2.11BSD#431 - /usr/src/local/less/main.c

   1: /*
   2:  * Entry point, initialization, miscellaneous routines.
   3:  */
   4: 
   5: #include "less.h"
   6: #include "position.h"
   7: #include <setjmp.h>
   8: 
   9: public int  ispipe;
  10: public jmp_buf  main_loop;
  11: public char *   first_cmd;
  12: public char *   every_first_cmd;
  13: public int  new_file;
  14: public int  is_tty;
  15: public char     current_file[128];
  16: public int  any_display;
  17: public int  ac;
  18: public char **  av;
  19: public int  curr_ac;
  20: #if LOGFILE
  21: public int  logfile = -1;
  22: public char *   namelogfile = NULL;
  23: #endif
  24: #if EDITOR
  25: public char *   editor;
  26: #endif
  27: 
  28: extern int file;
  29: extern int nbufs;
  30: extern int sigs;
  31: extern int quit_at_eof;
  32: extern int p_nbufs, f_nbufs;
  33: extern int back_scroll;
  34: extern int top_scroll;
  35: extern int sc_height;
  36: extern int errmsgs;
  37: 
  38: 
  39: /*
  40:  * Edit a new file.
  41:  * Filename "-" means standard input.
  42:  * No filename means the "current" file, from the command line.
  43:  */
  44:     public void
  45: edit(filename)
  46:     char *filename;
  47: {
  48:     register int f;
  49:     char message[100];
  50:     static didpipe;
  51: 
  52:     if (filename == NULL || *filename == '\0')
  53:     {
  54:         if (curr_ac >= ac)
  55:         {
  56:             error("No current file");
  57:             return;
  58:         }
  59:         filename = av[curr_ac];
  60:     }
  61:     if (strcmp(filename, "-") == 0)
  62:     {
  63:         /*
  64: 		 * Use standard input.
  65: 		 */
  66:         if (didpipe)
  67:         {
  68:             error("Can view standard input only once");
  69:             return;
  70:         }
  71:         f = 0;
  72:     } else if ((f = open(filename, 0)) < 0)
  73:     {
  74:         static char co[] = "Cannot open ";
  75:         strcpy(message, co);
  76:         strtcpy(message+sizeof(co)-1, filename,
  77:             sizeof(message)-sizeof(co));
  78:         error(message);
  79:         return;
  80:     }
  81: 
  82:     if (isatty(f))
  83:     {
  84:         /*
  85: 		 * Not really necessary to call this an error,
  86: 		 * but if the control terminal (for commands)
  87: 		 * and the input file (for data) are the same,
  88: 		 * we get weird results at best.
  89: 		 */
  90:         error("Can't take input from a terminal");
  91:         if (f > 0)
  92:             close(f);
  93:         return;
  94:     }
  95: 
  96: #if LOGFILE
  97:     /*
  98: 	 * If he asked for a log file and we have opened standard input,
  99: 	 * create the log file.
 100: 	 * We take care not to blindly overwrite an existing file.
 101: 	 */
 102:     end_logfile();
 103:     if (f == 0 && namelogfile != NULL && is_tty)
 104:     {
 105:         int exists;
 106:         int answer;
 107: 
 108:         /*
 109: 		 * {{ We could use access() here. }}
 110: 		 */
 111:         exists = open(namelogfile, 0);
 112:         close(exists);
 113:         exists = (exists >= 0);
 114: 
 115:         if (exists)
 116:         {
 117:             static char w[] = "WARNING: log file exists: ";
 118:             strcpy(message, w);
 119:             strtcpy(message+sizeof(w)-1, namelogfile,
 120:                 sizeof(message)-sizeof(w));
 121:             error(message);
 122:             answer = 'X';   /* Ask the user what to do */
 123:         } else
 124:             answer = 'O';   /* Create the log file */
 125: 
 126:     loop:
 127:         switch (answer)
 128:         {
 129:         case 'O': case 'o':
 130:             logfile = creat(namelogfile, 0644);
 131:             break;
 132:         case 'A': case 'a':
 133:             logfile = open(namelogfile, 1);
 134:             if (lseek(logfile, (off_t)0, 2) < 0)
 135:             {
 136:                 close(logfile);
 137:                 logfile = -1;
 138:             }
 139:             break;
 140:         case 'D': case 'd':
 141:             answer = 0; /* Don't print an error message */
 142:             break;
 143:         case 'q':
 144:             quit();
 145:         default:
 146:             puts("\n  Overwrite, Append, or Don't log? ");
 147:             answer = getc();
 148:             puts("\n");
 149:             flush();
 150:             goto loop;
 151:         }
 152: 
 153:         if (logfile < 0 && answer != 0)
 154:         {
 155:             sprintf(message, "Cannot write to \"%s\"",
 156:                 namelogfile);
 157:             error(message);
 158:         }
 159:     }
 160: #endif
 161: 
 162:     /*
 163: 	 * We are now committed to using the new file.
 164: 	 * Close the current input file and set up to use the new one.
 165: 	 */
 166:     if (file > 0)
 167:         close(file);
 168:     new_file = 1;
 169:     strtcpy(current_file, filename, sizeof(current_file));
 170:     ispipe = (f == 0);
 171:     if (ispipe)
 172:         didpipe = 1;
 173:     file = f;
 174:     ch_init( (ispipe) ? p_nbufs : f_nbufs );
 175:     init_mark();
 176: 
 177:     if (every_first_cmd != NULL)
 178:         first_cmd = every_first_cmd;
 179: 
 180:     if (is_tty)
 181:     {
 182:         int no_display = !any_display;
 183:         any_display = 1;
 184:         if (no_display && errmsgs > 0)
 185:         {
 186:             /*
 187: 			 * We displayed some messages on error output
 188: 			 * (file descriptor 2; see error() function).
 189: 			 * Before erasing the screen contents,
 190: 			 * display the file name and wait for a keystroke.
 191: 			 */
 192:             error(filename);
 193:         }
 194:         /*
 195: 		 * Indicate there is nothing displayed yet.
 196: 		 */
 197:         pos_clear();
 198:     }
 199: }
 200: 
 201: /*
 202:  * Edit the next file in the command line list.
 203:  */
 204:     public void
 205: next_file(n)
 206:     int n;
 207: {
 208:     if (curr_ac + n >= ac)
 209:     {
 210:         if (quit_at_eof)
 211:             quit();
 212:         error("No (N-th) next file");
 213:     } else
 214:         edit(av[curr_ac += n]);
 215: }
 216: 
 217: /*
 218:  * Edit the previous file in the command line list.
 219:  */
 220:     public void
 221: prev_file(n)
 222:     int n;
 223: {
 224:     if (curr_ac - n < 0)
 225:         error("No (N-th) previous file");
 226:     else
 227:         edit(av[curr_ac -= n]);
 228: }
 229: 
 230: /*
 231:  * Copy a file directly to standard output.
 232:  * Used if standard output is not a tty.
 233:  */
 234:     static void
 235: cat_file()
 236: {
 237:     register int c;
 238: 
 239:     while ((c = ch_forw_get()) != EOF)
 240:         putc(c);
 241:     flush();
 242: }
 243: 
 244: /*
 245:  * Entry point.
 246:  */
 247: main(argc, argv)
 248:     int argc;
 249:     char *argv[];
 250: {
 251:     char *getenv();
 252: 
 253: 
 254:     /*
 255: 	 * Process command line arguments and LESS environment arguments.
 256: 	 * Command line arguments override environment arguments.
 257: 	 */
 258:     init_option();
 259:     scan_option(getenv("LESS"));
 260:     argv++;
 261:     while ( (--argc > 0) &&
 262:         (argv[0][0] == '-' || argv[0][0] == '+') &&
 263:         argv[0][1] != '\0')
 264:         scan_option(*argv++);
 265: 
 266: #if EDITOR
 267:     editor = getenv("EDITOR");
 268:     if (editor == NULL || *editor == '\0')
 269:         editor = EDIT_PGM;
 270: #endif
 271: 
 272:     /*
 273: 	 * Set up list of files to be examined.
 274: 	 */
 275:     ac = argc;
 276:     av = argv;
 277:     curr_ac = 0;
 278: 
 279:     /*
 280: 	 * Set up terminal, etc.
 281: 	 */
 282:     is_tty = isatty(1);
 283:     if (!is_tty)
 284:     {
 285:         /*
 286: 		 * Output is not a tty.
 287: 		 * Just copy the input file(s) to output.
 288: 		 */
 289:         if (ac < 1)
 290:         {
 291:             edit("-");
 292:             cat_file();
 293:         } else
 294:         {
 295:             do
 296:             {
 297:                 edit((char *)NULL);
 298:                 if (file >= 0)
 299:                     cat_file();
 300:             } while (++curr_ac < ac);
 301:         }
 302:         exit(0);
 303:     }
 304: 
 305:     raw_mode(1);
 306:     get_term();
 307:     open_getc();
 308:     init();
 309: 
 310:     if (setjmp(main_loop))
 311:         quit();
 312:     init_signals();
 313: 
 314:     /*
 315: 	 * Select the first file to examine.
 316: 	 */
 317:     if (ac < 1)
 318:         edit("-");  /* Standard input */
 319:     else
 320:     {
 321:         /*
 322: 		 * Try all the files named as command arguments.
 323: 		 * We are simply looking for one which can be
 324: 		 * opened without error.
 325: 		 */
 326:         do
 327:         {
 328:             edit((char *)NULL);
 329:         } while (file < 0 && ++curr_ac < ac);
 330:     }
 331: 
 332:     if (file >= 0)
 333:         commands();
 334:     quit();
 335: }
 336: 
 337: /*
 338:  * Copy a string, truncating to the specified length if necessary.
 339:  * Unlike strncpy(), the resulting string is guaranteed to be null-terminated.
 340:  */
 341: strtcpy(to, from, len)
 342:     char *to;
 343:     char *from;
 344:     int len;
 345: {
 346:     strncpy(to, from, len);
 347:     to[len-1] = '\0';
 348: }
 349: 
 350: /*
 351:  * Exit the program.
 352:  */
 353:     public void
 354: quit()
 355: {
 356:     /*
 357: 	 * Put cursor at bottom left corner, clear the line,
 358: 	 * reset the terminal modes, and exit.
 359: 	 */
 360: #if LOGFILE
 361:     end_logfile();
 362: #endif
 363:     lower_left();
 364:     clear_eol();
 365:     deinit();
 366:     flush();
 367:     raw_mode(0);
 368:     exit(0);
 369: }

Defined functions

Defined variables