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author | John Firebaugh <john.firebaugh@gmail.com> | 2018-05-08 10:40:35 -0700 |
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committer | John Firebaugh <john.firebaugh@gmail.com> | 2018-05-09 07:32:16 -0700 |
commit | a1195f6a9dc57910f7c3e6c9217e3041929a01fb (patch) | |
tree | 850834874e2d77a4cd89b92853d441020b2d8b43 /platform/qt | |
parent | d1dff1d6e782bc6e9d7a7df27e566bf1f1cf862b (diff) | |
download | qtlocation-mapboxgl-a1195f6a9dc57910f7c3e6c9217e3041929a01fb.tar.gz |
Avoid exceptions for flow control during database creation
Unfortuntely, it's difficult to avoid all exceptions, because sqlite3_open_v2 does not reliably return SQLITE_NOTADB if the file is not a database. However, this should avoid cases where developers misinterpret the SQLITE_CANTOPEN exception as a crash, which is the common case.
Diffstat (limited to 'platform/qt')
-rw-r--r-- | platform/qt/src/sqlite3.cpp | 85 |
1 files changed, 47 insertions, 38 deletions
diff --git a/platform/qt/src/sqlite3.cpp b/platform/qt/src/sqlite3.cpp index 4bcaea0e31..351991f881 100644 --- a/platform/qt/src/sqlite3.cpp +++ b/platform/qt/src/sqlite3.cpp @@ -52,15 +52,6 @@ void checkDatabaseError(const QSqlDatabase &db) { } } -void checkDatabaseOpenError(const QSqlDatabase &db) { - // Assume every error when opening the data as CANTOPEN. Qt - // always returns -1 for `nativeErrorCode()` on database errors. - QSqlError lastError = db.lastError(); - if (lastError.type() != QSqlError::NoError) { - throw Exception { ResultCode::CantOpen, "Error opening the database." }; - } -} - namespace { QString incrementCounter() { static QAtomicInt count = 0; @@ -70,32 +61,9 @@ namespace { class DatabaseImpl { public: - DatabaseImpl(const char* filename, int flags) - : connectionName(QString::number(uint64_t(QThread::currentThread())) + incrementCounter()) + DatabaseImpl(QString connectionName_) + : connectionName(std::move(connectionName_)) { - if (!QSqlDatabase::drivers().contains("QSQLITE")) { - throw Exception { ResultCode::CantOpen, "SQLite driver not found." }; - } - - assert(!QSqlDatabase::contains(connectionName)); - auto db = QSqlDatabase::addDatabase("QSQLITE", connectionName); - - QString connectOptions = db.connectOptions(); - if (flags & OpenFlag::ReadOnly) { - if (!connectOptions.isEmpty()) connectOptions.append(';'); - connectOptions.append("QSQLITE_OPEN_READONLY"); - } - if (flags & OpenFlag::SharedCache) { - if (!connectOptions.isEmpty()) connectOptions.append(';'); - connectOptions.append("QSQLITE_ENABLE_SHARED_CACHE"); - } - - db.setConnectOptions(connectOptions); - db.setDatabaseName(QString(filename)); - - if (!db.open()) { - checkDatabaseOpenError(db); - } } ~DatabaseImpl() { @@ -127,12 +95,51 @@ public: template <typename T> using optional = std::experimental::optional<T>; +mapbox::util::variant<Database, Exception> Database::tryOpen(const std::string &filename, int flags) { + if (!QSqlDatabase::drivers().contains("QSQLITE")) { + return Exception { ResultCode::CantOpen, "SQLite driver not found." }; + } -Database::Database(const std::string& file, int flags) - : impl(std::make_unique<DatabaseImpl>(file.c_str(), flags)) { - assert(impl); + QString connectionName = QString::number(uint64_t(QThread::currentThread())) + incrementCounter(); + + assert(!QSqlDatabase::contains(connectionName)); + auto db = QSqlDatabase::addDatabase("QSQLITE", connectionName); + + QString connectOptions = db.connectOptions(); + if (flags & OpenFlag::ReadOnly) { + if (!connectOptions.isEmpty()) connectOptions.append(';'); + connectOptions.append("QSQLITE_OPEN_READONLY"); + } + if (flags & OpenFlag::SharedCache) { + if (!connectOptions.isEmpty()) connectOptions.append(';'); + connectOptions.append("QSQLITE_ENABLE_SHARED_CACHE"); + } + + db.setConnectOptions(connectOptions); + db.setDatabaseName(QString(filename.c_str())); + + if (!db.open()) { + // Assume every error when opening the data as CANTOPEN. Qt + // always returns -1 for `nativeErrorCode()` on database errors. + return Exception { ResultCode::CantOpen, "Error opening the database." }; + } + + return Database(std::make_unique<DatabaseImpl>(connectionName)); +} + +Database Database::open(const std::string &filename, int flags) { + auto result = tryOpen(filename, flags); + if (result.is<Exception>()) { + throw result.get<Exception>(); + } else { + return std::move(result.get<Database>()); + } } +Database::Database(std::unique_ptr<DatabaseImpl> impl_) + : impl(std::move(impl_)) +{} + Database::Database(Database &&other) : impl(std::move(other.impl)) { assert(impl); @@ -165,7 +172,9 @@ void Database::setBusyTimeout(std::chrono::milliseconds timeout) { } db.setConnectOptions(connectOptions); if (!db.open()) { - checkDatabaseOpenError(db); + // Assume every error when opening the data as CANTOPEN. Qt + // always returns -1 for `nativeErrorCode()` on database errors. + throw Exception { ResultCode::CantOpen, "Error opening the database." }; } } |