1 files changed, 89 insertions, 0 deletions
diff --git a/src/third_party/libmongocrypt/dist/src/mlib/check.hpp b/src/third_party/libmongocrypt/dist/src/mlib/check.hpp
new file mode 100644
index 00000000000..18642b2f624
--- /dev/null
+++ b/src/third_party/libmongocrypt/dist/src/mlib/check.hpp
@@ -0,0 +1,89 @@
+#ifndef MLIB_CHECK_HPP_INCLUDED
+#define MLIB_CHECK_HPP_INCLUDED
+
+#include <iostream>
+#include <cstdio>
+#include <string>
+
+namespace mlib
+{
+namespace detail
+{
+struct check_info {
+   const char *filename;
+   int line;
+   const char *expr;
+};
+
+struct nil {
+};
+
+template <typename Left> struct bound_lhs {
+   check_info info;
+   Left value;
+
+#define DEFOP(Oper)                                                         \
+   template <typename Rhs> nil operator Oper (Rhs rhs) const noexcept       \
+   {                                                                        \
+      if (value Oper rhs) {                                                 \
+         return {};                                                         \
+      }                                                                     \
+      std::fprintf (stderr,                                                 \
+                    "%s:%d: CHECK( %s ) failed!\n",                         \
+                    info.filename,                                          \
+                    info.line,                                              \
+                    info.expr);                                             \
+      std::cerr << "Expanded expression: " << value << " " #Oper " " << rhs \
+                << '\n';                                                    \
+      std::exit (2);                                                        \
+   }
+   DEFOP (==)
+   DEFOP (!=)
+   DEFOP (<)
+   DEFOP (<=)
+   DEFOP (>)
+   DEFOP (>=)
+#undef DEFOP
+};
+
+struct check_magic {
+   check_info info;
+
+   template <typename Oper>
+   bound_lhs<Oper>
+   operator->*(Oper op)
+   {
+      return bound_lhs<Oper>{info, op};
+   }
+};
+
+struct check_consume {
+   void
+   operator= (nil)
+   {
+   }
+
+   void
+   operator= (bound_lhs<bool> const &l)
+   {
+      // Invoke the test for truthiness:
+      (void) (l == true);
+   }
+};
+
+/**
+ * @brief Create an assertion that prints the expanded expression upon failure.
+ *
+ * Only supports simple comparison binary expressions, and plain boolean
+ * expressions
+ */
+#define MLIB_CHECK(Cond)                                        \
+   ::mlib::detail::check_consume{} =                            \
+      ::mlib::detail::check_magic{                              \
+         ::mlib::detail::check_info{__FILE__, __LINE__, #Cond}} \
+         ->*Cond
+
+} // namespace detail
+} // namespace mlib
+
+#endif // MLIB_CHECK_HPP_INCLUDED