* is built on top of libtar, and represents segments as TAR files and objects
* as files within them. */
-#ifndef _LBS_TARSTORE_H
-#define _LBS_TARSTORE_H
+#ifndef _LBS_STORE_H
+#define _LBS_STORE_H
#include <stdint.h>
#include <libtar.h>
#include <sstream>
#include "sha1.h"
+#include "ref.h"
+
+class LbsObject;
/* In memory datatype to represent key/value pairs of information, such as file
* metadata. Currently implemented as map<string, string>. */
private:
size_t size;
std::string segment_name;
- std::ostringstream checksums;
TAR *t;
};
// (segment/object) to refer to it. The optional parameter group can be
// used to control object placement; objects with different group
// parameters are kept in separate segments.
- std::string write_object(const char *data, size_t len,
- const std::string &group = "",
- const std::list<std::string> &refs = norefs);
+ ObjectReference write_object(const char *data, size_t len,
+ const std::string &group = "");
// Ensure all segments have been fully written.
void sync();
struct segment_info {
Tarfile *file;
std::string name; // UUID
- std::set<std::string> refs; // Other segments this one refers to
int count; // Objects written to this segment
};
std::string path;
std::map<std::string, struct segment_info *> segments;
- // An empty list which can be used as an argument to write_object to
- // indicate that this object depends on no others.
- static std::list<std::string> norefs;
-
// Ensure that all segments in the given group have been fully written.
void close_segment(const std::string &group);
std::string object_reference_to_segment(const std::string &object);
};
-#endif // _LBS_TARSTORE_H
+/* An in-memory representation of an object, which can be incrementally built
+ * before it is written out to a segment. */
+class LbsObject {
+public:
+ LbsObject();
+ ~LbsObject();
+
+ // If an object is placed in a group, it will be written out to segments
+ // only containing other objects in the same group. A group name is simply
+ // a string.
+ //std::string get_group() const { return group; }
+ void set_group(const std::string &g) { group = g; }
+
+ // Data in an object must be written all at once, and cannot be generated
+ // incrementally. Data can be an arbitrary block of binary data of any
+ // size. The pointer to the data need only remain valid until write() is
+ // called.
+ void set_data(const char *d, size_t len) { data = d; data_len = len; }
+
+ // Write an object to a segment, thus making it permanent. This function
+ // can be called at most once.
+ void write(TarSegmentStore *store);
+
+ // Compute the checksum of an object, and include it in the object
+ // reference. This should be called after write(), and the data specified
+ // by set_data() must remain valid through the call to checksum().
+ void checksum();
+
+ // An object is assigned a permanent name once it has been written to a
+ // segment. Until that time, its name cannot be determined.
+ std::string get_name() const { return ref.to_string(); }
+ ObjectReference get_ref() { return ref; }
+
+private:
+ std::string group;
+ const char *data;
+ size_t data_len;
+
+ bool written;
+ ObjectReference ref;
+};
+
+#endif // _LBS_STORE_H