Function diff_populate_filespec

diff.c:4497–4642

* While doing rename detection and pickaxe operation, we may need to * grab the data for the blob (or file) for our own in-core comparison. * diff_filespec has data and size fields for this purpose. */

 * diff_filespec has data and size fields for this purpose.
 */
int diff_populate_filespec(struct repository *r,
			   struct diff_filespec *s,
			   const struct diff_populate_filespec_options *options)
{
	int size_only = options ? options->check_size_only : 0;
	int check_binary = options ? options->check_binary : 0;
	int err = 0;
	int conv_flags = global_conv_flags_eol;
	/*
	 * demote FAIL to WARN to allow inspecting the situation
	 * instead of refusing.
	 */
	if (conv_flags & CONV_EOL_RNDTRP_DIE)
		conv_flags = CONV_EOL_RNDTRP_WARN;

	if (!DIFF_FILE_VALID(s))
		die("internal error: asking to populate invalid file.");
	if (S_ISDIR(s->mode))
		return -1;

	if (s->data)
		return 0;

	if (size_only && 0 < s->size)
		return 0;

	if (S_ISGITLINK(s->mode))
		return diff_populate_gitlink(s, size_only);

	if (!s->oid_valid ||
	    reuse_worktree_file(r->index, s->path, &s->oid, 0)) {
		struct strbuf buf = STRBUF_INIT;
		struct stat st;
		int fd;

		if (lstat(s->path, &st) < 0) {
		err_empty:
			err = -1;
		empty:
			s->data = (char *)"";
			s->size = 0;
			return err;
		}
		s->size = xsize_t(st.st_size);
		if (!s->size)
			goto empty;
		if (S_ISLNK(st.st_mode)) {
			struct strbuf sb = STRBUF_INIT;

			if (strbuf_readlink(&sb, s->path, s->size))
				goto err_empty;
			s->size = sb.len;
			s->data = strbuf_detach(&sb, NULL);
			s->should_free = 1;
			return 0;
		}

		/*