+++ /dev/null
-// -*- 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) 2013 Inktank Storage, 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 MAPCACHER_H
-#define MAPCACHER_H
-
-#include "common/sharedptr_registry.hpp"
-
-namespace MapCacher {
-/**
- * Abstraction for ordering key updates
- */
-template<typename K, typename V>
-class Transaction {
-public:
- /// Set keys according to map
- virtual void set_keys(
- const std::map<K, V> &keys ///< [in] keys/values to set
- ) = 0;
-
- /// Remove keys
- virtual void remove_keys(
- const std::set<K> &to_remove ///< [in] keys to remove
- ) = 0;
-
- /// Add context to fire when data is readable
- virtual void add_callback(
- Context *c ///< [in] Context to fire on readable
- ) = 0;
- virtual ~Transaction() {}
-};
-
-/**
- * Abstraction for fetching keys
- */
-template<typename K, typename V>
-class StoreDriver {
-public:
- /// Returns requested key values
- virtual int get_keys(
- const std::set<K> &keys, ///< [in] keys requested
- std::map<K, V> *got ///< [out] values for keys obtained
- ) = 0; ///< @return error value
-
- /// Returns next key
- virtual int get_next(
- const K &key, ///< [in] key after which to get next
- pair<K, V> *next ///< [out] first key after key
- ) = 0; ///< @return 0 on success, -ENOENT if there is no next
-
- virtual ~StoreDriver() {}
-};
-
-/**
- * Uses SharedPtrRegistry to cache objects of in progress writes
- * allowing the user to read/write a consistent view of the map
- * without flushing writes.
- */
-template<typename K, typename V>
-class MapCacher {
-private:
- StoreDriver<K, V> *driver;
-
- SharedPtrRegistry<K, boost::optional<V> > in_progress;
- typedef typename SharedPtrRegistry<K, boost::optional<V> >::VPtr VPtr;
- typedef ContainerContext<set<VPtr> > TransHolder;
-
-public:
- MapCacher(StoreDriver<K, V> *driver) : driver(driver) {}
-
- /// Fetch first key/value pair after specified key
- int get_next(
- K key, ///< [in] key after which to get next
- pair<K, V> *next ///< [out] next key
- ) {
- while (true) {
- pair<K, boost::optional<V> > cached;
- pair<K, V> store;
- bool got_cached = in_progress.get_next(key, &cached);
-
- bool got_store = false;
- int r = driver->get_next(key, &store);
- if (r < 0 && r != -ENOENT) {
- return r;
- } else if (r == 0) {
- got_store = true;
- }
-
- if (!got_cached && !got_store) {
- return -ENOENT;
- } else if (
- got_cached &&
- (!got_store || store.first >= cached.first)) {
- if (cached.second) {
- if (next)
- *next = make_pair(cached.first, cached.second.get());
- return 0;
- } else {
- key = cached.first;
- continue; // value was cached as removed, recurse
- }
- } else {
- if (next)
- *next = store;
- return 0;
- }
- }
- ceph_abort(); // not reachable
- return -EINVAL;
- } ///< @return error value, 0 on success, -ENOENT if no more entries
-
- /// Adds operation setting keys to Transaction
- void set_keys(
- const map<K, V> &keys, ///< [in] keys/values to set
- Transaction<K, V> *t ///< [out] transaction to use
- ) {
- std::set<VPtr> vptrs;
- for (typename map<K, V>::const_iterator i = keys.begin();
- i != keys.end();
- ++i) {
- VPtr ip = in_progress.lookup_or_create(i->first, i->second);
- *ip = i->second;
- vptrs.insert(ip);
- }
- t->set_keys(keys);
- t->add_callback(new TransHolder(vptrs));
- }
-
- /// Adds operation removing keys to Transaction
- void remove_keys(
- const set<K> &keys, ///< [in]
- Transaction<K, V> *t ///< [out] transaction to use
- ) {
- std::set<VPtr> vptrs;
- for (typename set<K>::const_iterator i = keys.begin();
- i != keys.end();
- ++i) {
- boost::optional<V> empty;
- VPtr ip = in_progress.lookup_or_create(*i, empty);
- *ip = empty;
- vptrs.insert(ip);
- }
- t->remove_keys(keys);
- t->add_callback(new TransHolder(vptrs));
- }
-
- /// Gets keys, uses cached values for unstable keys
- int get_keys(
- const set<K> &keys_to_get, ///< [in] set of keys to fetch
- map<K, V> *got ///< [out] keys gotten
- ) {
- set<K> to_get;
- map<K, V> _got;
- for (typename set<K>::const_iterator i = keys_to_get.begin();
- i != keys_to_get.end();
- ++i) {
- VPtr val = in_progress.lookup(*i);
- if (val) {
- if (*val)
- got->insert(make_pair(*i, val->get()));
- //else: value cached is empty, key doesn't exist
- } else {
- to_get.insert(*i);
- }
- }
- int r = driver->get_keys(to_get, &_got);
- if (r < 0)
- return r;
- for (typename map<K, V>::iterator i = _got.begin();
- i != _got.end();
- ++i) {
- got->insert(*i);
- }
- return 0;
- } ///< @return error value, 0 on success
-};
-} // namespace
-
-#endif
Code Review / stor4nfv.git / blobdiff