1 | /* |
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2 | * tclXtNotify.c -- |
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3 | * |
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4 | * This file contains the notifier driver implementation for the Xt |
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5 | * intrinsics. |
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6 | * |
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7 | * Copyright (c) 1997 by Sun Microsystems, Inc. |
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8 | * |
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9 | * See the file "license.terms" for information on usage and redistribution of |
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10 | * this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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11 | * |
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12 | * RCS: @(#) $Id: tclXtNotify.c,v 1.9 2007/04/16 13:36:36 dkf Exp $ |
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13 | */ |
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14 | |
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15 | #include <X11/Intrinsic.h> |
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16 | #include "tclInt.h" |
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17 | |
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18 | /* |
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19 | * This structure is used to keep track of the notifier info for a a |
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20 | * registered file. |
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21 | */ |
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22 | |
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23 | typedef struct FileHandler { |
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24 | int fd; |
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25 | int mask; /* Mask of desired events: TCL_READABLE, |
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26 | * etc. */ |
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27 | int readyMask; /* Events that have been seen since the last |
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28 | * time FileHandlerEventProc was called for |
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29 | * this file. */ |
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30 | XtInputId read; /* Xt read callback handle. */ |
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31 | XtInputId write; /* Xt write callback handle. */ |
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32 | XtInputId except; /* Xt exception callback handle. */ |
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33 | Tcl_FileProc *proc; /* Procedure to call, in the style of |
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34 | * Tcl_CreateFileHandler. */ |
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35 | ClientData clientData; /* Argument to pass to proc. */ |
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36 | struct FileHandler *nextPtr;/* Next in list of all files we care about. */ |
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37 | } FileHandler; |
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38 | |
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39 | /* |
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40 | * The following structure is what is added to the Tcl event queue when file |
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41 | * handlers are ready to fire. |
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42 | */ |
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43 | |
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44 | typedef struct FileHandlerEvent { |
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45 | Tcl_Event header; /* Information that is standard for all |
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46 | * events. */ |
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47 | int fd; /* File descriptor that is ready. Used to find |
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48 | * the FileHandler structure for the file |
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49 | * (can't point directly to the FileHandler |
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50 | * structure because it could go away while |
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51 | * the event is queued). */ |
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52 | } FileHandlerEvent; |
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53 | |
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54 | /* |
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55 | * The following static structure contains the state information for the Xt |
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56 | * based implementation of the Tcl notifier. |
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57 | */ |
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58 | |
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59 | static struct NotifierState { |
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60 | XtAppContext appContext; /* The context used by the Xt notifier. Can be |
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61 | * set with TclSetAppContext. */ |
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62 | int appContextCreated; /* Was it created by us? */ |
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63 | XtIntervalId currentTimeout;/* Handle of current timer. */ |
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64 | FileHandler *firstFileHandlerPtr; |
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65 | /* Pointer to head of file handler list. */ |
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66 | } notifier; |
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67 | |
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68 | /* |
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69 | * The following static indicates whether this module has been initialized. |
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70 | */ |
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71 | |
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72 | static int initialized = 0; |
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73 | |
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74 | /* |
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75 | * Static routines defined in this file. |
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76 | */ |
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77 | |
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78 | static int FileHandlerEventProc(Tcl_Event *evPtr, int flags); |
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79 | static void FileProc(caddr_t clientData, int *source, |
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80 | XtInputId *id); |
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81 | void InitNotifier(void); |
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82 | static void NotifierExitHandler(ClientData clientData); |
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83 | static void TimerProc(caddr_t clientData, XtIntervalId *id); |
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84 | static void CreateFileHandler(int fd, int mask, |
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85 | Tcl_FileProc * proc, ClientData clientData); |
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86 | static void DeleteFileHandler(int fd); |
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87 | static void SetTimer(Tcl_Time * timePtr); |
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88 | static int WaitForEvent(Tcl_Time * timePtr); |
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89 | |
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90 | /* |
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91 | * Functions defined in this file for use by users of the Xt Notifier: |
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92 | */ |
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93 | |
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94 | EXTERN XtAppContext TclSetAppContext(XtAppContext ctx); |
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95 | |
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96 | /* |
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97 | *---------------------------------------------------------------------- |
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98 | * |
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99 | * TclSetAppContext -- |
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100 | * |
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101 | * Set the notifier application context. |
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102 | * |
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103 | * Results: |
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104 | * None. |
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105 | * |
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106 | * Side effects: |
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107 | * Sets the application context used by the notifier. Panics if the |
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108 | * context is already set when called. |
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109 | * |
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110 | *---------------------------------------------------------------------- |
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111 | */ |
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112 | |
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113 | XtAppContext |
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114 | TclSetAppContext( |
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115 | XtAppContext appContext) |
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116 | { |
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117 | if (!initialized) { |
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118 | InitNotifier(); |
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119 | } |
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120 | |
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121 | /* |
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122 | * If we already have a context we check whether we were asked to set a |
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123 | * new context. If so, we panic because we try to prevent switching |
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124 | * contexts by mistake. Otherwise, we return the one we have. |
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125 | */ |
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126 | |
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127 | if (notifier.appContext != NULL) { |
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128 | if (appContext != NULL) { |
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129 | /* |
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130 | * We already have a context. We do not allow switching contexts |
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131 | * after initialization, so we panic. |
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132 | */ |
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133 | |
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134 | Tcl_Panic("TclSetAppContext: multiple application contexts"); |
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135 | } |
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136 | } else { |
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137 | /* |
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138 | * If we get here we have not yet gotten a context, so either create |
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139 | * one or use the one supplied by our caller. |
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140 | */ |
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141 | |
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142 | if (appContext == NULL) { |
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143 | /* |
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144 | * We must create a new context and tell our caller what it is, so |
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145 | * she can use it too. |
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146 | */ |
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147 | |
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148 | notifier.appContext = XtCreateApplicationContext(); |
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149 | notifier.appContextCreated = 1; |
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150 | } else { |
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151 | /* |
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152 | * Otherwise we remember the context that our caller gave us and |
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153 | * use it. |
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154 | */ |
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155 | |
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156 | notifier.appContextCreated = 0; |
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157 | notifier.appContext = appContext; |
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158 | } |
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159 | } |
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160 | |
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161 | return notifier.appContext; |
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162 | } |
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163 | |
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164 | /* |
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165 | *---------------------------------------------------------------------- |
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166 | * |
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167 | * InitNotifier -- |
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168 | * |
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169 | * Initializes the notifier state. |
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170 | * |
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171 | * Results: |
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172 | * None. |
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173 | * |
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174 | * Side effects: |
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175 | * Creates a new exit handler. |
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176 | * |
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177 | *---------------------------------------------------------------------- |
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178 | */ |
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179 | |
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180 | void |
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181 | InitNotifier(void) |
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182 | { |
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183 | Tcl_NotifierProcs notifier; |
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184 | |
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185 | /* |
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186 | * Only reinitialize if we are not in exit handling. The notifier can get |
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187 | * reinitialized after its own exit handler has run, because of exit |
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188 | * handlers for the I/O and timer sub-systems (order dependency). |
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189 | */ |
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190 | |
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191 | if (TclInExit()) { |
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192 | return; |
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193 | } |
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194 | |
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195 | notifier.createFileHandlerProc = CreateFileHandler; |
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196 | notifier.deleteFileHandlerProc = DeleteFileHandler; |
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197 | notifier.setTimerProc = SetTimer; |
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198 | notifier.waitForEventProc = WaitForEvent; |
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199 | Tcl_SetNotifier(¬ifier); |
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200 | |
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201 | /* |
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202 | * DO NOT create the application context yet; doing so would prevent |
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203 | * external applications from setting it for us to their own ones. |
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204 | */ |
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205 | |
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206 | initialized = 1; |
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207 | memset(¬ifier, 0, sizeof(notifier)); |
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208 | Tcl_CreateExitHandler(NotifierExitHandler, NULL); |
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209 | } |
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210 | |
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211 | /* |
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212 | *---------------------------------------------------------------------- |
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213 | * |
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214 | * NotifierExitHandler -- |
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215 | * |
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216 | * This function is called to cleanup the notifier state before Tcl is |
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217 | * unloaded. |
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218 | * |
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219 | * Results: |
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220 | * None. |
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221 | * |
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222 | * Side effects: |
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223 | * Destroys the notifier window. |
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224 | * |
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225 | *---------------------------------------------------------------------- |
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226 | */ |
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227 | |
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228 | static void |
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229 | NotifierExitHandler( |
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230 | ClientData clientData) /* Not used. */ |
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231 | { |
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232 | if (notifier.currentTimeout != 0) { |
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233 | XtRemoveTimeOut(notifier.currentTimeout); |
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234 | } |
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235 | for (; notifier.firstFileHandlerPtr != NULL; ) { |
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236 | Tcl_DeleteFileHandler(notifier.firstFileHandlerPtr->fd); |
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237 | } |
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238 | if (notifier.appContextCreated) { |
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239 | XtDestroyApplicationContext(notifier.appContext); |
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240 | notifier.appContextCreated = 0; |
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241 | notifier.appContext = NULL; |
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242 | } |
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243 | initialized = 0; |
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244 | } |
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245 | |
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246 | /* |
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247 | *---------------------------------------------------------------------- |
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248 | * |
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249 | * SetTimer -- |
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250 | * |
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251 | * This procedure sets the current notifier timeout value. |
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252 | * |
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253 | * Results: |
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254 | * None. |
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255 | * |
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256 | * Side effects: |
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257 | * Replaces any previous timer. |
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258 | * |
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259 | *---------------------------------------------------------------------- |
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260 | */ |
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261 | |
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262 | static void |
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263 | SetTimer( |
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264 | Tcl_Time *timePtr) /* Timeout value, may be NULL. */ |
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265 | { |
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266 | long timeout; |
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267 | |
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268 | if (!initialized) { |
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269 | InitNotifier(); |
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270 | } |
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271 | |
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272 | TclSetAppContext(NULL); |
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273 | if (notifier.currentTimeout != 0) { |
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274 | XtRemoveTimeOut(notifier.currentTimeout); |
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275 | } |
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276 | if (timePtr) { |
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277 | timeout = timePtr->sec * 1000 + timePtr->usec / 1000; |
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278 | notifier.currentTimeout = XtAppAddTimeOut(notifier.appContext, |
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279 | (unsigned long) timeout, TimerProc, NULL); |
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280 | } else { |
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281 | notifier.currentTimeout = 0; |
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282 | } |
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283 | } |
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284 | |
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285 | /* |
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286 | *---------------------------------------------------------------------- |
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287 | * |
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288 | * TimerProc -- |
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289 | * |
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290 | * This procedure is the XtTimerCallbackProc used to handle timeouts. |
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291 | * |
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292 | * Results: |
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293 | * None. |
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294 | * |
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295 | * Side effects: |
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296 | * Processes all queued events. |
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297 | * |
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298 | *---------------------------------------------------------------------- |
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299 | */ |
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300 | |
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301 | static void |
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302 | TimerProc( |
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303 | caddr_t data, /* Not used. */ |
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304 | XtIntervalId *id) |
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305 | { |
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306 | if (*id != notifier.currentTimeout) { |
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307 | return; |
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308 | } |
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309 | notifier.currentTimeout = 0; |
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310 | |
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311 | Tcl_ServiceAll(); |
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312 | } |
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313 | |
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314 | /* |
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315 | *---------------------------------------------------------------------- |
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316 | * |
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317 | * CreateFileHandler -- |
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318 | * |
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319 | * This procedure registers a file handler with the Xt notifier. |
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320 | * |
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321 | * Results: |
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322 | * None. |
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323 | * |
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324 | * Side effects: |
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325 | * Creates a new file handler structure and registers one or more input |
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326 | * procedures with Xt. |
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327 | * |
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328 | *---------------------------------------------------------------------- |
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329 | */ |
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330 | |
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331 | static void |
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332 | CreateFileHandler( |
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333 | int fd, /* Handle of stream to watch. */ |
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334 | int mask, /* OR'ed combination of TCL_READABLE, |
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335 | * TCL_WRITABLE, and TCL_EXCEPTION: indicates |
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336 | * conditions under which proc should be |
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337 | * called. */ |
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338 | Tcl_FileProc *proc, /* Procedure to call for each selected |
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339 | * event. */ |
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340 | ClientData clientData) /* Arbitrary data to pass to proc. */ |
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341 | { |
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342 | FileHandler *filePtr; |
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343 | |
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344 | if (!initialized) { |
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345 | InitNotifier(); |
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346 | } |
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347 | |
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348 | TclSetAppContext(NULL); |
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349 | |
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350 | for (filePtr = notifier.firstFileHandlerPtr; filePtr != NULL; |
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351 | filePtr = filePtr->nextPtr) { |
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352 | if (filePtr->fd == fd) { |
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353 | break; |
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354 | } |
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355 | } |
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356 | if (filePtr == NULL) { |
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357 | filePtr = (FileHandler*) ckalloc(sizeof(FileHandler)); |
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358 | filePtr->fd = fd; |
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359 | filePtr->read = 0; |
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360 | filePtr->write = 0; |
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361 | filePtr->except = 0; |
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362 | filePtr->readyMask = 0; |
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363 | filePtr->mask = 0; |
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364 | filePtr->nextPtr = notifier.firstFileHandlerPtr; |
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365 | notifier.firstFileHandlerPtr = filePtr; |
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366 | } |
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367 | filePtr->proc = proc; |
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368 | filePtr->clientData = clientData; |
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369 | |
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370 | /* |
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371 | * Register the file with the Xt notifier, if it hasn't been done yet. |
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372 | */ |
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373 | |
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374 | if (mask & TCL_READABLE) { |
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375 | if (!(filePtr->mask & TCL_READABLE)) { |
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376 | filePtr->read = XtAppAddInput(notifier.appContext, fd, |
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377 | XtInputReadMask, FileProc, filePtr); |
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378 | } |
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379 | } else { |
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380 | if (filePtr->mask & TCL_READABLE) { |
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381 | XtRemoveInput(filePtr->read); |
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382 | } |
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383 | } |
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384 | if (mask & TCL_WRITABLE) { |
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385 | if (!(filePtr->mask & TCL_WRITABLE)) { |
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386 | filePtr->write = XtAppAddInput(notifier.appContext, fd, |
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387 | XtInputWriteMask, FileProc, filePtr); |
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388 | } |
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389 | } else { |
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390 | if (filePtr->mask & TCL_WRITABLE) { |
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391 | XtRemoveInput(filePtr->write); |
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392 | } |
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393 | } |
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394 | if (mask & TCL_EXCEPTION) { |
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395 | if (!(filePtr->mask & TCL_EXCEPTION)) { |
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396 | filePtr->except = XtAppAddInput(notifier.appContext, fd, |
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397 | XtInputExceptMask, FileProc, filePtr); |
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398 | } |
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399 | } else { |
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400 | if (filePtr->mask & TCL_EXCEPTION) { |
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401 | XtRemoveInput(filePtr->except); |
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402 | } |
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403 | } |
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404 | filePtr->mask = mask; |
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405 | } |
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406 | |
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407 | /* |
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408 | *---------------------------------------------------------------------- |
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409 | * |
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410 | * DeleteFileHandler -- |
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411 | * |
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412 | * Cancel a previously-arranged callback arrangement for a file. |
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413 | * |
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414 | * Results: |
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415 | * None. |
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416 | * |
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417 | * Side effects: |
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418 | * If a callback was previously registered on file, remove it. |
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419 | * |
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420 | *---------------------------------------------------------------------- |
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421 | */ |
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422 | |
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423 | static void |
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424 | DeleteFileHandler( |
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425 | int fd) /* Stream id for which to remove callback |
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426 | * procedure. */ |
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427 | { |
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428 | FileHandler *filePtr, *prevPtr; |
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429 | |
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430 | if (!initialized) { |
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431 | InitNotifier(); |
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432 | } |
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433 | |
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434 | TclSetAppContext(NULL); |
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435 | |
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436 | /* |
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437 | * Find the entry for the given file (and return if there isn't one). |
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438 | */ |
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439 | |
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440 | for (prevPtr = NULL, filePtr = notifier.firstFileHandlerPtr; ; |
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441 | prevPtr = filePtr, filePtr = filePtr->nextPtr) { |
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442 | if (filePtr == NULL) { |
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443 | return; |
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444 | } |
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445 | if (filePtr->fd == fd) { |
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446 | break; |
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447 | } |
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448 | } |
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449 | |
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450 | /* |
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451 | * Clean up information in the callback record. |
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452 | */ |
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453 | |
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454 | if (prevPtr == NULL) { |
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455 | notifier.firstFileHandlerPtr = filePtr->nextPtr; |
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456 | } else { |
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457 | prevPtr->nextPtr = filePtr->nextPtr; |
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458 | } |
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459 | if (filePtr->mask & TCL_READABLE) { |
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460 | XtRemoveInput(filePtr->read); |
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461 | } |
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462 | if (filePtr->mask & TCL_WRITABLE) { |
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463 | XtRemoveInput(filePtr->write); |
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464 | } |
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465 | if (filePtr->mask & TCL_EXCEPTION) { |
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466 | XtRemoveInput(filePtr->except); |
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467 | } |
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468 | ckfree((char *) filePtr); |
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469 | } |
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470 | |
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471 | /* |
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472 | *---------------------------------------------------------------------- |
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473 | * |
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474 | * FileProc -- |
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475 | * |
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476 | * These procedures are called by Xt when a file becomes readable, |
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477 | * writable, or has an exception. |
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478 | * |
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479 | * Results: |
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480 | * None. |
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481 | * |
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482 | * Side effects: |
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483 | * Makes an entry on the Tcl event queue if the event is interesting. |
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484 | * |
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485 | *---------------------------------------------------------------------- |
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486 | */ |
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487 | |
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488 | static void |
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489 | FileProc( |
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490 | caddr_t clientData, |
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491 | int *fd, |
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492 | XtInputId *id) |
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493 | { |
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494 | FileHandler *filePtr = (FileHandler *)clientData; |
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495 | FileHandlerEvent *fileEvPtr; |
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496 | int mask = 0; |
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497 | |
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498 | /* |
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499 | * Determine which event happened. |
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500 | */ |
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501 | |
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502 | if (*id == filePtr->read) { |
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503 | mask = TCL_READABLE; |
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504 | } else if (*id == filePtr->write) { |
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505 | mask = TCL_WRITABLE; |
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506 | } else if (*id == filePtr->except) { |
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507 | mask = TCL_EXCEPTION; |
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508 | } |
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509 | |
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510 | /* |
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511 | * Ignore unwanted or duplicate events. |
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512 | */ |
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513 | |
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514 | if (!(filePtr->mask & mask) || (filePtr->readyMask & mask)) { |
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515 | return; |
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516 | } |
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517 | |
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518 | /* |
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519 | * This is an interesting event, so put it onto the event queue. |
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520 | */ |
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521 | |
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522 | filePtr->readyMask |= mask; |
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523 | fileEvPtr = (FileHandlerEvent *) ckalloc(sizeof(FileHandlerEvent)); |
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524 | fileEvPtr->header.proc = FileHandlerEventProc; |
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525 | fileEvPtr->fd = filePtr->fd; |
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526 | Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); |
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527 | |
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528 | /* |
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529 | * Process events on the Tcl event queue before returning to Xt. |
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530 | */ |
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531 | |
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532 | Tcl_ServiceAll(); |
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533 | } |
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534 | |
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535 | /* |
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536 | *---------------------------------------------------------------------- |
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537 | * |
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538 | * FileHandlerEventProc -- |
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539 | * |
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540 | * This procedure is called by Tcl_ServiceEvent when a file event reaches |
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541 | * the front of the event queue. This procedure is responsible for |
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542 | * actually handling the event by invoking the callback for the file |
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543 | * handler. |
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544 | * |
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545 | * Results: |
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546 | * Returns 1 if the event was handled, meaning it should be removed from |
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547 | * the queue. Returns 0 if the event was not handled, meaning it should |
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548 | * stay on the queue. The only time the event isn't handled is if the |
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549 | * TCL_FILE_EVENTS flag bit isn't set. |
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550 | * |
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551 | * Side effects: |
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552 | * Whatever the file handler's callback procedure does. |
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553 | * |
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554 | *---------------------------------------------------------------------- |
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555 | */ |
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556 | |
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557 | static int |
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558 | FileHandlerEventProc( |
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559 | Tcl_Event *evPtr, /* Event to service. */ |
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560 | int flags) /* Flags that indicate what events to handle, |
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561 | * such as TCL_FILE_EVENTS. */ |
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562 | { |
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563 | FileHandler *filePtr; |
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564 | FileHandlerEvent *fileEvPtr = (FileHandlerEvent *) evPtr; |
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565 | int mask; |
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566 | |
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567 | if (!(flags & TCL_FILE_EVENTS)) { |
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568 | return 0; |
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569 | } |
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570 | |
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571 | /* |
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572 | * Search through the file handlers to find the one whose handle matches |
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573 | * the event. We do this rather than keeping a pointer to the file handler |
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574 | * directly in the event, so that the handler can be deleted while the |
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575 | * event is queued without leaving a dangling pointer. |
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576 | */ |
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577 | |
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578 | for (filePtr = notifier.firstFileHandlerPtr; filePtr != NULL; |
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579 | filePtr = filePtr->nextPtr) { |
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580 | if (filePtr->fd != fileEvPtr->fd) { |
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581 | continue; |
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582 | } |
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583 | |
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584 | /* |
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585 | * The code is tricky for two reasons: |
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586 | * 1. The file handler's desired events could have changed since the |
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587 | * time when the event was queued, so AND the ready mask with the |
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588 | * desired mask. |
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589 | * 2. The file could have been closed and re-opened since the time |
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590 | * when the event was queued. This is why the ready mask is stored |
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591 | * in the file handler rather than the queued event: it will be |
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592 | * zeroed when a new file handler is created for the newly opened |
---|
593 | * file. |
---|
594 | */ |
---|
595 | |
---|
596 | mask = filePtr->readyMask & filePtr->mask; |
---|
597 | filePtr->readyMask = 0; |
---|
598 | if (mask != 0) { |
---|
599 | (*filePtr->proc)(filePtr->clientData, mask); |
---|
600 | } |
---|
601 | break; |
---|
602 | } |
---|
603 | return 1; |
---|
604 | } |
---|
605 | |
---|
606 | /* |
---|
607 | *---------------------------------------------------------------------- |
---|
608 | * |
---|
609 | * WaitForEvent -- |
---|
610 | * |
---|
611 | * This function is called by Tcl_DoOneEvent to wait for new events on |
---|
612 | * the message queue. If the block time is 0, then Tcl_WaitForEvent just |
---|
613 | * polls without blocking. |
---|
614 | * |
---|
615 | * Results: |
---|
616 | * Returns 1 if an event was found, else 0. This ensures that |
---|
617 | * Tcl_DoOneEvent will return 1, even if the event is handled by non-Tcl |
---|
618 | * code. |
---|
619 | * |
---|
620 | * Side effects: |
---|
621 | * Queues file events that are detected by the select. |
---|
622 | * |
---|
623 | *---------------------------------------------------------------------- |
---|
624 | */ |
---|
625 | |
---|
626 | static int |
---|
627 | WaitForEvent( |
---|
628 | Tcl_Time *timePtr) /* Maximum block time, or NULL. */ |
---|
629 | { |
---|
630 | int timeout; |
---|
631 | |
---|
632 | if (!initialized) { |
---|
633 | InitNotifier(); |
---|
634 | } |
---|
635 | |
---|
636 | TclSetAppContext(NULL); |
---|
637 | |
---|
638 | if (timePtr) { |
---|
639 | timeout = timePtr->sec * 1000 + timePtr->usec / 1000; |
---|
640 | if (timeout == 0) { |
---|
641 | if (XtAppPending(notifier.appContext)) { |
---|
642 | goto process; |
---|
643 | } else { |
---|
644 | return 0; |
---|
645 | } |
---|
646 | } else { |
---|
647 | Tcl_SetTimer(timePtr); |
---|
648 | } |
---|
649 | } |
---|
650 | |
---|
651 | process: |
---|
652 | XtAppProcessEvent(notifier.appContext, XtIMAll); |
---|
653 | return 1; |
---|
654 | } |
---|
655 | |
---|
656 | /* |
---|
657 | * Local Variables: |
---|
658 | * mode: c |
---|
659 | * c-basic-offset: 4 |
---|
660 | * fill-column: 78 |
---|
661 | * End: |
---|
662 | */ |
---|