assimp/include/assimp/DefaultLogger.hpp

/*
Open Asset Import Library (assimp)
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*/

/**
 *  @file DefaultLogger.hpp
 */

#pragma once
#ifndef INCLUDED_AI_DEFAULTLOGGER
#define INCLUDED_AI_DEFAULTLOGGER

#ifdef __GNUC__
#   pragma GCC system_header
#endif

#include "LogStream.hpp"
#include "Logger.hpp"
#include "NullLogger.hpp"
#include <vector>

namespace Assimp {
// ------------------------------------------------------------------------------------
class IOStream;
struct LogStreamInfo;

/** default name of log-file */
#define ASSIMP_DEFAULT_LOG_NAME "AssimpLog.txt"

// ------------------------------------------------------------------------------------
/** @brief CPP-API: Primary logging facility of Assimp.
 *
 *  The library stores its primary #Logger as a static member of this class.
 *  #get() returns this primary logger. By default the underlying implementation is
 *  just a #NullLogger which rejects all log messages. By calling #create(), logging
 *  is turned on. To capture the log output multiple log streams (#LogStream) can be
 *  attach to the logger. Some default streams for common streaming locations (such as
 *  a file, std::cout, OutputDebugString()) are also provided.
 *
 *  If you wish to customize the logging at an even deeper level supply your own
 *  implementation of #Logger to #set().
 *  @note The whole logging stuff causes a small extra overhead for all imports. */
class ASSIMP_API DefaultLogger : public Logger {
public:
    // ----------------------------------------------------------------------
    /** @brief Creates a logging instance.
     *  @param name Name for log file. Only valid in combination
     *    with the aiDefaultLogStream_FILE flag.
     *  @param severity Log severity, DEBUG turns on debug messages and VERBOSE turns on all messages.
     *  @param defStreams  Default log streams to be attached. Any bitwise
     *    combination of the aiDefaultLogStream enumerated values.
     *    If #aiDefaultLogStream_FILE is specified but an empty string is
     *    passed for 'name', no log file is created at all.
     *  @param  io IOSystem to be used to open external files (such as the
     *   log file). Pass nullptr to rely on the default implementation.
     *  This replaces the default #NullLogger with a #DefaultLogger instance. */
    static Logger *create(const char *name = ASSIMP_DEFAULT_LOG_NAME,
            LogSeverity severity = NORMAL,
            unsigned int defStreams = aiDefaultLogStream_DEBUGGER | aiDefaultLogStream_FILE,
            IOSystem *io = nullptr);

    // ----------------------------------------------------------------------
    /** @brief Setup a custom #Logger implementation.
     *
     *  Use this if the provided #DefaultLogger class doesn't fit into
     *  your needs. If the provided message formatting is OK for you,
     *  it's much easier to use #create() and to attach your own custom
     *  output streams to it.
     *  @param logger Pass NULL to setup a default NullLogger*/
    static void set(Logger *logger);

    // ----------------------------------------------------------------------
    /** @brief  Getter for singleton instance
     *   @return Only instance. This is never null, but it could be a
     *  NullLogger. Use isNullLogger to check this.*/
    static Logger *get();

    // ----------------------------------------------------------------------
    /** @brief  Return whether a #NullLogger is currently active
     *  @return true if the current logger is a #NullLogger.
     *  Use create() or set() to setup a logger that does actually do
     *  something else than just rejecting all log messages. */
    static bool isNullLogger();

    // ----------------------------------------------------------------------
    /** @brief  Kills the current singleton logger and replaces it with a
     *  #NullLogger instance. */
    static void kill();

    // ----------------------------------------------------------------------
    /** @copydoc Logger::attachStream   */
    bool attachStream(LogStream *pStream, unsigned int severity) override;

    // ----------------------------------------------------------------------
    /** @copydoc Logger::detachStream */
    bool detachStream(LogStream *pStream, unsigned int severity) override;

private:
    // ----------------------------------------------------------------------
    /** @briefPrivate construction for internal use by create().
     *  @param severity Logging granularity  */
    explicit DefaultLogger(LogSeverity severity);

    // ----------------------------------------------------------------------
    /** @briefDestructor    */
    ~DefaultLogger() override;

    /** @brief  Logs debug infos, only been written when severity level DEBUG or higher is set */
    void OnDebug(const char *message) override;

    /** @brief  Logs debug infos, only been written when severity level VERBOSE is set */
    void OnVerboseDebug(const char *message) override;

    /** @brief  Logs an info message */
    void OnInfo(const char *message) override;

    /** @brief  Logs a warning message */
    void OnWarn(const char *message) override;

    /** @brief  Logs an error message */
    void OnError(const char *message) override;

    // ----------------------------------------------------------------------
    /** @brief Writes a message to all streams */
    void WriteToStreams(const char *message, ErrorSeverity ErrorSev);

    // ----------------------------------------------------------------------
    /** @brief Returns the thread id.
     *  @note This is an OS specific feature, if not supported, a
     *    zero will be returned.
     */
    unsigned int GetThreadID();

private:
    //  Aliases for stream container
    using StreamArray = std::vector<LogStreamInfo *>;
    using StreamIt = std::vector<LogStreamInfo *>::iterator;
    using ConstStreamIt = std::vector<LogStreamInfo *>::const_iterator;

    //! only logging instance
    static Logger *m_pLogger;
    static NullLogger s_pNullLogger;

    //! Attached streams
    StreamArray m_StreamArray;

    bool noRepeatMsg;
    char lastMsg[MAX_LOG_MESSAGE_LENGTH * 2];
    size_t lastLen;
};

// ------------------------------------------------------------------------------------

} // Namespace Assimp

#endif // !! INCLUDED_AI_DEFAULTLOGGER