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diff --git a/src/include/CompatSet.h b/src/include/CompatSet.h
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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 <iostream>
+#include <map>
+#include <string>
+
+#include "include/buffer.h"
+#include "include/encoding.h"
+#include "include/types.h"
+#include "common/Formatter.h"
+
+struct CompatSet {
+
+ struct Feature {
+ uint64_t id;
+ std::string name;
+
+ Feature(uint64_t _id, const std::string& _name) : id(_id), name(_name) {}
+ };
+
+ class FeatureSet {
+ uint64_t mask;
+ std::map<uint64_t, std::string> names;
+
+ public:
+ friend struct CompatSet;
+ friend class CephCompatSet_AllSet_Test;
+ friend class CephCompatSet_other_Test;
+ friend class CephCompatSet_merge_Test;
+ friend std::ostream& operator<<(std::ostream& out, const CompatSet::FeatureSet& fs);
+ friend std::ostream& operator<<(std::ostream& out, const CompatSet& compat);
+ FeatureSet() : mask(1), names() {}
+ void insert(const Feature& f) {
+ ceph_assert(f.id > 0);
+ ceph_assert(f.id < 64);
+ mask |= ((uint64_t)1<<f.id);
+ names[f.id] = f.name;
+ }
+
+ bool contains(const Feature& f) const {
+ return names.count(f.id);
+ }
+ bool contains(uint64_t f) const {
+ return names.count(f);
+ }
+ /**
+ * Getter instead of using name[] to be const safe
+ */
+ std::string get_name(uint64_t const f) const {
+ std::map<uint64_t, std::string>::const_iterator i = names.find(f);
+ ceph_assert(i != names.end());
+ return i->second;
+ }
+
+ void remove(uint64_t f) {
+ if (names.count(f)) {
+ names.erase(f);
+ mask &= ~((uint64_t)1<<f);
+ }
+ }
+ void remove(const Feature& f) {
+ remove(f.id);
+ }
+
+ void encode(ceph::buffer::list& bl) const {
+ using ceph::encode;
+ /* 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(ceph::buffer::list::const_iterator& bl) {
+ using ceph::decode;
+ 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;
+ std::map<uint64_t, std::string> temp_names;
+ temp_names.swap(names);
+ for (auto i = temp_names.begin(); i != temp_names.end(); ++i) {
+ insert(Feature(i->first, i->second));
+ }
+ } else {
+ mask |= 1;
+ }
+ }
+
+ void dump(ceph::Formatter *f) const {
+ for (auto p = names.cbegin(); p != names.cend(); ++p) {
+ char s[18];
+ snprintf(s, sizeof(s), "feature_%llu", (unsigned long long)p->first);
+ f->dump_string(s, p->second);
+ }
+ }
+ };
+
+ // These features have no impact on the read / write status
+ FeatureSet compat;
+ // If any of these features are missing, read is possible ( as long
+ // as no incompat feature is missing ) but it is not possible to write
+ FeatureSet ro_compat;
+ // If any of these features are missing, read or write is not possible
+ FeatureSet 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 const& other) const {
+ return !((other.incompat.mask ^ incompat.mask) & other.incompat.mask);
+ }
+
+ /* does this filesystem implementation have the
+ features required to write the other? */
+ bool writeable(CompatSet const& other) const {
+ 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(const CompatSet& other) const {
+ 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(const CompatSet& other) const {
+ 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 id = 1; id < 64; ++id) {
+ uint64_t mask = (uint64_t)1 << id;
+ if (mask & other_compat) {
+ diff.compat.insert( Feature(id, other.compat.names.at(id)));
+ }
+ if (mask & other_ro_compat) {
+ diff.ro_compat.insert(Feature(id, other.ro_compat.names.at(id)));
+ }
+ if (mask & other_incompat) {
+ diff.incompat.insert( Feature(id, other.incompat.names.at(id)));
+ }
+ }
+ return diff;
+ }
+
+ /* Merge features supported by other CompatSet into this one.
+ * Return: true if some features were merged
+ */
+ bool merge(CompatSet const & other) {
+ 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);
+ if (!other_compat && !other_ro_compat && !other_incompat)
+ return false;
+ for (int id = 1; id < 64; ++id) {
+ uint64_t mask = (uint64_t)1 << id;
+ if (mask & other_compat) {
+ compat.insert( Feature(id, other.compat.get_name(id)));
+ }
+ if (mask & other_ro_compat) {
+ ro_compat.insert(Feature(id, other.ro_compat.get_name(id)));
+ }
+ if (mask & other_incompat) {
+ incompat.insert( Feature(id, other.incompat.get_name(id)));
+ }
+ }
+ return true;
+ }
+
+ std::ostream& printlite(std::ostream& o) const {
+ o << "{c=[" << std::hex << compat.mask << "]";
+ o << ",r=[" << std::hex << ro_compat.mask << "]";
+ o << ",i=[" << std::hex << incompat.mask << "]}";
+ o << std::dec;
+ return o;
+ }
+
+ void encode(ceph::buffer::list& bl) const {
+ compat.encode(bl);
+ ro_compat.encode(bl);
+ incompat.encode(bl);
+ }
+
+ void decode(ceph::buffer::list::const_iterator& bl) {
+ compat.decode(bl);
+ ro_compat.decode(bl);
+ incompat.decode(bl);
+ }
+
+ void dump(ceph::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(std::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 std::ostream& operator<<(std::ostream& out, const CompatSet::Feature& f)
+{
+ return out << "F(" << f.id << ", \"" << f.name << "\")";
+}
+
+inline std::ostream& operator<<(std::ostream& out, const CompatSet::FeatureSet& fs)
+{
+ return out << fs.names;
+}
+
+inline std::ostream& operator<<(std::ostream& out, const CompatSet& compat)
+{
+ return out << "compat=" << compat.compat
+ << ",rocompat=" << compat.ro_compat
+ << ",incompat=" << compat.incompat;
+}
+
+#endif
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