[core] Use better types for modified / expires / etag

2 files changed, 13 insertions, 8 deletions

diff --git a/src/mbgl/storage/http_request_base.cpp b/src/mbgl/storage/http_request_base.cpp
index 8a4a81b291..81be716ff2 100644
--- a/src/mbgl/storage/http_request_base.cpp
+++ b/src/mbgl/storage/http_request_base.cpp
@@ -5,15 +5,19 @@
 
 namespace mbgl {
 
-Seconds HTTPRequestBase::parseCacheControl(const char *value) {
-    if (value) {
-        const auto cacheControl = http::CacheControl::parse(value);
-        if (cacheControl.maxAge) {
-            return toSeconds(SystemClock::now()) + Seconds(*cacheControl.maxAge);
-        }
+optional<SystemTimePoint> HTTPRequestBase::parseCacheControl(const char *value) {
+    if (!value) {
+        return {};
     }
 
-    return Seconds::zero();
+    const auto cacheControl = http::CacheControl::parse(value);
+    if (!cacheControl.maxAge) {
+        return {};
+    }
+
+    // Round trip through time_t to truncate fractional seconds.
+    return SystemClock::from_time_t(SystemClock::to_time_t(
+        SystemClock::now() + std::chrono::seconds(*cacheControl.maxAge)));
 }
 
 } // namespace mbgl
diff --git a/src/mbgl/storage/http_request_base.hpp b/src/mbgl/storage/http_request_base.hpp
index 8f1caf7bdc..1a8cf73da6 100644
--- a/src/mbgl/storage/http_request_base.hpp
+++ b/src/mbgl/storage/http_request_base.hpp
@@ -3,6 +3,7 @@
 
 #include <mbgl/util/noncopyable.hpp>
 #include <mbgl/util/chrono.hpp>
+#include <mbgl/util/optional.hpp>
 
 #include <memory>
 #include <functional>
@@ -27,7 +28,7 @@ public:
     virtual void cancel() { cancelled = true; };
 
 protected:
-    static Seconds parseCacheControl(const char *value);
+    static optional<SystemTimePoint> parseCacheControl(const char *value);
 
     std::string url;
     Callback notify;