From 4e21c065517d6e125cb1d1b9a13e886b3046b0d8 Mon Sep 17 00:00:00 2001
From: iphydf <iphydf@users.noreply.github.com>
Date: Sat, 7 Jul 2018 22:15:08 +0000
Subject: Add a thread-safe version of unix_time and friends.

These are not used in a thread-safe way, but it opens the path towards
per-tox-instance time keeping and removal of some unsafe global state.
---
 toxcore/util.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++-----------
 toxcore/util.h | 12 +++++++++++-
 2 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/toxcore/util.c b/toxcore/util.c
index aa2786dd..0bc77c05 100644
--- a/toxcore/util.c
+++ b/toxcore/util.c
@@ -36,33 +36,70 @@
 #include "crypto_core.h" /* for CRYPTO_PUBLIC_KEY_SIZE */
 #include "network.h" /* for current_time_monotonic */
 
+#include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
 
 /* don't call into system billions of times for no reason */
-static uint64_t unix_time_value;
-static uint64_t unix_base_time_value;
+struct Unix_Time {
+    uint64_t time;
+    uint64_t base_time;
+};
 
-/* XXX: note that this is not thread-safe; if multiple threads call unix_time_update() concurrently, the return value of
- * unix_time() may fail to increase monotonically with increasing time */
-void unix_time_update(void)
+Unix_Time *unix_time_new(void)
 {
-    if (unix_base_time_value == 0) {
-        unix_base_time_value = ((uint64_t)time(nullptr) - (current_time_monotonic() / 1000ULL));
+    Unix_Time *unixtime = (Unix_Time *)malloc(sizeof(Unix_Time));
+
+    if (unixtime == nullptr) {
+        return nullptr;
     }
 
-    unix_time_value = (current_time_monotonic() / 1000ULL) + unix_base_time_value;
+    unixtime->time = 0;
+    unixtime->base_time = 0;
+
+    return unixtime;
 }
 
-uint64_t unix_time(void)
+void unix_time_free(Unix_Time *unixtime)
+{
+    free(unixtime);
+}
+
+void unix_time_update_r(Unix_Time *unixtime)
+{
+    if (unixtime->base_time == 0) {
+        unixtime->base_time = ((uint64_t)time(nullptr) - (current_time_monotonic() / 1000ULL));
+    }
+
+    unixtime->time = (current_time_monotonic() / 1000ULL) + unixtime->base_time;
+}
+
+uint64_t unix_time_get(const Unix_Time *unixtime)
+{
+    return unixtime->time;
+}
+
+int unix_time_is_timeout(const Unix_Time *unixtime, uint64_t timestamp, uint64_t timeout)
 {
-    return unix_time_value;
+    return timestamp + timeout <= unix_time_get(unixtime);
 }
 
+static Unix_Time global_time;
+
+/* XXX: note that this is not thread-safe; if multiple threads call unix_time_update() concurrently, the return value of
+ * unix_time() may fail to increase monotonically with increasing time */
+void unix_time_update(void)
+{
+    unix_time_update_r(&global_time);
+}
+uint64_t unix_time(void)
+{
+    return unix_time_get(&global_time);
+}
 int is_timeout(uint64_t timestamp, uint64_t timeout)
 {
-    return timestamp + timeout <= unix_time();
+    return unix_time_is_timeout(&global_time, timestamp, timeout);
 }
 
 
diff --git a/toxcore/util.h b/toxcore/util.h
index c4d55f12..de493ebe 100644
--- a/toxcore/util.h
+++ b/toxcore/util.h
@@ -39,11 +39,21 @@ extern "C" {
 #define MIN(a,b) (((a)<(b))?(a):(b))
 #define PAIR(TYPE1__, TYPE2__) struct { TYPE1__ first; TYPE2__ second; }
 
+typedef struct Unix_Time Unix_Time;
+
+Unix_Time *unix_time_new(void);
+void unix_time_free(Unix_Time *unixtime);
+
+// TODO(#405): Use per-tox unixtime, remove unix_time_update, and rename
+// unix_time_update_r to unix_time_update.
+void unix_time_update_r(Unix_Time *unixtime);
+uint64_t unix_time_get(const Unix_Time *unixtime);
+int unix_time_is_timeout(const Unix_Time *unixtime, uint64_t timestamp, uint64_t timeout);
+
 void unix_time_update(void);
 uint64_t unix_time(void);
 int is_timeout(uint64_t timestamp, uint64_t timeout);
 
-
 /* id functions */
 bool id_equal(const uint8_t *dest, const uint8_t *src);
 uint32_t id_copy(uint8_t *dest, const uint8_t *src); /* return value is CLIENT_ID_SIZE */
-- 
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