Compiler_Module_Resolver.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
#ifndef COMPILER_MODULE_RESOLVER_H
#define COMPILER_MODULE_RESOLVER_H
 
#include <sstream>
#include <string>
 
#include <ah-source.H>
#include <tpl_dynArray.H>
 
namespace Aleph {
struct Compiler_Module_Dependency
{
  std::string module_name;  
  Source_Span span;         
};
 
struct Compiler_Module_Descriptor
{
  std::string name;                              
  DynArray<Compiler_Module_Dependency> imports;  
};
 
enum class Compiler_Module_Resolution_Issue_Kind
{
  Missing_Dependency,
  Cyclic_Dependency
};
 
struct Compiler_Module_Resolution_Issue
{
  Compiler_Module_Resolution_Issue_Kind kind
    = Compiler_Module_Resolution_Issue_Kind::Missing_Dependency;
  size_t module_index = 0;                            
  size_t dependency_index = static_cast<size_t>(-1);  
  std::string module_name;                            
  std::string dependency_name;                        
  Source_Span span;  
};
 
struct Compiler_Module_Resolution_Result
{
  bool valid = true;       
  DynArray<size_t> order;  
  DynArray<Compiler_Module_Resolution_Issue> issues;  
};
 
inline const char *compiler_module_resolution_issue_name(
  const Compiler_Module_Resolution_Issue_Kind kind) noexcept
{
  switch (kind)
    {
    case Compiler_Module_Resolution_Issue_Kind::Missing_Dependency:
      return "Missing_Dependency";
    case Compiler_Module_Resolution_Issue_Kind::Cyclic_Dependency:
      return "Cyclic_Dependency";
    }
 
  return "Unknown";
}
 
inline std::string compiler_render_module_order(const DynArray<size_t> &order,
                                                const DynArray<Compiler_Module_Descriptor> &modules)
{
  std::ostringstream out;
  out << "ImportOrder\n";
  for (size_t i = 0; i < order.size(); ++i)
    {
      const auto index = order.access(i);
      const auto name = index < modules.size() ? modules.access(index).name : "<invalid-module>";
      out << "  [" << i << "] " << name << '\n';
    }
  return out.str();
}
 
namespace Compiler_Module_Resolver_Detail {
inline size_t find_module_index(const DynArray<Compiler_Module_Descriptor> &modules,
                                const std::string &name) noexcept
{
  for (size_t i = 0; i < modules.size(); ++i)
    if (modules.access(i).name == name)
      return i;
  return static_cast<size_t>(-1);
}
 
inline bool resolve_visit(const DynArray<Compiler_Module_Descriptor> &modules,
                          const size_t index,
                          DynArray<unsigned char> &states,
                          Compiler_Module_Resolution_Result &result)
{
  const auto state = states.access(index);
  if (state == 2)
    return true;
  if (state == 1 or state == 3)
    return false;
 
  states.access(index) = 1;
  const auto &module = modules.access(index);
  for (size_t i = 0; i < module.imports.size(); ++i)
    {
      const auto &dep = module.imports.access(i);
      const auto dep_index = find_module_index(modules, dep.module_name);
      if (dep_index == static_cast<size_t>(-1))
        {
          result.valid = false;
          result.issues.append({Compiler_Module_Resolution_Issue_Kind::Missing_Dependency,
                                index,
                                static_cast<size_t>(-1),
                                module.name,
                                dep.module_name,
                                dep.span});
          continue;
        }
 
      if (dep_index == index)
        {
          result.valid = false;
          result.issues.append({Compiler_Module_Resolution_Issue_Kind::Cyclic_Dependency,
                                index,
                                dep_index,
                                module.name,
                                dep.module_name,
                                dep.span});
          continue;
        }
 
      if (states.access(dep_index) == 1)
        {
          result.valid = false;
          result.issues.append({Compiler_Module_Resolution_Issue_Kind::Cyclic_Dependency,
                                index,
                                dep_index,
                                module.name,
                                dep.module_name,
                                dep.span});
          states.access(index) = 3;
          return false;
        }
 
      if (states.access(dep_index) == 0 and not resolve_visit(modules, dep_index, states, result))
        {
          states.access(index) = 3;
          return false;
        }
    }
 
  states.access(index) = 2;
  result.order.append(index);
  return true;
}
}  // namespace Compiler_Module_Resolver_Detail
 
inline Compiler_Module_Resolution_Result compiler_resolve_module_order(
  const DynArray<Compiler_Module_Descriptor> &modules)
{
  Compiler_Module_Resolution_Result result;
  DynArray<unsigned char> states;
  for (size_t i = 0; i < modules.size(); ++i)
    states.append(0);
 
  for (size_t i = 0; i < modules.size(); ++i)
    if (states.access(i) == 0)
      Compiler_Module_Resolver_Detail::resolve_visit(modules, i, states, result);
 
  return result;
}
}  // namespace Aleph
 
#endif