archive-tar: turn write_tar_entry into blob-writing only

diff --git a/csum-file.c b/csum-file.c
index fc97d6e04528b5c5b55fc211a462f3cb828f3d49..53f5375b6ca3368de6647cf5edcd7fb4dec79657 100644 (file)
--- a/csum-file.c
+++ b/csum-file.c
@@ -158,6 +158,26 @@ struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp
        return f;
 }
 
+void sha1file_checkpoint(struct sha1file *f, struct sha1file_checkpoint *checkpoint)
+{
+       sha1flush(f);
+       checkpoint->offset = f->total;
+       checkpoint->ctx = f->ctx;
+}
+
+int sha1file_truncate(struct sha1file *f, struct sha1file_checkpoint *checkpoint)
+{
+       off_t offset = checkpoint->offset;
+
+       if (ftruncate(f->fd, offset) ||
+           lseek(f->fd, offset, SEEK_SET) != offset)
+               return -1;
+       f->total = offset;
+       f->ctx = checkpoint->ctx;
+       f->offset = 0; /* sha1flush() was called in checkpoint */
+       return 0;
+}
+
 void crc32_begin(struct sha1file *f)
 {
        f->crc32 = crc32(0, NULL, 0);