Logger: improve for GUI display.

The biggest change is that the timestamp is pre-computed, because
calling strftime() 60 times (or more) per second is sure to have a
non-negligible cost.

src/Logger/Logger.cpp

@@ -45,9 +45,7 @@ inline Debug&
 operator<<(Debug& out, const LogEntry& entry) {
     using namespace Containers::Literals;
 
-    static char formatted_time[22] = {'\0'};
-    std::strftime(&formatted_time[0], sizeof(formatted_time)/sizeof(formatted_time[0]), "[%Y-%m-%d %H:%M:%S]", &entry.timestamp);
-    out << formatted_time;
+    out << "["_s << Debug::nospace << entry.timestamp << Debug::nospace << "]"_s;
 
 #ifdef SAVETOOL_DEBUG_BUILD
 #define COLOUR(col) << Debug::color(Debug::Color::col)
@@ -88,8 +86,14 @@ addEntry(EntryType type, StringView message) {
 
     auto time = std::time(nullptr);
 
+    static char formatted_time[20] = {'\0'};
+    std::strftime(&formatted_time[0], sizeof(formatted_time)/sizeof(formatted_time[0]),
+                  "%Y-%m-%d %H:%M:%S", // Because MSVCRT (which is the CRT I target by default) is not C99-compliant,
+                                       // I can't use "%F %T" as the format string.
+                  std::localtime(&time));
+
     LogEntry entry{
-        *std::localtime(&time), type,
+        formatted_time, type,
         (message.back() == '\n') ? String{message.exceptSuffix(1)} : String{message}
     };
 
@@ -106,6 +110,11 @@ addEntry(EntryType type, StringView message) {
     _logMutex.unlock();
 }
 
+ArrayView<const LogEntry>
+entries() {
+    return _entries;
+}
+
 } // Logger
 
 } // MassBuilderSaveTool

src/Logger/Logger.h

@@ -19,9 +19,11 @@
 #include <ctime>
 
 #include <Corrade/Containers/String.h>
+#include <Corrade/Containers/ArrayView.h>
 
 using namespace Corrade;
 
+using Containers::ArrayView;
 using Containers::String;
 using Containers::StringView;
 
@@ -35,7 +37,7 @@ enum class EntryType {
 };
 
 struct LogEntry {
-    std::tm timestamp;
+    String timestamp;
     EntryType type;
     String message;
 };
@@ -44,6 +46,8 @@ void initialise();
 
 void addEntry(EntryType type, StringView message);
 
+auto entries() -> ArrayView<const LogEntry>;
+
 } // Logger
 
 } // MassBuilderSaveTool