-/* 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. */
#include <assert.h>
#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
#include <uuid/uuid.h>
#include <string>
return string(buf);
}
+ObjectReference::ObjectReference()
+ : type(REF_NULL), segment(""), object("")
+{
+ clear_checksum();
+ clear_range();
+}
+
+ObjectReference::ObjectReference(RefType t)
+ : type(t), segment(""), object("")
+{
+ clear_checksum();
+ clear_range();
+}
ObjectReference::ObjectReference(const std::string& segment, int sequence)
- : segment(segment)
+ : type(REF_NORMAL), segment(segment)
{
char seq_buf[64];
sprintf(seq_buf, "%08x", sequence);
ObjectReference::ObjectReference(const std::string& segment,
const std::string& sequence)
- : segment(segment), object(sequence)
+ : type(REF_NORMAL), segment(segment), object(sequence)
{
clear_checksum();
clear_range();
string ObjectReference::to_string() const
{
- string result = segment + "/" + object;
+ if (type == REF_NULL)
+ return "null";
- if (checksum_valid)
- result += "(" + checksum + ")";
+ string result;
+ if (type == REF_ZERO) {
+ result = "zero";
+ } else if (type == REF_NORMAL) {
+ result = segment + "/" + object;
+
+ if (checksum_valid)
+ result += "(" + checksum + ")";
+ }
if (range_valid) {
char buf[64];
- sprintf(buf, "[%zu+%zu]", range_start, range_length);
+ if (range_exact || type == REF_ZERO) {
+ sprintf(buf, "[%zu]", range_length);
+ } else {
+ sprintf(buf, "[%zu+%zu]", range_start, range_length);
+ }
result += buf;
}
/* Parse a string object reference and return a pointer to a new
* ObjectReference. The caller is responsible for freeing the object. NULL is
* returned if there is an error in the syntax. */
-ObjectReference *ObjectReference::parse(const std::string& s)
+ObjectReference ObjectReference::parse(const std::string& str)
+{
+ const char *s = str.c_str();
+ const char *t;
+ ObjectReference::RefType type = ObjectReference::REF_NORMAL;
+
+ // Special case: explicit zero objects
+ if (strncmp(s, "zero", 4) == 0) {
+ type = ObjectReference::REF_ZERO;
+ s += 4;
+ }
+
+ // Segment
+ t = s;
+ if (type == ObjectReference::REF_NORMAL) {
+ while ((*t >= '0' && *t <= '9') || (*t >= 'a' && *t <= 'f')
+ || (*t == '-'))
+ t++;
+ if (*t != '/')
+ return ObjectReference();
+ }
+ string segment(s, t - s);
+
+ // Object sequence number
+ if (type == ObjectReference::REF_NORMAL) {
+ t++;
+ s = t;
+ while ((*t >= '0' && *t <= '9') || (*t >= 'a' && *t <= 'f'))
+ t++;
+ if (*t != '\0' && *t != '(' && *t != '[')
+ return ObjectReference();
+ }
+ string object(s, t - s);
+
+ // Checksum
+ string checksum;
+ if (*t == '(') {
+ t++;
+ s = t;
+ while (*t != ')' && *t != '\0')
+ t++;
+ if (*t != ')')
+ return ObjectReference();
+ checksum = string(s, t - s);
+ t++;
+ }
+
+ // Range
+ bool have_range = false, range_exact = false;
+ int64_t range1 = 0, range2 = 0;
+ if (*t == '[') {
+ t++;
+
+ // An equal sign was once used for a length assertion but is now
+ // deprecated. Skip it if present, and mark that we are expecting a
+ // length-only reference.
+ if (*t == '=') {
+ range_exact = true;
+ t++;
+ }
+
+ s = t;
+ while (*t >= '0' && *t <= '9')
+ t++;
+
+ // Abbreviated-length only range?
+ if (*t == ']') {
+ string val(s, t - s);
+ range2 = atoll(val.c_str());
+ range_exact = true;
+ } else {
+ if (*t != '+')
+ return ObjectReference();
+ if (range_exact)
+ return ObjectReference();
+
+ string val(s, t - s);
+ range1 = atoll(val.c_str());
+
+ t++;
+ s = t;
+ while (*t >= '0' && *t <= '9')
+ t++;
+ if (*t != ']')
+ return ObjectReference();
+
+ val = string(s, t - s);
+ range2 = atoll(val.c_str());
+ }
+
+ have_range = true;
+ }
+
+ ObjectReference ref;
+ switch (type) {
+ case ObjectReference::REF_ZERO:
+ ref = ObjectReference(ObjectReference::REF_ZERO);
+ break;
+ case ObjectReference::REF_NORMAL:
+ ref = ObjectReference(segment, object);
+ break;
+ default:
+ return ObjectReference();
+ }
+
+ if (checksum.size() > 0)
+ ref.set_checksum(checksum);
+
+ if (have_range)
+ ref.set_range(range1, range2, range_exact);
+
+ return ref;
+}
+
+/* Attempt to merge a new object reference into the current one. Returns a
+ * boolean indicating success; if successful this reference is modified so that
+ * it refers to the range of bytes originally covered by this reference plus
+ * the reference passed in. Merging only succeeds if both references refer to
+ * the same object and the byte ranges are contiguous. */
+bool ObjectReference::merge(ObjectReference ref)
{
- // TODO: Implement
- return NULL;
+ // Exception: We can always merge into a null object
+ if (is_null()) {
+ *this = ref;
+ return true;
+ }
+
+ if (segment != ref.segment)
+ return false;
+ if (object != ref.object)
+ return false;
+
+ // TODO: Allow the case where only one checksum was filled in
+ if (checksum_valid != ref.checksum_valid || checksum != ref.checksum)
+ return false;
+
+ if (!range_valid || !ref.range_valid)
+ return false;
+
+ if (range_exact || ref.range_exact)
+ return false;
+
+ if (range_start + range_length == ref.range_start) {
+ range_length += ref.range_length;
+ return true;
+ } else {
+ return false;
+ }
}
projects / cumulus.git / blobdiff