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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2009 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_COMPATSET_H
#define CEPH_COMPATSET_H
#include "include/buffer.h"
#include <vector>
#include "common/Formatter.h"
struct CompatSet {
struct Feature {
uint64_t id;
string name;
Feature(uint64_t _id, const char *_name) : id(_id), name(_name) {}
Feature(uint64_t _id, string& _name) : id(_id), name(_name) {}
};
struct FeatureSet {
uint64_t mask;
map <uint64_t,string> names;
FeatureSet() : mask(1), names() {}
void insert(Feature f) {
assert(f.id > 0);
assert(f.id < 63);
mask |= (1<<f.id);
names[f.id] = f.name;
}
bool contains(uint64_t f) const {
return names.count(f);
}
void remove(uint64_t f) {
if (names.count(f)) {
names.erase(f);
mask &= ~(1<<f);
}
}
void encode(bufferlist& bl) const {
/* See below, mask always has the lowest bit set in memory, but
* unset in the encoding */
::encode(mask & (~(uint64_t)1), bl);
::encode(names, bl);
}
void decode(bufferlist::iterator& bl) {
::decode(mask, bl);
::decode(names, bl);
/**
* Previously, there was a bug where insert did
* mask |= f.id rather than mask |= (1 << f.id).
* In FeatureSets from those version, mask always
* has the lowest bit set. Since then, masks always
* have the lowest bit unset.
*
* When we encounter such a FeatureSet, we have to
* reconstruct the mask from the names map.
*/
if (mask & 1) {
mask = 1;
map<uint64_t, string> temp_names;
temp_names.swap(names);
for (map<uint64_t, string>::iterator i = temp_names.begin();
i != temp_names.end();
++i) {
insert(Feature(i->first, i->second));
}
} else {
mask |= 1;
}
}
void dump(Formatter *f) const {
for (map<uint64_t,string>::const_iterator p = names.begin();
p != names.end();
++p) {
char s[10];
snprintf(s, sizeof(s), "%lld", (unsigned long long)p->first);
f->dump_string(s, p->second);
}
}
};
FeatureSet compat, ro_compat, incompat;
CompatSet(FeatureSet& _compat, FeatureSet& _ro_compat, FeatureSet& _incompat) :
compat(_compat), ro_compat(_ro_compat), incompat(_incompat) {}
CompatSet() : compat(), ro_compat(), incompat() { }
/* does this filesystem implementation have the
features required to read the other? */
bool readable(CompatSet& other) {
return !((other.incompat.mask ^ incompat.mask) & other.incompat.mask);
}
/* does this filesystem implementation have the
features required to write the other? */
bool writeable(CompatSet& other) {
return readable(other) &&
!((other.ro_compat.mask ^ ro_compat.mask) & other.ro_compat.mask);
}
/* Compare this CompatSet to another.
* CAREFULLY NOTE: This operation is NOT commutative.
* a > b DOES NOT imply that b < a.
* If returns:
* 0: The CompatSets have the same feature set.
* 1: This CompatSet's features are a strict superset of the other's.
* -1: This CompatSet is missing at least one feature
* described in the other. It may still have more features, though.
*/
int compare(CompatSet& other) {
if ((other.compat.mask == compat.mask) &&
(other.ro_compat.mask == ro_compat.mask) &&
(other.incompat.mask == incompat.mask)) return 0;
//okay, they're not the same
//if we're writeable we have a superset of theirs on incompat and ro_compat
if (writeable(other) && !((other.compat.mask ^ compat.mask)
& other.compat.mask)) return 1;
//if we make it here, we weren't writeable or had a difference compat set
return -1;
}
/* Get the features supported by other CompatSet but not this one,
* as a CompatSet.
*/
CompatSet unsupported(CompatSet& other) {
CompatSet diff;
uint64_t other_compat =
((other.compat.mask ^ compat.mask) & other.compat.mask);
uint64_t other_ro_compat =
((other.ro_compat.mask ^ ro_compat.mask) & other.ro_compat.mask);
uint64_t other_incompat =
((other.incompat.mask ^ incompat.mask) & other.incompat.mask);
for (int i = 0; i < 64; ++i) {
int mask = 1 << i;
if (mask & other_compat) {
diff.compat.insert( Feature(mask & other_compat,
other.compat.names[mask&other_compat]));
}
if (mask & other_ro_compat) {
diff.ro_compat.insert(Feature(mask & other_ro_compat,
other.compat.names[mask&other_ro_compat]));
}
if (mask & other_incompat) {
diff.incompat.insert( Feature(mask & other_incompat,
other.incompat.names[mask&other_incompat]));
}
}
return diff;
}
void encode(bufferlist& bl) const {
compat.encode(bl);
ro_compat.encode(bl);
incompat.encode(bl);
}
void decode(bufferlist::iterator& bl) {
compat.decode(bl);
ro_compat.decode(bl);
incompat.decode(bl);
}
void dump(Formatter *f) const {
f->open_object_section("compat");
compat.dump(f);
f->close_section();
f->open_object_section("ro_compat");
ro_compat.dump(f);
f->close_section();
f->open_object_section("incompat");
incompat.dump(f);
f->close_section();
}
static void generate_test_instances(list<CompatSet*>& o) {
o.push_back(new CompatSet);
o.push_back(new CompatSet);
o.back()->compat.insert(Feature(1, "one"));
o.back()->compat.insert(Feature(2, "two"));
o.back()->ro_compat.insert(Feature(4, "four"));
o.back()->incompat.insert(Feature(3, "three"));
}
};
WRITE_CLASS_ENCODER(CompatSet)
inline ostream& operator<<(ostream& out, const CompatSet::FeatureSet& fs)
{
return out << fs.names;
}
inline ostream& operator<<(ostream& out, const CompatSet& compat)
{
return out << "compat=" << compat.compat
<< ",rocompat=" << compat.ro_compat
<< ",incompat=" << compat.incompat;
}
#endif
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