slocker-lite/tests/support/fixtures.cpp

// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

#include "fixtures.h"

#include <fcntl.h>
#include <unistd.h>

#include <algorithm>
#include <cctype>
#include <cstdio>
#include <cstdlib>
#include <fstream>
#include <sstream>
#include <system_error>
#include <vector>

AppConfig g_test_app_config;

std::optional<std::filesystem::path> find_busybox_fixture() {
    std::error_code ec;
    auto path = std::filesystem::current_path(ec) / "images" / "busybox.tar";
    if (ec || !std::filesystem::exists(path, ec) || ec) {
        return std::nullopt;
    }
    return path;
}

namespace {

std::optional<std::string> getenv_opt(const char* name) {
    const char* value = std::getenv(name);
    if (!value) {
        return std::nullopt;
    }
    return std::string(value);
}

}  // namespace

ScratchXdgDirs::ScratchXdgDirs() {
    // Real bug found by testing, not assumed: an earlier version built
    // this vector from `std::string("...").begin()` paired with a
    // *separate* `std::string("...").end()` -- two distinct temporary
    // objects, even though they held identical content. Mixing iterators
    // from two different containers when constructing a third is
    // undefined behavior; here it manifested as an intermittent (SSO/heap
    // address dependent, hence flaky) `std::length_error: cannot create
    // std::vector larger than max_size()` from a garbage begin/end
    // distance, confirmed via ~10 repeated runs of the [integration] tests
    // together before it reproduced. Fixed by using one string instance
    // for both ends of the range.
    std::string tmpl_str = "/tmp/slocker-lite-test-XXXXXX";
    std::vector<char> tmpl(tmpl_str.begin(), tmpl_str.end());
    tmpl.push_back('\0');
    char* created = mkdtemp(tmpl.data());
    path_ = created ? std::filesystem::path(created) : std::filesystem::temp_directory_path() / "slocker-lite-test";
    std::filesystem::create_directories(path_);

    previous_config_home_ = getenv_opt("XDG_CONFIG_HOME");
    previous_state_home_ = getenv_opt("XDG_STATE_HOME");
    setenv("XDG_CONFIG_HOME", path_.c_str(), 1);
    setenv("XDG_STATE_HOME", path_.c_str(), 1);
}

ScratchXdgDirs::~ScratchXdgDirs() {
    if (previous_config_home_) {
        setenv("XDG_CONFIG_HOME", previous_config_home_->c_str(), 1);
    } else {
        unsetenv("XDG_CONFIG_HOME");
    }
    if (previous_state_home_) {
        setenv("XDG_STATE_HOME", previous_state_home_->c_str(), 1);
    } else {
        unsetenv("XDG_STATE_HOME");
    }

    std::error_code ec;
    std::filesystem::remove_all(path_, ec);
}

CapturedStdout::CapturedStdout() {
    std::string tmpl_str = "/tmp/slocker-lite-test-stdout-XXXXXX";
    std::vector<char> tmpl(tmpl_str.begin(), tmpl_str.end());
    tmpl.push_back('\0');
    int fd = mkstemp(tmpl.data());
    temp_path_ = tmpl.data();

    fflush(stdout);
    saved_fd_ = dup(STDOUT_FILENO);
    dup2(fd, STDOUT_FILENO);
    close(fd);
}

CapturedStdout::~CapturedStdout() {
    fflush(stdout);
    if (saved_fd_ >= 0) {
        dup2(saved_fd_, STDOUT_FILENO);
        close(saved_fd_);
    }
    std::error_code ec;
    std::filesystem::remove(temp_path_, ec);
}

std::string CapturedStdout::contents() {
    fflush(stdout);
    std::ifstream in(temp_path_);
    std::ostringstream out;
    out << in.rdbuf();
    return out.str();
}

std::vector<std::string> split_lines_trimmed(const std::string& text) {
    std::vector<std::string> lines;
    std::istringstream iss(text);
    std::string line;
    while (std::getline(iss, line)) {
        while (!line.empty() && std::isspace(static_cast<unsigned char>(line.back()))) {
            line.pop_back();
        }
        if (!line.empty()) {
            lines.push_back(line);
        }
    }
    return lines;
}

std::vector<std::string> extract_marked_lines(const std::string& text) {
    auto lines = split_lines_trimmed(text);
    auto begin = std::find(lines.begin(), lines.end(), "BEGIN-TEST-OUTPUT");
    auto end = std::find(lines.begin(), lines.end(), "END-TEST-OUTPUT");
    if (begin == lines.end() || end == lines.end() || end <= begin) {
        return {};
    }
    return std::vector<std::string>(begin + 1, end);
}