Improve View and ViewRegistry interfaces

Signed-off-by: Alejandro García Montoro <alejandro.garciamontoro@gmail.com>

Author: agarciamontoro

sql/analyzer/resolve_tables.go

@@ -55,7 +55,7 @@ func resolveTables(ctx *sql.Context, a *Analyzer, n sql.Node) (sql.Node, error)
 
 			if view, err := a.Catalog.ViewRegistry.View(db, name); err == nil {
 				a.Log("table %q is a view: replacing plans", t.Name())
-				return view.Definition, nil
+				return view.Definition(), nil
 			}
 		}
 

sql/analyzer/resolve_tables_test.go

@@ -110,7 +110,7 @@ func TestResolveViews(t *testing.T) {
 		plan.NewResolvedTable(table),
 	)
 	subqueryAlias := plan.NewSubqueryAlias("myview", subquery)
-	view := sql.View{"myview", subqueryAlias}
+	view := sql.NewView("myview", subqueryAlias)
 
 	catalog := sql.NewCatalog()
 	catalog.AddDatabase(db)

sql/parse/views.go

@@ -15,7 +15,7 @@ var ErrMalformedViewName = errors.NewKind("the view name '%s' is not correct")
 var ErrMalformedCreateView = errors.NewKind("view definition %#v is not a SELECT query")
 
 // Parses
-// CREATE [OR REPLACE] VIEW [db_name.]view_name [(col1, col2, ...)] AS select_statement
+// CREATE [OR REPLACE] VIEW [db_name.]view_name AS select_statement
 // and returns a NewCreateView node in case of success
 func parseCreateView(ctx *sql.Context, s string) (sql.Node, error) {
 	r := bufio.NewReader(strings.NewReader(s))

sql/plan/create_view.go

@@ -9,10 +9,10 @@ import (
 
 type CreateView struct {
 	UnaryNode
-	database sql.Database
-	Name     string
-	Columns  []string
-	Catalog  *sql.Catalog
+	database  sql.Database
+	Name      string
+	Columns   []string
+	Catalog   *sql.Catalog
 	IsReplace bool
 }
 
@@ -33,7 +33,13 @@ func NewCreateView(
 	}
 }
 
-// Children implements the Node interface.
+// View returns the view that will be created by this node
+func (create *CreateView) View() sql.View {
+	return sql.NewView(create.Name, create.Child)
+}
+
+// Children implements the Node interface. It returns the Child of the
+// CreateView node; i.e., the definition of the view that will be created.
 func (create *CreateView) Children() []sql.Node {
 	return []sql.Node{create.Child}
 }
@@ -46,10 +52,10 @@ func (create *CreateView) Resolved() bool {
 
 // RowIter implements the Node interface.
 func (create *CreateView) RowIter(ctx *sql.Context) (sql.RowIter, error) {
-	view := sql.View{create.Name, create.Child}
+	view := sql.NewView(create.Name, create.Child)
 
 	if create.IsReplace {
-		_ = create.Catalog.ViewRegistry.Delete(create.database.Name(), view.Name)
+		_ = create.Catalog.ViewRegistry.Delete(create.database.Name(), view.Name())
 	}
 
 	return sql.RowsToRowIter(), create.Catalog.ViewRegistry.Register(create.database.Name(), view)

sql/viewregistry.go

@@ -8,15 +8,33 @@ import (
 )
 
 var (
-	ErrExistingView = errors.NewKind("the view %s.%s already exists in the registry")
+	ErrExistingView    = errors.NewKind("the view %s.%s already exists in the registry")
 	ErrNonExistingView = errors.NewKind("the view %s.%s does not exist in the registry")
 )
 
+// A View is defined by a Node and has a name
 type View struct {
-	Name       string
-	Definition Node
+	name       string
+	definition Node
 }
 
+// Creates a View with the specified name and definition
+func NewView(name string, definition Node) View {
+	return View{name, definition}
+}
+
+// Returns the name of the view
+func (view *View) Name() string {
+	return view.name
+}
+
+// Returns the definition of the view
+func (view *View) Definition() Node {
+	return view.definition
+}
+
+// Views are scoped by the databases in which they were defined, so a key in
+// the view registry is a pair of names: database and view
 type viewKey struct {
 	dbName, viewName string
 }
@@ -41,10 +59,10 @@ func (registry *ViewRegistry) Register(database string, view View) error {
 	registry.mutex.Lock()
 	defer registry.mutex.Unlock()
 
-	key := newViewKey(database, view.Name)
+	key := newViewKey(database, view.Name())
 
 	if _, ok := registry.views[key]; ok {
-		return ErrExistingView.New(database, view.Name)
+		return ErrExistingView.New(database, view.Name())
 	}
 
 	registry.views[key] = view
@@ -54,6 +72,9 @@ func (registry *ViewRegistry) Register(database string, view View) error {
 // Deletes the view specified by the pair {databaseName, viewName}, returning
 // an error if it does not exist
 func (registry *ViewRegistry) Delete(databaseName, viewName string) error {
+	registry.mutex.Lock()
+	defer registry.mutex.Unlock()
+
 	key := newViewKey(databaseName, viewName)
 
 	if _, ok := registry.views[key]; !ok {
@@ -77,6 +98,15 @@ func (registry *ViewRegistry) View(databaseName, viewName string) (*View, error)
 	return nil, ErrNonExistingView.New(databaseName, viewName)
 }
 
+// Returns the map of all views in the registry
+func (registry *ViewRegistry) AllViews() map[viewKey]View {
+	registry.mutex.RLock()
+	defer registry.mutex.RUnlock()
+
+	return registry.views
+}
+
+// Returns an array of all the views registered under the specified database
 func (registry *ViewRegistry) ViewsInDatabase(databaseName string) (views []View) {
 	registry.mutex.RLock()
 	defer registry.mutex.RUnlock()