X-Git-Url: http://git.vrable.net/?p=cumulus.git;a=blobdiff_plain;f=ref.h;h=bbbf5b8c5a483868939c174434a09ebcf801face;hp=e7d41e1d998a8ae8a28582d30a29590da7351f58;hb=HEAD;hpb=ca9a4006c4ffc86a24d653d1b1b68bec4a6fbfdf

diff --git a/ref.h b/ref.h
index e7d41e1..bbbf5b8 100644
--- a/ref.h
+++ b/ref.h
@@ -1,7 +1,23 @@
-/* LBS: An LFS-inspired filesystem backup system
- * Copyright (C) 2007  Michael Vrable
+/* Cumulus: Efficient Filesystem Backup to the Cloud
+ * Copyright (C) 2007-2008 The Cumulus Developers
+ * See the AUTHORS file for a list of contributors.
  *
- * Backups are structured as a collection of objects, which may refer to other
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/* Backups are structured as a collection of objects, which may refer to other
  * objects.  Object references are used to name other objects or parts of them.
  * This file defines the class for representing object references and the
  * textual representation of these references. */
@@ -38,8 +54,12 @@
  * a substring rather than the entire string using a range specifier.  If no
  * range specifier is given, then by default the entire object is used.
  *    <range> ::= <start> "+" <length>
+ *                | <length>
+ *                | "=" <length>
  * Both <start> and <length> are decimal values.  If included, the range is
- * enclosed in brackets.
+ * enclosed in brackets.  As an abbreviation, if <start> is 0 then the range
+ * can be given as just <length> (no "+" needed).  The "=<length>" form asserts
+ * that the underlying object is exactly <length> bytes in size.
  *
  * When both a checksum and a range are included, note that the checksum is
  * taken over the entire original object, before the range is taken into
@@ -64,17 +84,22 @@ std::string generate_uuid();
  * and converted to and from the text representation. */
 class ObjectReference {
 public:
+    enum RefType { REF_NULL, REF_ZERO, REF_NORMAL };
+
     ObjectReference();
+    ObjectReference(RefType t);
     ObjectReference(const std::string& segment, int sequence);
     ObjectReference(const std::string& segment, const std::string& sequence);
 
-    bool is_null() const { return segment.size() == 0; }
+    bool is_null() const { return type == REF_NULL; }
+    bool is_normal() const { return type == REF_NORMAL; }
     std::string to_string() const;
     static ObjectReference parse(const std::string& s);
 
     std::string get_segment() const { return segment; }
     std::string get_sequence() const { return object; }
     std::string get_basename() const { return segment + "/" + object; }
+    ObjectReference base() const { return ObjectReference(segment, object); }
 
     bool has_checksum() const { return checksum_valid; }
     std::string get_checksum() const { return checksum; }
@@ -85,16 +110,27 @@ public:
     bool has_range() const { return range_valid; }
     size_t get_range_start() const { return range_start; }
     size_t get_range_length() const { return range_length; }
-    void clear_range() { range_start = range_length = 0; range_valid = false; }
-    void set_range(size_t start, size_t length)
-        { range_start = start; range_length = length; range_valid = true; }
+    bool range_is_exact() const { return range_exact; }
+    void clear_range()
+        { range_start = range_length = 0;
+          range_valid = false; range_exact = false; }
+    void set_range(size_t start, size_t length, bool exact = false)
+        { range_start = start; range_length = length;
+          range_valid = true; range_exact = exact; }
 
     bool merge(ObjectReference ref);
 
+    // Maybe provide non-string implementations?
+    bool operator==(const ObjectReference &x) const
+        { return to_string() == x.to_string(); }
+    bool operator<(const ObjectReference &x) const
+        { return to_string() < x.to_string(); }
+
 private:
+    RefType type;
     std::string segment, object, checksum;
     size_t range_start, range_length;
-    bool checksum_valid, range_valid;
+    bool checksum_valid, range_valid, range_exact;
 };
 
 #endif // _LBS_REF_H