From c4ed54934255916ccf1f5e8382e777cbb66ada3f Mon Sep 17 00:00:00 2001
From: Ian Gulliver <ian@flamingcow.tv>
Date: Wed, 3 Jun 2015 20:53:27 -0700
Subject: [PATCH] Move to condition variable communication.

---
 clients/c/test.c | 52 ++++++++++++++++++------------------------------
 1 file changed, 19 insertions(+), 33 deletions(-)

diff --git a/clients/c/test.c b/clients/c/test.c
index a9a8bda..6f7d4e5 100644
--- a/clients/c/test.c
+++ b/clients/c/test.c
@@ -1,5 +1,6 @@
 #include <assert.h>
 #include <pthread.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
 #include <time.h>
@@ -20,7 +21,9 @@ typedef struct {
   char instance_id[COSMO_UUID_SIZE];
 
   pthread_mutex_t lock;
-  int shutdown;
+  pthread_cond_t cond;
+  bool shutdown;
+  json_t *command_queue;
 
   pthread_t thread;
 } cosmo;
@@ -68,7 +71,7 @@ static char *cosmo_build_rpc(cosmo *instance) {
   return ret;
 }
 
-static int cosmo_send_http_int(cosmo *instance, cosmo_transfer *transfer, CURL *curl) {
+static bool cosmo_send_http_int(cosmo *instance, cosmo_transfer *transfer, CURL *curl) {
   CURLcode res;
  
   curl_easy_setopt(curl, CURLOPT_URL, "https://playground.cosmopolite.org/cosmopolite/api");
@@ -86,17 +89,17 @@ static int cosmo_send_http_int(cosmo *instance, cosmo_transfer *transfer, CURL *
 
   if (res != CURLE_OK) {
     fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
-    return -1;
+    return false;
   }
 
   long return_code;
   assert(curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &return_code) == CURLE_OK);
   if (return_code != 200) {
     fprintf(stderr, "server returned error: %ld\n", return_code);
-    return -1;
+    return false;
   }
 
-  return 0;
+  return true;
 }
 
 // Takes ownership of request
@@ -115,7 +118,7 @@ static char *cosmo_send_http(cosmo *instance, char *request) {
   curl_easy_cleanup(curl);
   free(request);
 
-  return ret ? NULL : transfer.recv_buf;
+  return ret ? transfer.recv_buf : NULL;
 }
 
 static void cosmo_send_rpc(cosmo *instance) {
@@ -145,32 +148,10 @@ static void *cosmo_thread_main(void *arg) {
 
   assert(!pthread_mutex_lock(&instance->lock));
   while (!instance->shutdown) {
-
-    pthread_mutex_unlock(&instance->lock);
-    {
-      time_t t1, t2;
-
-      assert(time(&t1) != -1);
-      cosmo_send_rpc(instance);
-
-      pthread_mutex_lock(&instance->lock);
-      if (instance->shutdown) {
-        break;
-      }
-      pthread_mutex_unlock(&instance->lock);
-
-      assert(time(&t2) != -1);
-      time_t elapsed = t2 - t1;
-      time_t to_wait = COSMO_CHECK_SECONDS - elapsed;
-
-      if (to_wait > 0) {
-        sleep(to_wait);
-      }
-    }
-    pthread_mutex_lock(&instance->lock);
-
+    cosmo_send_rpc(instance);
+    assert(!pthread_cond_wait(&instance->cond, &instance->lock));
   }
-  pthread_mutex_unlock(&instance->lock);
+  assert(!pthread_mutex_unlock(&instance->lock));
   return NULL;
 }
 
@@ -186,7 +167,9 @@ cosmo *cosmo_create(char *client_id) {
   strcpy(instance->client_id, client_id);
   cosmo_generate_uuid(instance->instance_id);
   assert(!pthread_mutex_init(&instance->lock, NULL));
-  instance->shutdown = 0;
+  assert(!pthread_cond_init(&instance->cond, NULL));
+  instance->shutdown = false;
+  instance->command_queue = json_array();
 
   assert(!pthread_create(&instance->thread, NULL, cosmo_thread_main, instance));
   return instance;
@@ -195,9 +178,12 @@ cosmo *cosmo_create(char *client_id) {
 void cosmo_destroy(cosmo *instance) {
   pthread_mutex_lock(&instance->lock);
   instance->shutdown = 1;
+  pthread_cond_signal(&instance->cond);
   pthread_mutex_unlock(&instance->lock);
   assert(!pthread_join(instance->thread, NULL));
   assert(!pthread_mutex_destroy(&instance->lock));
+  assert(!pthread_cond_destroy(&instance->cond));
+  json_decref(instance->command_queue);
   free(instance);
 
   curl_global_cleanup();
@@ -208,7 +194,7 @@ int main(int argc, char *argv[]) {
   char client_id[COSMO_CLIENT_ID_SIZE];
   cosmo_generate_client_id(client_id);
   cosmo *instance = cosmo_create(client_id);
-  sleep(60);
+  sleep(5);
   cosmo_destroy(instance);
 
   return 0;