ref: 065c3557af8de1b20d94c2e86a4a29c5d33ccc67
dir: /sys/src/cmd/python/Parser/myreadline.c/
/* 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" #ifdef MS_WINDOWS #define WIN32_LEAN_AND_MEAN #include "windows.h" #endif /* MS_WINDOWS */ #ifdef __VMS extern char* vms__StdioReadline(FILE *sys_stdin, FILE *sys_stdout, char *prompt); #endif PyThreadState* _PyOS_ReadlineTState; #ifdef WITH_THREAD #include "pythread.h" static PyThread_type_lock _PyOS_ReadlineLock = NULL; #endif int (*PyOS_InputHook)(void) = NULL; #ifdef RISCOS int Py_RISCOSWimpFlag; #endif /* 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 */ #ifdef MS_WINDOWS /* In the case of a Ctrl+C or some other external event interrupting the operation: Win2k/NT: ERROR_OPERATION_ABORTED is the most recent Win32 error code (and feof() returns TRUE). Win9x: Ctrl+C seems to have no effect on fgets() returning early - the signal handler is called, but the fgets() only returns "normally" (ie, when Enter hit or feof()) */ if (GetLastError()==ERROR_OPERATION_ABORTED) { /* Signals come asynchronously, so we sleep a brief moment before checking if the handler has been triggered (we cant just return 1 before the signal handler has been called, as the later signal may be treated as a separate interrupt). */ Sleep(1); if (PyOS_InterruptOccurred()) { return 1; /* Interrupt */ } /* Either the sleep wasn't long enough (need a short loop retrying?) or not interrupted at all (in which case we should revisit the whole thing!) Logging some warning would be nice. assert is not viable as under the debugger, the various dialogs mean the condition is not true. */ } #endif /* MS_WINDOWS */ if (feof(fp)) { return -1; /* EOF */ } #ifdef EINTR if (errno == EINTR) { int s; #ifdef WITH_THREAD PyEval_RestoreThread(_PyOS_ReadlineTState); #endif s = PyErr_CheckSignals(); #ifdef WITH_THREAD PyEval_SaveThread(); #endif if (s < 0) { return 1; } } #endif if (PyOS_InterruptOccurred()) { return 1; /* Interrupt */ } return -2; /* Error */ } /* NOTREACHED */ } /* Readline implementation using fgets() */ char * PyOS_StdioReadline(FILE *sys_stdin, FILE *sys_stdout, char *prompt) { size_t n; char *p; n = 100; if ((p = (char *)PyMem_MALLOC(n)) == NULL) return NULL; fflush(sys_stdout); #ifndef RISCOS if (prompt) fprintf(stderr, "%s", prompt); #else if (prompt) { if(Py_RISCOSWimpFlag) fprintf(stderr, "\x0cr%s\x0c", prompt); else fprintf(stderr, "%s", prompt); } #endif fflush(stderr); switch (my_fgets(p, (int)n, sys_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; } n = strlen(p); while (n > 0 && p[n-1] != '\n') { size_t incr = n+2; p = (char *)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, sys_stdin) != 0) break; n += strlen(p+n); } return (char *)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)(FILE *, FILE *, char *); /* Interface used by tokenizer.c and bltinmodule.c */ char * PyOS_Readline(FILE *sys_stdin, FILE *sys_stdout, char *prompt) { char *rv; if (_PyOS_ReadlineTState == PyThreadState_GET()) { PyErr_SetString(PyExc_RuntimeError, "can't re-enter readline"); return NULL; } if (PyOS_ReadlineFunctionPointer == NULL) { #ifdef __VMS PyOS_ReadlineFunctionPointer = vms__StdioReadline; #else PyOS_ReadlineFunctionPointer = PyOS_StdioReadline; #endif } #ifdef WITH_THREAD if (_PyOS_ReadlineLock == NULL) { _PyOS_ReadlineLock = PyThread_allocate_lock(); } #endif _PyOS_ReadlineTState = PyThreadState_GET(); Py_BEGIN_ALLOW_THREADS #ifdef WITH_THREAD PyThread_acquire_lock(_PyOS_ReadlineLock, 1); #endif /* This is needed to handle the unlikely case that the * interpreter is in interactive mode *and* stdin/out are not * a tty. This can happen, for example if python is run like * this: python -i < test1.py */ if (!isatty (fileno (sys_stdin)) || !isatty (fileno (sys_stdout))) rv = PyOS_StdioReadline (sys_stdin, sys_stdout, prompt); else rv = (*PyOS_ReadlineFunctionPointer)(sys_stdin, sys_stdout, prompt); Py_END_ALLOW_THREADS #ifdef WITH_THREAD PyThread_release_lock(_PyOS_ReadlineLock); #endif _PyOS_ReadlineTState = NULL; return rv; }