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/* Readline interface for tokenizer.c and [raw_]input() in bltinmodule.c.
By default, or when stdin is not a tty device, we have a super
simple my_readline function using fgets.
Optionally, we can use the GNU readline library.
my_readline() has a different return value from GNU readline():
- NULL if an interrupt occurred or if an error occurred
- a malloc'ed empty string if EOF was read
- a malloc'ed string ending in \n normally
*/
#include "Python.h"
int (*PyOS_InputHook)(void) = NULL;
/* This function restarts a fgets() after an EINTR error occurred
except if PyOS_InterruptOccurred() returns true. */
static int
my_fgets(char *buf, int len, FILE *fp)
{
char *p;
for (;;) {
if (PyOS_InputHook != NULL)
(void)(PyOS_InputHook)();
errno = 0;
p = fgets(buf, len, fp);
if (p != NULL)
return 0; /* No error */
if (feof(fp)) {
return -1; /* EOF */
}
#ifdef EINTR
if (errno == EINTR) {
if (PyOS_InterruptOccurred()) {
return 1; /* Interrupt */
}
continue;
}
#endif
if (PyOS_InterruptOccurred()) {
return 1; /* Interrupt */
}
return -2; /* Error */
}
/* NOTREACHED */
}
/* Readline implementation using fgets() */
char *
PyOS_StdioReadline(char *prompt)
{
size_t n;
char *p;
n = 100;
if ((p = PyMem_MALLOC(n)) == NULL)
return NULL;
fflush(stdout);
if (prompt)
fprintf(stderr, "%s", prompt);
fflush(stderr);
switch (my_fgets(p, (int)n, stdin)) {
case 0: /* Normal case */
break;
case 1: /* Interrupt */
PyMem_FREE(p);
return NULL;
case -1: /* EOF */
case -2: /* Error */
default: /* Shouldn't happen */
*p = '\0';
break;
}
#ifdef MPW
/* Hack for MPW C where the prompt comes right back in the input */
/* XXX (Actually this would be rather nice on most systems...) */
n = strlen(prompt);
if (strncmp(p, prompt, n) == 0)
memmove(p, p + n, strlen(p) - n + 1);
#endif
n = strlen(p);
while (n > 0 && p[n-1] != '\n') {
size_t incr = n+2;
p = PyMem_REALLOC(p, n + incr);
if (p == NULL)
return NULL;
if (incr > INT_MAX) {
PyErr_SetString(PyExc_OverflowError, "input line too long");
}
if (my_fgets(p+n, (int)incr, stdin) != 0)
break;
n += strlen(p+n);
}
return PyMem_REALLOC(p, n+1);
}
/* By initializing this function pointer, systems embedding Python can
override the readline function.
Note: Python expects in return a buffer allocated with PyMem_Malloc. */
char *(*PyOS_ReadlineFunctionPointer)(char *);
/* Interface used by tokenizer.c and bltinmodule.c */
char *
PyOS_Readline(char *prompt)
{
char *rv;
if (PyOS_ReadlineFunctionPointer == NULL) {
PyOS_ReadlineFunctionPointer = PyOS_StdioReadline;
}
Py_BEGIN_ALLOW_THREADS
rv = (*PyOS_ReadlineFunctionPointer)(prompt);
Py_END_ALLOW_THREADS
return rv;
}
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