1 files changed, 23 insertions, 17 deletions
diff --git a/libutils/Timers.cpp b/libutils/Timers.cpp
index 1172ae7841..fd3f4a9576 100644
--- a/libutils/Timers.cpp
+++ b/libutils/Timers.cpp
@@ -20,31 +20,37 @@
 #include <utils/Timers.h>
 
 #include <limits.h>
+#include <stdlib.h>
 #include <time.h>
 
-// host linux support requires Linux 2.6.39+
+#include <android-base/macros.h>
+
+static constexpr size_t clock_id_max = 5;
+
+static void checkClockId(int clock) {
+    if (clock < 0 || clock >= clock_id_max) abort();
+}
+
 #if defined(__linux__)
-nsecs_t systemTime(int clock)
-{
-    static const clockid_t clocks[] = {
-            CLOCK_REALTIME,
-            CLOCK_MONOTONIC,
-            CLOCK_PROCESS_CPUTIME_ID,
-            CLOCK_THREAD_CPUTIME_ID,
-            CLOCK_BOOTTIME
-    };
-    struct timespec t;
-    t.tv_sec = t.tv_nsec = 0;
+nsecs_t systemTime(int clock) {
+    checkClockId(clock);
+    static constexpr clockid_t clocks[] = {CLOCK_REALTIME, CLOCK_MONOTONIC,
+                                           CLOCK_PROCESS_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID,
+                                           CLOCK_BOOTTIME};
+    static_assert(clock_id_max == arraysize(clocks));
+    timespec t = {};
     clock_gettime(clocks[clock], &t);
     return nsecs_t(t.tv_sec)*1000000000LL + t.tv_nsec;
 }
 #else
-nsecs_t systemTime(int /*clock*/)
-{
+nsecs_t systemTime(int clock) {
+    // TODO: is this ever called with anything but REALTIME on mac/windows?
+    checkClockId(clock);
+
     // Clock support varies widely across hosts. Mac OS doesn't support
-    // CLOCK_BOOTTIME, and Windows is windows.
-    struct timeval t;
-    t.tv_sec = t.tv_usec = 0;
+    // CLOCK_BOOTTIME (and doesn't even have clock_gettime until 10.12).
+    // Windows is windows.
+    timeval t = {};
     gettimeofday(&t, nullptr);
     return nsecs_t(t.tv_sec)*1000000000LL + nsecs_t(t.tv_usec)*1000LL;
 }