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 /* sanitisecommandname:
  77  *
  78  * Converts the given command name to uppercase and checks for bad chars.
  79  *
  80  * Returns 1 if bad chars were found
  81  */
  82 static int sanitisecommandname(const char *cmdname, char *cmdbuf) {
  83   int len,i;
  84
  85   strncpy(cmdbuf,cmdname,MAX_COMMAND_LEN);
  86   cmdbuf[MAX_COMMAND_LEN-1]='\0';
  87
  88   len=strlen(cmdbuf);
  89
  90   /* Sanity check the string */
  91   for (i=0;i<len;i++) {
  92     cmdbuf[i]=toupper(cmdbuf[i]);
  93     if (cmdbuf[i]<'A' || cmdbuf[i]>'Z') {
  94       /* Someone tried to register an invalid command name */
  95       return 1;
  96     }
  97   }
  98
  99   return 0;
 100 }
 101
 102 /*
 103  * addcommandhelptotree:
 104  *
 105  * This installs a specific command in a tree, with a help paramater.
 106  *
 107  * This function builds the Command structure in addition to
 108  * installing it in the tree
 109  */
 110
 111 Command *addcommandhelptotree(CommandTree *ct, const char *cmdname, int level, int maxparams, CommandHandler handler, const char *help) {
 112   Command *nc, *c;
 113   char cmdbuf[MAX_COMMAND_LEN];
 114
 115   if (sanitisecommandname(cmdname, cmdbuf))
 116     return NULL;
 117
 118   /* Generate the struct.. */
 119   nc=(void *)malloc(sizeof(Command));
 120   nc->command=getsstring(cmdbuf, MAX_COMMAND_LEN);
 121   nc->level=level;
 122   nc->maxparams=maxparams;
 123   nc->handler=handler;
 124   nc->ext=NULL;
 125   nc->next=NULL;
 126   if (help) {
 127     nc->help=getsstring(help, 512);
 128   } else {
 129     nc->help=NULL;
 130   }
 131
 132   if ((c=findcommandintree(ct,cmdname,1))!=NULL) {
 133     /* Found something already.  Append our entry to the end */
 134     while (c->next!=NULL)
 135       c=(Command *)c->next;
 136     c->next=(struct Command *)nc;
 137   } else if (insertcommand(nc,ct,0)) {
 138     /* Erk, that didn't work.. */
 139     freesstring(nc->command);
 140     freesstring(nc->help);
 141     free(nc);
 142     return NULL;
 143   }
 144
 145   return nc;
 146 }
 147
 148 /*
 149  * insertcommand: internal recursive function to do actual command insertion
 150  */
 151
 152 int insertcommand(Command *c, CommandTree *ct, int depth) {
 153   int nextcharindex=c->command->content[depth]-'A';
 154
 155   if ((c->command->length==depth) || (countcommandtree(ct)==0)) {
 156     if(ct->cmd!=NULL) {
 157       int oldcharindex;
 158       /* There is already another command at this level */
 159       if(ct->final[0]=='\0') {
 160         /* It's a conflict with us, shouldn't happen */
 161         return 1;
 162       }
 163       oldcharindex=ct->final[0]-'A';
 164       if (ct->next[oldcharindex] != NULL) {
 165         /* Shouldn't happen */
 166         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 167       } else {
 168         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 169       }
 170       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 171     }
 172     ct->cmd=c;
 173     /* Use a static NUL string rather than the allocated one if possible. */
 174     if (c->command->length > depth)
 175       ct->final=&(c->command->content[depth]);
 176     else
 177       ct->final="";
 178     return 0;
 179   } else {
 180     if ((ct->cmd!=NULL) && (ct->final[0]!='\0')) {
 181       int oldcharindex=ct->final[0]-'A';
 182       /* Someone marked this node as final, we have to undo that since we're now here too */
 183       if (ct->next[oldcharindex] != NULL) {
 184         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 185         /* Shouldn't happen */
 186       } else {
 187         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 188       }
 189       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 190       ct->cmd=NULL;
 191       ct->final="";
 192     }
 193
 194     if (ct->next[nextcharindex]==NULL) {
 195       ct->next[nextcharindex]=(struct CommandTree *)newcommandtree();
 196     }
 197     return insertcommand(c,(CommandTree *)ct->next[nextcharindex],depth+1);
 198   }
 199 }
 200
 201 int deletecommandfromtree(CommandTree *ct, const char *cmdname, CommandHandler handler) {
 202   int i;
 203   char cmdbuf[MAX_COMMAND_LEN+1];
 204   sstring *tmpstr;
 205
 206   if (sanitisecommandname(cmdname, cmdbuf))
 207     return 1;
 208
 209   tmpstr=getsstring(cmdbuf, MAX_COMMAND_LEN);
 210   i=deletecommand(tmpstr,ct,0,handler);
 211   freesstring(tmpstr);
 212
 213   return i;
 214 }
 215
 216 int deletecommand(sstring *cmdname, CommandTree *ct, int depth, CommandHandler handler) {
 217   Command **ch, *c;
 218   int nextcharindex=(cmdname->content[depth])-'A';
 219   int i;
 220
 221   if (depth==cmdname->length) {
 222     /* Hit the end of the string.. the command should be in this node */
 223     if ((ct->cmd==NULL) ||
 224         (ct->cmd->command->length != cmdname->length) ||
 225         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 226       return 1;
 227     }
 228     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 229       if ((*ch)->handler==handler) {
 230         c=*ch;
 231         (*ch)=(Command *)((*ch)->next);
 232         freesstring(c->command);
 233         freesstring(c->help);
 234         free(c);
 235         return 0;
 236       }
 237     }
 238     return 1;
 239   } else if ((ct->final) && (ct->final[0]==cmdname->content[depth])) {
 240     /* We have a potentially matching final string here, double check */
 241     if ((ct->cmd->command->length != cmdname->length) ||
 242         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 243       return 1;
 244     }
 245     /* Find the command in the potential chain and remove it */
 246     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 247       if ((*ch)->handler==handler) {
 248         c=*ch;
 249         (*ch)=(Command *)((*ch)->next);
 250         freesstring(c->command);
 251         freesstring(c->help);
 252         free(c);
 253
 254         /* We need to regenerate the final pointer if needed;
 255          * if ct->cmd is still pointing to a command it has the same name.
 256          * Otherwise we should clear it.*/
 257         if (ct->cmd)
 258           ct->final=&(ct->cmd->command->content[depth]);
 259         else
 260           ct->final="";
 261
 262         return 0;
 263       }
 264     }
 265     return 1;
 266   } else {
 267     /* We're going to have to recurse.. */
 268     if (ct->next[nextcharindex]==NULL) {
 269       return 1;
 270     } else {
 271       i=deletecommand(cmdname,(CommandTree *)ct->next[nextcharindex],depth+1,handler);
 272       if (countcommandtree((CommandTree *)ct->next[nextcharindex])==0) {
 273         free(ct->next[nextcharindex]);
 274         ct->next[nextcharindex]=NULL;
 275       }
 276       return i;
 277     }
 278   }
 279 }
 280
 281 /*
 282  * findcommandintree: Takes a command string and returns the relevant
 283  *                    structure, if found.
 284  */
 285
 286 Command *findcommandintree(CommandTree *ct, const char *command, int strictcheck) {
 287   Command *c;
 288
 289   c=findcommand(ct,command,0);
 290
 291   if (c==NULL)
 292     return NULL;
 293
 294   if (strictcheck &&
 295       (ircd_strncmp(command,c->command->content,c->command->length) ||
 296        (c->command->length != strlen(command))))
 297     return NULL;
 298
 299   return c;
 300 }
 301
 302 /*
 303  * findcommand: Internal recursive function to find a command
 304  */
 305
 306 Command *findcommand(CommandTree *ct, const char *command, int depth) {
 307   int nextchar=toupper(command[depth]);
 308
 309   /* If we've run out of string, we return whatever we find in this node,
 310    * be it NULL or otherwise. */
 311   if (nextchar=='\0') {
 312     return ct->cmd;
 313   }
 314
 315   if ((ct->cmd!=NULL) && ct->final[0]==nextchar) {
 316     return ct->cmd;
 317   }
 318
 319   if (nextchar<'A' || nextchar>'Z') {
 320     return NULL;
 321   }
 322
 323   if (ct->next[nextchar-'A']==NULL) {
 324     return NULL;
 325   } else {
 326     return findcommand((CommandTree *)ct->next[nextchar-'A'], command, depth+1);
 327   }
 328 }
 329
 330 /*
 331  * getcommandlist: Returns the contents of a CommandTree in a user-supplied Command * array
 332  */
 333
 334 int getcommandlist(CommandTree *ct, Command **commandlist, int maxcommands) {
 335   int i=0,count=0;
 336
 337   if (maxcommands<0) {
 338     return 0;
 339   }
 340
 341   if (ct->cmd) {
 342     commandlist[count++]=ct->cmd;
 343   }
 344
 345   for (i=0;i<26;i++) {
 346     if(ct->next[i]) {
 347       count+=getcommandlist(ct->next[i], &commandlist[count], maxcommands-count);
 348     }
 349   }
 350
 351   return count;
 352 }
 353
 354 /* Returns the command name given a handler */
 355 sstring *getcommandname(CommandTree *ct, CommandHandler handler) {
 356   int i;
 357   sstring *s;
 358
 359   if(ct->cmd && ct->cmd->handler == handler) {
 360     return ct->cmd->command;
 361   }
 362
 363   for (i=0;i<26;i++) {
 364     if(ct->next[i]) {
 365       s=getcommandname(ct->next[i], handler);
 366       if(s)
 367         return s;
 368     }
 369   }
 370
 371   return NULL;
 372 }