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Diffstat (limited to '')
| -rw-r--r-- | sca-cpp/trunk/components/kvdb/leveldb.hpp | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/sca-cpp/trunk/components/kvdb/leveldb.hpp b/sca-cpp/trunk/components/kvdb/leveldb.hpp new file mode 100644 index 0000000000..893166c361 --- /dev/null +++ b/sca-cpp/trunk/components/kvdb/leveldb.hpp @@ -0,0 +1,249 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/* $Rev$ $Date$ */ + +#ifndef tuscany_leveldb_hpp +#define tuscany_leveldb_hpp + +#include <fcntl.h> +#include <unistd.h> +#include <sys/stat.h> +#include <leveldb/db.h> + +#include "string.hpp" +#include "list.hpp" +#include "value.hpp" +#include "monad.hpp" +#include "../../modules/scheme/eval.hpp" + +namespace tuscany { +namespace leveldb { + +/** + * A reallocatable buffer. + */ +class buffer { +public: + operator void*() const throw() { + return buf; + } + + operator unsigned char*() const throw() { + return (unsigned char*)buf; + } + + operator char*() const throw() { + return (char*)buf; + } + +private: + buffer(const unsigned int size, void* buf) : size(size), buf(buf) { + } + + unsigned int size; + void* buf; + + friend const buffer mkbuffer(const unsigned int sz); + friend const buffer mkbuffer(const buffer& b, const unsigned int newsz); + friend const bool free(const buffer& b); +}; + +/** + * Make a new buffer. + */ +const buffer mkbuffer(const unsigned int sz) { + return buffer(sz, malloc(sz)); +} + +/** + * Make a new buffer by reallocating an existing one. + */ +const buffer mkbuffer(const buffer& b, const unsigned int sz) { + if (sz <= b.size) + return b; + return buffer(sz, realloc(b.buf, sz)); +} + +/** + * Free a buffer. + */ +const bool free(const buffer&b) { + ::free(b.buf); + return true; +} + +/** + * Represents a LevelDB connection. + */ +class LevelDB { +public: + LevelDB() : owner(false), fd(-1) { + debug("leveldb::leveldb"); + st.st_ino = 0; + } + + LevelDB(const string& name) : owner(true), name(name), fd(-1) { + debug(name, "leveldb::leveldb::name"); + st.st_ino = 0; + } + + LevelDB(const LevelDB& c) : owner(false), name(c.name), fd(c.fd) { + debug("leveldb::leveldb::copy"); + st.st_ino = c.st.st_ino; + } + + ~LevelDB() { + debug("leveldb::~leveldb"); + if (!owner) + return; + if (fd == -1) + return; + close(fd); + } + +private: + bool owner; + string name; + leveldb::DB* db; + struct stat st; + + friend const string dbname(const LevelDB& db); + friend const failable<int> dbopen(LevelDB& db); + friend const failable<bool> dbclose(LevelDB& db); +}; + +/** + * Return the name of the database. + */ +const string dbname(const LevelDB& db) { + return db.name; +} + +/** + * Open a database. + */ +const failable<int> dbopen(LevelDB& db) { + + // Get database file serial number + struct stat st; + const int s = stat(c_str(db.name), &st); + if (s == -1) + return mkfailure<int>( + string("Couldn't leveldb read database stat ") + db.name); + + leveldb::DB* ldb; + leveldb::Options options; + options.create_if_missing = true; + leveldb::Status status = leveldb::DB::Open(options, s, &ldb); + db.db = ldb; +} + +/** + * Close a database. + */ +const failable<bool> dbclose(LevelDB& db) { + delete db.db; + db.db = NULL; + return true; +} + + +const failable<bool> post(const value& key, const value& val, LevelDB& db) { + debug(key, "leveldb::post::key"); + debug(val, "leveldb::post::value"); + debug(dbname(db), "leveldb::post::dbname"); + + const string ks(scheme::writeValue(key)); + const string vs(scheme::writeValue(val)); + + put(ks, vs, db); + + debug(r, "leveldb::post::result"); + return r; +} + + +const failable<bool> put(const value& key, const value& val, LevelDB& db) { + debug(key, "leveldb::put::key"); + debug(val, "leveldb::put::value"); + debug(dbname(db), "leveldb::put::dbname"); + + const string ks(scheme::writeValue(key)); + const string vs(scheme::writeValue(val)); + + debug(r, "leveldb::put::result"); + return r; +} + +/** + * Get an item from the database. + */ +const failable<value> get(const value& key, LevelDB& db) { + debug(key, "leveldb::get::key"); + debug(dbname(db), "leveldb::get::dbname"); + + const string ks(scheme::writeValue(key)); + + std::string data; + db.db->Get(leveldb::ReadOptions(), key, &data); + const value val(scheme::readValue(string(data))); + + debug(val, "leveldb::get::result"); + return val; +} + +/** + * Delete an item from the database + */ +struct delUpdate { + const string ks; + delUpdate(const string& ks) : ks(ks) { + } + const failable<bool> operator()(buffer& buf, const unsigned int klen, unused const unsigned int vlen) const { + if (ks == string((char*)buf, klen)) + return false; + return true; + } +}; + +struct delFinish { + delFinish() { + } + const failable<bool> operator()(unused struct db_make& dbm) const { + return true; + } +}; + +const failable<bool> del(const value& key, LevelDB& db) { + debug(key, "leveldb::delete::key"); + debug(dbname(db), "leveldb::delete::dbname"); + + const string ks(scheme::writeValue(key)); + + leveldb::Status s = db.db->Delete(leveldb::WriteOptions(), key); + + debug(r, "leveldb::delete::result"); + return s.ok(); +} + +} +} + +#endif /* tuscany_leveldb_hpp */ |