wownero/src/lmdb/database.cpp

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// 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
{
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constexpr const mdb_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));
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const mdb_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