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   if(ct->cmd) {
  50     if(ct->cmd->command)
  51       freesstring(ct->cmd->command);
  52     if(ct->cmd->ext && ct->cmd->destroyext)
  53       (ct->cmd->destroyext)(ct->cmd->ext);
  54     free(ct->cmd);
  55   }
  56   free(ct);
  57 }
  58
  59 /* countcommandtree:
  60  *
  61  * This returns the number of commands registered in
  62  * a particular (sub-)tree.  This will come in handy
  63  * later for deleting commands etc.
  64  */
  65
  66 int countcommandtree(CommandTree *ct) {
  67   int i;
  68   int sum;
  69
  70   if (ct->cmd!=NULL) {
  71     sum=1;
  72   } else {
  73     sum=0;
  74   }
  75
  76   for(i=0;i<26;i++)
  77     if (ct->next[i])
  78       sum+=countcommandtree((CommandTree *)ct->next[i]);
  79
  80   return sum;
  81 }
  82
  83 /* sanitisecommandname:
  84  *
  85  * Converts the given command name to uppercase and checks for bad chars.
  86  *
  87  * Returns 1 if bad chars were found
  88  */
  89 static int sanitisecommandname(const char *cmdname, char *cmdbuf) {
  90   int len,i;
  91
  92   strncpy(cmdbuf,cmdname,MAX_COMMAND_LEN);
  93   cmdbuf[MAX_COMMAND_LEN-1]='\0';
  94
  95   len=strlen(cmdbuf);
  96
  97   /* Sanity check the string */
  98   for (i=0;i<len;i++) {
  99     cmdbuf[i]=toupper(cmdbuf[i]);
 100     if (cmdbuf[i]<'A' || cmdbuf[i]>'Z') {
 101       /* Someone tried to register an invalid command name */
 102       return 1;
 103     }
 104   }
 105
 106   return 0;
 107 }
 108
 109 /*
 110  * addcommandhelptotree:
 111  *
 112  * This installs a specific command in a tree, with a help paramater.
 113  *
 114  * This function builds the Command structure in addition to
 115  * installing it in the tree
 116  */
 117
 118 Command *addcommandexttotree(CommandTree *ct, const char *cmdname, int level, int maxparams, CommandHandler handler, void *ext) {
 119   Command *nc, *c;
 120   char cmdbuf[MAX_COMMAND_LEN];
 121
 122   if (sanitisecommandname(cmdname, cmdbuf))
 123     return NULL;
 124
 125   /* Generate the struct.. */
 126   nc=(void *)malloc(sizeof(Command));
 127   nc->command=getsstring(cmdbuf, MAX_COMMAND_LEN);
 128   nc->level=level;
 129   nc->maxparams=maxparams;
 130   nc->handler=handler;
 131   nc->ext=NULL;
 132   nc->next=NULL;
 133   nc->destroyext=NULL;
 134
 135   if ((c=findcommandintree(ct,cmdname,1))!=NULL) {
 136     /* Found something already.  Append our entry to the end */
 137     while (c->next!=NULL)
 138       c=(Command *)c->next;
 139     c->next=(struct Command *)nc;
 140   } else if (insertcommand(nc,ct,0)) {
 141     /* Erk, that didn't work.. */
 142     freesstring(nc->command);
 143     free(nc);
 144     return NULL;
 145   }
 146
 147   if (ext)
 148     nc->ext=(void *)ext;
 149
 150   return nc;
 151 }
 152
 153 /*
 154  * insertcommand: internal recursive function to do actual command insertion
 155  */
 156
 157 int insertcommand(Command *c, CommandTree *ct, int depth) {
 158   int nextcharindex=c->command->content[depth]-'A';
 159
 160   if ((c->command->length==depth) || (countcommandtree(ct)==0)) {
 161     if(ct->cmd!=NULL) {
 162       int oldcharindex;
 163       /* There is already another command at this level */
 164       if(ct->final[0]=='\0') {
 165         /* It's a conflict with us, shouldn't happen */
 166         return 1;
 167       }
 168       oldcharindex=ct->final[0]-'A';
 169       if (ct->next[oldcharindex] != NULL) {
 170         /* Shouldn't happen */
 171         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 172       } else {
 173         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 174       }
 175       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 176     }
 177     ct->cmd=c;
 178     /* Use a static NUL string rather than the allocated one if possible. */
 179     if (c->command->length > depth)
 180       ct->final=&(c->command->content[depth]);
 181     else
 182       ct->final="";
 183     return 0;
 184   } else {
 185     if ((ct->cmd!=NULL) && (ct->final[0]!='\0')) {
 186       int oldcharindex=ct->final[0]-'A';
 187       /* Someone marked this node as final, we have to undo that since we're now here too */
 188       if (ct->next[oldcharindex] != NULL) {
 189         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 190         /* Shouldn't happen */
 191       } else {
 192         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 193       }
 194       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 195       ct->cmd=NULL;
 196       ct->final="";
 197     }
 198
 199     if (ct->next[nextcharindex]==NULL) {
 200       ct->next[nextcharindex]=(struct CommandTree *)newcommandtree();
 201     }
 202     return insertcommand(c,(CommandTree *)ct->next[nextcharindex],depth+1);
 203   }
 204 }
 205
 206 int deletecommandfromtree(CommandTree *ct, const char *cmdname, CommandHandler handler) {
 207   int i;
 208   char cmdbuf[MAX_COMMAND_LEN+1];
 209   sstring *tmpstr;
 210
 211   if (sanitisecommandname(cmdname, cmdbuf))
 212     return 1;
 213
 214   tmpstr=getsstring(cmdbuf, MAX_COMMAND_LEN);
 215   i=deletecommand(tmpstr,ct,0,handler);
 216   freesstring(tmpstr);
 217
 218   return i;
 219 }
 220
 221 int deletecommand(sstring *cmdname, CommandTree *ct, int depth, CommandHandler handler) {
 222   Command **ch, *c;
 223   int nextcharindex=(cmdname->content[depth])-'A';
 224   int i;
 225
 226   if (depth==cmdname->length) {
 227     /* Hit the end of the string.. the command should be in this node */
 228     if ((ct->cmd==NULL) ||
 229         (ct->cmd->command->length != cmdname->length) ||
 230         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 231       return 1;
 232     }
 233     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 234       if ((*ch)->handler==handler) {
 235         c=*ch;
 236         (*ch)=(Command *)((*ch)->next);
 237         freesstring(c->command);
 238         if(c->ext && c->destroyext)
 239           (c->destroyext)(c->ext);
 240         free(c);
 241         return 0;
 242       }
 243     }
 244     return 1;
 245   } else if ((ct->final) && (ct->final[0]==cmdname->content[depth])) {
 246     /* We have a potentially matching final string here, double check */
 247     if ((ct->cmd->command->length != cmdname->length) ||
 248         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 249       return 1;
 250     }
 251     /* Find the command in the potential chain and remove it */
 252     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 253       if ((*ch)->handler==handler) {
 254         c=*ch;
 255         (*ch)=(Command *)((*ch)->next);
 256         freesstring(c->command);
 257         if(c->ext && c->destroyext)
 258           (c->destroyext)(c->ext);
 259         free(c);
 260
 261         /* We need to regenerate the final pointer if needed;
 262          * if ct->cmd is still pointing to a command it has the same name.
 263          * Otherwise we should clear it.*/
 264         if (ct->cmd)
 265           ct->final=&(ct->cmd->command->content[depth]);
 266         else
 267           ct->final="";
 268
 269         return 0;
 270       }
 271     }
 272     return 1;
 273   } else {
 274     /* We're going to have to recurse.. */
 275     if (ct->next[nextcharindex]==NULL) {
 276       return 1;
 277     } else {
 278       i=deletecommand(cmdname,(CommandTree *)ct->next[nextcharindex],depth+1,handler);
 279       if (countcommandtree((CommandTree *)ct->next[nextcharindex])==0) {
 280         free(ct->next[nextcharindex]);
 281         ct->next[nextcharindex]=NULL;
 282       }
 283       return i;
 284     }
 285   }
 286 }
 287
 288 /*
 289  * findcommandintree: Takes a command string and returns the relevant
 290  *                    structure, if found.
 291  */
 292
 293 Command *findcommandintree(CommandTree *ct, const char *command, int strictcheck) {
 294   Command *c;
 295
 296   c=findcommand(ct,command,0);
 297
 298   if (c==NULL)
 299     return NULL;
 300
 301   if (strictcheck &&
 302       (ircd_strncmp(command,c->command->content,c->command->length) ||
 303        (c->command->length != strlen(command))))
 304     return NULL;
 305
 306   return c;
 307 }
 308
 309 /*
 310  * findcommand: Internal recursive function to find a command
 311  */
 312
 313 Command *findcommand(CommandTree *ct, const char *command, int depth) {
 314   int nextchar=toupper(command[depth]);
 315
 316   /* If we've run out of string, we return whatever we find in this node,
 317    * be it NULL or otherwise. */
 318   if (nextchar=='\0') {
 319     return ct->cmd;
 320   }
 321
 322   if ((ct->cmd!=NULL) && ct->final[0]==nextchar) {
 323     return ct->cmd;
 324   }
 325
 326   if (nextchar<'A' || nextchar>'Z') {
 327     return NULL;
 328   }
 329
 330   if (ct->next[nextchar-'A']==NULL) {
 331     return NULL;
 332   } else {
 333     return findcommand((CommandTree *)ct->next[nextchar-'A'], command, depth+1);
 334   }
 335 }
 336
 337 /*
 338  * getcommandlist: Returns the contents of a CommandTree in a user-supplied Command * array
 339  */
 340
 341 int getcommandlist(CommandTree *ct, Command **commandlist, int maxcommands) {
 342   int i=0,count=0;
 343
 344   if (maxcommands<0) {
 345     return 0;
 346   }
 347
 348   if (ct->cmd) {
 349     commandlist[count++]=ct->cmd;
 350   }
 351
 352   for (i=0;i<26;i++) {
 353     if(ct->next[i]) {
 354       count+=getcommandlist(ct->next[i], &commandlist[count], maxcommands-count);
 355     }
 356   }
 357
 358   return count;
 359 }
 360
 361 /* Returns the command name given a handler */
 362 sstring *getcommandname(CommandTree *ct, CommandHandler handler) {
 363   int i;
 364   sstring *s;
 365
 366   if(ct->cmd && ct->cmd->handler == handler) {
 367     return ct->cmd->command;
 368   }
 369
 370   for (i=0;i<26;i++) {
 371     if(ct->next[i]) {
 372       s=getcommandname(ct->next[i], handler);
 373       if(s)
 374         return s;
 375     }
 376   }
 377
 378   return NULL;
 379 }