ways.
@end deftypefn
+@anchor{open_channel}
+@deftypefun int open_channel (emacs_env *@var{env}, emacs_value @var{pipe_process})
+This function, which is available since Emacs 27, opens a channel to
+an existing pipe process. @var{pipe_process} must refer to an
+existing pipe process created by @code{make-pipe-process}. @ref{Pipe
+Processes}. If successful, the return value will be a new file
+descriptor that you can use to write to the pipe. Unlike all other
+module functions, you can use the returned file descriptor from
+arbitrary threads, even if no module environment is active. You can
+use the @code{write} function to write to the file descriptor. Once
+done, close the file descriptor using @code{close}. @ref{Low-Level
+I/O,,,libc}.
+@end deftypefun
+
@node Module Nonlocal
@subsection Nonlocal Exits in Modules
@cindex nonlocal exits, in modules
cases, this function does nothing and returns @code{nil}.
@end defun
+@anchor{Pipe Processes}
@defun make-pipe-process &rest args
This function creates a bidirectional pipe which can be attached to a
child process. This is useful with the @code{:stderr} keyword of
'set_function_finalizer' to set the finalizer and
'get_function_finalizer' to retrieve it.
+** Modules can now open a channel to an existing pipe process using
+the new module function 'open_channel'. Modules can use this
+functionality to asynchronously send data back to Emacs.
+
** 'file-modes', 'set-file-modes', and 'set-file-times' now have an
optional argument specifying whether to follow symbolic links.
#include "dynlib.h"
#include "coding.h"
#include "keyboard.h"
+#include "process.h"
#include "syssignal.h"
#include "sysstdio.h"
#include "thread.h"
return lisp_to_value (env, make_integer_mpz ());
}
+static int
+module_open_channel (emacs_env *env, emacs_value pipe_process)
+{
+ MODULE_FUNCTION_BEGIN (-1);
+ return open_channel_for_module (value_to_lisp (pipe_process));
+}
+
\f
/* Subroutines. */
env->make_big_integer = module_make_big_integer;
env->get_function_finalizer = module_get_function_finalizer;
env->set_function_finalizer = module_set_function_finalizer;
+ env->open_channel = module_open_channel;
Vmodule_environments = Fcons (make_mint_ptr (env), Vmodule_environments);
return env;
}
void (*set_function_finalizer) (emacs_env *env, emacs_value arg,
void (*fin) (void *) EMACS_NOEXCEPT)
EMACS_ATTRIBUTE_NONNULL (1);
+
+ int (*open_channel) (emacs_env *env, emacs_value pipe_process)
+ EMACS_ATTRIBUTE_NONNULL (1);
#endif
}
+int
+open_channel_for_module (Lisp_Object process)
+{
+ CHECK_PROCESS (process);
+ CHECK_TYPE (PIPECONN_P (process), Qpipe_process_p, process);
+ int fd = dup (XPROCESS (process)->open_fd[SUBPROCESS_STDOUT]);
+ if (fd == -1)
+ report_file_error ("Cannot duplicate file descriptor", Qnil);
+ return fd;
+}
+
\f
/* This is not called "init_process" because that is the name of a
Mach system call, so it would cause problems on Darwin systems. */
DEFSYM (Qinterrupt_process_functions, "interrupt-process-functions");
DEFSYM (Qnull, "null");
+ DEFSYM (Qpipe_process_p, "pipe-process-p");
defsubr (&Sprocessp);
defsubr (&Sget_process);
extern void update_processes_for_thread_death (Lisp_Object);
extern void dissociate_controlling_tty (void);
+extern int open_channel_for_module (Lisp_Object);
+
INLINE_HEADER_END
#endif /* EMACS_PROCESS_H */
#include <string.h>
#include <time.h>
+#include <pthread.h>
+#include <unistd.h>
+
#ifdef HAVE_GMP
#include <gmp.h>
#else
}
static void
-signal_errno (emacs_env *env, const char *function)
+signal_system_error (emacs_env *env, int error, const char *function)
{
- const char *message = strerror (errno);
+ const char *message = strerror (error);
emacs_value message_value = env->make_string (env, message, strlen (message));
emacs_value symbol = env->intern (env, "file-error");
emacs_value elements[2]
env->non_local_exit_signal (env, symbol, data);
}
+static void
+signal_errno (emacs_env *env, const char *function)
+{
+ signal_system_error (env, errno, function);
+}
+
/* A long-running operation that occasionally calls `should_quit' or
`process_input'. */
return env->funcall (env, Flist, 2, list_args);
}
+static void *
+write_to_pipe (void *arg)
+{
+ /* We sleep a bit to test that writing to a pipe is indeed possible
+ if no environment is active. */
+ const struct timespec sleep = {0, 500000000};
+ if (nanosleep (&sleep, NULL) != 0)
+ perror ("nanosleep");
+ FILE *stream = arg;
+ if (fputs ("data from thread", stream) < 0)
+ perror ("fputs");
+ if (fclose (stream) != 0)
+ perror ("close");
+ return NULL;
+}
+
+static emacs_value
+Fmod_test_async_pipe (emacs_env *env, ptrdiff_t nargs, emacs_value *args,
+ void *data)
+{
+ assert (nargs == 1);
+ int fd = env->open_channel (env, args[0]);
+ if (env->non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
+ FILE *stream = fdopen (fd, "w");
+ if (stream == NULL)
+ {
+ signal_errno (env, "fdopen");
+ return NULL;
+ }
+ pthread_t thread;
+ int error
+ = pthread_create (&thread, NULL, write_to_pipe, stream);
+ if (error != 0)
+ {
+ signal_system_error (env, error, "pthread_create");
+ if (fclose (stream) != 0)
+ perror ("fclose");
+ return NULL;
+ }
+ return env->intern (env, "nil");
+}
+
/* Lisp utilities for easier readability (simple wrappers). */
/* Provide FEATURE to Emacs. */
Fmod_test_make_function_with_finalizer, 0, 0, NULL, NULL);
DEFUN ("mod-test-function-finalizer-calls",
Fmod_test_function_finalizer_calls, 0, 0, NULL, NULL);
+ DEFUN ("mod-test-async-pipe", Fmod_test_async_pipe, 1, 1, NULL, NULL);
#undef DEFUN
;; but at least one.
(should (> valid-after valid-before)))))
+(ert-deftest module/async-pipe ()
+ "Check that writing data from another thread works."
+ (with-temp-buffer
+ (let ((process (make-pipe-process :name "module/async-pipe"
+ :buffer (current-buffer)
+ :coding 'utf-8-unix
+ :noquery t)))
+ (unwind-protect
+ (progn
+ (mod-test-async-pipe process)
+ (should (accept-process-output process 1))
+ (should (equal (buffer-string) "data from thread")))
+ (delete-process process)))))
+
;;; emacs-module-tests.el ends here
projects / emacs.git / commitdiff