diff options
Diffstat (limited to 'Source')
| -rw-r--r-- | Source/kwsys/SystemTools.cxx | 179 |
1 files changed, 122 insertions, 57 deletions
diff --git a/Source/kwsys/SystemTools.cxx b/Source/kwsys/SystemTools.cxx index 331f16e..c5160a9 100644 --- a/Source/kwsys/SystemTools.cxx +++ b/Source/kwsys/SystemTools.cxx @@ -82,6 +82,10 @@ # include <signal.h> /* sigprocmask */ #endif +#ifdef __linux +# include <linux/fs.h> +#endif + // Windows API. #if defined(_WIN32) # include <windows.h> @@ -2158,6 +2162,120 @@ bool SystemTools::FilesDiffer(const std::string& source, } /** + * Blockwise copy source to destination file + */ +static bool CopyFileContentBlockwise(const std::string& source, + const std::string& destination) +{ +// Open files +#if defined(_WIN32) + kwsys::ifstream fin( + Encoding::ToNarrow(Encoding::ToWindowsExtendedPath(source)).c_str(), + std::ios::in | std::ios::binary); +#else + kwsys::ifstream fin(source.c_str(), std::ios::in | std::ios::binary); +#endif + if (!fin) { + return false; + } + + // try and remove the destination file so that read only destination files + // can be written to. + // If the remove fails continue so that files in read only directories + // that do not allow file removal can be modified. + SystemTools::RemoveFile(destination); + +#if defined(_WIN32) + kwsys::ofstream fout( + Encoding::ToNarrow(Encoding::ToWindowsExtendedPath(destination)).c_str(), + std::ios::out | std::ios::trunc | std::ios::binary); +#else + kwsys::ofstream fout(destination.c_str(), + std::ios::out | std::ios::trunc | std::ios::binary); +#endif + if (!fout) { + return false; + } + + // This copy loop is very sensitive on certain platforms with + // slightly broken stream libraries (like HPUX). Normally, it is + // incorrect to not check the error condition on the fin.read() + // before using the data, but the fin.gcount() will be zero if an + // error occurred. Therefore, the loop should be safe everywhere. + while (fin) { + const int bufferSize = 4096; + char buffer[bufferSize]; + + fin.read(buffer, bufferSize); + if (fin.gcount()) { + fout.write(buffer, fin.gcount()); + } else { + break; + } + } + + // Make sure the operating system has finished writing the file + // before closing it. This will ensure the file is finished before + // the check below. + fout.flush(); + + fin.close(); + fout.close(); + + if (!fout) { + return false; + } + + return true; +} + +/** + * Clone the source file to the destination file + * + * If available, the Linux FICLONE ioctl is used to create a check + * copy-on-write clone of the source file. + * + * The method returns false for the following cases: + * - The code has not been compiled on Linux or the ioctl was unknown + * - The source and destination is on different file systems + * - The underlying filesystem does not support file cloning + * - An unspecified error occurred + */ +static bool CloneFileContent(const std::string& source, + const std::string& destination) +{ +#if defined(__linux) && defined(FICLONE) + int in = open(source.c_str(), O_RDONLY); + if (in < 0) { + return false; + } + + SystemTools::RemoveFile(destination); + + int out = + open(destination.c_str(), O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); + if (out < 0) { + close(in); + return false; + } + + int result = ioctl(out, FICLONE, in); + close(in); + close(out); + + if (result < 0) { + return false; + } + + return true; +#else + (void)source; + (void)destination; + return false; +#endif +} + +/** * Copy a file named by "source" to the file named by "destination". */ bool SystemTools::CopyFileAlways(const std::string& source, @@ -2174,9 +2292,6 @@ bool SystemTools::CopyFileAlways(const std::string& source, if (SystemTools::FileIsDirectory(source)) { SystemTools::MakeDirectory(destination); } else { - const int bufferSize = 4096; - char buffer[bufferSize]; - // If destination is a directory, try to create a file with the same // name as the source in that directory. @@ -2195,62 +2310,12 @@ bool SystemTools::CopyFileAlways(const std::string& source, SystemTools::MakeDirectory(destination_dir); -// Open files -#if defined(_WIN32) - kwsys::ifstream fin( - Encoding::ToNarrow(Encoding::ToWindowsExtendedPath(source)).c_str(), - std::ios::in | std::ios::binary); -#else - kwsys::ifstream fin(source.c_str(), std::ios::in | std::ios::binary); -#endif - if (!fin) { - return false; - } - - // try and remove the destination file so that read only destination files - // can be written to. - // If the remove fails continue so that files in read only directories - // that do not allow file removal can be modified. - SystemTools::RemoveFile(real_destination); - -#if defined(_WIN32) - kwsys::ofstream fout( - Encoding::ToNarrow(Encoding::ToWindowsExtendedPath(real_destination)) - .c_str(), - std::ios::out | std::ios::trunc | std::ios::binary); -#else - kwsys::ofstream fout(real_destination.c_str(), - std::ios::out | std::ios::trunc | std::ios::binary); -#endif - if (!fout) { - return false; - } - - // This copy loop is very sensitive on certain platforms with - // slightly broken stream libraries (like HPUX). Normally, it is - // incorrect to not check the error condition on the fin.read() - // before using the data, but the fin.gcount() will be zero if an - // error occurred. Therefore, the loop should be safe everywhere. - while (fin) { - fin.read(buffer, bufferSize); - if (fin.gcount()) { - fout.write(buffer, fin.gcount()); - } else { - break; + if (!CloneFileContent(source, real_destination)) { + // if cloning did not succeed, fall back to blockwise copy + if (!CopyFileContentBlockwise(source, real_destination)) { + return false; } } - - // Make sure the operating system has finished writing the file - // before closing it. This will ensure the file is finished before - // the check below. - fout.flush(); - - fin.close(); - fout.close(); - - if (!fout) { - return false; - } } if (perms) { if (!SystemTools::SetPermissions(real_destination, perm)) { |