On Thu, Jun 1, 2017 at 11:20 PM, Stefan Beller <sbeller@xxxxxxxxxx> wrote:
> On Thu, Jun 1, 2017 at 11:20 AM, Ævar Arnfjörð Bjarmason
> <avarab@xxxxxxxxx> wrote:
>
>> + if (num_threads == 1)
>> + num_threads = 0;
>
> I would think that it is easier to maintain the code when keep the 1
> hard coded, and apply the following diff instead. If we encounter
> a 0 later on, it is not clear what the original user input was.
> (Did the user ask for 0 as a proxy for GREP_NUM_THREADS_DEFAULT ?
> do they care about the number of threads?)
> It is less complexity in the decision logic here.
>
> --8<-- (white space broken)
> diff --git a/builtin/grep.c b/builtin/grep.c
> index c6c26e9b9e..6ad9b3da20 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -1231,7 +1231,7 @@ int cmd_grep(int argc, const char **argv, const
> char *prefix)
> #endif
>
> #ifndef NO_PTHREADS
> - if (num_threads) {
> + if (num_threads > 1) {
> if (!(opt.name_only || opt.unmatch_name_only || opt.count)
> && (opt.pre_context || opt.post_context ||
> opt.file_break || opt.funcbody))
> @@ -1295,7 +1295,7 @@ int cmd_grep(int argc, const char **argv, const
> char *prefix)
> hit = grep_objects(&opt, &pathspec, &list);
> }
>
> - if (num_threads)
> + if (num_threads > 1)
> hit |= wait_all();
> if (hit && show_in_pager)
> run_pager(&opt, prefix);
> --8<--
If I've understood you correctly (what I applied on top of this based
on the above at the end of the mail) this segfaults because now we
won't compile the pattern.
I agree that this logic is a bit tricky, but it must be considered
with the "!num_threads" logic in preceding "grep: don't redundantly
compile throwaway patterns under threading" patch.
I.e. we already have num_threads being assigned to 0 under
NO_PTHREADS, doing the same for the PTHREADS codepath seemed like the
simplest solution to me.
diff --git a/builtin/grep.c b/builtin/grep.c
index a0a3922f92..6d16df2526 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -1238,25 +1238,23 @@ int cmd_grep(int argc, const char **argv,
const char *prefix)
num_threads = GREP_NUM_THREADS_DEFAULT;
else if (num_threads < 0)
die(_("invalid number of threads specified (%d)"), num_threads);
- if (num_threads == 1)
- num_threads = 0;
#else
if (num_threads)
warning(_("no threads support, ignoring --threads"));
- num_threads = 0;
+ num_threads = 0; /* If we have no threads... */
#endif
- if (!num_threads)
+ if (num_threads) /* Or if we've decided not to use them... */
/*
* The compiled patterns on the main path are only
* used when not using threading. Otherwise
* start_threads() below calls compile_grep_patterns()
* for each thread.
*/
- compile_grep_patterns(&opt);
+ compile_grep_patterns(&opt); /* We'll compile the
pattern here */
#ifndef NO_PTHREADS
- if (num_threads) {
+ if (num_threads > 1) {
if (!(opt.name_only || opt.unmatch_name_only || opt.count)
&& (opt.pre_context || opt.post_context ||
opt.file_break || opt.funcbody))
@@ -1320,7 +1318,7 @@ int cmd_grep(int argc, const char **argv, const
char *prefix)
hit = grep_objects(&opt, &pathspec, &list);
}
- if (num_threads)
+ if (num_threads > 1)
hit |= wait_all();
if (hit && show_in_pager)
run_pager(&opt, prefix);