Class SubprocessLauncher

All Implemented Interfaces:
PointerInterface

public class SubprocessLauncher extends Object
This class contains a set of options for launching child processes,
such as where its standard input and output will be directed, the
argument list, the environment, and more.

While the #GSubprocess class has high level functions covering
popular cases, use of this class allows access to more advanced
options. It can also be used to launch multiple subprocesses with
a similar configuration.

https://docs.gtk.org/gio/class.SubprocessLauncher.html

  • Constructor Details

    • SubprocessLauncher

      public SubprocessLauncher(PointerContainer pointer)
    • SubprocessLauncher

      public SubprocessLauncher(int flags)
      Creates a new #GSubprocessLauncher.

      The launcher is created with the default options. A copy of the
      environment of the calling process is made at the time of this call
      and will be used as the environment that the process is launched in.
      Parameters:
      flags - #GSubprocessFlags
  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()
    • close

      public void close()
      Closes all the file descriptors previously passed to the object with
      g_subprocess_launcher_take_fd(), g_subprocess_launcher_take_stderr_fd(), etc.

      After calling this method, any subsequent calls to g_subprocess_launcher_spawn() or g_subprocess_launcher_spawnv() will
      return %G_IO_ERROR_CLOSED. This method is idempotent if
      called more than once.

      This function is called automatically when the #GSubprocessLauncher
      is disposed, but is provided separately so that garbage collected
      language bindings can call it earlier to guarantee when FDs are closed.
    • getenv

      public Str getenv(@Nonnull Str variable)
      Returns the value of the environment variable @variable in the
      environment of processes launched from this launcher.

      On UNIX, the returned string can be an arbitrary byte string.
      On Windows, it will be UTF-8.
      Parameters:
      variable - the environment variable to get
      Returns:
      the value of the environment variable, %NULL if unset
    • getenv

      public Str getenv(String variable)
      Returns the value of the environment variable @variable in the
      environment of processes launched from this launcher.

      On UNIX, the returned string can be an arbitrary byte string.
      On Windows, it will be UTF-8.
      Parameters:
      variable - the environment variable to get
      Returns:
      the value of the environment variable, %NULL if unset
    • setChildSetup

      public void setChildSetup(SubprocessLauncher.OnSpawnChildSetupFunc child_setup, @Nullable Pointer user_data, SubprocessLauncher.OnDestroyNotify destroy_notify)
      Sets up a child setup function.

      The child setup function will be called after fork() but before
      exec() on the child's side.

      @destroy_notify will not be automatically called on the child's side
      of the fork(). It will only be called when the last reference on the
      #GSubprocessLauncher is dropped or when a new child setup function is
      given.

      %NULL can be given as @child_setup to disable the functionality.

      Child setup functions are only available on UNIX.
      Parameters:
      child_setup - a #GSpawnChildSetupFunc to use as the child setup function
      user_data - user data for @child_setup
      destroy_notify - a #GDestroyNotify for @user_data
    • setCwd

      public void setCwd(@Nonnull Str cwd)
      Sets the current working directory that processes will be launched
      with.

      By default processes are launched with the current working directory
      of the launching process at the time of launch.
      Parameters:
      cwd - the cwd for launched processes
    • setCwd

      public void setCwd(String cwd)
      Sets the current working directory that processes will be launched
      with.

      By default processes are launched with the current working directory
      of the launching process at the time of launch.
      Parameters:
      cwd - the cwd for launched processes
    • setFlags

      public void setFlags(int flags)
      Sets the flags on the launcher.

      The default flags are %G_SUBPROCESS_FLAGS_NONE.

      You may not set flags that specify conflicting options for how to
      handle a particular stdio stream (eg: specifying both
      %G_SUBPROCESS_FLAGS_STDIN_PIPE and
      %G_SUBPROCESS_FLAGS_STDIN_INHERIT).

      You may also not set a flag that conflicts with a previous call to a
      function like g_subprocess_launcher_set_stdin_file_path() or
      g_subprocess_launcher_take_stdout_fd().
      Parameters:
      flags - #GSubprocessFlags
    • setStderrFilePath

      public void setStderrFilePath(@Nullable Str path)
      Sets the file path to use as the stderr for spawned processes.

      If @path is %NULL then any previously given path is unset.

      The file will be created or truncated when the process is spawned, as
      would be the case if using '2>' at the shell.

      If you want to send both stdout and stderr to the same file then use
      %G_SUBPROCESS_FLAGS_STDERR_MERGE.

      You may not set a stderr file path if a stderr fd is already set or
      if the launcher flags contain any flags directing stderr elsewhere.

      This feature is only available on UNIX.
      Parameters:
      path - a filename or %NULL
    • setStderrFilePath

      public void setStderrFilePath(String path)
      Sets the file path to use as the stderr for spawned processes.

      If @path is %NULL then any previously given path is unset.

      The file will be created or truncated when the process is spawned, as
      would be the case if using '2>' at the shell.

      If you want to send both stdout and stderr to the same file then use
      %G_SUBPROCESS_FLAGS_STDERR_MERGE.

      You may not set a stderr file path if a stderr fd is already set or
      if the launcher flags contain any flags directing stderr elsewhere.

      This feature is only available on UNIX.
      Parameters:
      path - a filename or %NULL
    • setStdinFilePath

      public void setStdinFilePath(@Nonnull Str path)
      Sets the file path to use as the stdin for spawned processes.

      If @path is %NULL then any previously given path is unset.

      The file must exist or spawning the process will fail.

      You may not set a stdin file path if a stdin fd is already set or if
      the launcher flags contain any flags directing stdin elsewhere.

      This feature is only available on UNIX.
      Parameters:
      path -
    • setStdinFilePath

      public void setStdinFilePath(String path)
      Sets the file path to use as the stdin for spawned processes.

      If @path is %NULL then any previously given path is unset.

      The file must exist or spawning the process will fail.

      You may not set a stdin file path if a stdin fd is already set or if
      the launcher flags contain any flags directing stdin elsewhere.

      This feature is only available on UNIX.
      Parameters:
      path -
    • setStdoutFilePath

      public void setStdoutFilePath(@Nullable Str path)
      Sets the file path to use as the stdout for spawned processes.

      If @path is %NULL then any previously given path is unset.

      The file will be created or truncated when the process is spawned, as
      would be the case if using '>' at the shell.

      You may not set a stdout file path if a stdout fd is already set or
      if the launcher flags contain any flags directing stdout elsewhere.

      This feature is only available on UNIX.
      Parameters:
      path - a filename or %NULL
    • setStdoutFilePath

      public void setStdoutFilePath(String path)
      Sets the file path to use as the stdout for spawned processes.

      If @path is %NULL then any previously given path is unset.

      The file will be created or truncated when the process is spawned, as
      would be the case if using '>' at the shell.

      You may not set a stdout file path if a stdout fd is already set or
      if the launcher flags contain any flags directing stdout elsewhere.

      This feature is only available on UNIX.
      Parameters:
      path - a filename or %NULL
    • setenv

      public void setenv(@Nonnull Str variable, @Nonnull Str value, boolean overwrite)
      Sets the environment variable @variable in the environment of
      processes launched from this launcher.

      On UNIX, both the variable's name and value can be arbitrary byte
      strings, except that the variable's name cannot contain '='.
      On Windows, they should be in UTF-8.
      Parameters:
      variable - the environment variable to set, must not contain '='
      value - the new value for the variable
      overwrite - whether to change the variable if it already exists
    • setenv

      public void setenv(String variable, String value, boolean overwrite)
      Sets the environment variable @variable in the environment of
      processes launched from this launcher.

      On UNIX, both the variable's name and value can be arbitrary byte
      strings, except that the variable's name cannot contain '='.
      On Windows, they should be in UTF-8.
      Parameters:
      variable - the environment variable to set, must not contain '='
      value - the new value for the variable
      overwrite - whether to change the variable if it already exists
    • takeFd

      public void takeFd(int source_fd, int target_fd)
      Transfer an arbitrary file descriptor from parent process to the
      child. This function takes ownership of the @source_fd; it will be closed
      in the parent when @self is freed.

      By default, all file descriptors from the parent will be closed.
      This function allows you to create (for example) a custom `pipe()` or
      `socketpair()` before launching the process, and choose the target
      descriptor in the child.

      An example use case is GNUPG, which has a command line argument
      `--passphrase-fd` providing a file descriptor number where it expects
      the passphrase to be written.
      Parameters:
      source_fd - File descriptor in parent process
      target_fd - Target descriptor for child process
    • takeStderrFd

      public void takeStderrFd(int fd)
      Sets the file descriptor to use as the stderr for spawned processes.

      If @fd is -1 then any previously given fd is unset.

      Note that the default behaviour is to pass stderr through to the
      stderr of the parent process.

      The passed @fd belongs to the #GSubprocessLauncher. It will be
      automatically closed when the launcher is finalized. The file
      descriptor will also be closed on the child side when executing the
      spawned process.

      You may not set a stderr fd if a stderr file path is already set or
      if the launcher flags contain any flags directing stderr elsewhere.

      This feature is only available on UNIX.
      Parameters:
      fd - a file descriptor, or -1
    • takeStdinFd

      public void takeStdinFd(int fd)
      Sets the file descriptor to use as the stdin for spawned processes.

      If @fd is -1 then any previously given fd is unset.

      Note that if your intention is to have the stdin of the calling
      process inherited by the child then %G_SUBPROCESS_FLAGS_STDIN_INHERIT
      is a better way to go about doing that.

      The passed @fd is noted but will not be touched in the current
      process. It is therefore necessary that it be kept open by the
      caller until the subprocess is spawned. The file descriptor will
      also not be explicitly closed on the child side, so it must be marked
      O_CLOEXEC if that's what you want.

      You may not set a stdin fd if a stdin file path is already set or if
      the launcher flags contain any flags directing stdin elsewhere.

      This feature is only available on UNIX.
      Parameters:
      fd - a file descriptor, or -1
    • takeStdoutFd

      public void takeStdoutFd(int fd)
      Sets the file descriptor to use as the stdout for spawned processes.

      If @fd is -1 then any previously given fd is unset.

      Note that the default behaviour is to pass stdout through to the
      stdout of the parent process.

      The passed @fd is noted but will not be touched in the current
      process. It is therefore necessary that it be kept open by the
      caller until the subprocess is spawned. The file descriptor will
      also not be explicitly closed on the child side, so it must be marked
      O_CLOEXEC if that's what you want.

      You may not set a stdout fd if a stdout file path is already set or
      if the launcher flags contain any flags directing stdout elsewhere.

      This feature is only available on UNIX.
      Parameters:
      fd - a file descriptor, or -1
    • unsetenv

      public void unsetenv(@Nonnull Str variable)
      Removes the environment variable @variable from the environment of
      processes launched from this launcher.

      On UNIX, the variable's name can be an arbitrary byte string not
      containing '='. On Windows, it should be in UTF-8.
      Parameters:
      variable - the environment variable to unset, must not contain '='
    • unsetenv

      public void unsetenv(String variable)
      Removes the environment variable @variable from the environment of
      processes launched from this launcher.

      On UNIX, the variable's name can be an arbitrary byte string not
      containing '='. On Windows, it should be in UTF-8.
      Parameters:
      variable - the environment variable to unset, must not contain '='
    • getTypeID

      public static long getTypeID()
    • getParentTypeID

      public static long getParentTypeID()
    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()
    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()
    • getInstanceSize

      public static int getInstanceSize()