chore(embedded/sql): Add support for core pg_catalog tables (pg_class, pg_namespace, pg_roles)

Signed-off-by: Stefano Scafiti <stefano.scafiti96@gmail.com>

Author: ostafen

.gitignore

@@ -12,6 +12,9 @@
 *.out
 coverage.txt
 
+# Output of goyacc
+embedded/sql/y.output
+
 # Editor
 .vscode
 .idea
@@ -50,4 +53,4 @@ token_admin
 
 swagger/dist
 swagger/swaggerembedded
-webconsole/webconsoleembedded
+webconsole/webconsoleembedded

embedded/sql/engine.go

@@ -118,6 +118,7 @@ type Engine struct {
 	lazyIndexConstraintValidation bool
 	parseTxMetadata               func([]byte) (map[string]interface{}, error)
 	multidbHandler                MultiDBHandler
+	tableResolvers                map[string]TableResolver
 }
 
 type MultiDBHandler interface {
@@ -134,6 +135,11 @@ type MultiDBHandler interface {
 	ExecPreparedStmts(ctx context.Context, opts *TxOptions, stmts []SQLStmt, params map[string]interface{}) (ntx *SQLTx, committedTxs []*SQLTx, err error)
 }
 
+type TableResolver interface {
+	Table() string
+	Resolve(ctx context.Context, tx *SQLTx, alias string) (RowReader, error)
+}
+
 type User interface {
 	Username() string
 	Permission() Permission
@@ -176,6 +182,10 @@ func NewEngine(st *store.ImmuStore, opts *Options) (*Engine, error) {
 		return nil, err
 	}
 
+	for _, r := range opts.tableResolvers {
+		e.registerTableResolver(r.Table(), r)
+	}
+
 	// TODO: find a better way to handle parsing errors
 	yyErrorVerbose = true
 
@@ -728,3 +738,17 @@ func (e *Engine) GetStore() *store.ImmuStore {
 func (e *Engine) GetPrefix() []byte {
 	return e.prefix
 }
+
+func (e *Engine) tableResolveFor(tableName string) TableResolver {
+	if e.tableResolvers == nil {
+		return nil
+	}
+	return e.tableResolvers[tableName]
+}
+
+func (e *Engine) registerTableResolver(tableName string, r TableResolver) {
+	if e.tableResolvers == nil {
+		e.tableResolvers = make(map[string]TableResolver)
+	}
+	e.tableResolvers[tableName] = r
+}

embedded/sql/engine_test.go

@@ -4616,6 +4616,10 @@ func TestOrderBy(t *testing.T) {
 			directions:     []int{1, -1},
 			positionalRefs: []int{4, 5},
 		},
+		{
+			exps:       []string{"weight/(height*height)"},
+			directions: []int{1},
+		},
 	}
 
 	runTest := func(t *testing.T, test *test, expectedTempFiles int) []*Row {
@@ -9552,6 +9556,40 @@ func TestFunctions(t *testing.T) {
 	})
 }
 
+func TestTableResolver(t *testing.T) {
+	st, err := store.Open(t.TempDir(), store.DefaultOptions().WithMultiIndexing(true))
+	require.NoError(t, err)
+	defer closeStore(t, st)
+
+	r := &mockTableResolver{
+		name: "my_table",
+		cols: []ColDescriptor{
+			{Column: "varchar_col", Type: VarcharType},
+			{Column: "int_col", Type: IntegerType},
+			{Column: "bool_col", Type: BooleanType},
+		},
+		values: [][]ValueExp{{NewVarchar("test"), NewInteger(1), NewBool(true)}},
+	}
+
+	engine, err := NewEngine(
+		st,
+		DefaultOptions().
+			WithPrefix(sqlPrefix).
+			WithTableResolvers(r),
+	)
+	require.NoError(t, err)
+
+	assertQueryShouldProduceResults(
+		t,
+		engine,
+		"SELECT int_col, varchar_col, bool_col FROM my_table",
+		`SELECT * FROM (
+			VALUES
+				(1, 'test', true)
+		)`,
+	)
+}
+
 func assertQueryShouldProduceResults(t *testing.T, e *Engine, query, resultQuery string) {
 	queryReader, err := e.Query(context.Background(), nil, query, nil)
 	require.NoError(t, err)
@@ -9572,3 +9610,24 @@ func assertQueryShouldProduceResults(t *testing.T, e *Engine, query, resultQuery
 		require.Equal(t, expectedRow.ValuesByPosition, actualRow.ValuesByPosition)
 	}
 }
+
+type mockTableResolver struct {
+	name   string
+	cols   []ColDescriptor
+	values [][]ValueExp
+}
+
+func (r *mockTableResolver) Table() string {
+	return r.name
+}
+
+func (r *mockTableResolver) Resolve(ctx context.Context, tx *SQLTx, alias string) (RowReader, error) {
+	return NewValuesRowReader(
+		tx,
+		nil,
+		r.cols,
+		false,
+		r.name,
+		r.values,
+	)
+}