grbc/src/ext_cmake.cc

#include "grbc/ext_cmake.h"
#include "grbc/cJSON.h"
#include "grbc/ext.h"
#include "grbc/helpers.h"
#include "grbc/spec.h"
#include "sol/raii.hpp"
#include <cstdlib>
#include <filesystem>

std::filesystem::path cmake_eval_symlink(const std::filesystem::path &build_dir,
                                         const std::filesystem::path &path) {
  std::filesystem::path c_path = path;

  while (std::filesystem::is_symlink(c_path)) {
    c_path = std::filesystem::read_symlink(c_path);

    // Make path absolute if its relative
    if (c_path.is_relative())
      c_path = path.parent_path() / c_path;

    std::filesystem::path target_path = build_dir / c_path.filename();

    if (std::filesystem::exists(target_path))
      std::filesystem::remove(target_path);

    std::filesystem::copy(c_path, target_path);
  }

  return c_path;
}

std::string cmake_util_read_file(FILE *file) {
  // http://www.fundza.com/c4serious/fileIO_reading_all/index.html

  char line[190];
  std::string result;

  while (fgets(line, 190, file))
    result += line;

  if (result.back() == '\n')
    result.pop_back();

  return result;
}

CMakeProject EXT_grbc_import_cmake(const std::string &cmake_path,
                                   const CMakeConfig &cfg) {
  CMakeProject project{};

  log_msg(("configuring cmake project: " + cmake_path).c_str());

  if (!std::filesystem::exists(cmake_path)) {
    grbc_exception("CMake cannot configure in non-existant directory: " +
                   cmake_path);
  }

  if (!std::filesystem::exists(cmake_path + "/CMakeLists.txt")) {
    grbc_exception("No CMakeLists.txt file in: " + cmake_path);
  }

  std::filesystem::path old_path = std::filesystem::current_path();

  // Change directory into the cmake dir
  std::filesystem::current_path(cmake_path);

  std::filesystem::create_directory("grbc_configure");

  std::filesystem::current_path("./grbc_configure");

  project.build_dir = std::filesystem::current_path().string();

  // Create configure arg string
  std::string configure_arguments;

  for (const std::string &argument : cfg.configure_arguments) {
    configure_arguments += argument + " ";
  }

  // Run configure
  int exit_code =
      std::system(("cmake -S .. -B . -GNinja " + configure_arguments).c_str());

  if (exit_code != EXIT_SUCCESS)
    grbc_exception("Failed to configure cmake project in: " + cmake_path);

  // Collect compilation database
  FILE *compdb = popen("ninja -t compdb", "r");
  std::string compdb_raw = cmake_util_read_file(compdb);

  pclose(compdb);

  project.compdb = cJSON_Parse(compdb_raw.c_str());

  // Build the cmake subproject, we need this so we can copy artifacts later on in the build step

  grbc_log("building cmake subproject...");
  int build_exit_code = std::system("ninja");

  if (build_exit_code != EXIT_SUCCESS)
    grbc_exception("Failed to build cmake project in: " + project.build_dir);

  std::filesystem::current_path(old_path);


  return project;
}

Package EXT_grbc_get_cmake_library(const CMakeProject &self,
                                   const std::string &library_name) {

  // Loop over every output in the compdb

  for (int i = 0; i < cJSON_GetArraySize(self.compdb); i++) {
    cJSON *compdb_item = cJSON_GetArrayItem(self.compdb, i);

    if (!cJSON_HasObjectItem(compdb_item, "output"))
      grbc_exception("Ninja produced invalid compilation database!");

    if (!cJSON_HasObjectItem(compdb_item, "command"))
      grbc_exception("Compilation database item is missing 'command'");

    if (!cJSON_HasObjectItem(compdb_item, "file"))
      grbc_exception("Compilation database item is missing 'file'");

    std::string command =
        cJSON_GetStringValue(cJSON_GetObjectItem(compdb_item, "command"));

    // Only handle objects with an empty command
    // In the compilation databse objects with no command, but an output, and
    // file give us the info we need Info needed: Target name, output name

    if (!command.empty())
      continue;

    std::string output_name =
        cJSON_GetStringValue(cJSON_GetObjectItem(compdb_item, "output"));
    std::string library_path =
        cJSON_GetStringValue(cJSON_GetObjectItem(compdb_item, "file"));

    if (output_name != library_name)
      continue;

    std::filesystem::path full_lib_path = self.build_dir + "/" + library_path;
    full_lib_path =
        cmake_eval_symlink(grbc_get_config().build_dir, full_lib_path);

    Package pkg{};
    pkg.name = output_name;
    pkg.linker_flags = grbc_get_config().build_dir + "/" + full_lib_path.filename().generic_string();

    grbc_log("found cmake library at: " + full_lib_path.generic_string());

    return pkg;
  }

  grbc_exception("Failed to find library with name: " + library_name);

  return Package{};
}

std::string EXT_grbc_get_cmake_library_string(const CMakeProject &self) {
  std::string library_string;

  for (int i = 0; i < cJSON_GetArraySize(self.compdb); i++) {
    cJSON *compdb_item = cJSON_GetArrayItem(self.compdb, i);

    if (!cJSON_HasObjectItem(compdb_item, "output"))
      grbc_exception("Ninja produced invalid compilation database!");

    if (!cJSON_HasObjectItem(compdb_item, "command"))
      grbc_exception("Compilation database item is missing 'command'");

    if (!cJSON_HasObjectItem(compdb_item, "file"))
      grbc_exception("Compilation database item is missing 'file'");

    std::string cmd =
        cJSON_GetStringValue(cJSON_GetObjectItem(compdb_item, "command"));

    if (!cmd.empty())
      continue;

    std::string file =
        cJSON_GetStringValue(cJSON_GetObjectItem(compdb_item, "file"));
    std::string output =
        cJSON_GetStringValue(cJSON_GetObjectItem(compdb_item, "output"));

    library_string += "Target: " + output + "\n";
    library_string += "\tOutputting to file: " + output + "\n\n";
  }

  return library_string;
}

void grbc_cmake_init(sol::state &lua) {
  lua.new_usertype<CMakeConfig>(
      "CMakeConfig", sol::constructors<CMakeConfig(sol::table)>(),
      "configure_arguments", &CMakeConfig::configure_arguments);
  lua.new_usertype<CMakeProject>("CMakeProject", "source_dir",
                                 &CMakeProject::source_dir, "build_dir",
                                 &CMakeProject::build_dir);

  lua["CMakeProject"]["get_library"] = EXT_grbc_get_cmake_library;
  lua["CMakeProject"]["get_library_string"] = EXT_grbc_get_cmake_library_string;

  lua.set("grbc_import_cmake", EXT_grbc_import_cmake);
}

Extension grbc_cmake() {
  Extension ext{};
  ext.name = GRBC_EXT_cmake_NAME;
  ext.hook_init = grbc_cmake_init;

  return ext;
}