Add Finalize method to go2idl Generator interface

cmd/libs/go2idl/generator/default_generator.go

@@ -50,6 +50,7 @@ func (d DefaultGen) PackageConsts(*Context) []string                     { retur
 func (d DefaultGen) GenerateType(*Context, *types.Type, io.Writer) error { return nil }
 func (d DefaultGen) Filename() string                                    { return d.OptionalName + ".go" }
 func (d DefaultGen) FileType() string                                    { return GolangFileType }
+func (d DefaultGen) Finalize(*Context, io.Writer) error                  { return nil }
 
 func (d DefaultGen) Init(c *Context, w io.Writer) error {
 	_, err := w.Write(d.OptionalBody)

cmd/libs/go2idl/generator/execute.go

@@ -302,5 +302,8 @@ func (c *Context) executeBody(w io.Writer, generator Generator) error {
 			return err
 		}
 	}
+	if err := generator.Finalize(c, et); err != nil {
+		return err
+	}
 	return et.Error()
 }

cmd/libs/go2idl/generator/generator.go

@@ -110,6 +110,11 @@ type Generator interface {
 	// Generators.)
 	Init(*Context, io.Writer) error
 
+	// Finalize should write finish up codes, and any other content that's not
+	// generated per-type. For example if you are generating one block (function,
+	// type, etc) for all types, this function can be used to close the block.
+	Finalize(*Context, io.Writer) error
+
 	// PackageVars should emit an array of variable lines. They will be
 	// placed in a var ( ... ) block. There's no need to include a leading
 	// \t or trailing \n.

cmd/libs/go2idl/import-boss/generators/import_restrict.go

@@ -252,6 +252,7 @@ func (r *importRules) GenerateType(*generator.Context, *types.Type, io.Writer) e
 func (r *importRules) Filename() string                                              { return ".import-restrictions" }
 func (r *importRules) FileType() string                                              { return importBossFileType }
 func (r *importRules) Init(c *generator.Context, w io.Writer) error                  { return nil }
+func (r *importRules) Finalize(c *generator.Context, w io.Writer) error              { return nil }
 
 func dfsImports(dest *[]string, seen map[string]bool, p *types.Package) {
 	for _, p2 := range p.Imports {