parser/parser.c

   1 /* parser.c */
   2
   3 #include "parser.h"
   4 #include "../lib/sstring.h"
   5 #include "../lib/irc_string.h"
   6 #include "../core/error.h"
   7 #include <assert.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <ctype.h>
  11 #include <stdio.h>
  12
  13 /* Local functions */
  14 int insertcommand(Command *c, CommandTree *ct, int depth);
  15 int deletecommand(sstring *cmdname, CommandTree *ct, int depth, CommandHandler handler);
  16 Command *findcommand(CommandTree *ct, const char *command, int depth);
  17 int countcommandtree(CommandTree *ct);
  18
  19 /* newcommandtree:
  20  *
  21  * This creates a new command tree.
  22  *
  23  * Uses malloc() as it's a pretty rare event.
  24  */
  25
  26 CommandTree *newcommandtree() {
  27   CommandTree *nct;
  28
  29   nct=(void *)malloc(sizeof(CommandTree));
  30   memset(nct,0,sizeof(CommandTree));
  31
  32   return nct;
  33 }
  34
  35 /* destroycommandtree:
  36  *
  37  * This frees a tree and all it's subtrees
  38  */
  39
  40 void destroycommandtree(CommandTree *ct) {
  41   int i;
  42
  43   for (i=0;i<26;i++) {
  44     if (ct->next[i]) {
  45       destroycommandtree((CommandTree *)ct->next[i]);
  46     }
  47   }
  48
  49   free(ct);
  50 }
  51
  52 /* countcommandtree:
  53  *
  54  * This returns the number of commands registered in
  55  * a particular (sub-)tree.  This will come in handy
  56  * later for deleting commands etc.
  57  */
  58
  59 int countcommandtree(CommandTree *ct) {
  60   int i;
  61   int sum;
  62
  63   if (ct->cmd!=NULL) {
  64     sum=1;
  65   } else {
  66     sum=0;
  67   }
  68
  69   for(i=0;i<26;i++)
  70     if (ct->next[i])
  71       sum+=countcommandtree((CommandTree *)ct->next[i]);
  72
  73   return sum;
  74 }
  75
  76 /*
  77  * addcommandtotree:
  78  *
  79  * This installs a specific command in a tree.
  80  *
  81  * This function builds the Command structure in addition to
  82  * installing it in the tree
  83  */
  84
  85 Command *addcommandtotree(CommandTree *ct, const char *cmdname, int level, int maxparams, CommandHandler handler) {
  86   Command *nc, *c;
  87   int i;
  88
  89   /* Generate the struct.. */
  90   nc=(void *)malloc(sizeof(Command));
  91   nc->command=getsstring(cmdname, MAX_COMMAND_LEN);
  92   nc->level=level;
  93   nc->maxparams=maxparams;
  94   nc->handler=handler;
  95   nc->next=NULL;
  96
  97   /* Sanity check the string */
  98   for (i=0;i<nc->command->length;i++) {
  99     nc->command->content[i]=toupper(nc->command->content[i]);
 100     if (nc->command->content[i]<'A' || nc->command->content[i]>'Z') {
 101       /* Someone tried to register an invalid command name */
 102       freesstring(nc->command);
 103       free(nc);
 104       return NULL;
 105     }
 106   }
 107
 108   if ((c=findcommandintree(ct,cmdname,1))!=NULL) {
 109     /* Found something already.  Append our entry to the end */
 110     while (c->next!=NULL)
 111       c=(Command *)c->next;
 112     c->next=(struct Command *)nc;
 113   } else if (insertcommand(nc,ct,0)) {
 114     /* Erk, that didn't work.. */
 115     freesstring(nc->command);
 116     free(nc);
 117     return NULL;
 118   }
 119
 120   return nc;
 121 }
 122
 123 /*
 124  * insertcommand: internal recursive function to do actual command insertion
 125  */
 126
 127 int insertcommand(Command *c, CommandTree *ct, int depth) {
 128   int nextcharindex=c->command->content[depth]-'A';
 129
 130   if ((c->command->length==depth) || (countcommandtree(ct)==0)) {
 131     if(ct->cmd!=NULL) {
 132       int oldcharindex;
 133       /* There is already another command at this level */
 134       if(ct->final[0]=='\0') {
 135         /* It's a conflict with us, shouldn't happen */
 136         return 1;
 137       }
 138       oldcharindex=ct->final[0]-'A';
 139       if (ct->next[oldcharindex] != NULL) {
 140         /* Shouldn't happen */
 141         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 142       } else {
 143         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 144       }
 145       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 146     }
 147     ct->cmd=c;
 148     ct->final=&(c->command->content[depth]);
 149     return 0;
 150   } else {
 151     if ((ct->cmd!=NULL) && (ct->final[0]!='\0')) {
 152       int oldcharindex=ct->final[0]-'A';
 153       /* Someone marked this node as final, we have to undo that since we're now here too */
 154       if (ct->next[oldcharindex] != NULL) {
 155         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 156         /* Shouldn't happen */
 157       } else {
 158         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 159       }
 160       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 161       ct->cmd=NULL;
 162       ct->final="";
 163     }
 164
 165     if (ct->next[nextcharindex]==NULL) {
 166       ct->next[nextcharindex]=(struct CommandTree *)newcommandtree();
 167     }
 168     return insertcommand(c,(CommandTree *)ct->next[nextcharindex],depth+1);
 169   }
 170 }
 171
 172 int deletecommandfromtree(CommandTree *ct, const char *cmdname, CommandHandler handler) {
 173   int i;
 174   sstring *tmpstr;
 175
 176   tmpstr=getsstring(cmdname,MAX_COMMAND_LEN);
 177
 178   /* Sanity check input string */
 179   for (i=0;i<tmpstr->length;i++) {
 180     tmpstr->content[i]=toupper(tmpstr->content[i]);
 181     if (tmpstr->content[i]<'A' || tmpstr->content[i]>'Z') {
 182       /* Someone tried to delete an invalid command name */
 183       freesstring(tmpstr);
 184       return 1;
 185     }
 186   }
 187   i=deletecommand(tmpstr,ct,0,handler);
 188   freesstring(tmpstr);
 189   return i;
 190 }
 191
 192 int deletecommand(sstring *cmdname, CommandTree *ct, int depth, CommandHandler handler) {
 193   Command **ch, *c;
 194   int nextcharindex=(cmdname->content[depth])-'A';
 195   int i;
 196
 197   if (depth==cmdname->length) {
 198     /* Hit the end of the string.. the command should be in this node */
 199     if ((ct->cmd==NULL) ||
 200         (ct->cmd->command->length != cmdname->length) ||
 201         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 202       return 1;
 203     }
 204     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 205       if ((*ch)->handler==handler) {
 206         c=*ch;
 207         (*ch)=(Command *)((*ch)->next);
 208         freesstring(c->command);
 209         free(c);
 210         return 0;
 211       }
 212     }
 213     return 1;
 214   } else if ((ct->final) && (ct->final[0]==cmdname->content[depth])) {
 215     /* We have a potentially matching final string here, double check */
 216     if ((ct->cmd->command->length != cmdname->length) ||
 217         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 218       return 1;
 219     }
 220     /* Find the command in the potential chain and remove it */
 221     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 222       if ((*ch)->handler==handler) {
 223         c=*ch;
 224         (*ch)=(Command *)((*ch)->next);
 225         freesstring(c->command);
 226         free(c);
 227         return 0;
 228       }
 229     }
 230     return 1;
 231   } else {
 232     /* We're going to have to recurse.. */
 233     if (ct->next[nextcharindex]==NULL) {
 234       return 1;
 235     } else {
 236       i=deletecommand(cmdname,(CommandTree *)ct->next[nextcharindex],depth+1,handler);
 237       if (countcommandtree((CommandTree *)ct->next[nextcharindex])==0) {
 238         free(ct->next[nextcharindex]);
 239         ct->next[nextcharindex]=NULL;
 240       }
 241       return i;
 242     }
 243   }
 244 }
 245
 246 /*
 247  * findcommandintree: Takes a command string and returns the relevant
 248  *                    structure, if found.
 249  */
 250
 251 Command *findcommandintree(CommandTree *ct, const char *command, int strictcheck) {
 252   Command *c;
 253
 254   c=findcommand(ct,command,0);
 255
 256   if (c==NULL)
 257     return NULL;
 258
 259   if (strictcheck &&
 260       (ircd_strncmp(command,c->command->content,c->command->length) ||
 261        (c->command->length != strlen(command))))
 262     return NULL;
 263
 264   return c;
 265 }
 266
 267 /*
 268  * findcommand: Internal recursive function to find a command
 269  */
 270
 271 Command *findcommand(CommandTree *ct, const char *command, int depth) {
 272   int nextchar=toupper(command[depth]);
 273
 274   /* If we've run out of string, we return whatever we find in this node,
 275    * be it NULL or otherwise. */
 276   if (nextchar=='\0') {
 277     return ct->cmd;
 278   }
 279
 280   if ((ct->cmd!=NULL) && ct->final[0]==nextchar) {
 281     return ct->cmd;
 282   }
 283
 284   if (nextchar<'A' || nextchar>'Z') {
 285     return NULL;
 286   }
 287
 288   if (ct->next[nextchar-'A']==NULL) {
 289     return NULL;
 290   } else {
 291     return findcommand((CommandTree *)ct->next[nextchar-'A'], command, depth+1);
 292   }
 293 }
 294
 295 /*
 296  * getcommandlist: Returns the contents of a CommandTree in a user-supplied Command * array
 297  */
 298
 299 int getcommandlist(CommandTree *ct, Command **commandlist, int maxcommands) {
 300   int i=0,count=0;
 301
 302   if (maxcommands<0) {
 303     return 0;
 304   }
 305
 306   if (ct->cmd) {
 307     commandlist[count++]=ct->cmd;
 308   }
 309
 310   for (i=0;i<26;i++) {
 311     if(ct->next[i]) {
 312       count+=getcommandlist(ct->next[i], &commandlist[count], maxcommands-count);
 313     }
 314   }
 315
 316   return count;
 317 }