run-command: add first helper for pp child states

There is a recurring pattern of testing parallel process child states
and file descriptors to determine if a child is running, receiving any
input or if it's ready for cleanup.

Name the pp_child structure and introduce a first helper to make these
checks more readable. Next commits will add more helpers and checks.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 17 insertions, 10 deletions

diff --git a/run-command.c b/run-command.c
index ed9575bd6a..82eeac38bf 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1478,15 +1478,22 @@ enum child_state {
 	GIT_CP_WAIT_CLEANUP,
 };
 
+struct parallel_child {
+	enum child_state state;
+	struct child_process process;
+	struct strbuf err;
+	void *data;
+};
+
+static int child_is_working(const struct parallel_child *pp_child)
+{
+	return pp_child->state == GIT_CP_WORKING;
+}
+
 struct parallel_processes {
 	size_t nr_processes;
 
-	struct {
-		enum child_state state;
-		struct child_process process;
-		struct strbuf err;
-		void *data;
-	} *children;
+	struct parallel_child *children;
 	/*
 	 * The struct pollfd is logically part of *children,
 	 * but the system call expects it as its own array.
@@ -1509,7 +1516,7 @@ static void kill_children(const struct parallel_processes *pp,
 			  int signo)
 {
 	for (size_t i = 0; i < opts->processes; i++)
-		if (pp->children[i].state == GIT_CP_WORKING)
+		if (child_is_working(&pp->children[i]))
 			kill(pp->children[i].process.pid, signo);
 }
 
@@ -1665,7 +1672,7 @@ static void pp_buffer_stderr(struct parallel_processes *pp,
 
 	/* Buffer output from all pipes. */
 	for (size_t i = 0; i < opts->processes; i++) {
-		if (pp->children[i].state == GIT_CP_WORKING &&
+		if (child_is_working(&pp->children[i]) &&
 		    pp->pfd[i].revents & (POLLIN | POLLHUP)) {
 			int n = strbuf_read_once(&pp->children[i].err,
 						 pp->children[i].process.err, 0);
@@ -1683,7 +1690,7 @@ static void pp_output(const struct parallel_processes *pp)
 {
 	size_t i = pp->output_owner;
 
-	if (pp->children[i].state == GIT_CP_WORKING &&
+	if (child_is_working(&pp->children[i]) &&
 	    pp->children[i].err.len) {
 		strbuf_write(&pp->children[i].err, stderr);
 		strbuf_reset(&pp->children[i].err);
@@ -1748,7 +1755,7 @@ static int pp_collect_finished(struct parallel_processes *pp,
 			 * running process time.
 			 */
 			for (i = 0; i < n; i++)
-				if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
+				if (child_is_working(&pp->children[(pp->output_owner + i) % n]))
 					break;
 			pp->output_owner = (pp->output_owner + i) % n;
 		}