1 /* Cumulus: Efficient Filesystem Backup to the Cloud
2 * Copyright (C) 2007-2008 The Cumulus Developers
3 * See the AUTHORS file for a list of contributors.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 /* Backups are structured as a collection of objects, which may refer to other
21 * objects. Object references are used to name other objects or parts of them.
22 * This file defines the class for representing object references and the
23 * textual representation of these references. */
30 #include <uuid/uuid.h>
38 /* Generate a new UUID, and return the text representation of it. This is
39 * suitable for generating the name for a new segment. */
40 string generate_uuid()
46 uuid_unparse_lower(uuid, buf);
50 ObjectReference::ObjectReference()
51 : type(REF_NULL), segment(""), object("")
57 ObjectReference::ObjectReference(RefType t)
58 : type(t), segment(""), object("")
64 ObjectReference::ObjectReference(const std::string& segment, int sequence)
65 : type(REF_NORMAL), segment(segment)
68 sprintf(seq_buf, "%08x", sequence);
75 ObjectReference::ObjectReference(const std::string& segment,
76 const std::string& sequence)
77 : type(REF_NORMAL), segment(segment), object(sequence)
83 string ObjectReference::to_string() const
89 if (type == REF_ZERO) {
91 } else if (type == REF_NORMAL) {
92 result = segment + "/" + object;
95 result += "(" + checksum + ")";
101 sprintf(buf, "[=%zu]", range_length);
102 } else if (type == REF_ZERO) {
103 sprintf(buf, "[%zu]", range_length);
105 sprintf(buf, "[%zu+%zu]", range_start, range_length);
113 /* Parse a string object reference and return a pointer to a new
114 * ObjectReference. The caller is responsible for freeing the object. NULL is
115 * returned if there is an error in the syntax. */
116 ObjectReference ObjectReference::parse(const std::string& str)
118 const char *s = str.c_str();
120 ObjectReference::RefType type = ObjectReference::REF_NORMAL;
122 // Special case: explicit zero objects
123 if (strncmp(s, "zero", 4) == 0) {
124 type = ObjectReference::REF_ZERO;
130 if (type == ObjectReference::REF_NORMAL) {
131 while ((*t >= '0' && *t <= '9') || (*t >= 'a' && *t <= 'f')
135 return ObjectReference();
137 string segment(s, t - s);
139 // Object sequence number
140 if (type == ObjectReference::REF_NORMAL) {
143 while ((*t >= '0' && *t <= '9') || (*t >= 'a' && *t <= 'f'))
145 if (*t != '\0' && *t != '(' && *t != '[')
146 return ObjectReference();
148 string object(s, t - s);
155 while (*t != ')' && *t != '\0')
158 return ObjectReference();
159 checksum = string(s, t - s);
164 bool have_range = false, range_exact = false;
165 int64_t range1 = 0, range2 = 0;
175 while (*t >= '0' && *t <= '9')
178 // Abbreviated-length only range?
180 string val(s, t - s);
181 range2 = atoll(val.c_str());
184 return ObjectReference();
186 return ObjectReference();
188 string val(s, t - s);
189 range1 = atoll(val.c_str());
193 while (*t >= '0' && *t <= '9')
196 return ObjectReference();
198 val = string(s, t - s);
199 range2 = atoll(val.c_str());
207 case ObjectReference::REF_ZERO:
208 ref = ObjectReference(ObjectReference::REF_ZERO);
210 case ObjectReference::REF_NORMAL:
211 ref = ObjectReference(segment, object);
214 return ObjectReference();
217 if (checksum.size() > 0)
218 ref.set_checksum(checksum);
221 ref.set_range(range1, range2, range_exact);
226 /* Attempt to merge a new object reference into the current one. Returns a
227 * boolean indicating success; if successful this reference is modified so that
228 * it refers to the range of bytes originally covered by this reference plus
229 * the reference passed in. Merging only succeeds if both references refer to
230 * the same object and the byte ranges are contiguous. */
231 bool ObjectReference::merge(ObjectReference ref)
233 // Exception: We can always merge into a null object
239 if (segment != ref.segment)
241 if (object != ref.object)
244 // TODO: Allow the case where only one checksum was filled in
245 if (checksum_valid != ref.checksum_valid || checksum != ref.checksum)
248 if (!range_valid || !ref.range_valid)
251 if (range_exact || ref.range_exact)
254 if (range_start + range_length == ref.range_start) {
255 range_length += ref.range_length;