1// Copyright 2011 The Kyua Authors. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 9// notice, this list of conditions and the following disclaimer. 10// * Redistributions in binary form must reproduce the above copyright 11// notice, this list of conditions and the following disclaimer in the 12// documentation and/or other materials provided with the distribution. 13// * Neither the name of Google Inc. nor the names of its contributors 14// may be used to endorse or promote products derived from this software 15// without specific prior written permission. 16// 17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29#include "store/read_backend.hpp" 30 31#include "store/exceptions.hpp" 32#include "store/metadata.hpp" 33#include "store/read_transaction.hpp" 34#include "store/write_backend.hpp" 35#include "utils/format/macros.hpp" 36#include "utils/fs/path.hpp" 37#include "utils/noncopyable.hpp" 38#include "utils/sqlite/database.hpp" 39#include "utils/sqlite/exceptions.hpp" 40 41namespace fs = utils::fs; 42namespace sqlite = utils::sqlite; 43 44 45/// Opens a database and defines session pragmas. 46/// 47/// This auxiliary function ensures that, every time we open a SQLite database, 48/// we define the same set of pragmas for it. 49/// 50/// \param file The database file to be opened. 51/// \param flags The flags for the open; see sqlite::database::open. 52/// 53/// \return The opened database. 54/// 55/// \throw store::error If there is a problem opening or creating the database. 56sqlite::database 57store::detail::open_and_setup(const fs::path& file, const int flags) 58{ 59 try { 60 sqlite::database database = sqlite::database::open(file, flags); 61 database.exec("PRAGMA foreign_keys = ON"); 62 return database; 63 } catch (const sqlite::error& e) { 64 throw store::error(F("Cannot open '%s': %s") % file % e.what()); 65 } 66} 67 68 69/// Internal implementation for the backend. 70struct store::read_backend::impl : utils::noncopyable { 71 /// The SQLite database this backend talks to. 72 sqlite::database database; 73 74 /// Constructor. 75 /// 76 /// \param database_ The SQLite database instance. 77 /// \param metadata_ The metadata for the loaded database. This must match 78 /// the schema version we implement in this module; otherwise, a 79 /// migration is necessary. 80 /// 81 /// \throw integrity_error If the schema in the database is too modern, 82 /// which might indicate some form of corruption or an old binary. 83 /// \throw old_schema_error If the schema in the database is older than our 84 /// currently-implemented version and needs an upgrade. The caller can 85 /// use migrate_schema() to fix this problem. 86 impl(sqlite::database& database_, const metadata& metadata_) : 87 database(database_) 88 { 89 const int database_version = metadata_.schema_version(); 90 91 if (database_version == detail::current_schema_version) { 92 // OK. 93 } else if (database_version < detail::current_schema_version) { 94 throw old_schema_error(database_version); 95 } else if (database_version > detail::current_schema_version) { 96 throw integrity_error( 97 F("Database at schema version %s, which is newer than the " 98 "supported version %s") 99 % database_version % detail::current_schema_version); 100 } 101 } 102}; 103 104 105/// Constructs a new backend. 106/// 107/// \param pimpl_ The internal data. 108store::read_backend::read_backend(impl* pimpl_) : 109 _pimpl(pimpl_) 110{ 111} 112 113 114/// Destructor. 115store::read_backend::~read_backend(void) 116{ 117} 118 119 120/// Opens a database in read-only mode. 121/// 122/// \param file The database file to be opened. 123/// 124/// \return The backend representation. 125/// 126/// \throw store::error If there is any problem opening the database. 127store::read_backend 128store::read_backend::open_ro(const fs::path& file) 129{ 130 sqlite::database db = detail::open_and_setup(file, sqlite::open_readonly); 131 return read_backend(new impl(db, metadata::fetch_latest(db))); 132} 133 134 135/// Closes the SQLite database. 136void 137store::read_backend::close(void) 138{ 139 _pimpl->database.close(); 140} 141 142 143/// Gets the connection to the SQLite database. 144/// 145/// \return A database connection. 146sqlite::database& 147store::read_backend::database(void) 148{ 149 return _pimpl->database; 150} 151 152 153/// Opens a read-only transaction. 154/// 155/// \return A new transaction. 156store::read_transaction 157store::read_backend::start_read(void) 158{ 159 return read_transaction(*this); 160} 161