Fix exception handling and logging in the code

Author: mutouyun

include/libconcur/element.h

@@ -74,10 +74,9 @@ class element {
     LIBIMP_LOG_();
     LIBIMP_TRY {
       data_ = std::forward<U>(src);
-    } LIBIMP_CATCH(std::exception const &e) {
-      log.error("failed: `data = std::forward<U>(src)`. error = ", e.what());
     } LIBIMP_CATCH(...) {
-      log.error("failed: `data = std::forward<U>(src)`. error = unknown");
+      log.error("failed: `data = std::forward<U>(src)`.",
+                "\n\texception: ", ::LIBIMP::log::exception_string(std::current_exception()));
     }
   }
 

include/libimp/log.h

@@ -102,20 +102,26 @@ inline auto &make_std_out() noexcept {
   return std_out;
 }
 
-/// \brief Record the last information when an exception occurs.
-inline void log_exception(char const *func, std::exception_ptr eptr) noexcept {
+/// \brief Get the exception information.
+inline char const *exception_string(std::exception_ptr eptr) noexcept {
   LIBIMP_TRY {
-    if (func == nullptr) {
-      func = "-";
-    }
     if (eptr) {
       std::rethrow_exception(eptr);
     }
   } LIBIMP_CATCH(std::exception const &e) {
-    std::fprintf(stderr, "[F][%s] exception: %s\n", func, e.what());
+    return e.what();
   } LIBIMP_CATCH(...) {
-    std::fprintf(stderr, "[F][%s] exception: unknown\n", func);
+    return "unknown";
+  }
+  return "none";
+}
+
+/// \brief Record the last information when an exception occurs.
+inline void exception_print(char const *func, std::exception_ptr eptr) noexcept {
+  if (func == nullptr) {
+    func = "-";
   }
+  std::fprintf(stderr, "[F][%s] exception: %s\n", func, exception_string(eptr));
 }
 
 /**
@@ -155,7 +161,7 @@ class logger : public logger_base {
         std::forward_as_tuple(std::forward<A>(args)...),
       });
     } LIBIMP_CATCH(...) {
-      log_exception(func_, std::current_exception());
+      exception_print(func_, std::current_exception());
     }
     return *this;
   }

src/libimp/platform/win/system.h

@@ -49,8 +49,9 @@ std::string error_string(DWORD code) noexcept {
     std::string ret(len, '\0');
     cvt_cstr(lpErrText, msg_len, &ret[0], ret.size());
     return ret;
-  } LIBIMP_CATCH(std::exception const &e) {
-    log.failed(e.what());
+  } LIBIMP_CATCH(...) {
+    log.error("failed: FormatMessage(dwMessageId = ", code, ").",
+              "\n\texception: ", ::LIBIMP::log::exception_string(std::current_exception()));
   }
   return {};
 }

src/libpmr/monotonic_buffer_resource.cpp

@@ -28,7 +28,8 @@ Node *make_node(allocator const &upstream, std::size_t initial_size, std::size_t
     return node;
   } LIBIMP_CATCH(...) {
     log.error("failed: allocate memory for `monotonic_buffer_resource`'s node.", 
-              " bytes = ", initial_size, ", alignment = ", alignment);
+              " bytes = ", initial_size, ", alignment = ", alignment,
+              "\n\texception: ", ::LIBIMP::log::exception_string(std::current_exception()));
     return nullptr;
   }
 }
@@ -86,7 +87,8 @@ void monotonic_buffer_resource::release() noexcept {
       free_list_ = next;
     }
   } LIBIMP_CATCH(...) {
-    log.error("failed: deallocate memory for `monotonic_buffer_resource`.");
+    log.error("failed: deallocate memory for `monotonic_buffer_resource`.",
+              "\n\texception: ", ::LIBIMP::log::exception_string(std::current_exception()));
   }
   // reset to initial state at contruction
   if ((head_ = initial_buffer_) != nullptr) {