Pool

6 files changed, 480 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index d17ef6afb..b71a35942 100644
--- a/.gitignore
+++ b/.gitignore
@@ -455,6 +455,7 @@ paludis-*.*.*.tar.bz2
 /paludis/util/mutex_TEST
 /paludis/util/options_TEST
 /paludis/util/outputwrapper
+/paludis/util/pool_TEST
 /paludis/util/pretty_print_TEST
 /paludis/util/process_TEST
 /paludis/util/pty_TEST
diff --git a/paludis/util/files.m4 b/paludis/util/files.m4
index 4f4e82382..1a84de7d0 100644
--- a/paludis/util/files.m4
+++ b/paludis/util/files.m4
@@ -60,6 +60,7 @@ add(`operators',                         `hh')
 add(`options',                           `hh', `fwd', `cc', `test')
 add(`pimp',                              `hh', `impl')
 add(`pipe',                              `hh', `cc')
+add(`pool',                              `hh', `cc', `impl', `test')
 add(`pretty_print',                      `hh', `cc', `test')
 add(`process',                           `hh', `cc', `fwd', `test', `testscript')
 add(`pty',                               `hh', `cc', `test')
diff --git a/paludis/util/pool-impl.hh b/paludis/util/pool-impl.hh
new file mode 100644
index 000000000..ac40c6516
--- /dev/null
+++ b/paludis/util/pool-impl.hh
@@ -0,0 +1,120 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2011 Ciaran McCreesh
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis 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., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PALUDIS_GUARD_PALUDIS_UTIL_POOL_IMPL_HH
+#define PALUDIS_GUARD_PALUDIS_UTIL_POOL_IMPL_HH 1
+
+#include <paludis/util/pool.hh>
+#include <paludis/util/mutex.hh>
+#include <paludis/util/hashes.hh>
+#include <unordered_map>
+#include <memory>
+
+namespace paludis
+{
+    template <typename Arg_, typename... Args_>
+    void
+    PoolKeys::add(const Arg_ & arg, const Args_ & ... args)
+    {
+        add_one(std::make_shared<ConcretePoolKey<Arg_> >(arg));
+        add(args...);
+    }
+
+    template <typename T_>
+    struct Imp<Pool<T_> >
+    {
+        mutable Mutex mutex;
+        mutable std::unordered_map<PoolKeys, std::shared_ptr<const T_>, PoolKeysHasher, PoolKeysComparator> store;
+    };
+
+    template <typename T_>
+    Pool<T_>::Pool() :
+        _imp()
+    {
+    }
+
+    template <typename T_>
+    Pool<T_>::~Pool() = default;
+
+    template <typename T_>
+    struct PreventConversion
+    {
+        const T_ & ref;
+
+        PreventConversion(const T_ & r) :
+            ref(r)
+        {
+        }
+
+        operator const T_ & ()
+        {
+            return ref;
+        }
+    };
+
+    template <typename T_>
+    template <typename... Args_>
+    const std::shared_ptr<const T_>
+    Pool<T_>::create(Args_ ... args) const
+    {
+        PoolKeys keys;
+        keys.add(args...);
+
+        Lock lock(_imp->mutex);
+        auto i(_imp->store.find(keys));
+        if (i == _imp->store.end())
+            i = _imp->store.insert(std::make_pair(keys, std::make_shared<const T_>(PreventConversion<Args_>(args)...))).first;
+
+        return i->second;
+    }
+
+    template <typename T_>
+    ConcretePoolKey<T_>::ConcretePoolKey(const T_ & t) :
+        PoolKey(PoolKeyTypeCodes::get<T_>()),
+        _value(t)
+    {
+    }
+
+    template <typename T_>
+    ConcretePoolKey<T_>::~ConcretePoolKey() = default;
+
+    template <typename T_>
+    std::size_t
+    ConcretePoolKey<T_>::hash() const
+    {
+        return Hash<T_>()(_value);
+    }
+
+    template <typename T_>
+    bool
+    ConcretePoolKey<T_>::same_value(const PoolKey & other) const
+    {
+        return _value == static_cast<const ConcretePoolKey<T_> &>(other)._value;
+    }
+
+    template <typename T_>
+    int
+    PoolKeyTypeCodes::get()
+    {
+        static int result(next());
+        return result;
+    }
+}
+
+#endif
diff --git a/paludis/util/pool.cc b/paludis/util/pool.cc
new file mode 100644
index 000000000..6ad46fd29
--- /dev/null
+++ b/paludis/util/pool.cc
@@ -0,0 +1,124 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2011 Ciaran McCreesh
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis 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., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <paludis/util/pool-impl.hh>
+#include <paludis/util/pimp-impl.hh>
+#include <paludis/util/mutex.hh>
+#include <list>
+#include <memory>
+
+using namespace paludis;
+
+typedef std::list<std::shared_ptr<const PoolKey> > PoolKeyList;
+
+namespace paludis
+{
+    template <>
+    struct Imp<PoolKeys>
+    {
+        std::shared_ptr<PoolKeyList> values;
+
+        Imp() :
+            values(std::make_shared<PoolKeyList>())
+        {
+        }
+
+        Imp(const std::shared_ptr<PoolKeyList> & v) :
+            values(v)
+        {
+        }
+    };
+}
+
+PoolKeys::PoolKeys() :
+    _imp()
+{
+}
+
+PoolKeys::PoolKeys(const PoolKeys & other) :
+    _imp(other._imp->values)
+{
+}
+
+PoolKeys::~PoolKeys() = default;
+
+void
+PoolKeys::add()
+{
+}
+
+void
+PoolKeys::add_one(const std::shared_ptr<const PoolKey> & k)
+{
+    _imp->values->push_back(k);
+}
+
+PoolKey::PoolKey(int tc) :
+    _tc(tc)
+{
+}
+
+PoolKey::~PoolKey() = default;
+
+bool
+PoolKey::same_type_and_value(const PoolKey & other) const
+{
+    return _tc == other._tc && same_value(other);
+}
+
+std::size_t
+PoolKeysHasher::operator() (const PoolKeys & keys) const
+{
+    std::size_t result(0);
+
+    for (auto i(keys._imp->values->begin()), i_end(keys._imp->values->end()) ;
+            i != i_end ; ++i)
+    {
+        result <<= 4;
+        result ^= (*i)->hash();
+    }
+
+    return result;
+}
+
+bool
+PoolKeysComparator::operator() (const PoolKeys & a, const PoolKeys & b) const
+{
+    for (auto i(a._imp->values->begin()), j(b._imp->values->begin()), i_end(a._imp->values->end()), j_end(b._imp->values->end()) ;
+            (i != i_end || j != j_end) ; ++i, ++j)
+    {
+        if (i == i_end || j == j_end || ! (*i)->same_type_and_value(**j))
+            return false;
+    }
+
+    return true;
+}
+
+int
+PoolKeyTypeCodes::next()
+{
+    static Mutex mutex;
+    static int result(0);
+
+    Lock lock(mutex);
+    return ++result;
+}
+
+template class Pimp<PoolKeys>;
+
diff --git a/paludis/util/pool.hh b/paludis/util/pool.hh
new file mode 100644
index 000000000..58e919b38
--- /dev/null
+++ b/paludis/util/pool.hh
@@ -0,0 +1,132 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2011 Ciaran McCreesh
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis 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., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PALUDIS_GUARD_PALUDIS_UTIL_POOL_HH
+#define PALUDIS_GUARD_PALUDIS_UTIL_POOL_HH 1
+
+#include <paludis/util/singleton.hh>
+#include <paludis/util/pimp.hh>
+#include <memory>
+
+namespace paludis
+{
+    class PoolKeysHasher;
+    class PoolKeysComparator;
+
+    template <typename T_>
+    class PALUDIS_VISIBLE Pool :
+        public Singleton<Pool<T_> >
+    {
+        friend class Singleton<Pool<T_> >;
+
+        private:
+            Pimp<Pool<T_> > _imp;
+
+            Pool();
+            ~Pool();
+
+        public:
+            template <typename... Args_>
+            const std::shared_ptr<const T_> create(Args_ ...) const PALUDIS_ATTRIBUTE((warn_unused_result));
+    };
+
+    class PALUDIS_VISIBLE PoolKey
+    {
+        private:
+            int _tc;
+
+        protected:
+            explicit PoolKey(int tc);
+
+            virtual bool same_value(const PoolKey &) const = 0;
+
+        public:
+            virtual ~PoolKey() = 0;
+
+            virtual std::size_t hash() const = 0;
+
+            bool same_type_and_value(const PoolKey &) const;
+    };
+
+    template <typename T_>
+    class PALUDIS_VISIBLE ConcretePoolKey :
+        public PoolKey
+    {
+        friend class PoolKeysHasher;
+        friend class PoolKeysComparator;
+
+        private:
+            T_ _value;
+
+        public:
+            explicit ConcretePoolKey(const T_ &);
+
+            virtual ~ConcretePoolKey();
+
+            virtual std::size_t hash() const;
+
+            bool same_value(const PoolKey &) const;
+    };
+
+    class PALUDIS_VISIBLE PoolKeys
+    {
+        friend class PoolKeysHasher;
+        friend class PoolKeysComparator;
+
+        private:
+            Pimp<PoolKeys> _imp;
+
+            void add_one(const std::shared_ptr<const PoolKey> &);
+            void add();
+
+        public:
+            PoolKeys();
+            PoolKeys(const PoolKeys &);
+            ~PoolKeys();
+
+            template <typename Arg_, typename... Args_>
+            void add(const Arg_ &, const Args_ & ...);
+    };
+
+    class PALUDIS_VISIBLE PoolKeysHasher
+    {
+        public:
+            std::size_t operator() (const PoolKeys &) const PALUDIS_VISIBLE;
+    };
+
+    class PALUDIS_VISIBLE PoolKeysComparator
+    {
+        public:
+            bool operator() (const PoolKeys &, const PoolKeys &) const PALUDIS_VISIBLE;
+    };
+
+    class PALUDIS_VISIBLE PoolKeyTypeCodes
+    {
+        private:
+            static int next();
+
+        public:
+            template <typename T_>
+            static int get();
+    };
+
+    extern template class Pimp<PoolKeys>;
+}
+
+#endif
diff --git a/paludis/util/pool_TEST.cc b/paludis/util/pool_TEST.cc
new file mode 100644
index 000000000..c4b802d68
--- /dev/null
+++ b/paludis/util/pool_TEST.cc
@@ -0,0 +1,102 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2011 Ciaran McCreesh
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis 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., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <paludis/util/pool-impl.hh>
+#include <paludis/util/singleton-impl.hh>
+#include <paludis/util/pimp-impl.hh>
+#include <test/test_runner.hh>
+#include <test/test_framework.hh>
+
+using namespace paludis;
+using namespace test;
+
+namespace
+{
+    struct Monkey
+    {
+        std::string name;
+
+        explicit Monkey(const std::string & n) :
+            name(n)
+        {
+        }
+    };
+
+    struct Weasel
+    {
+        std::string name;
+        int viciousness;
+
+        explicit Weasel(const std::string & n, int v) :
+            name(n),
+            viciousness(v)
+        {
+        }
+    };
+}
+
+namespace test_cases
+{
+    struct PoolMonkeyTest : TestCase
+    {
+        PoolMonkeyTest() : TestCase("pool monkey test") { }
+
+        void run()
+        {
+            auto a(Pool<Monkey>::get_instance()->create(std::string("alexander")));
+            auto b(Pool<Monkey>::get_instance()->create(std::string("gunther")));
+            auto c(Pool<Monkey>::get_instance()->create(std::string("alexander")));
+
+            TEST_CHECK(a->name == "alexander");
+            TEST_CHECK(b->name == "gunther");
+            TEST_CHECK(c->name == "alexander");
+
+            TEST_CHECK(a == c);
+        }
+    } test_pool_monkey;
+
+    struct PoolWeaselTest : TestCase
+    {
+        PoolWeaselTest() : TestCase("pool weasel test") { }
+
+        void run()
+        {
+            auto a(Pool<Weasel>::get_instance()->create(std::string("william"), 8));
+            auto b(Pool<Weasel>::get_instance()->create(std::string("tony"), 5));
+            auto c(Pool<Weasel>::get_instance()->create(std::string("william"), 8));
+            auto d(Pool<Weasel>::get_instance()->create(std::string("tony"), 10));
+
+            TEST_CHECK(a->name == "william");
+            TEST_CHECK(a->viciousness == 8);
+
+            TEST_CHECK(b->name == "tony");
+            TEST_CHECK(b->viciousness == 5);
+
+            TEST_CHECK(c->name == "william");
+            TEST_CHECK(c->viciousness == 8);
+
+            TEST_CHECK(d->name == "tony");
+            TEST_CHECK(d->viciousness == 10);
+
+            TEST_CHECK(a == c);
+            TEST_CHECK(b != d);
+        }
+    } test_pool_weasel;
+}
+