1 2 /* Readline interface for tokenizer.c and [raw_]input() in bltinmodule.c. 3 By default, or when stdin is not a tty device, we have a super 4 simple my_readline function using fgets. 5 Optionally, we can use the GNU readline library. 6 my_readline() has a different return value from GNU readline(): 7 - NULL if an interrupt occurred or if an error occurred 8 - a malloc'ed empty string if EOF was read 9 - a malloc'ed string ending in \n normally 10 */ 11 12 #include "Python.h" 13 #ifdef MS_WINDOWS 14 #define WIN32_LEAN_AND_MEAN 15 #include "windows.h" 16 #endif /* MS_WINDOWS */ 17 18 #ifdef __VMS 19 extern char* vms__StdioReadline(FILE *sys_stdin, FILE *sys_stdout, char *prompt); 20 #endif 21 22 23 PyThreadState* _PyOS_ReadlineTState; 24 25 #ifdef WITH_THREAD 26 #include "pythread.h" 27 static PyThread_type_lock _PyOS_ReadlineLock = NULL; 28 #endif 29 30 int (*PyOS_InputHook)(void) = NULL; 31 32 #ifdef RISCOS 33 int Py_RISCOSWimpFlag; 34 #endif 35 36 /* This function restarts a fgets() after an EINTR error occurred 37 except if PyOS_InterruptOccurred() returns true. */ 38 39 static int 40 my_fgets(char *buf, int len, FILE *fp) 41 { 42 char *p; 43 while (1) { 44 if (PyOS_InputHook != NULL) 45 (void)(PyOS_InputHook)(); 46 errno = 0; 47 p = fgets(buf, len, fp); 48 if (p != NULL) 49 return 0; /* No error */ 50 #ifdef MS_WINDOWS 51 /* In the case of a Ctrl+C or some other external event 52 interrupting the operation: 53 Win2k/NT: ERROR_OPERATION_ABORTED is the most recent Win32 54 error code (and feof() returns TRUE). 55 Win9x: Ctrl+C seems to have no effect on fgets() returning 56 early - the signal handler is called, but the fgets() 57 only returns "normally" (ie, when Enter hit or feof()) 58 */ 59 if (GetLastError()==ERROR_OPERATION_ABORTED) { 60 /* Signals come asynchronously, so we sleep a brief 61 moment before checking if the handler has been 62 triggered (we cant just return 1 before the 63 signal handler has been called, as the later 64 signal may be treated as a separate interrupt). 65 */ 66 Sleep(1); 67 if (PyOS_InterruptOccurred()) { 68 return 1; /* Interrupt */ 69 } 70 /* Either the sleep wasn't long enough (need a 71 short loop retrying?) or not interrupted at all 72 (in which case we should revisit the whole thing!) 73 Logging some warning would be nice. assert is not 74 viable as under the debugger, the various dialogs 75 mean the condition is not true. 76 */ 77 } 78 #endif /* MS_WINDOWS */ 79 if (feof(fp)) { 80 clearerr(fp); 81 return -1; /* EOF */ 82 } 83 #ifdef EINTR 84 if (errno == EINTR) { 85 int s; 86 #ifdef WITH_THREAD 87 PyEval_RestoreThread(_PyOS_ReadlineTState); 88 #endif 89 s = PyErr_CheckSignals(); 90 #ifdef WITH_THREAD 91 PyEval_SaveThread(); 92 #endif 93 if (s < 0) 94 return 1; 95 /* try again */ 96 continue; 97 } 98 #endif 99 if (PyOS_InterruptOccurred()) { 100 return 1; /* Interrupt */ 101 } 102 return -2; /* Error */ 103 } 104 /* NOTREACHED */ 105 } 106 107 108 /* Readline implementation using fgets() */ 109 110 char * 111 PyOS_StdioReadline(FILE *sys_stdin, FILE *sys_stdout, char *prompt) 112 { 113 size_t n; 114 char *p; 115 n = 100; 116 if ((p = (char *)PyMem_MALLOC(n)) == NULL) 117 return NULL; 118 fflush(sys_stdout); 119 #ifndef RISCOS 120 if (prompt) 121 fprintf(stderr, "%s", prompt); 122 #else 123 if (prompt) { 124 if(Py_RISCOSWimpFlag) 125 fprintf(stderr, "\x0cr%s\x0c", prompt); 126 else 127 fprintf(stderr, "%s", prompt); 128 } 129 #endif 130 fflush(stderr); 131 switch (my_fgets(p, (int)n, sys_stdin)) { 132 case 0: /* Normal case */ 133 break; 134 case 1: /* Interrupt */ 135 PyMem_FREE(p); 136 return NULL; 137 case -1: /* EOF */ 138 case -2: /* Error */ 139 default: /* Shouldn't happen */ 140 *p = '\0'; 141 break; 142 } 143 n = strlen(p); 144 while (n > 0 && p[n-1] != '\n') { 145 size_t incr = n+2; 146 p = (char *)PyMem_REALLOC(p, n + incr); 147 if (p == NULL) 148 return NULL; 149 if (incr > INT_MAX) { 150 PyErr_SetString(PyExc_OverflowError, "input line too long"); 151 } 152 if (my_fgets(p+n, (int)incr, sys_stdin) != 0) 153 break; 154 n += strlen(p+n); 155 } 156 return (char *)PyMem_REALLOC(p, n+1); 157 } 158 159 160 /* By initializing this function pointer, systems embedding Python can 161 override the readline function. 162 163 Note: Python expects in return a buffer allocated with PyMem_Malloc. */ 164 165 char *(*PyOS_ReadlineFunctionPointer)(FILE *, FILE *, char *); 166 167 168 /* Interface used by tokenizer.c and bltinmodule.c */ 169 170 char * 171 PyOS_Readline(FILE *sys_stdin, FILE *sys_stdout, char *prompt) 172 { 173 char *rv; 174 175 if (_PyOS_ReadlineTState == PyThreadState_GET()) { 176 PyErr_SetString(PyExc_RuntimeError, 177 "can't re-enter readline"); 178 return NULL; 179 } 180 181 182 if (PyOS_ReadlineFunctionPointer == NULL) { 183 #ifdef __VMS 184 PyOS_ReadlineFunctionPointer = vms__StdioReadline; 185 #else 186 PyOS_ReadlineFunctionPointer = PyOS_StdioReadline; 187 #endif 188 } 189 190 #ifdef WITH_THREAD 191 if (_PyOS_ReadlineLock == NULL) { 192 _PyOS_ReadlineLock = PyThread_allocate_lock(); 193 } 194 #endif 195 196 _PyOS_ReadlineTState = PyThreadState_GET(); 197 Py_BEGIN_ALLOW_THREADS 198 #ifdef WITH_THREAD 199 PyThread_acquire_lock(_PyOS_ReadlineLock, 1); 200 #endif 201 202 /* This is needed to handle the unlikely case that the 203 * interpreter is in interactive mode *and* stdin/out are not 204 * a tty. This can happen, for example if python is run like 205 * this: python -i < test1.py 206 */ 207 if (!isatty (fileno (sys_stdin)) || !isatty (fileno (sys_stdout))) 208 rv = PyOS_StdioReadline (sys_stdin, sys_stdout, prompt); 209 else 210 rv = (*PyOS_ReadlineFunctionPointer)(sys_stdin, sys_stdout, 211 prompt); 212 Py_END_ALLOW_THREADS 213 214 #ifdef WITH_THREAD 215 PyThread_release_lock(_PyOS_ReadlineLock); 216 #endif 217 218 _PyOS_ReadlineTState = NULL; 219 220 return rv; 221 } 222
