1 files changed, 305 insertions, 0 deletions

diff --git a/src/include/compact_set.h b/src/include/compact_set.h
new file mode 100644
index 00000000..ba743fb0
--- /dev/null
+++ b/src/include/compact_set.h
@@ -0,0 +1,305 @@
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2015 Red Hat, Inc
+ *
+ * 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_COMPACT_SET_H
+#define CEPH_COMPACT_SET_H
+
+#include "buffer.h"
+#include "encoding.h"
+
+#include <memory>
+#include <set>
+
+template <class T, class Set>
+class compact_set_base {
+protected:
+  std::unique_ptr<Set> set;
+  void alloc_internal() {
+    if (!set)
+      set.reset(new Set);
+  }
+  void free_internal() {
+    set.reset();
+  }
+  template <class It>
+  class iterator_base {
+  private:
+    const compact_set_base* set;
+    It it;
+    iterator_base() : set(0) { }
+    iterator_base(const compact_set_base* s) : set(s) { }
+    iterator_base(const compact_set_base* s, const It& i) : set(s), it(i) { }
+    friend class compact_set_base;
+  public:
+    iterator_base(const iterator_base& o) {
+      set = o.set;
+      it = o.it;
+    }
+    bool operator==(const iterator_base& o) const {
+      return (set == o.set) && (!set->set || it == o.it);
+    }
+    bool operator!=(const iterator_base& o) const {
+      return !(*this == o);;
+    }
+    iterator_base& operator=(const iterator_base& o) {
+      set->set = o.set;
+      it = o.it;
+      return *this;
+    }
+    iterator_base& operator++() {
+      ++it;
+      return *this;
+    }
+    iterator_base operator++(int) {
+      iterator_base tmp = *this;
+      ++it;
+      return tmp;
+    }
+    iterator_base& operator--() {
+      --it;
+      return *this;
+    }
+    const T& operator*() {
+      return *it;
+    }
+  };
+public:
+  class const_iterator : public iterator_base<typename Set::const_iterator> {
+    public:
+      const_iterator() { }
+      const_iterator(const iterator_base<typename Set::const_iterator>& o)
+	: iterator_base<typename Set::const_iterator>(o) { }
+      const_iterator(const compact_set_base* s) : iterator_base<typename Set::const_iterator>(s) { }
+      const_iterator(const compact_set_base* s, const typename Set::const_iterator& i)
+	: iterator_base<typename Set::const_iterator>(s, i) { }
+  };
+  class iterator : public iterator_base<typename Set::iterator> {
+    public:
+      iterator() { }
+      iterator(const iterator_base<typename Set::iterator>& o)
+	: iterator_base<typename Set::iterator>(o) { }
+      iterator(compact_set_base* s) : iterator_base<typename Set::iterator>(s) { }
+      iterator(compact_set_base* s, const typename Set::iterator& i)
+	: iterator_base<typename Set::iterator>(s, i) { }
+      operator const_iterator() const {
+	return const_iterator(this->set, this->it);
+      }
+  };
+  class const_reverse_iterator : public iterator_base<typename Set::const_reverse_iterator> {
+    public:
+      const_reverse_iterator() { }
+      const_reverse_iterator(const iterator_base<typename Set::const_reverse_iterator>& o)
+	: iterator_base<typename Set::const_reverse_iterator>(o) { }
+      const_reverse_iterator(const compact_set_base* s) : iterator_base<typename Set::const_reverse_iterator>(s) { }
+      const_reverse_iterator(const compact_set_base* s, const typename Set::const_reverse_iterator& i)
+	: iterator_base<typename Set::const_reverse_iterator>(s, i) { }
+  };
+  class reverse_iterator : public iterator_base<typename Set::reverse_iterator> {
+    public:
+      reverse_iterator() { }
+      reverse_iterator(const iterator_base<typename Set::reverse_iterator>& o)
+	: iterator_base<typename Set::reverse_iterator>(o) { }
+      reverse_iterator(compact_set_base* s) : iterator_base<typename Set::reverse_iterator>(s) { }
+      reverse_iterator(compact_set_base* s, const typename Set::reverse_iterator& i)
+	: iterator_base<typename Set::reverse_iterator>(s, i) { }
+      operator const_iterator() const {
+	return const_iterator(this->set, this->it);
+      }
+  };
+
+  compact_set_base() {}
+  compact_set_base(const compact_set_base& o) {
+    if (o.set) {
+      alloc_internal();
+      *set = *o.set;
+    }
+  }
+  ~compact_set_base() {}
+
+
+  bool empty() const {
+    return !set || set->empty();
+  }
+  size_t size() const {
+    return set ? set->size() : 0;
+  }
+  bool operator==(const compact_set_base& o) const {
+    return (empty() && o.empty()) || (set && o.set && *set == *o.set);
+  }
+  bool operator!=(const compact_set_base& o) const {
+    return !(*this == o);
+  }
+  size_t count(const T& t) const {
+    return set ? set->count(t) : 0;
+  }
+  iterator erase (iterator p) {
+    if (set) {
+      ceph_assert(this == p.set);
+      auto it = set->erase(p.it);
+      if (set->empty()) {
+        free_internal();
+        return iterator(this);
+      } else {
+        return iterator(this, it);
+      }
+    } else {
+      return iterator(this);
+    }
+  }
+  size_t erase (const T& t) {
+    if (!set)
+      return 0;
+    size_t r = set->erase(t);
+    if (set->empty())
+      free_internal();
+    return r;
+  }
+  void clear() {
+    free_internal();
+  }
+  void swap(compact_set_base& o) {
+    set.swap(o.set);
+  }
+  compact_set_base& operator=(const compact_set_base& o) {
+    if (o.set) {
+      alloc_internal();
+      *set = *o.set;
+    } else
+      free_internal();
+    return *this;
+  }
+  std::pair<iterator,bool> insert(const T& t) {
+    alloc_internal();
+    std::pair<typename Set::iterator,bool> r = set->insert(t);
+    return std::make_pair(iterator(this, r.first), r.second);
+  }
+  template <class... Args>
+  std::pair<iterator,bool> emplace ( Args&&... args ) {
+    alloc_internal();
+    auto em = set->emplace(std::forward<Args>(args)...);
+    return std::pair<iterator,bool>(iterator(this, em.first), em.second);
+  }
+
+  iterator begin() {
+   if (!set)
+     return iterator(this);
+   return iterator(this, set->begin());
+  }
+  iterator end() {
+   if (!set)
+     return iterator(this);
+   return iterator(this, set->end());
+  }
+  reverse_iterator rbegin() {
+   if (!set)
+     return reverse_iterator(this);
+   return reverse_iterator(this, set->rbegin());
+  }
+  reverse_iterator rend() {
+   if (!set)
+     return reverse_iterator(this);
+   return reverse_iterator(this, set->rend());
+  }
+  iterator find(const T& t) {
+    if (!set)
+      return iterator(this);
+    return iterator(this, set->find(t));
+  }
+  iterator lower_bound(const T& t) {
+    if (!set)
+      return iterator(this);
+    return iterator(this, set->lower_bound(t));
+  }
+  iterator upper_bound(const T& t) {
+    if (!set)
+      return iterator(this);
+    return iterator(this, set->upper_bound(t));
+  }
+  const_iterator begin() const {
+   if (!set)
+     return const_iterator(this);
+   return const_iterator(this, set->begin());
+  }
+  const_iterator end() const {
+   if (!set)
+     return const_iterator(this);
+   return const_iterator(this, set->end());
+  }
+  const_reverse_iterator rbegin() const {
+   if (!set)
+     return const_reverse_iterator(this);
+   return const_reverse_iterator(this, set->rbegin());
+  }
+  const_reverse_iterator rend() const {
+   if (!set)
+     return const_reverse_iterator(this);
+   return const_reverse_iterator(this, set->rend());
+  }
+  const_iterator find(const T& t) const {
+    if (!set)
+      return const_iterator(this);
+    return const_iterator(this, set->find(t));
+  }
+  const_iterator lower_bound(const T& t) const {
+    if (!set)
+      return const_iterator(this);
+    return const_iterator(this, set->lower_bound(t));
+  }
+  const_iterator upper_bound(const T& t) const {
+    if (!set)
+      return const_iterator(this);
+    return const_iterator(this, set->upper_bound(t));
+  }
+  void encode(bufferlist &bl) const {
+    using ceph::encode;
+    if (set)
+      encode(*set, bl);
+    else
+      encode((uint32_t)0, bl);
+  }
+  void decode(bufferlist::const_iterator& p) {
+    using ceph::decode;
+    uint32_t n;
+    decode(n, p);
+    if (n > 0) {
+      alloc_internal();
+      decode_nohead(n, *set, p);
+    } else
+      free_internal();
+  }
+};
+
+template<class T, class Set>
+inline void encode(const compact_set_base<T, Set>& m, bufferlist& bl) {
+  m.encode(bl);
+}
+template<class T, class Set>
+inline void decode(compact_set_base<T, Set>& m, bufferlist::const_iterator& p) {
+  m.decode(p);
+}
+
+template <class T, class Compare = std::less<T>, class Alloc = std::allocator<T> >
+class compact_set : public compact_set_base<T, std::set<T, Compare, Alloc> > {
+};
+
+template <class T, class Compare = std::less<T>, class Alloc = std::allocator<T> >
+inline std::ostream& operator<<(std::ostream& out, const compact_set<T,Compare,Alloc>& s)
+{
+  bool first = true;
+  for (auto &v : s) {
+    if (!first)
+      out << ",";
+    out << v;
+    first = false;
+  }
+  return out;
+}
+#endif