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->ext=NULL;
  96   nc->next=NULL;
  97
  98   /* Sanity check the string */
  99   for (i=0;i<nc->command->length;i++) {
 100     nc->command->content[i]=toupper(nc->command->content[i]);
 101     if (nc->command->content[i]<'A' || nc->command->content[i]>'Z') {
 102       /* Someone tried to register an invalid command name */
 103       freesstring(nc->command);
 104       free(nc);
 105       return NULL;
 106     }
 107   }
 108
 109   if ((c=findcommandintree(ct,cmdname,1))!=NULL) {
 110     /* Found something already.  Append our entry to the end */
 111     while (c->next!=NULL)
 112       c=(Command *)c->next;
 113     c->next=(struct Command *)nc;
 114   } else if (insertcommand(nc,ct,0)) {
 115     /* Erk, that didn't work.. */
 116     freesstring(nc->command);
 117     free(nc);
 118     return NULL;
 119   }
 120
 121   return nc;
 122 }
 123
 124 /*
 125  * insertcommand: internal recursive function to do actual command insertion
 126  */
 127
 128 int insertcommand(Command *c, CommandTree *ct, int depth) {
 129   int nextcharindex=c->command->content[depth]-'A';
 130
 131   if ((c->command->length==depth) || (countcommandtree(ct)==0)) {
 132     if(ct->cmd!=NULL) {
 133       int oldcharindex;
 134       /* There is already another command at this level */
 135       if(ct->final[0]=='\0') {
 136         /* It's a conflict with us, shouldn't happen */
 137         return 1;
 138       }
 139       oldcharindex=ct->final[0]-'A';
 140       if (ct->next[oldcharindex] != NULL) {
 141         /* Shouldn't happen */
 142         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 143       } else {
 144         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 145       }
 146       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 147     }
 148     ct->cmd=c;
 149     ct->final=&(c->command->content[depth]);
 150     return 0;
 151   } else {
 152     if ((ct->cmd!=NULL) && (ct->final[0]!='\0')) {
 153       int oldcharindex=ct->final[0]-'A';
 154       /* Someone marked this node as final, we have to undo that since we're now here too */
 155       if (ct->next[oldcharindex] != NULL) {
 156         Error("parser",ERR_ERROR,"Unexpected command subtree conflicts with final value");
 157         /* Shouldn't happen */
 158       } else {
 159         ct->next[oldcharindex]=(struct CommandTree *)newcommandtree();
 160       }
 161       insertcommand(ct->cmd,(CommandTree *)ct->next[oldcharindex],depth+1);
 162       ct->cmd=NULL;
 163       ct->final="";
 164     }
 165
 166     if (ct->next[nextcharindex]==NULL) {
 167       ct->next[nextcharindex]=(struct CommandTree *)newcommandtree();
 168     }
 169     return insertcommand(c,(CommandTree *)ct->next[nextcharindex],depth+1);
 170   }
 171 }
 172
 173 int deletecommandfromtree(CommandTree *ct, const char *cmdname, CommandHandler handler) {
 174   int i;
 175   sstring *tmpstr;
 176
 177   tmpstr=getsstring(cmdname,MAX_COMMAND_LEN);
 178
 179   /* Sanity check input string */
 180   for (i=0;i<tmpstr->length;i++) {
 181     tmpstr->content[i]=toupper(tmpstr->content[i]);
 182     if (tmpstr->content[i]<'A' || tmpstr->content[i]>'Z') {
 183       /* Someone tried to delete an invalid command name */
 184       freesstring(tmpstr);
 185       return 1;
 186     }
 187   }
 188   i=deletecommand(tmpstr,ct,0,handler);
 189   freesstring(tmpstr);
 190   return i;
 191 }
 192
 193 int deletecommand(sstring *cmdname, CommandTree *ct, int depth, CommandHandler handler) {
 194   Command **ch, *c;
 195   int nextcharindex=(cmdname->content[depth])-'A';
 196   int i;
 197
 198   if (depth==cmdname->length) {
 199     /* Hit the end of the string.. the command should be in this node */
 200     if ((ct->cmd==NULL) ||
 201         (ct->cmd->command->length != cmdname->length) ||
 202         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 203       return 1;
 204     }
 205     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 206       if ((*ch)->handler==handler) {
 207         c=*ch;
 208         (*ch)=(Command *)((*ch)->next);
 209         freesstring(c->command);
 210         free(c);
 211         return 0;
 212       }
 213     }
 214     return 1;
 215   } else if ((ct->final) && (ct->final[0]==cmdname->content[depth])) {
 216     /* We have a potentially matching final string here, double check */
 217     if ((ct->cmd->command->length != cmdname->length) ||
 218         (strncmp(ct->cmd->command->content,cmdname->content,cmdname->length))) {
 219       return 1;
 220     }
 221     /* Find the command in the potential chain and remove it */
 222     for(ch=&(ct->cmd);*ch;ch=(Command **)&((*ch)->next)) {
 223       if ((*ch)->handler==handler) {
 224         c=*ch;
 225         (*ch)=(Command *)((*ch)->next);
 226         freesstring(c->command);
 227         free(c);
 228         return 0;
 229       }
 230     }
 231     return 1;
 232   } else {
 233     /* We're going to have to recurse.. */
 234     if (ct->next[nextcharindex]==NULL) {
 235       return 1;
 236     } else {
 237       i=deletecommand(cmdname,(CommandTree *)ct->next[nextcharindex],depth+1,handler);
 238       if (countcommandtree((CommandTree *)ct->next[nextcharindex])==0) {
 239         free(ct->next[nextcharindex]);
 240         ct->next[nextcharindex]=NULL;
 241       }
 242       return i;
 243     }
 244   }
 245 }
 246
 247 /*
 248  * findcommandintree: Takes a command string and returns the relevant
 249  *                    structure, if found.
 250  */
 251
 252 Command *findcommandintree(CommandTree *ct, const char *command, int strictcheck) {
 253   Command *c;
 254
 255   c=findcommand(ct,command,0);
 256
 257   if (c==NULL)
 258     return NULL;
 259
 260   if (strictcheck &&
 261       (ircd_strncmp(command,c->command->content,c->command->length) ||
 262        (c->command->length != strlen(command))))
 263     return NULL;
 264
 265   return c;
 266 }
 267
 268 /*
 269  * findcommand: Internal recursive function to find a command
 270  */
 271
 272 Command *findcommand(CommandTree *ct, const char *command, int depth) {
 273   int nextchar=toupper(command[depth]);
 274
 275   /* If we've run out of string, we return whatever we find in this node,
 276    * be it NULL or otherwise. */
 277   if (nextchar=='\0') {
 278     return ct->cmd;
 279   }
 280
 281   if ((ct->cmd!=NULL) && ct->final[0]==nextchar) {
 282     return ct->cmd;
 283   }
 284
 285   if (nextchar<'A' || nextchar>'Z') {
 286     return NULL;
 287   }
 288
 289   if (ct->next[nextchar-'A']==NULL) {
 290     return NULL;
 291   } else {
 292     return findcommand((CommandTree *)ct->next[nextchar-'A'], command, depth+1);
 293   }
 294 }
 295
 296 /*
 297  * getcommandlist: Returns the contents of a CommandTree in a user-supplied Command * array
 298  */
 299
 300 int getcommandlist(CommandTree *ct, Command **commandlist, int maxcommands) {
 301   int i=0,count=0;
 302
 303   if (maxcommands<0) {
 304     return 0;
 305   }
 306
 307   if (ct->cmd) {
 308     commandlist[count++]=ct->cmd;
 309   }
 310
 311   for (i=0;i<26;i++) {
 312     if(ct->next[i]) {
 313       count+=getcommandlist(ct->next[i], &commandlist[count], maxcommands-count);
 314     }
 315   }
 316
 317   return count;
 318 }