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