Vendor tiny-process-library

Fixes #113.

external/tpl/process.hpp

@@ -0,0 +1,169 @@
+#ifndef TINY_PROCESS_LIBRARY_HPP_
+#define TINY_PROCESS_LIBRARY_HPP_
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <unordered_map>
+#include <vector>
+#ifndef _WIN32
+#include <sys/wait.h>
+#endif
+
+namespace TinyProcessLib {
+/// Additional parameters to Process constructors.
+struct Config {
+  /// Buffer size for reading stdout and stderr. Default is 131072 (128 kB).
+  std::size_t buffer_size = 131072;
+  /// Set to true to inherit file descriptors from parent process. Default is false.
+  /// On Windows: has no effect unless read_stdout==nullptr, read_stderr==nullptr and open_stdin==false.
+  bool inherit_file_descriptors = false;
+
+  /// On Windows only: controls how the process is started, mimics STARTUPINFO's wShowWindow.
+  /// See: https://docs.microsoft.com/en-us/windows/desktop/api/processthreadsapi/ns-processthreadsapi-startupinfoa
+  /// and https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-showwindow
+  enum class ShowWindow {
+    hide = 0,
+    show_normal = 1,
+    show_minimized = 2,
+    maximize = 3,
+    show_maximized = 3,
+    show_no_activate = 4,
+    show = 5,
+    minimize = 6,
+    show_min_no_active = 7,
+    show_na = 8,
+    restore = 9,
+    show_default = 10,
+    force_minimize = 11
+  };
+  /// On Windows only: controls how the window is shown.
+  ShowWindow show_window{ShowWindow::show_default};
+};
+
+/// Platform independent class for creating processes.
+/// Note on Windows: it seems not possible to specify which pipes to redirect.
+/// Thus, at the moment, if read_stdout==nullptr, read_stderr==nullptr and open_stdin==false,
+/// the stdout, stderr and stdin are sent to the parent process instead.
+class Process {
+public:
+#ifdef _WIN32
+  typedef unsigned long id_type; // Process id type
+  typedef void *fd_type;         // File descriptor type
+#ifdef UNICODE
+  typedef std::wstring string_type;
+#else
+  typedef std::string string_type;
+#endif
+#else
+  typedef pid_t id_type;
+  typedef int fd_type;
+  typedef std::string string_type;
+#endif
+  typedef std::unordered_map<string_type, string_type> environment_type;
+
+private:
+  class Data {
+  public:
+    Data() noexcept;
+    id_type id;
+#ifdef _WIN32
+    void *handle{nullptr};
+#endif
+    int exit_status{-1};
+  };
+
+public:
+  /// Starts a process with the environment of the calling process.
+  Process(const std::vector<string_type> &arguments, const string_type &path = string_type(),
+          std::function<void(const char *bytes, size_t n)> read_stdout = nullptr,
+          std::function<void(const char *bytes, size_t n)> read_stderr = nullptr,
+          bool open_stdin = false,
+          const Config &config = {}) noexcept;
+  /// Starts a process with the environment of the calling process.
+  Process(const string_type &command, const string_type &path = string_type(),
+          std::function<void(const char *bytes, size_t n)> read_stdout = nullptr,
+          std::function<void(const char *bytes, size_t n)> read_stderr = nullptr,
+          bool open_stdin = false,
+          const Config &config = {}) noexcept;
+
+  /// Starts a process with specified environment.
+  Process(const std::vector<string_type> &arguments,
+          const string_type &path,
+          const environment_type &environment,
+          std::function<void(const char *bytes, size_t n)> read_stdout = nullptr,
+          std::function<void(const char *bytes, size_t n)> read_stderr = nullptr,
+          bool open_stdin = false,
+          const Config &config = {}) noexcept;
+  /// Starts a process with specified environment.
+  Process(const string_type &command,
+          const string_type &path,
+          const environment_type &environment,
+          std::function<void(const char *bytes, size_t n)> read_stdout = nullptr,
+          std::function<void(const char *bytes, size_t n)> read_stderr = nullptr,
+          bool open_stdin = false,
+          const Config &config = {}) noexcept; /// Starts a process with specified environment.
+#ifndef _WIN32
+  /// Starts a process with the environment of the calling process.
+  /// Supported on Unix-like systems only.
+  Process(const std::function<void()> &function,
+          std::function<void(const char *bytes, size_t n)> read_stdout = nullptr,
+          std::function<void(const char *bytes, size_t n)> read_stderr = nullptr,
+          bool open_stdin = false,
+          const Config &config = {}) noexcept;
+#endif
+  ~Process() noexcept;
+
+  /// Get the process id of the started process.
+  id_type get_id() const noexcept;
+  /// Wait until process is finished, and return exit status.
+  int get_exit_status() noexcept;
+  /// If process is finished, returns true and sets the exit status. Returns false otherwise.
+  bool try_get_exit_status(int &exit_status) noexcept;
+  /// Write to stdin.
+  bool write(const char *bytes, size_t n);
+  /// Write to stdin. Convenience function using write(const char *, size_t).
+  bool write(const std::string &str);
+  /// Close stdin. If the process takes parameters from stdin, use this to notify that all parameters have been sent.
+  void close_stdin() noexcept;
+
+  /// Kill the process. force=true is only supported on Unix-like systems.
+  void kill(bool force = false) noexcept;
+  /// Kill a given process id. Use kill(bool force) instead if possible. force=true is only supported on Unix-like systems.
+  static void kill(id_type id, bool force = false) noexcept;
+#ifndef _WIN32
+  /// Send the signal signum to the process.
+  void signal(int signum) noexcept;
+#endif
+
+private:
+  Data data;
+  bool closed;
+  std::mutex close_mutex;
+  std::function<void(const char *bytes, size_t n)> read_stdout;
+  std::function<void(const char *bytes, size_t n)> read_stderr;
+#ifndef _WIN32
+  std::thread stdout_stderr_thread;
+#else
+  std::thread stdout_thread, stderr_thread;
+#endif
+  bool open_stdin;
+  std::mutex stdin_mutex;
+
+  Config config;
+
+  std::unique_ptr<fd_type> stdout_fd, stderr_fd, stdin_fd;
+
+  id_type open(const std::vector<string_type> &arguments, const string_type &path, const environment_type *environment = nullptr) noexcept;
+  id_type open(const string_type &command, const string_type &path, const environment_type *environment = nullptr) noexcept;
+#ifndef _WIN32
+  id_type open(const std::function<void()> &function) noexcept;
+#endif
+  void async_read() noexcept;
+  void close_fds() noexcept;
+};
+
+} // namespace TinyProcessLib
+
+#endif // TINY_PROCESS_LIBRARY_HPP_