1 files changed, 35 insertions, 37 deletions
diff --git a/deps/icu-small/source/common/mutex.h b/deps/icu-small/source/common/mutex.h
index 5223397bbc..44b1f90ba0 100644
--- a/deps/icu-small/source/common/mutex.h
+++ b/deps/icu-small/source/common/mutex.h
@@ -28,50 +28,48 @@
 
 U_NAMESPACE_BEGIN
 
-//----------------------------------------------------------------------------
-// Code within that accesses shared static or global data should
-// should instantiate a Mutex object while doing so. You should make your own
-// private mutex where possible.
-
-// For example:
-//
-// UMutex myMutex = U_MUTEX_INITIALIZER;
-//
-// void Function(int arg1, int arg2)
-// {
-//    static Object* foo;     // Shared read-write object
-//    Mutex mutex(&myMutex);  // or no args for the global lock
-//    foo->Method();
-//    // When 'mutex' goes out of scope and gets destroyed here, the lock is released
-// }
-//
-// Note:  Do NOT use the form 'Mutex mutex();' as that merely forward-declares a function
-//        returning a Mutex. This is a common mistake which silently slips through the
-//        compiler!!
-//
+/**
+  * Mutex is a helper class for convenient locking and unlocking of a UMutex.
+  *
+  * Creating a local scope Mutex will lock a UMutex, holding the lock until the Mutex
+  * goes out of scope.
+  *
+  *  If no UMutex is specified, the ICU global mutex is implied.
+  *
+  *  For example:
+  *
+  *  static UMutex myMutex;
+  *
+  *  void Function(int arg1, int arg2)
+  *  {
+  *     static Object* foo;      // Shared read-write object
+  *     Mutex mutex(&myMutex);   // or no args for the global lock
+  *     foo->Method();
+  *     // When 'mutex' goes out of scope and gets destroyed here, the lock is released
+  *  }
+  *
+  *  Note:  Do NOT use the form 'Mutex mutex();' as that merely forward-declares a function
+  *         returning a Mutex. This is a common mistake which silently slips through the
+  *         compiler!!
+  */
 
 class U_COMMON_API Mutex : public UMemory {
 public:
-  inline Mutex(UMutex *mutex = NULL);
-  inline ~Mutex();
+    Mutex(UMutex *mutex = nullptr) : fMutex(mutex) {
+        umtx_lock(fMutex);
+    }
+    ~Mutex() {
+        umtx_unlock(fMutex);
+    }
 
-private:
-  UMutex   *fMutex;
+    Mutex(const Mutex &other) = delete; // forbid assigning of this class
+    Mutex &operator=(const Mutex &other) = delete; // forbid copying of this class
+    void *operator new(size_t s) = delete;  // forbid heap allocation. Locals only.
 
-  Mutex(const Mutex &other); // forbid copying of this class
-  Mutex &operator=(const Mutex &other); // forbid copying of this class
+private:
+    UMutex   *fMutex;
 };
 
-inline Mutex::Mutex(UMutex *mutex)
-  : fMutex(mutex)
-{
-  umtx_lock(fMutex);
-}
-
-inline Mutex::~Mutex()
-{
-  umtx_unlock(fMutex);
-}
 
 U_NAMESPACE_END