Remove old store implementation.

[cumulus.git] / tarstore.h

diff --git a/tarstore.h b/tarstore.h
index 923c75a..6acee7f 100644 (file)
--- a/tarstore.h
+++ b/tarstore.h
@@ -12,20 +12,93 @@
 #include <stdint.h>
 #include <libtar.h>
 
+#include <list>
+#include <map>
+#include <set>
 #include <string>
+#include <iostream>
+#include <sstream>
 
-#include "store.h"
+#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;
+
+/* 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
+ * reading an individual file are less so. */
+class IOException : public std::exception {
+private:
+    std::string error;
+public:
+    explicit IOException(const std::string &err) { error = err; }
+    virtual ~IOException() throw () { }
+    std::string getError() const { return error; }
+};
+
+/* A simple wrapper around a single TAR file to represent a segment.  Objects
+ * may only be written out all at once, since the tar header must be written
+ * first; incremental writing is not supported. */
 class Tarfile {
 public:
     Tarfile(const std::string &path, const std::string &segment);
-    virtual ~Tarfile();
+    ~Tarfile();
 
     void write_object(int id, const char *data, size_t len);
 
+    // Return an estimate of the size of the file.
+    size_t size_estimate() { return size; }
+
+    void internal_write_object(const std::string &path,
+                               const char *data, size_t len);
+
 private:
+    size_t size;
     std::string segment_name;
+    std::ostringstream checksums;
     TAR *t;
 };
 
+class TarSegmentStore {
+public:
+    // New segments will be stored in the given directory.
+    TarSegmentStore(const std::string &path) { this->path = path; }
+    ~TarSegmentStore() { sync(); }
+
+    // Writes an object to segment in the store, and returns the name
+    // (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);
+
+    // Ensure all segments have been fully written.
+    void sync();
+
+private:
+    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);
+
+    // Parse an object reference string and return just the segment name
+    // portion.
+    std::string object_reference_to_segment(const std::string &object);
+};
+
 #endif // _LBS_TARSTORE_H