Add log regex filter (#9)

src/common/logging/backend.cpp

@@ -3,6 +3,7 @@
 // Refer to the license.txt file included.
 
 #include <chrono>
+#include <boost/regex.hpp>
 
 #include <fmt/format.h>
 
@@ -234,6 +235,19 @@ public:
         filter = f;
     }
 
+    bool SetRegexFilter(const std::string& regex) {
+        if (regex.empty()) {
+            regex_filter = boost::regex();
+            return true;
+        }
+        regex_filter = boost::regex(regex, boost::regex_constants::no_except);
+        if (regex_filter.status() != 0) {
+            regex_filter = boost::regex();
+            return false;
+        }
+        return true;
+    }
+
     void SetColorConsoleBackendEnabled(bool enabled) {
         color_console_backend.SetEnabled(enabled);
     }
@@ -243,8 +257,13 @@ public:
         if (!filter.CheckMessage(log_class, log_level)) {
             return;
         }
-        message_queue.EmplaceWait(
-            CreateEntry(log_class, log_level, filename, line_num, function, std::move(message)));
+        Entry new_entry =
+            CreateEntry(log_class, log_level, filename, line_num, function, std::move(message));
+        if (!regex_filter.empty() &&
+            !boost::regex_search(FormatLogMessage(new_entry), regex_filter)) {
+            return;
+        }
+        message_queue.EmplaceWait(new_entry);
     }
 
 private:
@@ -406,6 +425,7 @@ private:
     static inline std::unique_ptr<Impl, decltype(&Deleter)> instance{nullptr, Deleter};
 
     Filter filter;
+    boost::regex regex_filter;
     DebuggerBackend debugger_backend{};
     ColorConsoleBackend color_console_backend{};
     FileBackend file_backend;
@@ -446,6 +466,10 @@ void SetGlobalFilter(const Filter& filter) {
     Impl::Instance().SetGlobalFilter(filter);
 }
 
+bool SetRegexFilter(const std::string& regex) {
+    return Impl::Instance().SetRegexFilter(regex);
+}
+
 void SetColorConsoleBackendEnabled(bool enabled) {
     Impl::Instance().SetColorConsoleBackendEnabled(enabled);
 }

src/common/logging/backend.h

@@ -26,5 +26,11 @@ void DisableLoggingInTests();
  */
 void SetGlobalFilter(const Filter& filter);
 
+/**
+ * Only allow messages that match the specified regex. The regex is matched against the final log
+ * text.
+ */
+bool SetRegexFilter(const std::string& regex);
+
 void SetColorConsoleBackendEnabled(bool enabled);
 } // namespace Common::Log

src/common/settings.h

@@ -542,6 +542,7 @@ struct Values {
 
     // Miscellaneous
     Setting<std::string> log_filter{"*:Info", "log_filter"};
+    Setting<std::string> log_regex_filter{"", "log_regex_filter"};
 
     // Video Dumping
     std::string output_format;