161 lines
5.2 KiB
C++
161 lines
5.2 KiB
C++
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// Copyright 2011 The Kyua Authors.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors
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// may be used to endorse or promote products derived from this software
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// without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "store/read_backend.hpp"
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#include "store/exceptions.hpp"
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#include "store/metadata.hpp"
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#include "store/read_transaction.hpp"
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#include "store/write_backend.hpp"
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#include "utils/format/macros.hpp"
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#include "utils/fs/path.hpp"
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#include "utils/noncopyable.hpp"
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#include "utils/sqlite/database.hpp"
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#include "utils/sqlite/exceptions.hpp"
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namespace fs = utils::fs;
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namespace sqlite = utils::sqlite;
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/// Opens a database and defines session pragmas.
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///
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/// This auxiliary function ensures that, every time we open a SQLite database,
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/// we define the same set of pragmas for it.
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///
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/// \param file The database file to be opened.
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/// \param flags The flags for the open; see sqlite::database::open.
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///
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/// \return The opened database.
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///
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/// \throw store::error If there is a problem opening or creating the database.
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sqlite::database
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store::detail::open_and_setup(const fs::path& file, const int flags)
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{
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try {
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sqlite::database database = sqlite::database::open(file, flags);
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database.exec("PRAGMA foreign_keys = ON");
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return database;
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} catch (const sqlite::error& e) {
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throw store::error(F("Cannot open '%s': %s") % file % e.what());
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}
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}
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/// Internal implementation for the backend.
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struct store::read_backend::impl : utils::noncopyable {
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/// The SQLite database this backend talks to.
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sqlite::database database;
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/// Constructor.
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///
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/// \param database_ The SQLite database instance.
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/// \param metadata_ The metadata for the loaded database. This must match
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/// the schema version we implement in this module; otherwise, a
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/// migration is necessary.
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///
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/// \throw integrity_error If the schema in the database is too modern,
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/// which might indicate some form of corruption or an old binary.
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/// \throw old_schema_error If the schema in the database is older than our
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/// currently-implemented version and needs an upgrade. The caller can
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/// use migrate_schema() to fix this problem.
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impl(sqlite::database& database_, const metadata& metadata_) :
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database(database_)
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{
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const int database_version = metadata_.schema_version();
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if (database_version == detail::current_schema_version) {
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// OK.
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} else if (database_version < detail::current_schema_version) {
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throw old_schema_error(database_version);
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} else if (database_version > detail::current_schema_version) {
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throw integrity_error(
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F("Database at schema version %s, which is newer than the "
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"supported version %s")
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% database_version % detail::current_schema_version);
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}
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}
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};
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/// Constructs a new backend.
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///
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/// \param pimpl_ The internal data.
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store::read_backend::read_backend(impl* pimpl_) :
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_pimpl(pimpl_)
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{
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}
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/// Destructor.
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store::read_backend::~read_backend(void)
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{
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}
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/// Opens a database in read-only mode.
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///
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/// \param file The database file to be opened.
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///
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/// \return The backend representation.
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///
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/// \throw store::error If there is any problem opening the database.
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store::read_backend
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store::read_backend::open_ro(const fs::path& file)
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{
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sqlite::database db = detail::open_and_setup(file, sqlite::open_readonly);
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return read_backend(new impl(db, metadata::fetch_latest(db)));
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}
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/// Closes the SQLite database.
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void
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store::read_backend::close(void)
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{
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_pimpl->database.close();
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}
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/// Gets the connection to the SQLite database.
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///
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/// \return A database connection.
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sqlite::database&
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store::read_backend::database(void)
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{
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return _pimpl->database;
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}
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/// Opens a read-only transaction.
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///
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/// \return A new transaction.
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store::read_transaction
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store::read_backend::start_read(void)
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{
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return read_transaction(*this);
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}
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