file_helper-inl.h

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// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
#pragma once
 
#ifndef SPDLOG_HEADER_ONLY
#include <spdlog/details/file_helper.h>
#endif
 
#include <spdlog/details/os.h>
#include <spdlog/common.h>
 
#include <cerrno>
#include <chrono>
#include <cstdio>
#include <string>
#include <thread>
#include <tuple>
 
namespace spdlog
{
    namespace details
    {
 
        SPDLOG_INLINE file_helper::file_helper(const file_event_handlers& event_handlers)
            : event_handlers_(event_handlers)
        {
        }
 
        SPDLOG_INLINE file_helper::~file_helper()
        {
            close();
        }
 
        SPDLOG_INLINE void file_helper::open(const filename_t& fname, bool truncate)
        {
            close();
            filename_ = fname;
 
            auto* mode       = SPDLOG_FILENAME_T("ab");
            auto* trunc_mode = SPDLOG_FILENAME_T("wb");
 
            if (event_handlers_.before_open)
            {
                event_handlers_.before_open(filename_);
            }
            for (int tries = 0; tries < open_tries_; ++tries)
            {
                // create containing folder if not exists already.
                os::create_dir(os::dir_name(fname));
                if (truncate)
                {
                    // Truncate by opening-and-closing a tmp file in "wb" mode, always
                    // opening the actual log-we-write-to in "ab" mode, since that
                    // interacts more politely with eternal processes that might
                    // rotate/truncate the file underneath us.
                    std::FILE* tmp;
                    if (os::fopen_s(&tmp, fname, trunc_mode))
                    {
                        continue;
                    }
                    std::fclose(tmp);
                }
                if (!os::fopen_s(&fd_, fname, mode))
                {
                    if (event_handlers_.after_open)
                    {
                        event_handlers_.after_open(filename_, fd_);
                    }
                    return;
                }
 
                details::os::sleep_for_millis(open_interval_);
            }
 
            throw_spdlog_ex("Failed opening file " + os::filename_to_str(filename_) + " for writing", errno);
        }
 
        SPDLOG_INLINE void file_helper::reopen(bool truncate)
        {
            if (filename_.empty())
            {
                throw_spdlog_ex("Failed re opening file - was not opened before");
            }
            this->open(filename_, truncate);
        }
 
        SPDLOG_INLINE void file_helper::flush()
        {
            if (std::fflush(fd_) != 0)
            {
                throw_spdlog_ex("Failed flush to file " + os::filename_to_str(filename_), errno);
            }
        }
 
        SPDLOG_INLINE void file_helper::sync()
        {
            if (!os::fsync(fd_))
            {
                throw_spdlog_ex("Failed to fsync file " + os::filename_to_str(filename_), errno);
            }
        }
 
        SPDLOG_INLINE void file_helper::close()
        {
            if (fd_ != nullptr)
            {
                if (event_handlers_.before_close)
                {
                    event_handlers_.before_close(filename_, fd_);
                }
 
                std::fclose(fd_);
                fd_ = nullptr;
 
                if (event_handlers_.after_close)
                {
                    event_handlers_.after_close(filename_);
                }
            }
        }
 
        SPDLOG_INLINE void file_helper::write(const memory_buf_t& buf)
        {
            size_t msg_size = buf.size();
            auto   data     = buf.data();
            if (std::fwrite(data, 1, msg_size, fd_) != msg_size)
            {
                throw_spdlog_ex("Failed writing to file " + os::filename_to_str(filename_), errno);
            }
        }
 
        SPDLOG_INLINE size_t file_helper::size() const
        {
            if (fd_ == nullptr)
            {
                throw_spdlog_ex("Cannot use size() on closed file " + os::filename_to_str(filename_));
            }
            return os::filesize(fd_);
        }
 
        SPDLOG_INLINE const filename_t& file_helper::filename() const
        {
            return filename_;
        }
 
        //
        // return file path and its extension:
        //
        // "mylog.txt" => ("mylog", ".txt")
        // "mylog" => ("mylog", "")
        // "mylog." => ("mylog.", "")
        // "/dir1/dir2/mylog.txt" => ("/dir1/dir2/mylog", ".txt")
        //
        // the starting dot in filenames is ignored (hidden files):
        //
        // ".mylog" => (".mylog". "")
        // "my_folder/.mylog" => ("my_folder/.mylog", "")
        // "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
        SPDLOG_INLINE std::tuple<filename_t, filename_t> file_helper::split_by_extension(const filename_t& fname)
        {
            auto ext_index = fname.rfind('.');
 
            // no valid extension found - return whole path and empty string as
            // extension
            if (ext_index == filename_t::npos || ext_index == 0 || ext_index == fname.size() - 1)
            {
                return std::make_tuple(fname, filename_t());
            }
 
            // treat cases like "/etc/rc.d/somelogfile or "/abc/.hiddenfile"
            auto folder_index = fname.find_last_of(details::os::folder_seps_filename);
            if (folder_index != filename_t::npos && folder_index >= ext_index - 1)
            {
                return std::make_tuple(fname, filename_t());
            }
 
            // finally - return a valid base and extension tuple
            return std::make_tuple(fname.substr(0, ext_index), fname.substr(ext_index));
        }
 
    } // namespace details
} // namespace spdlog