diff options
Diffstat (limited to 'src/lmdb')
| -rw-r--r-- | src/lmdb/CMakeLists.txt | 33 | ||||
| -rw-r--r-- | src/lmdb/database.cpp | 187 | ||||
| -rw-r--r-- | src/lmdb/database.h | 138 | ||||
| -rw-r--r-- | src/lmdb/error.cpp | 98 | ||||
| -rw-r--r-- | src/lmdb/error.h | 64 | ||||
| -rw-r--r-- | src/lmdb/key_stream.h | 264 | ||||
| -rw-r--r-- | src/lmdb/table.cpp | 43 | ||||
| -rw-r--r-- | src/lmdb/table.h | 120 | ||||
| -rw-r--r-- | src/lmdb/transaction.h | 95 | ||||
| -rw-r--r-- | src/lmdb/util.h | 149 | ||||
| -rw-r--r-- | src/lmdb/value_stream.cpp | 74 | ||||
| -rw-r--r-- | src/lmdb/value_stream.h | 287 |
12 files changed, 1552 insertions, 0 deletions
diff --git a/src/lmdb/CMakeLists.txt b/src/lmdb/CMakeLists.txt new file mode 100644 index 000000000..1f369f114 --- /dev/null +++ b/src/lmdb/CMakeLists.txt @@ -0,0 +1,33 @@ +# Copyright (c) 2014-2018, The Monero Project +# +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without modification, are +# permitted provided that the following conditions are met: +# +# 1. Redistributions of source code must retain the above copyright notice, this list of +# conditions and the following disclaimer. +# +# 2. Redistributions in binary form must reproduce the above copyright notice, this list +# of conditions and the following disclaimer in the documentation and/or other +# materials provided with the distribution. +# +# 3. Neither the name of the copyright holder nor the names of its contributors may be +# used to endorse or promote products derived from this software without specific +# prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +# THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +# THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +set(lmdb_sources database.cpp error.cpp table.cpp value_stream.cpp) +set(lmdb_headers database.h error.h key_stream.h table.h transaction.h util.h value_stream.h) + +monero_add_library(lmdb_lib ${lmdb_sources} ${lmdb_headers}) +target_link_libraries(lmdb_lib common ${LMDB_LIBRARY}) diff --git a/src/lmdb/database.cpp b/src/lmdb/database.cpp new file mode 100644 index 000000000..c6b244671 --- /dev/null +++ b/src/lmdb/database.cpp @@ -0,0 +1,187 @@ +// Copyright (c) 2014-2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#include "database.h" +#include "lmdb/error.h" +#include "lmdb/util.h" + +#ifdef _WIN32 +namespace +{ + constexpr const mdb_mode_t open_flags = 0; +} +#else +#include <sys/stat.h> + +namespace +{ + constexpr const mdb_mode_t open_flags = (S_IRUSR | S_IWUSR); +} +#endif + +namespace lmdb +{ + namespace + { + constexpr const std::size_t max_resize = 1 * 1024 * 1024 * 1024; // 1 GB + void acquire_context(context& ctx) noexcept + { + while (ctx.lock.test_and_set()); + ++(ctx.active); + ctx.lock.clear(); + } + + void release_context(context& ctx) noexcept + { + --(ctx.active); + } + } + + void release_read_txn::operator()(MDB_txn* ptr) const noexcept + { + if (ptr) + { + MDB_env* const env = mdb_txn_env(ptr); + abort_txn{}(ptr); + if (env) + { + context* ctx = reinterpret_cast<context*>(mdb_env_get_userctx(env)); + if (ctx) + release_context(*ctx); + } + } + } + + expect<environment> open_environment(const char* path, MDB_dbi max_dbs) noexcept + { + MONERO_PRECOND(path != nullptr); + + MDB_env* obj = nullptr; + MONERO_LMDB_CHECK(mdb_env_create(std::addressof(obj))); + environment out{obj}; + + MONERO_LMDB_CHECK(mdb_env_set_maxdbs(out.get(), max_dbs)); + MONERO_LMDB_CHECK(mdb_env_open(out.get(), path, 0, open_flags)); + return {std::move(out)}; + } + + expect<write_txn> database::do_create_txn(unsigned int flags) noexcept + { + MONERO_PRECOND(handle() != nullptr); + + for (unsigned attempts = 0; attempts < 3; ++attempts) + { + acquire_context(ctx); + + MDB_txn* txn = nullptr; + const int err = + mdb_txn_begin(handle(), nullptr, flags, &txn); + if (!err && txn != nullptr) + return write_txn{txn}; + + release_context(ctx); + if (err != MDB_MAP_RESIZED) + return {lmdb::error(err)}; + MONERO_CHECK(this->resize()); + } + return {lmdb::error(MDB_MAP_RESIZED)}; + } + + database::database(environment env) + : env(std::move(env)), ctx{{}, ATOMIC_FLAG_INIT} + { + if (handle()) + { + const int err = mdb_env_set_userctx(handle(), std::addressof(ctx)); + if (err) + MONERO_THROW(lmdb::error(err), "Failed to set user context"); + } + } + + database::~database() noexcept + { + while (ctx.active); + } + + expect<void> database::resize() noexcept + { + MONERO_PRECOND(handle() != nullptr); + + while (ctx.lock.test_and_set()); + while (ctx.active); + + MDB_envinfo info{}; + MONERO_LMDB_CHECK(mdb_env_info(handle(), &info)); + + const std::size_t resize = std::min(info.me_mapsize, max_resize); + const int err = mdb_env_set_mapsize(handle(), info.me_mapsize + resize); + ctx.lock.clear(); + if (err) + return {lmdb::error(err)}; + return success(); + } + + expect<read_txn> database::create_read_txn(suspended_txn txn) noexcept + { + if (txn) + { + acquire_context(ctx); + const int err = mdb_txn_renew(txn.get()); + if (err) + { + release_context(ctx); + return {lmdb::error(err)}; + } + return read_txn{txn.release()}; + } + auto new_txn = do_create_txn(MDB_RDONLY); + if (new_txn) + return read_txn{new_txn->release()}; + return new_txn.error(); + } + + expect<suspended_txn> database::reset_txn(read_txn txn) noexcept + { + MONERO_PRECOND(txn != nullptr); + mdb_txn_reset(txn.get()); + release_context(ctx); + return suspended_txn{txn.release()}; + } + + expect<write_txn> database::create_write_txn() noexcept + { + return do_create_txn(0); + } + + expect<void> database::commit(write_txn txn) noexcept + { + MONERO_PRECOND(txn != nullptr); + MONERO_LMDB_CHECK(mdb_txn_commit(txn.get())); + txn.release(); + release_context(ctx); + return success(); + } +} // lmdb diff --git a/src/lmdb/database.h b/src/lmdb/database.h new file mode 100644 index 000000000..269f8c8a1 --- /dev/null +++ b/src/lmdb/database.h @@ -0,0 +1,138 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#pragma once + +#include <atomic> +#include <cstddef> +#include <lmdb.h> +#include <memory> +#include <type_traits> + +#include "common/expect.h" +#include "lmdb/error.h" +#include "lmdb/transaction.h" + +namespace lmdb +{ + //! Closes LMDB environment handle. + struct close_env + { + void operator()(MDB_env* ptr) const noexcept + { + if (ptr) + mdb_env_close(ptr); + } + }; + + using environment = std::unique_ptr<MDB_env, close_env>; + + //! \return LMDB environment at `path` with a max of `max_dbs` tables. + expect<environment> open_environment(const char* path, MDB_dbi max_dbs) noexcept; + + //! Context given to LMDB. + struct context + { + std::atomic<std::size_t> active; + std::atomic_flag lock; + }; + + //! Manages a LMDB environment for safe memory-map resizing. Thread-safe. + class database + { + environment env; + context ctx; + + //! \return The LMDB environment associated with the object. + MDB_env* handle() const noexcept { return env.get(); } + + expect<write_txn> do_create_txn(unsigned int flags) noexcept; + + public: + database(environment env); + + database(database&&) = delete; + database(database const&) = delete; + + virtual ~database() noexcept; + + database& operator=(database&&) = delete; + database& operator=(database const&) = delete; + + /*! + Resize the memory map for the LMDB environment. Will block until + all reads/writes on the environment complete. + */ + expect<void> resize() noexcept; + + //! \return A read only LMDB transaction, reusing `txn` if provided. + expect<read_txn> create_read_txn(suspended_txn txn = nullptr) noexcept; + + //! \return `txn` after releasing context. + expect<suspended_txn> reset_txn(read_txn txn) noexcept; + + //! \return A read-write LMDB transaction. + expect<write_txn> create_write_txn() noexcept; + + //! Commit the read-write transaction. + expect<void> commit(write_txn txn) noexcept; + + /*! + Create a write transaction, pass it to `f`, then try to commit + the write if `f` succeeds. + + \tparam F must be callable with signature `expect<T>(MDB_txn&)`. + \param f must be re-startable if `lmdb::error(MDB_MAP_FULL)`. + + \return The result of calling `f`. + */ + template<typename F> + typename std::result_of<F(MDB_txn&)>::type try_write(F f, unsigned attempts = 3) + { + for (unsigned i = 0; i < attempts; ++i) + { + expect<write_txn> txn = create_write_txn(); + if (!txn) + return txn.error(); + + MONERO_PRECOND(*txn != nullptr); + const auto wrote = f(*(*txn)); + if (wrote) + { + MONERO_CHECK(commit(std::move(*txn))); + return wrote; + } + if (wrote != lmdb::error(MDB_MAP_FULL)) + return wrote; + + txn->reset(); + MONERO_CHECK(this->resize()); + } + return {lmdb::error(MDB_MAP_FULL)}; + } + }; +} // lmdb + diff --git a/src/lmdb/error.cpp b/src/lmdb/error.cpp new file mode 100644 index 000000000..359677064 --- /dev/null +++ b/src/lmdb/error.cpp @@ -0,0 +1,98 @@ +// Copyright (c) 2014-2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "error.h" + +#include <lmdb.h> +#include <string> + +namespace { + struct category final : std::error_category + { + virtual const char* name() const noexcept override final + { + return "lmdb::error_category()"; + } + + virtual std::string message(int value) const override final + { + char const* const msg = mdb_strerror(value); + if (msg) + return msg; + return "Unknown lmdb::error_category() value"; + } + + virtual std::error_condition default_error_condition(int value) const noexcept override final + { + switch (value) + { + case MDB_KEYEXIST: + case MDB_NOTFOUND: + break; // map to nothing generic + case MDB_PAGE_NOTFOUND: + case MDB_CORRUPTED: + return std::errc::state_not_recoverable; + case MDB_PANIC: + case MDB_VERSION_MISMATCH: + case MDB_INVALID: + break; // map to nothing generic + case MDB_MAP_FULL: + return std::errc::no_buffer_space; + case MDB_DBS_FULL: + break; // map to nothing generic + case MDB_READERS_FULL: + case MDB_TLS_FULL: + return std::errc::no_lock_available; + case MDB_TXN_FULL: + case MDB_CURSOR_FULL: + case MDB_PAGE_FULL: + case MDB_MAP_RESIZED: + break; // map to nothing generic + case MDB_INCOMPATIBLE: + return std::errc::invalid_argument; + case MDB_BAD_RSLOT: + case MDB_BAD_TXN: + case MDB_BAD_VALSIZE: + case MDB_BAD_DBI: + return std::errc::invalid_argument; + default: + return std::error_condition{value, std::generic_category()}; + } + return std::error_condition{value, *this}; + } + }; +} + +namespace lmdb +{ + std::error_category const& error_category() noexcept + { + static const category instance{}; + return instance; + } +} + diff --git a/src/lmdb/error.h b/src/lmdb/error.h new file mode 100644 index 000000000..2944adf78 --- /dev/null +++ b/src/lmdb/error.h @@ -0,0 +1,64 @@ +// Copyright (c) 2014-2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#pragma once + +#include <system_error> +#include <type_traits> + +//! Executes a LMDB command, and returns errors via `lmdb::error` enum. +#define MONERO_LMDB_CHECK(...) \ + do \ + { \ + const int err = __VA_ARGS__ ; \ + if (err) \ + return {lmdb::error(err)}; \ + } while (0) + +namespace lmdb +{ + //! Tracks LMDB error codes. + enum class error : int + { + // 0 is reserved for no error, as per expect<T> + // All other errors are the values reported by LMDB + }; + + std::error_category const& error_category() noexcept; + + inline std::error_code make_error_code(error value) noexcept + { + return std::error_code{int(value), error_category()}; + } +} + +namespace std +{ + template<> + struct is_error_code_enum<::lmdb::error> + : true_type + {}; +} diff --git a/src/lmdb/key_stream.h b/src/lmdb/key_stream.h new file mode 100644 index 000000000..40434d3a1 --- /dev/null +++ b/src/lmdb/key_stream.h @@ -0,0 +1,264 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#pragma once + +#include <boost/range/iterator_range.hpp> +#include <cstdint> +#include <cstring> +#include <iterator> +#include <lmdb.h> +#include <utility> + +#include "lmdb/value_stream.h" +#include "span.h" + +namespace lmdb +{ + + /*! + An InputIterator for a fixed-sized LMDB key and value. `operator++` + iterates over keys. + + \tparam K Key type in database records. + \tparam V Value type in database records. + + \note This meets requirements for an InputIterator only. The iterator + can only be incremented and dereferenced. All copies of an iterator + share the same LMDB cursor, and therefore incrementing any copy will + change the cursor state for all (incrementing an iterator will + invalidate all prior copies of the iterator). Usage is identical + to `std::istream_iterator`. + */ + template<typename K, typename V> + class key_iterator + { + MDB_cursor* cur; + epee::span<const std::uint8_t> key; + + void increment() + { + // MDB_NEXT_MULTIPLE doesn't work if only one value is stored :/ + if (cur) + key = lmdb::stream::get(*cur, MDB_NEXT_NODUP, sizeof(K), sizeof(V)).first; + } + + public: + using value_type = std::pair<K, boost::iterator_range<value_iterator<V>>>; + using reference = value_type; + using pointer = void; + using difference_type = std::size_t; + using iterator_category = std::input_iterator_tag; + + //! Construct an "end" iterator. + key_iterator() noexcept + : cur(nullptr), key() + {} + + /*! + \param cur Iterate over keys starting at this cursor position. + \throw std::system_error if unexpected LMDB error. This can happen + if `cur` is invalid. + */ + key_iterator(MDB_cursor* cur) + : cur(cur), key() + { + if (cur) + key = lmdb::stream::get(*cur, MDB_GET_CURRENT, sizeof(K), sizeof(V)).first; + } + + //! \return True if `this` is one-past the last key. + bool is_end() const noexcept { return key.empty(); } + + //! \return True iff `rhs` is referencing `this` key. + bool equal(key_iterator const& rhs) const noexcept + { + return + (key.empty() && rhs.key.empty()) || + key.data() == rhs.key.data(); + } + + /*! + Moves iterator to next key or end. Invalidates all prior copies of + the iterator. + */ + key_iterator& operator++() + { + increment(); + return *this; + } + + /*! + Moves iterator to next key or end. + + \return A copy that is already invalidated, ignore + */ + key_iterator operator++(int) + { + key_iterator out{*this}; + increment(); + return out; + } + + //! \pre `!is_end()` \return {current key, current value range} + value_type operator*() const + { + return {get_key(), make_value_range()}; + } + + //! \pre `!is_end()` \return Current key + K get_key() const noexcept + { + assert(!is_end()); + K out; + std::memcpy(std::addressof(out), key.data(), sizeof(out)); + return out; + } + + /*! + Return a C++ iterator over database values from current cursor + position that will reach `.is_end()` after the last duplicate key + record. Calling `make_iterator()` will return an iterator whose + `operator*` will return an entire value (`V`). + `make_iterator<MONERO_FIELD(account, id)>()` will return an + iterator whose `operator*` will return a `decltype(account.id)` + object - the other fields in the struct `account` are never copied + from the database. + + \throw std::system_error if LMDB has unexpected errors. + \return C++ iterator starting at current cursor position. + */ + template<typename T = V, typename F = T, std::size_t offset = 0> + value_iterator<T, F, offset> make_value_iterator() const + { + static_assert(std::is_same<T, V>(), "bad MONERO_FIELD usage?"); + return {cur}; + } + + /*! + Return a range from current cursor position until last duplicate + key record. Useful in for-each range loops or in templated code + expecting a range of elements. Calling `make_range()` will return + a range of `T` objects. `make_range<MONERO_FIELD(account, id)>()` + will return a range of `decltype(account.id)` objects - the other + fields in the struct `account` are never copied from the database. + + \throw std::system_error if LMDB has unexpected errors. + \return An InputIterator range over values at cursor position. + */ + template<typename T = V, typename F = T, std::size_t offset = 0> + boost::iterator_range<value_iterator<T, F, offset>> make_value_range() const + { + return {make_value_iterator<T, F, offset>(), value_iterator<T, F, offset>{}}; + } + }; + + /*! + C++ wrapper for a LMDB read-only cursor on a fixed-sized key `K` and + value `V`. + + \tparam K key type being stored by each record. + \tparam V value type being stored by each record. + \tparam D cleanup functor for the cursor; usually unique per db/table. + */ + template<typename K, typename V, typename D> + class key_stream + { + std::unique_ptr<MDB_cursor, D> cur; + public: + + //! Take ownership of `cur` without changing position. `nullptr` valid. + explicit key_stream(std::unique_ptr<MDB_cursor, D> cur) + : cur(std::move(cur)) + {} + + key_stream(key_stream&&) = default; + key_stream(key_stream const&) = delete; + ~key_stream() = default; + key_stream& operator=(key_stream&&) = default; + key_stream& operator=(key_stream const&) = delete; + + /*! + Give up ownership of the cursor. `make_iterator()` and + `make_range()` can still be invoked, but return the empty set. + + \return Currently owned LMDB cursor. + */ + std::unique_ptr<MDB_cursor, D> give_cursor() noexcept + { + return {std::move(cur)}; + } + + /*! + Place the stream back at the first key/value. Newly created + iterators will start at the first value again. + + \note Invalidates all current iterators, including those created + with `make_iterator` or `make_range`. Also invalidates all + `value_iterator`s created with `key_iterator`. + */ + void reset() + { + if (cur) + lmdb::stream::get(*cur, MDB_FIRST, 0, 0); + } + + /*! + \throw std::system_error if LMDB has unexpected errors. + \return C++ iterator over database keys from current cursor + position that will reach `.is_end()` after the last key. + */ + key_iterator<K, V> make_iterator() const + { + return {cur.get()}; + } + + /*! + \throw std::system_error if LMDB has unexpected errors. + \return Range from current cursor position until last key record. + Useful in for-each range loops or in templated code + */ + boost::iterator_range<key_iterator<K, V>> make_range() const + { + return {make_iterator(), key_iterator<K, V>{}}; + } + }; + + template<typename K, typename V> + inline + bool operator==(key_iterator<K, V> const& lhs, key_iterator<K, V> const& rhs) noexcept + { + return lhs.equal(rhs); + } + + template<typename K, typename V> + inline + bool operator!=(key_iterator<K, V> const& lhs, key_iterator<K, V> const& rhs) noexcept + { + return !lhs.equal(rhs); + } +} // lmdb + diff --git a/src/lmdb/table.cpp b/src/lmdb/table.cpp new file mode 100644 index 000000000..0818b74e6 --- /dev/null +++ b/src/lmdb/table.cpp @@ -0,0 +1,43 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#include "table.h" + +namespace lmdb +{ + expect<MDB_dbi> table::open(MDB_txn& write_txn) const noexcept + { + MONERO_PRECOND(name != nullptr); + + MDB_dbi out; + MONERO_LMDB_CHECK(mdb_dbi_open(&write_txn, name, flags, &out)); + if (key_cmp && !(flags & MDB_INTEGERKEY)) + MONERO_LMDB_CHECK(mdb_set_compare(&write_txn, out, key_cmp)); + if (value_cmp && !(flags & MDB_INTEGERDUP)) + MONERO_LMDB_CHECK(mdb_set_dupsort(&write_txn, out, value_cmp)); + return out; + } +} diff --git a/src/lmdb/table.h b/src/lmdb/table.h new file mode 100644 index 000000000..41a3de296 --- /dev/null +++ b/src/lmdb/table.h @@ -0,0 +1,120 @@ +#pragma once + +#include <utility> + +#include "common/expect.h" +#include "lmdb/error.h" +#include "lmdb/key_stream.h" +#include "lmdb/util.h" +#include "lmdb/value_stream.h" + +namespace lmdb +{ + //! Helper for grouping typical LMDB DBI options. + struct table + { + char const* const name; + const unsigned flags; + MDB_cmp_func const* const key_cmp; + MDB_cmp_func const* const value_cmp; + + //! \pre `name != nullptr` \return Open table. + expect<MDB_dbi> open(MDB_txn& write_txn) const noexcept; + }; + + //! Helper for grouping typical LMDB DBI options when key and value are fixed types. + template<typename K, typename V> + struct basic_table : table + { + using key_type = K; + using value_type = V; + + //! \return Additional LMDB flags based on `flags` value. + static constexpr unsigned compute_flags(const unsigned flags) noexcept + { + return flags | ((flags & MDB_DUPSORT) ? MDB_DUPFIXED : 0); + } + + constexpr explicit basic_table(const char* name, unsigned flags = 0, MDB_cmp_func value_cmp = nullptr) noexcept + : table{name, compute_flags(flags), &lmdb::less<lmdb::native_type<K>>, value_cmp} + {} + + /*! + \tparam U must be same as `V`; used for sanity checking. + \tparam F is the type within `U` that is being extracted. + \tparam offset to `F` within `U`. + + \note If using `F` and `offset` to retrieve a specific field, use + `MONERO_FIELD` macro in `src/lmdb/util.h` which calculates the + offset automatically. + + \return Value of type `F` at `offset` within `value` which has + type `U`. + */ + template<typename U, typename F = U, std::size_t offset = 0> + static expect<F> get_value(MDB_val value) noexcept + { + static_assert(std::is_same<U, V>(), "bad MONERO_FIELD?"); + static_assert(std::is_pod<F>(), "F must be POD"); + static_assert(sizeof(F) + offset <= sizeof(U), "bad field type and/or offset"); + + if (value.mv_size != sizeof(U)) + return {lmdb::error(MDB_BAD_VALSIZE)}; + + F out; + std::memcpy(std::addressof(out), static_cast<char*>(value.mv_data) + offset, sizeof(out)); + return out; + } + + /*! + \pre `cur != nullptr`. + \param cur Active cursor on table. Returned in object on success, + otherwise destroyed. + \return A handle to the first key/value in the table linked + to `cur` or an empty `key_stream`. + */ + template<typename D> + expect<key_stream<K, V, D>> + static get_key_stream(std::unique_ptr<MDB_cursor, D> cur) noexcept + { + MONERO_PRECOND(cur != nullptr); + + MDB_val key; + MDB_val value; + const int err = mdb_cursor_get(cur.get(), &key, &value, MDB_FIRST); + if (err) + { + if (err != MDB_NOTFOUND) + return {lmdb::error(err)}; + cur.reset(); // return empty set + } + return key_stream<K, V, D>{std::move(cur)}; + } + + /*! + \pre `cur != nullptr`. + \param cur Active cursor on table. Returned in object on success, + otherwise destroyed. + \return A handle to the first value at `key` in the table linked + to `cur` or an empty `value_stream`. + */ + template<typename D> + expect<value_stream<V, D>> + static get_value_stream(K const& key, std::unique_ptr<MDB_cursor, D> cur) noexcept + { + MONERO_PRECOND(cur != nullptr); + + MDB_val key_bytes = lmdb::to_val(key); + MDB_val value; + const int err = mdb_cursor_get(cur.get(), &key_bytes, &value, MDB_SET); + if (err) + { + if (err != MDB_NOTFOUND) + return {lmdb::error(err)}; + cur.reset(); // return empty set + } + return value_stream<V, D>{std::move(cur)}; + } + }; +} // lmdb + diff --git a/src/lmdb/transaction.h b/src/lmdb/transaction.h new file mode 100644 index 000000000..cdd80696c --- /dev/null +++ b/src/lmdb/transaction.h @@ -0,0 +1,95 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#pragma once + +#include <lmdb.h> +#include <memory> + +#include "lmdb/error.h" + +//! Uses C++ type system to differentiate between cursors +#define MONERO_CURSOR(name) \ + struct close_ ## name : ::lmdb::close_cursor {}; \ + using name = std::unique_ptr< MDB_cursor, close_ ## name >; + +namespace lmdb +{ + struct abort_txn + { + void operator()(MDB_txn* ptr) const noexcept + { + if (ptr) + mdb_txn_abort(ptr); + } + }; + + /*! + Only valid if used via `create_read_txn()`. Decrements active count in + associated `context`, and aborts a LMDB transaction (`mdb_txn_abort`). + */ + struct release_read_txn + { + void operator()(MDB_txn* ptr) const noexcept; + // implementation in database.cpp + }; + + /*! + Only valid if used via `create_write_txn()`. Decrements active count in + associated `context`, and aborts a LMDB transaction (`mdb_txn_abort`). + */ + struct abort_write_txn + { + void operator()(MDB_txn* ptr) const noexcept + { + release_read_txn{}(ptr); + } + }; + + struct close_cursor + { + void operator()(MDB_cursor* ptr) const noexcept + { + if (ptr) + mdb_cursor_close(ptr); + } + }; + + template<typename D> + inline expect<std::unique_ptr<MDB_cursor, D>> + open_cursor(MDB_txn& txn, MDB_dbi tbl) noexcept + { + MDB_cursor* cur = nullptr; + MONERO_LMDB_CHECK(mdb_cursor_open(&txn, tbl, &cur)); + return std::unique_ptr<MDB_cursor, D>{cur}; + } + + // The below use the C++ type system to designate `MDB_txn` status. + + using suspended_txn = std::unique_ptr<MDB_txn, abort_txn>; + using read_txn = std::unique_ptr<MDB_txn, release_read_txn>; + using write_txn = std::unique_ptr<MDB_txn, abort_write_txn>; +} // lmdb diff --git a/src/lmdb/util.h b/src/lmdb/util.h new file mode 100644 index 000000000..50162b7c8 --- /dev/null +++ b/src/lmdb/util.h @@ -0,0 +1,149 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#pragma once + +#include <cstddef> +#include <cstring> +#include <lmdb.h> +#include <type_traits> +#include <utility> + +#include "span.h" + +/*! Calculates types and offset of struct field. Use in template arguments for + `table::get_value`, `value_iterator::get_value`, + `value_stream::make_iterator`, or `value_stream::make_range`. */ +#define MONERO_FIELD(obj, field) \ + obj , decltype(std::declval<obj>().field) , offsetof(obj, field) + +//! Expands to `lmdb::less` for the value `field` within `obj`. +#define MONERO_SORT_BY(obj, field) \ + &::lmdb::less< \ + lmdb::native_type<decltype(std::declval<obj>().field)>, \ + offsetof(obj, field) \ + > + +//! Expands to `lmdb::compare` for the value `field` within `obj`. +#define MONERO_COMPARE(obj, field) \ + &::lmdb::compare< \ + decltype(std::declval<obj>().field), \ + offsetof(obj, field) \ + > + +namespace lmdb +{ + //! Prevent instantiation of `std::underlying_type<T>` when `T` is not enum. + template<typename T> + struct identity + { + using type = T; + }; + + /*! + Get the native type for enums, or return `T` unchanged. Useful for + merging generated machine code for templated functions that use enums + with identical size-widths without relying on aggressive identical + comdat folding (ICF) support in linker. So with enum defintion + `enum class enum_foo : unsigned long {};` will always yield + `assert(&func_foo<unsigned long> == &func_foo<native_type<enum_foo>>)`. + */ + template<typename T> + using native_type = typename std::conditional< + std::is_enum<T>::value, std::underlying_type<T>, identity<T> + >::type::type; + + //! \return `value` as its native type. + template<typename T, typename U = typename std::underlying_type<T>::type> + inline constexpr U to_native(T value) noexcept + { + return U(value); + } + + //! \return `value` bytes in a LMDB `MDB_val` object. + template<typename T> + inline MDB_val to_val(T&& value) noexcept + { + // lmdb does not touch user data, so const_cast is acceptable + static_assert(!std::is_rvalue_reference<T&&>(), "cannot use temporary value"); + void const* const temp = reinterpret_cast<void const*>(std::addressof(value)); + return MDB_val{sizeof(value), const_cast<void*>(temp)}; + } + + //! \return A span over the same chunk of memory as `value`. + inline constexpr epee::span<const std::uint8_t> to_byte_span(MDB_val value) noexcept + { + return {static_cast<const std::uint8_t*>(value.mv_data), value.mv_size}; + } + + /*! + A LMDB comparison function that uses `operator<`. + + \tparam T has a defined `operator<` . + \tparam offset to `T` within the value. + + \return -1 if `left < right`, 1 if `right < left`, and 0 otherwise. + */ + template<typename T, std::size_t offset = 0> + inline int less(MDB_val const* left, MDB_val const* right) noexcept + { + if (!left || !right || left->mv_size < sizeof(T) + offset || right->mv_size < sizeof(T) + offset) + { + assert("invalid use of custom comparison" == 0); + return -1; + } + + T left_val; + T right_val; + std::memcpy(std::addressof(left_val), static_cast<char*>(left->mv_data) + offset, sizeof(T)); + std::memcpy(std::addressof(right_val), static_cast<char*>(right->mv_data) + offset, sizeof(T)); + return left_val < right_val ? -1 : bool(right_val < left_val); + } + + /*! + A LMDB comparison function that uses `std::memcmp`. + + \toaram T is `!epee::has_padding` + \tparam offset to `T` within the value. + + \return The result of `std::memcmp` over the value. + */ + template<typename T, std::size_t offset = 0> + inline int compare(MDB_val const* left, MDB_val const* right) noexcept + { + static_assert(!epee::has_padding<T>(), "memcmp will not work"); + if (!left || !right || left->mv_size < sizeof(T) + offset || right->mv_size < sizeof(T) + offset) + { + assert("invalid use of custom comparison" == 0); + return -1; + } + return std::memcmp( + static_cast<char*>(left->mv_data) + offset, + static_cast<char*>(right->mv_data) + offset, + sizeof(T) + ); + } +} // lmdb diff --git a/src/lmdb/value_stream.cpp b/src/lmdb/value_stream.cpp new file mode 100644 index 000000000..1024deb06 --- /dev/null +++ b/src/lmdb/value_stream.cpp @@ -0,0 +1,74 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#include "value_stream.h" + +#include <stdexcept> + +#include "common/expect.h" +#include "lmdb/error.h" +#include "lmdb/util.h" + +namespace lmdb +{ + namespace stream + { + std::size_t count(MDB_cursor* cur) + { + std::size_t out = 0; + if (cur) + { + const int rc = mdb_cursor_count(cur, &out); + if (rc) + MONERO_THROW(lmdb::error(rc), "mdb_cursor_count"); + } + return out; + } + + std::pair<epee::span<const std::uint8_t>, epee::span<const std::uint8_t>> + get(MDB_cursor& cur, MDB_cursor_op op, std::size_t key, std::size_t value) + { + MDB_val key_bytes{}; + MDB_val value_bytes{}; + const int rc = mdb_cursor_get(&cur, &key_bytes, &value_bytes, op); + if (rc) + { + if (rc == MDB_NOTFOUND) + return {}; + MONERO_THROW(lmdb::error(rc), "mdb_cursor_get"); + } + + if (key && key != key_bytes.mv_size) + MONERO_THROW(lmdb::error(MDB_BAD_VALSIZE), "mdb_cursor_get key"); + + if (value && (value_bytes.mv_size % value != 0 || value_bytes.mv_size == 0)) + MONERO_THROW(lmdb::error(MDB_BAD_VALSIZE), "mdb_cursor_get value"); + + return {lmdb::to_byte_span(key_bytes), lmdb::to_byte_span(value_bytes)}; + } + } +} + diff --git a/src/lmdb/value_stream.h b/src/lmdb/value_stream.h new file mode 100644 index 000000000..c9977221f --- /dev/null +++ b/src/lmdb/value_stream.h @@ -0,0 +1,287 @@ +// Copyright (c) 2018, The Monero Project +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without modification, are +// permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this list of +// conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, this list +// of conditions and the following disclaimer in the documentation and/or other +// materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its contributors may be +// used to endorse or promote products derived from this software without specific +// prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY +// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#pragma once + +#include <boost/range/iterator_range.hpp> +#include <cstdint> +#include <cstring> +#include <iterator> +#include <lmdb.h> +#include <utility> + +#include "span.h" + +namespace lmdb +{ + namespace stream + { + /* + \throw std::system_error if unexpected LMDB error. + \return 0 if `cur == nullptr`, otherwise count of values at current key. + */ + std::size_t count(MDB_cursor* cur); + + /*! + Calls `mdb_cursor_get` and does some error checking. + + \param cur is given to `mdb_cursor_get` without modification. + \param op is passed to `mdb_cursor_get` without modification. + \param key expected key size or 0 to skip key size check. + \param value expected value size or 0 to skip value size check. + + \throw std::system_error if `key != 0` and `key_.mv_size != key`. + \throw std::system_error if `value != 0` and `value_.mv_size != value`. + \throw std::system_error if `mdb_cursor_get` returns any error + other than `MDB_NOTFOUND`. + + \return {key bytes, value bytes} or two empty spans if `MDB_NOTFOUND`. + */ + std::pair<epee::span<const std::uint8_t>, epee::span<const std::uint8_t>> + get(MDB_cursor& cur, MDB_cursor_op op, std::size_t key, std::size_t value); + } + + /*! + An InputIterator for a fixed-sized LMDB value at a specific key. + + \tparam T The value type at the specific key. + \tparam F The value type being returned when dereferenced. + \tparam offset to `F` within `T`. + + \note This meets requirements for an InputIterator only. The iterator + can only be incremented and dereferenced. All copies of an iterator + share the same LMDB cursor, and therefore incrementing any copy will + change the cursor state for all (incrementing an iterator will + invalidate all prior copies of the iterator). Usage is identical + to `std::istream_iterator`. + */ + template<typename T, typename F = T, std::size_t offset = 0> + class value_iterator + { + MDB_cursor* cur; + epee::span<const std::uint8_t> values; + + void increment() + { + values.remove_prefix(sizeof(T)); + if (values.empty() && cur) + values = lmdb::stream::get(*cur, MDB_NEXT_DUP, 0, sizeof(T)).second; + } + + public: + using value_type = F; + using reference = value_type; + using pointer = void; + using difference_type = std::size_t; + using iterator_category = std::input_iterator_tag; + + //! Construct an "end" iterator. + value_iterator() noexcept + : cur(nullptr), values() + {} + + /*! + \param cur Iterate over values starting at this cursor position. + \throw std::system_error if unexpected LMDB error. This can happen + if `cur` is invalid. + */ + value_iterator(MDB_cursor* cur) + : cur(cur), values() + { + if (cur) + values = lmdb::stream::get(*cur, MDB_GET_CURRENT, 0, sizeof(T)).second; + } + + value_iterator(value_iterator const&) = default; + ~value_iterator() = default; + value_iterator& operator=(value_iterator const&) = default; + + //! \return True if `this` is one-past the last value. + bool is_end() const noexcept { return values.empty(); } + + //! \return True iff `rhs` is referencing `this` value. + bool equal(value_iterator const& rhs) const noexcept + { + return + (values.empty() && rhs.values.empty()) || + values.data() == rhs.values.data(); + } + + //! Invalidates all prior copies of the iterator. + value_iterator& operator++() + { + increment(); + return *this; + } + + //! \return A copy that is already invalidated, ignore + value_iterator operator++(int) + { + value_iterator out{*this}; + increment(); + return out; + } + + /*! + Get a specific field within `F`. Default behavior is to return + the entirety of `U`, despite the filtering logic of `operator*`. + + \pre `!is_end()` + + \tparam U must match `T`, used for `MONERO_FIELD` sanity checking. + \tparam G field type to extract from the value + \tparam uoffset to `G` type, or `0` when `std::is_same<U, G>()`. + + \return The field `G`, at `uoffset` within `U`. + */ + template<typename U, typename G = U, std::size_t uoffset = 0> + G get_value() const noexcept + { + static_assert(std::is_same<U, T>(), "bad MONERO_FIELD usage?"); + static_assert(std::is_pod<U>(), "value type must be pod"); + static_assert(std::is_pod<G>(), "field type must be pod"); + static_assert(sizeof(G) + uoffset <= sizeof(U), "bad field and/or offset"); + assert(sizeof(G) + uoffset <= values.size()); + assert(!is_end()); + + G value; + std::memcpy(std::addressof(value), values.data() + uoffset, sizeof(value)); + return value; + } + + //! \pre `!is_end()` \return The field `F`, at `offset`, within `T`. + value_type operator*() const noexcept { return get_value<T, F, offset>(); } + }; + + /*! + C++ wrapper for a LMDB read-only cursor on a fixed-sized value `T`. + + \tparam T value type being stored by each record. + \tparam D cleanup functor for the cursor; usually unique per db/table. + */ + template<typename T, typename D> + class value_stream + { + std::unique_ptr<MDB_cursor, D> cur; + public: + + //! Take ownership of `cur` without changing position. `nullptr` valid. + explicit value_stream(std::unique_ptr<MDB_cursor, D> cur) + : cur(std::move(cur)) + {} + + value_stream(value_stream&&) = default; + value_stream(value_stream const&) = delete; + ~value_stream() = default; + value_stream& operator=(value_stream&&) = default; + value_stream& operator=(value_stream const&) = delete; + + /*! + Give up ownership of the cursor. `count()`, `make_iterator()` and + `make_range()` can still be invoked, but return the empty set. + + \return Currently owned LMDB cursor. + */ + std::unique_ptr<MDB_cursor, D> give_cursor() noexcept + { + return {std::move(cur)}; + } + + /*! + Place the stream back at the first value. Newly created iterators + will start at the first value again. + + \note Invalidates all current iterators from `this`, including + those created with `make_iterator` or `make_range`. + */ + void reset() + { + if (cur) + lmdb::stream::get(*cur, MDB_FIRST_DUP, 0, 0); + } + + /*! + \throw std::system_error if LMDB has unexpected errors. + \return Number of values at this key. + */ + std::size_t count() const + { + return lmdb::stream::count(cur.get()); + } + + /*! + Return a C++ iterator over database values from current cursor + position that will reach `.is_end()` after the last duplicate key + record. Calling `make_iterator()` will return an iterator whose + `operator*` will return entire value (`T`). + `make_iterator<MONERO_FIELD(account, id)>()` will return an + iterator whose `operator*` will return a `decltype(account.id)` + object - the other fields in the struct `account` are never copied + from the database. + + \throw std::system_error if LMDB has unexpected errors. + \return C++ iterator starting at current cursor position. + */ + template<typename U = T, typename F = U, std::size_t offset = 0> + value_iterator<U, F, offset> make_iterator() const + { + static_assert(std::is_same<U, T>(), "was MONERO_FIELD used with wrong type?"); + return {cur.get()}; + } + + /*! + Return a range from current cursor position until last duplicate + key record. Useful in for-each range loops or in templated code + expecting a range of elements. Calling `make_range()` will return + a range of `T` objects. `make_range<MONERO_FIELD(account, id)>()` + will return a range of `decltype(account.id)` objects - the other + fields in the struct `account` are never copied from the database. + + \throw std::system_error if LMDB has unexpected errors. + \return An InputIterator range over values at cursor position. + */ + template<typename U = T, typename F = U, std::size_t offset = 0> + boost::iterator_range<value_iterator<U, F, offset>> make_range() const + { + return {make_iterator<U, F, offset>(), value_iterator<U, F, offset>{}}; + } + }; + + template<typename T, typename F, std::size_t offset> + inline + bool operator==(value_iterator<T, F, offset> const& lhs, value_iterator<T, F, offset> const& rhs) noexcept + { + return lhs.equal(rhs); + } + + template<typename T, typename F, std::size_t offset> + inline + bool operator!=(value_iterator<T, F, offset> const& lhs, value_iterator<T, F, offset> const& rhs) noexcept + { + return !lhs.equal(rhs); + } +} // lmdb + |