iZo/include/izo/Process.hpp

#pragma once

#include <cstdint>
#include <filesystem>
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

namespace izo {

struct ProcessOptions {
    std::filesystem::path executable;
    std::vector<std::string> arguments;
    std::filesystem::path workingDirectory;
    bool detached = false;
    bool captureOutput = false;
    bool pipeStdin = false;
    // Used by RunProcess. A negative value waits indefinitely.
    std::int64_t timeoutMs = -1;
};

struct ProcessResult {
    bool started = false;
    std::uint32_t processId = 0;
    std::string errorMessage;
    explicit operator bool() const noexcept { return started; }
};

ProcessResult LaunchProcess(const ProcessOptions& options);

class Process {
public:
    Process() = default;
    ~Process();
    Process(Process&&) noexcept = default;
    Process& operator=(Process&& other) noexcept;
    Process(const Process&) = delete;
    Process& operator=(const Process&) = delete;

    explicit operator bool() const noexcept { return state_ != nullptr; }
    std::uint32_t Id() const noexcept;
    bool IsRunning() const;
    // Returns false if the timeout expires or this Process is invalid.
    bool Wait(std::int64_t timeoutMs = -1, std::string* errorMessage = nullptr);
    // Forcefully terminates the child process.
    bool Terminate(std::string* errorMessage = nullptr);
    std::optional<int> ExitCode() const;

    bool WriteStdin(std::string_view data, std::string* errorMessage = nullptr);
    bool CloseStdin(std::string* errorMessage = nullptr);
    // Captured output is complete after Wait succeeds.
    std::string Stdout() const;
    std::string Stderr() const;

private:
    struct State;
    explicit Process(std::shared_ptr<State> state) : state_(std::move(state)) {}
    std::shared_ptr<State> state_;

    friend Process StartProcess(const ProcessOptions&, std::string*);
};

Process StartProcess(const ProcessOptions& options, std::string* errorMessage = nullptr);

struct RunProcessResult {
    bool started = false;
    bool timedOut = false;
    int exitCode = -1;
    std::string stdoutText;
    std::string stderrText;
    std::string errorMessage;

    explicit operator bool() const noexcept { return started && !timedOut && exitCode == 0; }
};

RunProcessResult RunProcess(const ProcessOptions& options);

bool IsProcessRunning(std::uint32_t processId) noexcept;
std::uint32_t GetCurrentProcessId() noexcept;
std::uint32_t GetParentProcessId() noexcept;

} // namespace izo