builtin/stripspace.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3
   4 /*
   5  * Returns the length of a line, without trailing spaces.
   6  *
   7  * If the line ends with newline, it will be removed too.
   8  */
   9 static size_t cleanup(char *line, size_t len)
  10 {
  11         while (len) {
  12                 unsigned char c = line[len - 1];
  13                 if (!isspace(c))
  14                         break;
  15                 len--;
  16         }
  17
  18         return len;
  19 }
  20
  21 /*
  22  * Remove empty lines from the beginning and end
  23  * and also trailing spaces from every line.
  24  *
  25  * Turn multiple consecutive empty lines between paragraphs
  26  * into just one empty line.
  27  *
  28  * If the input has only empty lines and spaces,
  29  * no output will be produced.
  30  *
  31  * If last line does not have a newline at the end, one is added.
  32  *
  33  * Enable skip_comments to skip every line starting with "#".
  34  */
  35 void stripspace(struct strbuf *sb, int skip_comments)
  36 {
  37         int empties = 0;
  38         size_t i, j, len, newlen;
  39         char *eol;
  40
  41         /* We may have to add a newline. */
  42         strbuf_grow(sb, 1);
  43
  44         for (i = j = 0; i < sb->len; i += len, j += newlen) {
  45                 eol = memchr(sb->buf + i, '\n', sb->len - i);
  46                 len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;
  47
  48                 if (skip_comments && len && sb->buf[i] == '#') {
  49                         newlen = 0;
  50                         continue;
  51                 }
  52                 newlen = cleanup(sb->buf + i, len);
  53
  54                 /* Not just an empty line? */
  55                 if (newlen) {
  56                         if (empties > 0 && j > 0)
  57                                 sb->buf[j++] = '\n';
  58                         empties = 0;
  59                         memmove(sb->buf + j, sb->buf + i, newlen);
  60                         sb->buf[newlen + j++] = '\n';
  61                 } else {
  62                         empties++;
  63                 }
  64         }
  65
  66         strbuf_setlen(sb, j);
  67 }
  68
  69 int cmd_stripspace(int argc, const char **argv, const char *prefix)
  70 {
  71         struct strbuf buf = STRBUF_INIT;
  72         int strip_comments = 0;
  73
  74         if (argc == 2 && (!strcmp(argv[1], "-s") ||
  75                                 !strcmp(argv[1], "--strip-comments")))
  76                 strip_comments = 1;
  77         else if (argc > 1)
  78                 usage("git stripspace [-s | --strip-comments] < input");
  79
  80         if (strbuf_read(&buf, 0, 1024) < 0)
  81                 die_errno("could not read the input");
  82
  83         stripspace(&buf, strip_comments);
  84
  85         write_or_die(1, buf.buf, buf.len);
  86         strbuf_release(&buf);
  87         return 0;
  88 }