initial round of logger integration

include/LogVisor/LogVisor.hpp

@@ -0,0 +1,124 @@
+#ifndef __LOG_VISOR_HPP__
+#define __LOG_VISOR_HPP__
+
+#include <stdarg.h>
+#include <string.h>
+#include <stdio.h>
+#include <vector>
+#include <memory>
+
+namespace LogVisor
+{
+
+#if WIN32 && UNICODE
+#define LOG_UCS2 1
+#endif
+
+/**
+ * @brief Severity level for log messages
+ */
+enum Level
+{
+    INFO,        /**< Non-error informative message */
+    WARNING,     /**< Non-error warning message */
+    ERROR,       /**< Recoverable error message */
+    FATAL_ERROR  /**< Non-recoverable error message (calls abort) */
+};
+
+/**
+ * @brief Backend interface for receiving app-wide log events
+ */
+struct ILogger
+{
+    virtual ~ILogger() {}
+    virtual void report(const char* modName, Level severity,
+                        const char* format, va_list ap)=0;
+    virtual void report(const char* modName, Level severity,
+                        const wchar_t* format, va_list ap)=0;
+};
+
+/**
+ * @brief Assign calling thread a descriptive name
+ * @param name Descriptive thread name
+ */
+void RegisterThreadName(const char* name);
+
+/**
+ * @brief Centralized logger vector
+ *
+ * All loggers added to this vector will receive reports as they occur
+ */
+extern std::vector<std::unique_ptr<ILogger>> MainLoggers;
+
+/**
+ * @brief Centralized frame index
+ *
+ * All log events include this as part of their timestamp if non-zero.
+ * The default value is zero, the app is responsible for updating it
+ * within its main loop.
+ */
+extern uint64_t FrameIndex;
+
+/**
+ * @brief Restore centralized logger vector to default state (silent operation)
+ */
+static inline void UnregisterLoggers() {MainLoggers.clear();}
+
+/**
+ * @brief Construct and register a real-time console logger singleton
+ *
+ * This will output to stderr on POSIX platforms and spawn a new console window on Windows.
+ * If there's already a registered console logger, this is a no-op.
+ */
+void RegisterConsoleLogger();
+
+/**
+ * @brief Construct and register a file logger
+ * @param filepath Path to write the file
+ *
+ * If there's already a file logger registered to the same file, this is a no-op.
+ */
+void RegisterFileLogger(const char* filepath);
+
+#if LOG_UCS2
+
+/**
+ * @brief Construct and register a file logger (wchar_t version)
+ * @param filepath Path to write the file
+ *
+ * If there's already a file logger registered to the same file, this is a no-op.
+ */
+void RegisterFileLogger(const wchar_t* filepath);
+
+#endif
+
+/**
+ * @brief This is constructed per-subsystem in a locally centralized fashon
+ */
+class LogModule
+{
+    const char* m_modName;
+public:
+    LogModule(const char* modName) : m_modName(modName) {}
+
+    /**
+     * @brief Route new log message to centralized ILogger
+     * @param severity Level of log report severity
+     * @param format Standard printf-style format string
+     */
+    template <typename CharType>
+    inline void report(Level severity, const CharType* format, ...)
+    {
+        va_list ap;
+        va_start(ap, format);
+        for (auto& logger : MainLoggers)
+            logger->report(m_modName, severity, format, ap);
+        va_end(ap);
+        if (severity == FATAL_ERROR)
+            abort();
+    }
+};
+
+}
+
+#endif // __LOG_VISOR_HPP__