1 /* LBS: An LFS-inspired filesystem backup system
2 * Copyright (C) 2007 Michael Vrable
4 * Backups are structured as a collection of objects, which may refer to other
5 * objects. Object references are used to name other objects or parts of them.
6 * This file defines the class for representing object references and the
7 * textual representation of these references. */
11 #include <uuid/uuid.h>
19 /* Generate a new UUID, and return the text representation of it. This is
20 * suitable for generating the name for a new segment. */
21 string generate_uuid()
27 uuid_unparse_lower(uuid, buf);
31 ObjectReference::ObjectReference()
32 : segment(""), object("")
36 ObjectReference::ObjectReference(const std::string& segment, int sequence)
40 sprintf(seq_buf, "%08x", sequence);
47 ObjectReference::ObjectReference(const std::string& segment,
48 const std::string& sequence)
49 : segment(segment), object(sequence)
55 string ObjectReference::to_string() const
60 string result = segment + "/" + object;
63 result += "(" + checksum + ")";
67 sprintf(buf, "[%zu+%zu]", range_start, range_length);
74 /* Parse a string object reference and return a pointer to a new
75 * ObjectReference. The caller is responsible for freeing the object. NULL is
76 * returned if there is an error in the syntax. */
77 ObjectReference ObjectReference::parse(const std::string& str)
79 const char *s = str.c_str();
84 while ((*t >= '0' && *t <= '9') || (*t >= 'a' && *t <= 'f') || (*t == '-'))
87 return ObjectReference();
88 string segment(s, t - s);
90 // Object sequence number
93 while ((*t >= '0' && *t <= '9') || (*t >= 'a' && *t <= 'f'))
95 if (*t != '\0' && *t != '(' && *t != '[')
96 return ObjectReference();
97 string object(s, t - s);
104 while (*t != ')' && *t != '\0')
107 return ObjectReference();
108 checksum = string(s, t - s);
113 bool have_range = false;
114 int64_t range1, range2;
118 while (*t >= '0' && *t <= '9')
121 return ObjectReference();
123 string val(s, t - s);
124 range1 = atoll(val.c_str());
128 while (*t >= '0' && *t <= '9')
131 return ObjectReference();
133 val = string(s, t - s);
134 range2 = atoll(val.c_str());
139 ObjectReference ref(segment, object);
140 if (checksum.size() > 0)
141 ref.set_checksum(checksum);
144 ref.set_range(range1, range2);
149 /* Attempt to merge a new object reference into the current one. Returns a
150 * boolean indicating success; if successful this reference is modified so that
151 * it refers to the range of bytes originally covered by this reference plus
152 * the reference passed in. Merging only succeeds if both references refer to
153 * the same object and the byte ranges are contiguous. */
154 bool ObjectReference::merge(ObjectReference ref)
156 // Exception: We can always merge into a null object
162 if (segment != ref.segment)
164 if (object != ref.object)
167 // TODO: Allow the case where only one checksum was filled in
168 if (checksum_valid != ref.checksum_valid || checksum != ref.checksum)
171 if (!range_valid || !ref.range_valid)
174 if (range_start + range_length == ref.range_start) {
175 range_length += ref.range_length;