On Tue, 16 Apr 2019 02:00:15 +0300
Slavomir Kaslev <kaslevs@xxxxxxxxxx> wrote:
> static char *make_pid_filter(char *curr_filter, const char *field)
> {
> + int curr_len = 0, last_exclude = -1;
Small nit. Usually when adding multiple variables on one line like
this, the variables should be related. Because curr_len and
last_exclude are not related, it is best to keep them separate.
> + int start_pid = -1, last_pid = -1;
start_pid and last_pid are fine on the same line or separate.
> + char *filter = NULL, *save;
Note, It's better to keep variables separate. It makes it easier to see
them and also when code changes and you get the "variable x is not
used" warnings from gcc, it's easier to remove them. In emacs it brings
you to the warning and places the cursor on the problem line. Then a
simple "delete line" works well.
save could also be moved below.
> struct filter_pids *p;
> - char *filter;
> - char *orit;
> - char *match;
> - char *str;
> - int curr_len = 0;
> - int len;
>
> /* Use the new method if possible */
> if (have_set_event_pid)
> return NULL;
>
> - len = len_filter_pids + (strlen(field) + strlen("(==)||")) * nr_filter_pids;
> -
> - if (curr_filter) {
> - curr_len = strlen(curr_filter);
> - filter = realloc(curr_filter, curr_len + len + strlen("(&&())"));
> - if (!filter)
> - die("realloc");
> - memmove(filter+1, curr_filter, curr_len);
> - filter[0] = '(';
> - strcat(filter, ")&&(");
> - curr_len = strlen(filter);
> - } else
> - filter = malloc(len);
> - if (!filter)
> - die("Failed to allocate pid filter");
> -
> - /* Last '||' that is not used will cover the \0 */
> - str = filter + curr_len;
> + if (!filter_pids)
> + return curr_filter;
>
> for (p = filter_pids; p; p = p->next) {
> - if (p->exclude) {
> - match = "!=";
> - orit = "&&";
> - } else {
> - match = "==";
> - orit = "||";
> + /* PIDs are inserted in `filter_pids` from the front and that's
Comment notation should be:
/*
* PIDs are inserted in ...
Only the Networking folks are allowed to do it that way in the
kernel ;-)
> + * why we expect them in descending order here.
> + */
> + if (p->pid == last_pid - 1 && p->exclude == last_exclude) {
> + last_pid = p->pid;
> + continue;
> }
> - if (p == filter_pids)
> - orit = "";
>
> - len = sprintf(str, "%s(%s%s%d)", orit, field, match, p->pid);
> - str += len;
> + if (start_pid != -1)
> + append_filter_pid_range(&filter, &curr_len, field,
> + last_pid, start_pid,
> + last_exclude);
> +
> + start_pid = last_pid = p->pid;
> + last_exclude = p->exclude;
> +
> }
> + append_filter_pid_range(&filter, &curr_len, field,
> + last_pid, start_pid, last_exclude);
>
> - if (curr_len)
> - sprintf(str, ")");
> + if (curr_filter) {
As save is only used here, we could have:
char *save = filter;
> + save = filter;
> + asprintf(&filter, "(%s)&&(%s)", curr_filter, filter);
> + free(save);
> + }
>
> return filter;
> }
-- Steve
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