path_resolver.cpp

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// Copyright 2021 CEA LIST
// SPDX-FileCopyrightText: 2022 CEA LIST <gael.de-chalendar@cea.fr>
//
// SPDX-License-Identifier: MIT
 
#include <cstdlib>
#include <iostream>
#include <sstream>
#include <vector>
 
#include <boost/filesystem.hpp>
 
#include "path_resolver.h"
 
using namespace std;
namespace fs = boost::filesystem;
 
namespace deeplima
{
 
PathResolver::PathResolver(const std::string& paths)
{
  init(paths);
}
 
string PathResolver::resolve(const string& prefix, const string& path, const vector<string>& accepted_ext) const
{
  fs::path p;
  if (prefix.empty())
  {
    p = path;
  }
  else
  {
    p = fs::path(prefix) / path;
  }
 
  if (p.is_absolute())
  {
    return p.string();
  }
 
  vector<string> candidates = { p.string() };
  if (!p.extension().empty())
  {
    candidates.push_back(p.stem().string());
  }
 
  for (const string& resources_path : m_resources_paths)
  {
    for (const string& fn : candidates)
    {
      if (fn.empty())
      {
        continue;
      }
 
      fs::path full_path = fs::path(resources_path) / fn;
      if (fs::is_regular_file(full_path) || fs::is_symlink(full_path))
      {
        return full_path.string();
      }
 
      for (const string& ext : accepted_ext)
      {
        if (ext.empty())
        {
          continue;
        }
 
        full_path = fs::path(resources_path) / fn;
        if (ext.substr(0, 1) != ".")
        {
          full_path += ".";
        }
        full_path += ext;
 
        if (fs::is_regular_file(full_path) || fs::is_symlink(full_path))
        {
          return full_path.string();
        }
      }
    }
  }
 
  return "";
}
 
string PathResolver::find_user_data_home()
{
  fs::path user_data_home;
  const char* p_xdg_data_home = getenv("XDG_DATA_HOME");
 
  if (nullptr != p_xdg_data_home)
  {
    user_data_home = p_xdg_data_home;
  }
 
  if (user_data_home.empty())
  {
    user_data_home = getenv("HOME");
    if (!user_data_home.empty())
    {
      user_data_home = user_data_home / ".local" / "share";
    }
  }
 
  return user_data_home.string();
}
 
std::vector<std::string> split (const std::string &s, char delim) {
    std::vector<std::string> result;
    std::stringstream ss (s);
    std::string item;
 
    while (getline (ss, item, delim)) {
        result.push_back (item);
    }
 
    return result;
}
 
void PathResolver::init(const std::string& paths)
{
  auto var = std::getenv("LIMA_RESOURCES");
  auto dirs = split(paths, ':');
  if (var)
  {
    dirs = split(var, ':');
  }
  m_resources_paths.insert(std::end(m_resources_paths), std::begin(dirs), std::end(dirs));
  fs::path user_data_home = find_user_data_home();
  if (!user_data_home.empty())
  {
    m_resources_paths.emplace_back((user_data_home / "lima" / "resources").string());
  }
}
 
}