Allow "aborting" a save file, to bail out safely, or prepare for discarding.

It effectively reverts to the last commit.  This is the safest thing to do in
an error, and if we're going to delete the save file, it doesn't matter.

1 files changed, 2 insertions, 0 deletions

diff --git a/crawl-ref/source/package.h b/crawl-ref/source/package.h
index 344a10bec8..028bc3c4d4 100644
--- a/crawl-ref/source/package.h
+++ b/crawl-ref/source/package.h
@@ -70,12 +70,14 @@ public:
     void delete_chunk(const std::string name);
     bool has_chunk(const std::string name);
     std::vector<std::string> list_chunks();
+    void abort();
 private:
     bool rw;
     int fd;
     len_t file_len;
     int n_users;
     bool dirty;
+    bool aborted;
     std::map<std::string, len_t> directory;
     std::map<len_t, len_t> free_blocks;
     std::stack<len_t> unlinked_blocks;