diff options
| -rw-r--r-- | src/MinedMap.cpp | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/src/MinedMap.cpp b/src/MinedMap.cpp index a106204..bc9683f 100644 --- a/src/MinedMap.cpp +++ b/src/MinedMap.cpp @@ -41,7 +41,11 @@ #include <arpa/inet.h> #include <dirent.h> +#include <fcntl.h> #include <png.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <unistd.h> using namespace MinedMap; @@ -96,11 +100,38 @@ static void writePNG(const char *filename, const uint32_t data[DIM][DIM]) { } static void doRegion(const std::string &input, const std::string &output) { + struct stat instat, outstat; + + if (stat(input.c_str(), &instat) < 0) { + std::fprintf(stderr, "Unable to stat %s: %s\n", input.c_str(), std::strerror(errno)); + return; + } + + if (stat(output.c_str(), &outstat) == 0) { + if (instat.st_mtim.tv_sec < outstat.st_mtim.tv_sec || + (instat.st_mtim.tv_sec == outstat.st_mtim.tv_sec && instat.st_mtim.tv_nsec <= outstat.st_mtim.tv_nsec)) { + std::fprintf(stderr, "%s is up-to-date.\n", output.c_str()); + return; + } + } + std::fprintf(stderr, "Generating %s from %s...\n", output.c_str(), input.c_str()); + const std::string tmpfile = output + ".tmp"; + uint32_t image[DIM][DIM] = {}; World::Region::visitChunks(input.c_str(), [&image] (size_t X, size_t Z, const World::Chunk *chunk) { addChunk(image, X, Z, chunk); }); - writePNG(output.c_str(), image); + + writePNG(tmpfile.c_str(), image); + + struct timespec times[2] = {instat.st_mtim, instat.st_mtim}; + if (utimensat(AT_FDCWD, tmpfile.c_str(), times, 0) < 0) + std::fprintf(stderr, "Warning: failed to set utime on %s: %s\n", tmpfile.c_str(), std::strerror(errno)); + + if (std::rename(tmpfile.c_str(), output.c_str()) < 0) { + std::fprintf(stderr, "Unable to save %s: %s\n", output.c_str(), std::strerror(errno)); + unlink(tmpfile.c_str()); + } } int main(int argc, char *argv[]) { |