cpython/Modules/readline.c

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/* This module makes GNU readline available to Python. It has ideas
* contributed by Lee Busby, LLNL, and William Magro, Cornell Theory
* Center. The completer interface was inspired by Lele Gaifax.
*
* More recently, it was largely rewritten by Guido van Rossum who is
* now maintaining it.
*/
/* Standard definitions */
#include "Python.h"
#include <setjmp.h>
#include <signal.h>
#include <errno.h>
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#ifdef HAVE_UNISTD_H
#include <unistd.h> /* For isatty() */
#endif
/* GNU readline definitions */
#include <readline/readline.h> /* You may need to add an -I option to Setup */
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extern int rl_parse_and_bind();
extern int rl_read_init_file();
extern int rl_insert_text();
extern int rl_bind_key();
extern int rl_bind_key_in_map();
extern int rl_initialize();
extern int add_history();
/* Pointers needed from outside (but not declared in a header file). */
extern int (*PyOS_InputHook)();
extern char *(*PyOS_ReadlineFunctionPointer) Py_PROTO((char *));
/* Exported function to send one line to readline's init file parser */
static PyObject *
parse_and_bind(self, args)
PyObject *self;
PyObject *args;
{
char *s;
if (!PyArg_ParseTuple(args, "s", &s))
return NULL;
rl_parse_and_bind(s);
Py_INCREF(Py_None);
return Py_None;
}
static char doc_parse_and_bind[] = "\
parse_and_bind(string) -> None\n\
Parse and execute single line of a readline init file.\
";
/* Exported function to parse a readline init file */
static PyObject *
read_init_file(self, args)
PyObject *self;
PyObject *args;
{
char *s = NULL;
if (!PyArg_ParseTuple(args, "|z", &s))
return NULL;
errno = rl_read_init_file(s);
if (errno)
return PyErr_SetFromErrno(PyExc_IOError);
Py_INCREF(Py_None);
return Py_None;
}
static char doc_read_init_file[] = "\
read_init_file([filename]) -> None\n\
Parse a readline initialization file.\n\
The default filename is the last filename used.\
";
/* Exported function to specify a word completer in Python */
static PyObject *completer = NULL;
static PyThreadState *tstate = NULL;
static PyObject *
set_completer(self, args)
PyObject *self;
PyObject *args;
{
PyObject *function = Py_None;
if (!PyArg_ParseTuple(args, "|O", &function))
return NULL;
if (function == Py_None) {
Py_XDECREF(completer);
completer = NULL;
tstate = NULL;
}
else if (PyCallable_Check(function)) {
PyObject *tmp = completer;
Py_INCREF(function);
completer = function;
Py_XDECREF(tmp);
tstate = PyThreadState_Get();
}
else {
PyErr_SetString(PyExc_TypeError,
"set_completer(func): argument not callable");
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
static char doc_set_completer[] = "\
set_completer([function]) -> None\n\
Set or remove the completer function.\n\
The function is called as function(text, state),\n\
for i in [0, 1, 2, ...] until it returns a non-string.\n\
It should return the next possible completion starting with 'text'.\
";
/* Exported function to read the current line buffer */
static PyObject *
get_line_buffer(self, args)
PyObject *self;
PyObject *args;
{
if (PyArg_NoArgs(args))
return NULL;
return PyString_FromString(rl_line_buffer);
}
static char doc_get_line_buffer[] = "\
get_line_buffer([function]) -> string\n\
return the current contents of the line buffer.\
";
/* Exported function to insert text into the line buffer */
static PyObject *
insert_text(self, args)
PyObject *self;
PyObject *args;
{
char *s;
if (!PyArg_ParseTuple(args, "s", &s))
return NULL;
rl_insert_text(s);
Py_INCREF(Py_None);
return Py_None;
}
static char doc_insert_text[] = "\
insert_text(string) -> None\n\
Insert text into the command line.\
";
/* Table of functions exported by the module */
static struct PyMethodDef readline_methods[] =
{
{"parse_and_bind", parse_and_bind, 1, doc_parse_and_bind},
{"get_line_buffer", get_line_buffer, 1, doc_get_line_buffer},
{"insert_text", insert_text, 1, doc_insert_text},
{"read_init_file", read_init_file, 1, doc_read_init_file},
{"set_completer", set_completer, 1, doc_set_completer},
{0, 0}
};
/* C function to call the Python completer. */
static char *
on_completion(text, state)
char *text;
int state;
{
char *result = NULL;
if (completer != NULL) {
PyObject *r;
PyThreadState *save_tstate;
/* Note that readline is called with the interpreter
lock released! */
save_tstate = PyThreadState_Swap(NULL);
PyEval_RestoreThread(tstate);
r = PyObject_CallFunction(completer, "si", text, state);
if (r == NULL)
goto error;
if (r == Py_None) {
result = NULL;
}
else {
char *s = PyString_AsString(r);
if (s == NULL)
goto error;
result = strdup(s);
}
Py_DECREF(r);
goto done;
error:
PyErr_Clear();
Py_XDECREF(r);
done:
PyEval_SaveThread();
PyThreadState_Swap(save_tstate);
}
return result;
}
/* Helper to initialize GNU readline properly. */
static void
setup_readline()
{
rl_readline_name = "python";
/* Force rebind of TAB to insert-tab */
rl_bind_key('\t', rl_insert);
/* Bind both ESC-TAB and ESC-ESC to the completion function */
rl_bind_key_in_map ('\t', rl_complete, emacs_meta_keymap);
rl_bind_key_in_map ('\033', rl_complete, emacs_meta_keymap);
/* Set our completion function */
rl_completion_entry_function = (Function *) on_completion;
/* Set Python word break characters */
rl_completer_word_break_characters =
" \t\n`~!@#$%^&*()-=+[{]}\\|;:'\",<>/?";
/* All nonalphanums except '.' */
/* Initialize (allows .inputrc to override) */
rl_initialize();
}
/* Interrupt handler */
static jmp_buf jbuf;
/* ARGSUSED */
static RETSIGTYPE
onintr(sig)
int sig;
{
longjmp(jbuf, 1);
}
/* Wrapper around GNU readline that handles signals differently. */
static char *
call_readline(prompt)
char *prompt;
{
int n;
char *p;
RETSIGTYPE (*old_inthandler)();
old_inthandler = signal(SIGINT, onintr);
if (setjmp(jbuf)) {
#ifdef HAVE_SIGRELSE
/* This seems necessary on SunOS 4.1 (Rasmus Hahn) */
sigrelse(SIGINT);
#endif
signal(SIGINT, old_inthandler);
return NULL;
}
rl_event_hook = PyOS_InputHook;
p = readline(prompt);
signal(SIGINT, old_inthandler);
if (p == NULL) {
p = malloc(1);
if (p != NULL)
*p = '\0';
return p;
}
n = strlen(p);
if (n > 0)
add_history(p);
if ((p = realloc(p, n+2)) != NULL) {
p[n] = '\n';
p[n+1] = '\0';
}
return p;
}
/* Initialize the module */
static char doc_module[] =
"Importing this module enables command line editing using GNU readline.";
void
initreadline()
{
PyObject *m;
m = Py_InitModule4("readline", readline_methods, doc_module,
(PyObject *)NULL, PYTHON_API_VERSION);
if (isatty(fileno(stdin))) {
PyOS_ReadlineFunctionPointer = call_readline;
setup_readline();
}
}