
#include <cstring>
 
#include "../chaiscript_defines.hpp"
#include "../chaiscript_threading.hpp"
#include "../dispatchkit/boxed_cast_helper.hpp"
#include "../dispatchkit/boxed_value.hpp"
#include "../dispatchkit/dispatchkit.hpp"
#include "../dispatchkit/type_conversions.hpp"
#include "../dispatchkit/proxy_functions.hpp"
#include "chaiscript_common.hpp"
 
#if defined(__linux__) || defined(__unix__) || defined(__APPLE__) || defined(__HAIKU__)
#include <unistd.h>
#endif
 
#if !defined(CHAISCRIPT_NO_DYNLOAD) && defined(_POSIX_VERSION) && !defined(__CYGWIN__)
#include <dlfcn.h>
#endif
 
#if defined(CHAISCRIPT_NO_DYNLOAD)
#include "chaiscript_unknown.hpp"
#elif defined(CHAISCRIPT_WINDOWS)
#include "chaiscript_windows.hpp"
#elif _POSIX_VERSION
#include "chaiscript_posix.hpp"
#else
#include "chaiscript_unknown.hpp"
#endif
 
 
#include "../dispatchkit/exception_specification.hpp"
 
namespace chaiscript
{
   using Namespace = dispatch::Dynamic_Object;
 
  namespace detail
  {
    typedef std::shared_ptr<Loadable_Module> Loadable_Module_Ptr;
  }
 

  class ChaiScript_Basic {
 
    mutable chaiscript::detail::threading::shared_mutex m_mutex;
    mutable chaiscript::detail::threading::recursive_mutex m_use_mutex;
 
    std::set<std::string> m_used_files;
    std::map<std::string, detail::Loadable_Module_Ptr> m_loaded_modules;
    std::set<std::string> m_active_loaded_modules;
 
    std::vector<std::string> m_module_paths;
    std::vector<std::string> m_use_paths;
 
    std::unique_ptr<parser::ChaiScript_Parser_Base> m_parser;
 
    chaiscript::detail::Dispatch_Engine m_engine;
 
    std::map<std::string, std::function<Namespace&()>> m_namespace_generators;

    Boxed_Value do_eval(const std::string &t_input, const std::string &t_filename = "__EVAL__", bool /* t_internal*/  = false) 
    {
      try {
        const auto p = m_parser->parse(t_input, t_filename);
        return p->eval(chaiscript::detail::Dispatch_State(m_engine));
      }
      catch (chaiscript::eval::detail::Return_Value &rv) {
        return rv.retval;
      }
    }
 
 

    const Boxed_Value internal_eval_file(const std::string &t_filename) {
      for (const auto &path : m_use_paths)
      {
        try {
          const auto appendedpath = path + t_filename;
          return do_eval(load_file(appendedpath), appendedpath, true);
        } catch (const exception::file_not_found_error &) {
          // failed to load, try the next path
        } catch (const exception::eval_error &t_ee) {
          throw Boxed_Value(t_ee);
        }
      }
 
      // failed to load by any name
      throw exception::file_not_found_error(t_filename);
 
    }
 
 

    const Boxed_Value internal_eval(const std::string &t_e) {
      try {
        return do_eval(t_e, "__EVAL__", true);
      } catch (const exception::eval_error &t_ee) {
        throw Boxed_Value(t_ee);
      }
    }

    chaiscript::detail::Dispatch_Engine &get_eval_engine() {
      return m_engine;
    }

    void build_eval_system(const ModulePtr &t_lib, const std::vector<Options> &t_opts) {
      if (t_lib)
      {
        add(t_lib);
      }
 
      m_engine.add(fun([this](){ m_engine.dump_system(); }), "dump_system");
      m_engine.add(fun([this](const Boxed_Value &t_bv){ m_engine.dump_object(t_bv); }), "dump_object");
      m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_type){ return m_engine.is_type(t_bv, t_type); }), "is_type");
      m_engine.add(fun([this](const Boxed_Value &t_bv){ return m_engine.type_name(t_bv); }), "type_name");
      m_engine.add(fun([this](const std::string &t_f){ return m_engine.function_exists(t_f); }), "function_exists");
      m_engine.add(fun([this](){ return m_engine.get_function_objects(); }), "get_functions");
      m_engine.add(fun([this](){ return m_engine.get_scripting_objects(); }), "get_objects");
 
      m_engine.add(
          dispatch::make_dynamic_proxy_function(
              [this](const std::vector<Boxed_Value> &t_params) {
                return m_engine.call_exists(t_params);
              })
          , "call_exists");
 
 
      m_engine.add(fun(
            [=](const dispatch::Proxy_Function_Base &t_fun, const std::vector<Boxed_Value> &t_params) -> Boxed_Value {
              Type_Conversions_State s(this->m_engine.conversions(), this->m_engine.conversions().conversion_saves());
              return t_fun(t_params, s);
            }), "call");
 
 
      m_engine.add(fun([this](const Type_Info &t_ti){ return m_engine.get_type_name(t_ti); }), "name");
 
      m_engine.add(fun([this](const std::string &t_type_name, bool t_throw){ return m_engine.get_type(t_type_name, t_throw); }), "type");
      m_engine.add(fun([this](const std::string &t_type_name){ return m_engine.get_type(t_type_name, true); }), "type");
 
      m_engine.add(fun(
            [=](const Type_Info &t_from, const Type_Info &t_to, const std::function<Boxed_Value (const Boxed_Value &)> &t_func) {
              m_engine.add(chaiscript::type_conversion(t_from, t_to, t_func));
            }
          ), "add_type_conversion");
 
 
 
      if (std::find(t_opts.begin(), t_opts.end(), Options::No_Load_Modules) == t_opts.end()
          && std::find(t_opts.begin(), t_opts.end(), Options::Load_Modules) != t_opts.end()) 
      {
        m_engine.add(fun([this](const std::string &t_module, const std::string &t_file){ return load_module(t_module, t_file); }), "load_module");
        m_engine.add(fun([this](const std::string &t_module){ return load_module(t_module); }), "load_module");
      }
 
      if (std::find(t_opts.begin(), t_opts.end(), Options::No_External_Scripts) == t_opts.end()
          && std::find(t_opts.begin(), t_opts.end(), Options::External_Scripts) != t_opts.end())
      {
        m_engine.add(fun([this](const std::string &t_file){ return use(t_file); }), "use");
        m_engine.add(fun([this](const std::string &t_file){ return internal_eval_file(t_file); }), "eval_file");
      }
 
      m_engine.add(fun([this](const std::string &t_str){ return internal_eval(t_str); }), "eval");
      m_engine.add(fun([this](const AST_Node &t_ast){ return eval(t_ast); }), "eval");
 
      m_engine.add(fun([this](const std::string &t_str, const bool t_dump){ return parse(t_str, t_dump); }), "parse");
      m_engine.add(fun([this](const std::string &t_str){ return parse(t_str); }), "parse");
 
 
      m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_name){ add_global_const(t_bv, t_name); }), "add_global_const");
      m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_name){ add_global(t_bv, t_name); }), "add_global");
      m_engine.add(fun([this](const Boxed_Value &t_bv, const std::string &t_name){ set_global(t_bv, t_name); }), "set_global");
 
      m_engine.add(fun([this](const std::string& t_namespace_name) { register_namespace([](Namespace& /*space*/) {}, t_namespace_name); import(t_namespace_name); }), "namespace");
      m_engine.add(fun([this](const std::string& t_namespace_name) { import(t_namespace_name); }), "import");
    }

    static bool skip_bom(std::ifstream &infile) {
        size_t bytes_needed = 3;
        char buffer[3];
 
        memset(buffer, '\0', bytes_needed);
 
        infile.read(buffer, static_cast<std::streamsize>(bytes_needed));
 
        if ((buffer[0] == '\xef')
            && (buffer[1] == '\xbb')
            && (buffer[2] == '\xbf')) {
 
            infile.seekg(3);
            return true;
        }
 
        infile.seekg(0);
 
        return false;
    }

    static std::string load_file(const std::string &t_filename) {
      std::ifstream infile(t_filename.c_str(), std::ios::in | std::ios::ate | std::ios::binary );
 
      if (!infile.is_open()) {
        throw chaiscript::exception::file_not_found_error(t_filename);
      }
 
      auto size = infile.tellg();
      infile.seekg(0, std::ios::beg);
 
      assert(size >= 0);
 
      if (skip_bom(infile)) {
          size-=3; // decrement the BOM size from file size, otherwise we'll get parsing errors
          assert(size >= 0); //and check if there's more text
      }
 
      if (size == std::streampos(0))
      {
        return std::string();
      } else {
        std::vector<char> v(static_cast<size_t>(size));
        infile.read(&v[0], static_cast<std::streamsize>(size));
        return std::string(v.begin(), v.end());
      }
    }
 
    std::vector<std::string> ensure_minimum_path_vec(std::vector<std::string> paths)
    {
      if (paths.empty()) { return {""}; }
      else { return paths; }
    }
 
  public:

    ChaiScript_Basic(const ModulePtr &t_lib,
                     std::unique_ptr<parser::ChaiScript_Parser_Base> &&parser,
                     std::vector<std::string> t_module_paths = {},
                     std::vector<std::string> t_use_paths = {},
                     const std::vector<chaiscript::Options> &t_opts = chaiscript::default_options())
      : m_module_paths(ensure_minimum_path_vec(std::move(t_module_paths))),
        m_use_paths(ensure_minimum_path_vec(std::move(t_use_paths))),
        m_parser(std::move(parser)),
        m_engine(*m_parser)
    {
#if !defined(CHAISCRIPT_NO_DYNLOAD) && defined(_POSIX_VERSION) && !defined(__CYGWIN__)
      // If on Unix, add the path of the current executable to the module search path
      // as windows would do
 
      union cast_union
      {
        Boxed_Value (ChaiScript_Basic::*in_ptr)(const std::string&);
        void *out_ptr;
      };
 
      Dl_info rInfo; 
      memset( &rInfo, 0, sizeof(rInfo) ); 
      cast_union u;
      u.in_ptr = &ChaiScript_Basic::use;
      if ( (dladdr(static_cast<void*>(u.out_ptr), &rInfo) != 0) && (rInfo.dli_fname != nullptr) ) { 
        std::string dllpath(rInfo.dli_fname);
        const size_t lastslash = dllpath.rfind('/');
        if (lastslash != std::string::npos)
        {
          dllpath.erase(lastslash);
        }
 
        // Let's see if this is a link that we should expand
        std::vector<char> buf(2048);
        const auto pathlen = readlink(dllpath.c_str(), &buf.front(), buf.size());
        if (pathlen > 0 && static_cast<size_t>(pathlen) < buf.size())
        {
          dllpath = std::string(&buf.front(), static_cast<size_t>(pathlen));
        }
 
        m_module_paths.insert(m_module_paths.begin(), dllpath+"/");
      }
#endif
      build_eval_system(t_lib, t_opts);
    }
 
#ifndef CHAISCRIPT_NO_DYNLOAD
    explicit ChaiScript_Basic(std::unique_ptr<parser::ChaiScript_Parser_Base> &&parser,
                     std::vector<std::string> t_module_paths = {},
                     std::vector<std::string> t_use_paths = {},
                     const std::vector<chaiscript::Options> &t_opts = chaiscript::default_options())
      : ChaiScript_Basic({}, std::move(parser), t_module_paths, t_use_paths, t_opts)
    {
      try {
        // attempt to load the stdlib
        load_module("chaiscript_stdlib-" + Build_Info::version());
      } catch (const exception::load_module_error &t_err) {
        std::cout << "An error occured while trying to load the chaiscript standard library.\n"
                  << "\n"
                  << "You must either provide a standard library, or compile it in.\n"
                  << "For an example of compiling the standard library in,\n"
                  << "see: https://gist.github.com/lefticus/9456197\n"
                  << "Compiling the stdlib in is the recommended and MOST SUPPORTED method.\n"
                  << "\n"
                  << "\n"
                  << t_err.what();
        throw;
      }
    }
#else // CHAISCRIPT_NO_DYNLOAD
explicit ChaiScript_Basic(std::unique_ptr<parser::ChaiScript_Parser_Base> &&parser,
                          std::vector<std::string> t_module_paths = {},
                          std::vector<std::string> t_use_paths = {},
                          const std::vector<chaiscript::Options> &t_opts = chaiscript::default_options()) = delete;
#endif
 
    parser::ChaiScript_Parser_Base &get_parser()
    {
      return *m_parser;
    }
 
    const Boxed_Value eval(const AST_Node &t_ast)
    {
      try {
        return t_ast.eval(chaiscript::detail::Dispatch_State(m_engine));
      } catch (const exception::eval_error &t_ee) {
        throw Boxed_Value(t_ee);
      }
    }
 
    AST_NodePtr parse(const std::string &t_input, const bool t_debug_print = false)
    {
      auto ast = m_parser->parse(t_input, "PARSE");
      if (t_debug_print) {
        m_parser->debug_print(*ast);
      }
      return ast;
    }
 
 
    std::string get_type_name(const Type_Info &ti) const
    {
      return m_engine.get_type_name(ti);
    }
 
    template<typename T>
    std::string get_type_name() const
    {
      return get_type_name(user_type<T>());
    }
 

    Boxed_Value use(const std::string &t_filename)
    {
      for (const auto &path : m_use_paths)
      {
        const auto appendedpath = path + t_filename;
        try {
 
          chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
          chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::shared_mutex> l2(m_mutex);
 
          Boxed_Value retval;
 
          if (m_used_files.count(appendedpath) == 0)
          {
            l2.unlock();
            retval = eval_file(appendedpath);
            l2.lock();
            m_used_files.insert(appendedpath);
          }
 
          return retval; // return, we loaded it, or it was already loaded
        } catch (const exception::file_not_found_error &e) {
          if (e.filename != appendedpath) {
            // a nested file include failed
            throw;
          }
          // failed to load, try the next path
        }
      }
 
      // failed to load by any name
      throw exception::file_not_found_error(t_filename);
    }

    ChaiScript_Basic &add_global_const(const Boxed_Value &t_bv, const std::string &t_name)
    {
      Name_Validator::validate_object_name(t_name);
      m_engine.add_global_const(t_bv, t_name);
      return *this;
    }

    ChaiScript_Basic &add_global(const Boxed_Value &t_bv, const std::string &t_name)
    {
      Name_Validator::validate_object_name(t_name);
      m_engine.add_global(t_bv, t_name);
      return *this;
    }
 
    ChaiScript_Basic &set_global(const Boxed_Value &t_bv, const std::string &t_name)
    {
      Name_Validator::validate_object_name(t_name);
      m_engine.set_global(t_bv, t_name);
      return *this;
    }

    struct State
    {
      std::set<std::string> used_files;
      chaiscript::detail::Dispatch_Engine::State engine_state;
      std::set<std::string> active_loaded_modules;
    };

    State get_state() const
    {
      chaiscript::detail::threading::lock_guard<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
      chaiscript::detail::threading::shared_lock<chaiscript::detail::threading::shared_mutex> l2(m_mutex);
 
      State s;
      s.used_files = m_used_files;
      s.engine_state = m_engine.get_state();
      s.active_loaded_modules = m_active_loaded_modules;
      return s;
    }

    void set_state(const State &t_state)
    {
      chaiscript::detail::threading::lock_guard<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
      chaiscript::detail::threading::shared_lock<chaiscript::detail::threading::shared_mutex> l2(m_mutex);
 
      m_used_files = t_state.used_files;
      m_active_loaded_modules = t_state.active_loaded_modules;
      m_engine.set_state(t_state.engine_state);
    }

    std::map<std::string, Boxed_Value> get_locals() const
    {
      return m_engine.get_locals();
    }

    void set_locals(const std::map<std::string, Boxed_Value> &t_locals)
    {
      m_engine.set_locals(t_locals);
    }

    template<typename T>
    ChaiScript_Basic &add(const T &t_t, const std::string &t_name)
    {
      Name_Validator::validate_object_name(t_name);
      m_engine.add(t_t, t_name);
      return *this;
    }

    ChaiScript_Basic &add(const Type_Conversion &d)
    {
      m_engine.add(d);
      return *this;
    }

    ChaiScript_Basic &add(const ModulePtr &t_p)
    {
      t_p->apply(*this, this->get_eval_engine());
      return *this;
    }

    std::string load_module(const std::string &t_module_name)
    {
#ifdef CHAISCRIPT_NO_DYNLOAD
      (void)t_module_name; // -Wunused-parameter
      throw chaiscript::exception::load_module_error("Loadable module support was disabled (CHAISCRIPT_NO_DYNLOAD)");
#else
      std::vector<exception::load_module_error> errors;
      std::string version_stripped_name = t_module_name;
      size_t version_pos = version_stripped_name.find("-" + Build_Info::version());
      if (version_pos != std::string::npos)
      {
        version_stripped_name.erase(version_pos);
      }
 
      std::vector<std::string> prefixes{"lib", "cyg", ""};
 
      std::vector<std::string> postfixes{".dll", ".so", ".bundle", ""};
 
      for (auto & elem : m_module_paths)
      {
        for (auto & prefix : prefixes)
        {
          for (auto & postfix : postfixes)
          {
            try {
              const auto name = elem + prefix + t_module_name + postfix;
              // std::cerr << "trying location: " << name << '\n';
              load_module(version_stripped_name, name);
              return name;
            } catch (const chaiscript::exception::load_module_error &e) {
              // std::cerr << "error: " << e.what() << '\n';
              errors.push_back(e);
              // Try next set
            }
          }
        }
      }
 
      throw chaiscript::exception::load_module_error(t_module_name, errors);
#endif
    }

    void load_module(const std::string &t_module_name, const std::string &t_filename)
    {
      chaiscript::detail::threading::lock_guard<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
 
      if (m_loaded_modules.count(t_module_name) == 0)
      {
        detail::Loadable_Module_Ptr lm(new detail::Loadable_Module(t_module_name, t_filename));
        m_loaded_modules[t_module_name] = lm;
        m_active_loaded_modules.insert(t_module_name);
        add(lm->m_moduleptr);
      } else if (m_active_loaded_modules.count(t_module_name) == 0) {
        m_active_loaded_modules.insert(t_module_name);
        add(m_loaded_modules[t_module_name]->m_moduleptr);
      } 
    }
 

    Boxed_Value operator()(const std::string &t_script, const Exception_Handler &t_handler = Exception_Handler())
    {
      return eval(t_script, t_handler);
    }

    template<typename T>
    T eval(const std::string &t_input, const Exception_Handler &t_handler = Exception_Handler(), const std::string &t_filename="__EVAL__")
    {
      return m_engine.boxed_cast<T>(eval(t_input, t_handler, t_filename));
    }

    template<typename Type>
      decltype(auto) boxed_cast(const Boxed_Value &bv) const
      {
        return(m_engine.boxed_cast<Type>(bv));
      }
 

    Boxed_Value eval(const std::string &t_input, const Exception_Handler &t_handler = Exception_Handler(), const std::string &t_filename="__EVAL__")
    {
      try {
        return do_eval(t_input, t_filename);
      } catch (Boxed_Value &bv) {
        if (t_handler) {
          t_handler->handle(bv, m_engine);
        }
        throw;
      }
    }

    Boxed_Value eval_file(const std::string &t_filename, const Exception_Handler &t_handler = Exception_Handler()) {
      return eval(load_file(t_filename), t_handler, t_filename);
    }

    template<typename T>
    T eval_file(const std::string &t_filename, const Exception_Handler &t_handler = Exception_Handler()) {
      return m_engine.boxed_cast<T>(eval_file(t_filename, t_handler));
    }

    void import(const std::string& t_namespace_name)
    {
       chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
 
       if (m_engine.get_scripting_objects().count(t_namespace_name)) {
          throw std::runtime_error("Namespace: " + t_namespace_name + " was already defined");
       }
       else if (m_namespace_generators.count(t_namespace_name)) {
          m_engine.add_global(var(std::ref(m_namespace_generators[t_namespace_name]())), t_namespace_name);
       }
       else {
          throw std::runtime_error("No registered namespace: " + t_namespace_name);
       }
    }

    void register_namespace(const std::function<void(Namespace&)>& t_namespace_generator, const std::string& t_namespace_name)
    {
       chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
 
       if (!m_namespace_generators.count(t_namespace_name)) {
          // contain the namespace object memory within the m_namespace_generators map
          m_namespace_generators.emplace(std::make_pair(t_namespace_name, [=, space = Namespace()]() mutable -> Namespace& { t_namespace_generator(space); return space; }));
       }
       else {
          throw std::runtime_error("Namespace: " + t_namespace_name + " was already registered.");
       }
    }
  };
 
}
#endif /* CHAISCRIPT_ENGINE_HPP_ */