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#include "engine/googletest.hpp"

extern "C" {
#include <unistd.h>
}

#include <cerrno>
#include <cstdlib>
#include <fstream>

#include "engine/googletest_list.hpp"
#include "engine/googletest_result.hpp"
#include "engine/exceptions.hpp"
#include "model/test_case.hpp"
#include "model/test_program.hpp"
#include "model/test_result.hpp"
#include "utils/defs.hpp"
#include "utils/env.hpp"
#include "utils/format/macros.hpp"
#include "utils/fs/path.hpp"
#include "utils/logging/macros.hpp"
#include "utils/optional.ipp"
#include "utils/process/exceptions.hpp"
#include "utils/process/operations.hpp"
#include "utils/process/status.hpp"
#include "utils/stream.hpp"

namespace config = utils::config;
namespace fs = utils::fs;
namespace process = utils::process;

using utils::optional;


namespace {


/// Basename of the file containing the result written by the googletest
/// testcase.
///
/// TODO: Use more structured output format someday, like the googletest's JSON
/// or XML format to avoid dealing with upstream formatting changes, as there's
/// no guarantee that the output format (which is more or less custom/freeform)
/// won't change in the future, making compatibility with all versions
/// potentially difficult to scrape for.
///
/// Using either format will require pulling in a third party library and
/// understanding the schema of the format. As it stands in 1.9.0,
/// googletest doesn't document this expectation very well and instead seems
/// to rely on third-party solutions for doing structured output via the
/// listener interfaces.


/// Magic numbers returned by exec_list when exec(2) fails.
enum list_exit_code {
    exit_eacces = 90,
    exit_enoent,
    exit_enoexec,
};


}  // anonymous namespace


/// Executes a test program's list operation.
///
/// This method is intended to be called within a subprocess and is expected
/// to terminate execution either by exec(2)ing the test program or by
/// exiting with a failure.
///
/// \param test_program The test program to execute.
void
engine::googletest_interface::exec_list(
    const model::test_program& test_program,
    const config::properties_map& /*vars*/) const
{
    const process::args_vector args{
        "--gtest_color=no",
        "--gtest_list_tests",
    };

    try {
        process::exec_unsafe(test_program.absolute_path(), args);
    } catch (const process::system_error& e) {
        if (e.original_errno() == EACCES)
            ::_exit(exit_eacces);
        else if (e.original_errno() == ENOENT)
            ::_exit(exit_enoent);
        else if (e.original_errno() == ENOEXEC)
            ::_exit(exit_enoexec);
        throw;
    }
}


/// Computes the test cases list of a test program.
///
/// \param status The termination status of the subprocess used to execute
///     the exec_test() method or none if the test timed out.
/// \param stdout_path Path to the file containing the stdout of the test.
///
/// \return A list of test cases.
///
/// \throw error If there is a problem parsing the test case list.
model::test_cases_map
engine::googletest_interface::parse_list(
    const optional< process::status >& status,
    const fs::path& stdout_path,
    const fs::path& /* stderr_path */) const
{
    if (!status)
        throw engine::error("Test case list timed out");
    if (status.get().exited()) {
        const int exitstatus = status.get().exitstatus();
        if (exitstatus == EXIT_SUCCESS) {
            // Nothing to do; fall through.
        } else if (exitstatus == exit_eacces) {
            throw engine::error("Permission denied to run test program");
        } else if (exitstatus == exit_enoent) {
            throw engine::error("Cannot find test program");
        } else if (exitstatus == exit_enoexec) {
            throw engine::error("Invalid test program format");
        } else {
            throw engine::error("Test program did not exit cleanly; exited "
                                "with status: " + std::to_string(exitstatus));
        }
    } else {
        throw engine::error("Test program received signal");
    }

    std::ifstream input(stdout_path.c_str());
    if (!input)
        throw engine::load_error(stdout_path, "Cannot open file for read");
    const model::test_cases_map test_cases = parse_googletest_list(input);

    return test_cases;
}


/// Executes a test case of the test program.
///
/// This method is intended to be called within a subprocess and is expected
/// to terminate execution either by exec(2)ing the test program or by
/// exiting with a failure.
///
/// \param test_program The test program to execute.
/// \param test_case_name Name of the test case to invoke.
/// \param vars User-provided variables to pass to the test program.
void
engine::googletest_interface::exec_test(
    const model::test_program& test_program,
    const std::string& test_case_name,
    const config::properties_map& vars,
    const fs::path& /* control_directory */) const
{
    for (config::properties_map::const_iterator iter = vars.begin();
         iter != vars.end(); ++iter) {
        utils::setenv(F("TEST_ENV_%s") % (*iter).first, (*iter).second);
    }

    process::args_vector args{
        "--gtest_color=no",
        F("--gtest_filter=%s") % (test_case_name)
    };
    process::exec(test_program.absolute_path(), args);
    __builtin_unreachable();
}


/// Computes the result of a test case based on its termination status.
///
/// \param status The termination status of the subprocess used to execute
///     the exec_test() method or none if the test timed out.
/// \param stdout_path Path to the file containing the stdout of the
///     test.
///
/// \return A test result.
model::test_result
engine::googletest_interface::compute_result(
    const optional< process::status >& status,
    const fs::path& /* control_directory */,
    const fs::path& stdout_path,
    const fs::path& /* stderr_path */) const
{
    if (!status) {
        return model::test_result(model::test_result_broken,
                                  "Test case body timed out");
    }

    return calculate_googletest_result(status, stdout_path);
}