Apply suggestions from code review

Co-authored-by: str4d <thestr4d@gmail.com>
Co-authored-by: Daira Hopwood <daira@jacaranda.org>

src/rpc/misc.cpp

@@ -500,8 +500,7 @@ UniValue setmocktime(const UniValue& params, bool fHelp)
             "\nSet the local time to given timestamp (-regtest only).\n"
             "The node must be started with `-mocktime` in order to use this API.\n"
             "\nArguments:\n"
-            "1. timestamp  (integer, required) Unix seconds-since-epoch timestamp\n"
-            "   Pass 0 to go back to using the system time."
+            "1. timestamp  (integer, required) Unix seconds-since-epoch timestamp."
         );
 
     if (!Params().MineBlocksOnDemand())

src/util/time.cpp

@@ -15,7 +15,9 @@
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/thread.hpp>
 
+// This guards accesses to FixedClock and OffsetClock.
 RecursiveMutex cs_clock;
+
 static CClock* zcashdClock = SystemClock::Instance();
 
 const CClock* GetNodeClock() {

src/util/time.h

@@ -24,8 +24,8 @@ class SystemClock: public CClock {
 private:
     SystemClock() {}
     ~SystemClock() {}
-    SystemClock(SystemClock const&)    = delete;
-    SystemClock& operator=(const SystemClock&)= delete;
+    SystemClock(SystemClock const&) = delete;
+    SystemClock& operator=(const SystemClock&) = delete;
 public:
     static SystemClock* Instance() {
         static SystemClock instance;
@@ -33,8 +33,8 @@ public:
     }
 
     /**
-     * Sets the clock used by zcashd to the system clock.  This must only be
-     * called by `init()`, or in tests.
+     * Sets the clock used by zcashd to the system clock. This is not thread-safe,
+     * and must only be called in a single-threaded context such as `init`.
      */
     static void SetGlobal();
 
@@ -56,8 +56,8 @@ public:
     }
 
     /**
-     * Sets the clock used by zcashd to a fixed clock. This must only be used
-     * by `init()`, or in tests.
+     * Sets the clock used by zcashd to a fixed clock. This is not thread-safe
+     * and must only be called in a single-threaded context such as `init`.
      */
     static void SetGlobal();
 
@@ -81,8 +81,8 @@ public:
 
     /**
      * Sets the clock used by zcashd to a clock that returns the current system
-     * time modified by the specified offset.  This must only be called by
-     * `init()`, or in tests.
+     * time modified by the specified offset. This is not thread-safe and must
+     * only be called in a single-threaded context such as `init`.
      */
     static void SetGlobal();