The transactional save packager.

1 files changed, 96 insertions, 0 deletions

diff --git a/crawl-ref/source/package.h b/crawl-ref/source/package.h
new file mode 100644
index 0000000000..9ff525c49c
--- /dev/null
+++ b/crawl-ref/source/package.h
@@ -0,0 +1,96 @@
+#ifndef PACKAGE_H
+#define PACKAGE_H
+
+#define USE_ZLIB
+
+#include <stdint.h>
+#include <string>
+#include <map>
+#include <vector>
+#include <stack>
+
+#ifdef USE_ZLIB
+#include <zlib.h>
+#endif
+
+typedef uint32_t len_t;
+
+class package;
+
+class chunk_writer
+{
+private:
+    chunk_writer(package *parent, const std::string _name);
+    package *pkg;
+    std::string name;
+    len_t first_block;
+    len_t cur_block;
+    len_t block_len;
+#ifdef USE_ZLIB
+    z_stream zs;
+    Bytef *z_buffer;
+#endif
+    void raw_write(const void *data, len_t len);
+    void finish_block(len_t next);
+public:
+    ~chunk_writer();
+    void write(const void *data, len_t len);
+    friend class package;
+};
+
+class chunk_reader
+{
+private:
+    chunk_reader(package *parent, len_t start);
+    package *pkg;
+    len_t next_block;
+    len_t off, block_left;
+#ifdef USE_ZLIB
+    bool eof;
+    z_stream zs;
+    Bytef z_buffer[32768];
+#endif
+    len_t raw_read(void *data, len_t len);
+public:
+    ~chunk_reader();
+    len_t read(void *data, len_t len);
+    friend class package;
+};
+
+class package
+{
+public:
+    package(const char* file, bool writeable, bool empty = false);
+    ~package();
+    chunk_writer* writer(const std::string name);
+    chunk_reader* reader(const std::string name);
+    void commit();
+    void delete_chunk(const std::string name);
+    bool has_chunk(const std::string name);
+    std::vector<std::string> list_chunks();
+private:
+    bool rw;
+    int fd;
+    len_t file_len;
+    int n_users;
+    bool dirty;
+    std::map<std::string, len_t> directory;
+    std::map<len_t, len_t> free_blocks;
+    std::stack<len_t> unlinked_blocks;
+    std::map<len_t, std::pair<len_t, len_t> > block_map;
+    len_t extend_block(len_t at, len_t size, len_t by);
+    len_t alloc_block();
+    void finish_chunk(const std::string name, len_t at);
+    void free_chunk(const std::string name);
+    len_t write_directory();
+    void collect_blocks();
+    void free_block(len_t at, len_t size);
+    void seek(len_t to);
+    void fsck();
+    void read_directory(len_t start);
+    void trace_chunk(len_t start);
+    friend class chunk_writer;
+    friend class chunk_reader;
+};
+
+#endif