#include <sstream>
#include <vector>
+#include "sha1.h"
+
/* In memory datatype to represent key/value pairs of information, such as file
* metadata. Currently implemented as map<string, string>. */
typedef std::map<std::string, std::string> dictionary;
+/* In-memory representation of a UUID (Universally-Unique Identifier), which is
+ * used to name a segment. */
+struct uuid {
+ uint8_t bytes[16];
+};
+
/* IOException will be thrown if an error occurs while reading or writing in
* one of the I/O wrappers. Depending upon the context; this may be fatal or
* not--typically, errors reading/writing the store will be serious, but errors
void write_varint(uint64_t val);
+ void write_uuid(const struct uuid &u);
void write_string(const std::string &s);
void write_dictionary(const dictionary &d);
OutputStream ℜ
};
+/* Like WrapperOutputStream, but additionally computes a checksum of data as it
+ * is written. */
+class ChecksumOutputStream : public OutputStream {
+public:
+ explicit ChecksumOutputStream(OutputStream &o);
+ virtual ~ChecksumOutputStream() { }
+
+ /* Once a checksum is computed, no further data should be written to the
+ * stream. */
+ const uint8_t *finish_and_checksum();
+ size_t checksum_size() const { return csum.checksum_size(); }
+
+protected:
+ virtual void write_internal(const void *data, size_t len);
+
+private:
+ OutputStream ℜ
+ SHA1Checksum csum;
+};
+
/* Simple wrappers that encode integers using a StringOutputStream and return
* the encoded result. */
std::string encode_u16(uint16_t val);
std::string encode_u32(uint32_t val);
std::string encode_u64(uint64_t val);
-
-struct uuid {
- uint8_t bytes[16];
-};
+std::string encode_objref(const struct uuid &segment, uint32_t object);
/* A class which is used to pack multiple objects into a single segment, with a
* lookup table to quickly locate each object. Call new_object() to get an
struct uuid get_uuid() const { return id; }
// Start writing out a new object to this segment.
- OutputStream *new_object();
+ OutputStream *new_object(int *id, const char *type);
void finish_object();
+ // Determine size of segment data written out so far.
+ size_t get_size() const { return raw_out->get_pos(); }
+
// Utility functions for generating and formatting UUIDs for display.
static struct uuid generate_uuid();
static std::string format_uuid(const struct uuid u);
private:
- typedef std::vector<std::pair<int64_t, int64_t> > object_table;
+ struct index_info {
+ int64_t offset; // File offset at which object starts
+ int64_t size; // Size of object in bytes
+ char type[4]; // Object type code
+ };
+
+ typedef std::vector<struct index_info> object_table;
- OutputStream *out;
+ ChecksumOutputStream *out; // Output stream with checksumming enabled
+ OutputStream *raw_out; // Raw output stream, without checksumming
struct uuid id;
- int64_t object_start_offset;
OutputStream *object_stream;
object_table objects;
std::string directory;
};
+/* A SegmentPartitioner helps to divide objects up among a collection of
+ * segments to meet a rough size limit per segment. Like a SegmentWriter, only
+ * one object should be written at a time; however, multiple
+ * SegmentPartitioners can be created using the same base SegmentStore. */
+class SegmentPartitioner {
+public:
+ explicit SegmentPartitioner(SegmentStore *s);
+ ~SegmentPartitioner();
+
+ OutputStream *new_object(struct uuid *uuid, int *id, const char *type);
+
+private:
+ size_t target_size;
+
+ SegmentStore *store;
+ SegmentWriter *segment;
+ OutputStream *object;
+};
+
#endif // _LBS_STORE_H