LibSQL+SQLServer: Return a NonnullRefPtr from Database::get_table

Database::get_table currently either returns a RefPtr to an existing
table, a nullptr if the table doesn't exist, or an Error if some
internal error occured. Change this to return a NonnullRefPtr to an
exisiting table, or a SQL::Result with any error, including if the
table was not found. Callers can then handle that specific error code
if they want.

Returning a NonnullRefPtr will enable some further cleanup. This had
some fallout of needing to change some other methods' return types from
AK::ErrorOr to SQL::Result so that TRY may continue to be used.

Tests/LibSQL/TestSqlDatabase.cpp

@@ -44,10 +44,7 @@ NonnullRefPtr<SQL::TableDef> setup_table(SQL::Database& db)
 
 void insert_into_table(SQL::Database& db, int count)
 {
-    auto table_or_error = db.get_table("TestSchema", "TestTable");
-    EXPECT(!table_or_error.is_error());
-    auto table = table_or_error.value();
-    EXPECT(table);
+    auto table = MUST(db.get_table("TestSchema", "TestTable"));
 
     for (int ix = 0; ix < count; ix++) {
         SQL::Row row(*table);
@@ -63,10 +60,7 @@ void insert_into_table(SQL::Database& db, int count)
 
 void verify_table_contents(SQL::Database& db, int expected_count)
 {
-    auto table_or_error = db.get_table("TestSchema", "TestTable");
-    EXPECT(!table_or_error.is_error());
-    auto table = table_or_error.value();
-    EXPECT(table);
+    auto table = MUST(db.get_table("TestSchema", "TestTable"));
 
     int sum = 0;
     int count = 0;
@@ -196,10 +190,8 @@ TEST_CASE(get_table_from_database)
     {
         auto db = SQL::Database::construct("/tmp/test.db");
         EXPECT(!db->open().is_error());
-        auto table_or_error = db->get_table("TestSchema", "TestTable");
-        EXPECT(!table_or_error.is_error());
-        auto table = table_or_error.value();
-        EXPECT(table);
+
+        auto table = MUST(db->get_table("TestSchema", "TestTable"));
         EXPECT_EQ(table->name(), "TestTable");
         EXPECT_EQ(table->num_columns(), 2u);
     }

Tests/LibSQL/TestSqlStatementExecution.cpp

@@ -81,7 +81,6 @@ TEST_CASE(create_table)
     create_table(database);
     auto table_or_error = database->get_table("TESTSCHEMA", "TESTTABLE");
     EXPECT(!table_or_error.is_error());
-    EXPECT(table_or_error.value());
 }
 
 TEST_CASE(insert_into_table)
@@ -93,9 +92,7 @@ TEST_CASE(insert_into_table)
     auto result = execute(database, "INSERT INTO TestSchema.TestTable ( TextColumn, IntColumn ) VALUES ( 'Test', 42 );");
     EXPECT(result.size() == 1);
 
-    auto table_or_error = database->get_table("TESTSCHEMA", "TESTTABLE");
-    EXPECT(!table_or_error.is_error());
-    auto table = table_or_error.value();
+    auto table = MUST(database->get_table("TESTSCHEMA", "TESTTABLE"));
 
     int count = 0;
     auto rows_or_error = database->select_all(*table);
@@ -172,9 +169,8 @@ TEST_CASE(insert_without_column_names)
     auto result = execute(database, "INSERT INTO TestSchema.TestTable VALUES ('Test_1', 42), ('Test_2', 43);");
     EXPECT(result.size() == 2);
 
-    auto table_or_error = database->get_table("TESTSCHEMA", "TESTTABLE");
-    EXPECT(!table_or_error.is_error());
-    auto rows_or_error = database->select_all(*(table_or_error.value()));
+    auto table = MUST(database->get_table("TESTSCHEMA", "TESTTABLE"));
+    auto rows_or_error = database->select_all(*table);
     EXPECT(!rows_or_error.is_error());
     EXPECT_EQ(rows_or_error.value().size(), 2u);
 }

Userland/Libraries/LibSQL/AST/CreateTable.cpp

@@ -12,16 +12,9 @@ namespace SQL::AST {
 ResultOr<ResultSet> CreateTable::execute(ExecutionContext& context) const
 {
     auto schema_def = TRY(context.database->get_schema(m_schema_name));
-    auto table_def = TRY(context.database->get_table(m_schema_name, m_table_name));
-    if (table_def) {
-        if (m_is_error_if_table_exists)
-            return Result { SQLCommand::Create, SQLErrorCode::TableExists, m_table_name };
-        return ResultSet { SQLCommand::Create };
-    }
-
-    table_def = TableDef::construct(schema_def, m_table_name);
+    auto table_def = TableDef::construct(schema_def, m_table_name);
 
-    for (auto& column : m_columns) {
+    for (auto const& column : m_columns) {
         SQLType type;
 
         if (column.type_name()->name().is_one_of("VARCHAR"sv, "TEXT"sv))
@@ -38,7 +31,11 @@ ResultOr<ResultSet> CreateTable::execute(ExecutionContext& context) const
         table_def->append_column(column.name(), type);
     }
 
-    TRY(context.database->add_table(*table_def));
+    if (auto result = context.database->add_table(*table_def); result.is_error()) {
+        if (result.error().error() != SQLErrorCode::TableExists || m_is_error_if_table_exists)
+            return result.release_error();
+    }
+
     return ResultSet { SQLCommand::Create };
 }
 

Userland/Libraries/LibSQL/AST/Describe.cpp

@@ -14,15 +14,9 @@ namespace SQL::AST {
 
 ResultOr<ResultSet> DescribeTable::execute(ExecutionContext& context) const
 {
-    auto schema_name = m_qualified_table_name->schema_name();
-    auto table_name = m_qualified_table_name->table_name();
-
+    auto const& schema_name = m_qualified_table_name->schema_name();
+    auto const& table_name = m_qualified_table_name->table_name();
     auto table_def = TRY(context.database->get_table(schema_name, table_name));
-    if (!table_def) {
-        if (schema_name.is_empty())
-            schema_name = "default"sv;
-        return Result { SQLCommand::Describe, SQLErrorCode::TableDoesNotExist, String::formatted("{}.{}", schema_name, table_name) };
-    }
 
     auto describe_table_def = MUST(context.database->get_table("master"sv, "internal_describe_table"sv));
     auto descriptor = describe_table_def->to_tuple_descriptor();

Userland/Libraries/LibSQL/AST/Insert.cpp

@@ -25,11 +25,6 @@ ResultOr<ResultSet> Insert::execute(ExecutionContext& context) const
 {
     auto table_def = TRY(context.database->get_table(m_schema_name, m_table_name));
 
-    if (!table_def) {
-        auto schema_name = m_schema_name.is_empty() ? String("default"sv) : m_schema_name;
-        return Result { SQLCommand::Insert, SQLErrorCode::TableDoesNotExist, String::formatted("{}.{}", schema_name, m_table_name) };
-    }
-
     Row row(table_def);
     for (auto& column : m_column_names) {
         if (!row.has(column))

Userland/Libraries/LibSQL/AST/Select.cpp

@@ -24,8 +24,6 @@ ResultOr<ResultSet> Select::execute(ExecutionContext& context) const
             return Result { SQLCommand::Select, SQLErrorCode::NotYetImplemented, "Sub-selects are not yet implemented"sv };
 
         auto table_def = TRY(context.database->get_table(table_descriptor.schema_name(), table_descriptor.table_name()));
-        if (!table_def)
-            return Result { SQLCommand::Select, SQLErrorCode::TableDoesNotExist, table_descriptor.table_name() };
 
         if (result_column_list.size() == 1 && result_column_list[0].type() == ResultType::All) {
             for (auto& col : table_def->columns()) {

Userland/Libraries/LibSQL/Database.cpp

@@ -61,12 +61,14 @@ ResultOr<void> Database::open()
     (void)TRY(ensure_schema_exists("default"sv));
     auto master_schema = TRY(ensure_schema_exists("master"sv));
 
-    auto table_def = TRY(get_table("master", "internal_describe_table"));
-    if (!table_def) {
-        auto describe_internal_table = TableDef::construct(master_schema, "internal_describe_table");
-        describe_internal_table->append_column("Name", SQLType::Text);
-        describe_internal_table->append_column("Type", SQLType::Text);
-        TRY(add_table(*describe_internal_table));
+    if (auto result = get_table("master"sv, "internal_describe_table"sv); result.is_error()) {
+        if (result.error().error() != SQLErrorCode::TableDoesNotExist)
+            return result.release_error();
+
+        auto internal_describe_table = TableDef::construct(master_schema, "internal_describe_table");
+        internal_describe_table->append_column("Name", SQLType::Text);
+        internal_describe_table->append_column("Type", SQLType::Text);
+        TRY(add_table(*internal_describe_table));
     }
 
     return {};
@@ -118,16 +120,18 @@ ResultOr<NonnullRefPtr<SchemaDef>> Database::get_schema(String const& schema)
     return schema_def;
 }
 
-ErrorOr<void> Database::add_table(TableDef& table)
+ResultOr<void> Database::add_table(TableDef& table)
 {
     VERIFY(is_open());
-    if (!m_tables->insert(table.key())) {
-        warnln("Duplicate table name '{}'.'{}'"sv, table.parent()->name(), table.name());
-        return Error::from_string_literal("Duplicate table name");
-    }
+
+    if (!m_tables->insert(table.key()))
+        return Result { SQLCommand::Unknown, SQLErrorCode::TableExists, table.name() };
+
     for (auto& column : table.columns()) {
-        VERIFY(m_table_columns->insert(column.key()));
+        if (!m_table_columns->insert(column.key()))
+            VERIFY_NOT_REACHED();
     }
+
     return {};
 }
 
@@ -138,32 +142,33 @@ Key Database::get_table_key(String const& schema_name, String const& table_name)
     return key;
 }
 
-ResultOr<RefPtr<TableDef>> Database::get_table(String const& schema, String const& name)
+ResultOr<NonnullRefPtr<TableDef>> Database::get_table(String const& schema, String const& name)
 {
     VERIFY(is_open());
+
     auto schema_name = schema;
-    if (schema.is_null() || schema.is_empty())
-        schema_name = "default";
+    if (schema.is_empty())
+        schema_name = "default"sv;
+
     Key key = get_table_key(schema_name, name);
-    auto table_def_opt = m_table_cache.get(key.hash());
-    if (table_def_opt.has_value())
-        return RefPtr<TableDef>(table_def_opt.value());
+    if (auto it = m_table_cache.find(key.hash()); it != m_table_cache.end())
+        return it->value;
+
     auto table_iterator = m_tables->find(key);
-    if (table_iterator.is_end() || (*table_iterator != key)) {
-        return RefPtr<TableDef>(nullptr);
-    }
+    if (table_iterator.is_end() || (*table_iterator != key))
+        return Result { SQLCommand::Unknown, SQLErrorCode::TableDoesNotExist, String::formatted("{}.{}", schema_name, name) };
+
     auto schema_def = TRY(get_schema(schema));
-    auto ret = TableDef::construct(schema_def, name);
-    ret->set_pointer((*table_iterator).pointer());
-    m_table_cache.set(key.hash(), ret);
-    auto hash = ret->hash();
-    auto column_key = ColumnDef::make_key(ret);
-    for (auto column_iterator = m_table_columns->find(column_key);
-         !column_iterator.is_end() && ((*column_iterator)["table_hash"].to_u32().value() == hash);
-         column_iterator++) {
-        ret->append_column(*column_iterator);
-    }
-    return RefPtr<TableDef>(ret);
+    auto table_def = TableDef::construct(schema_def, name);
+    table_def->set_pointer((*table_iterator).pointer());
+    m_table_cache.set(key.hash(), table_def);
+
+    auto table_hash = table_def->hash();
+    auto column_key = ColumnDef::make_key(table_def);
+    for (auto it = m_table_columns->find(column_key); !it.is_end() && ((*it)["table_hash"].to_u32().value() == table_hash); ++it)
+        table_def->append_column(*it);
+
+    return table_def;
 }
 
 ErrorOr<Vector<Row>> Database::select_all(TableDef const& table)

Userland/Libraries/LibSQL/Database.h

@@ -37,9 +37,9 @@ public:
     static Key get_schema_key(String const&);
     ResultOr<NonnullRefPtr<SchemaDef>> get_schema(String const&);
 
-    ErrorOr<void> add_table(TableDef& table);
+    ResultOr<void> add_table(TableDef& table);
     static Key get_table_key(String const&, String const&);
-    ResultOr<RefPtr<TableDef>> get_table(String const&, String const&);
+    ResultOr<NonnullRefPtr<TableDef>> get_table(String const&, String const&);
 
     ErrorOr<Vector<Row>> select_all(TableDef const&);
     ErrorOr<Vector<Row>> match(TableDef const&, Key const&);
@@ -57,7 +57,7 @@ private:
     RefPtr<BTree> m_table_columns;
 
     HashMap<u32, NonnullRefPtr<SchemaDef>> m_schema_cache;
-    HashMap<u32, RefPtr<TableDef>> m_table_cache;
+    HashMap<u32, NonnullRefPtr<TableDef>> m_table_cache;
 };
 
 }