├── LICENSE ├── README.md ├── ast.go ├── ast_test.go └── testpkg ├── check.go ├── service1.go ├── service2.go └── uncheckedservice.go /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. Definitions. 8 | 9 | "License" shall mean the terms and conditions for use, reproduction, 10 | and distribution as defined by Sections 1 through 9 of this document. 11 | 12 | "Licensor" shall mean the copyright owner or entity authorized by 13 | the copyright owner that is granting the License. 14 | 15 | "Legal Entity" shall mean the union of the acting entity and all 16 | other entities that control, are controlled by, or are under common 17 | control with that entity. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright {yyyy} {name of copyright owner} 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | 203 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # go-astquery 2 | 3 | A simple library for querying the AST of a Go program. Good for writing quick, static checks to guarantee invariants in 4 | code. 5 | -------------------------------------------------------------------------------- /ast.go: -------------------------------------------------------------------------------- 1 | package astquery 2 | 3 | import ( 4 | "fmt" 5 | "go/ast" 6 | "reflect" 7 | "regexp" 8 | ) 9 | 10 | type Filter interface { 11 | Filter(node ast.Node) bool 12 | } 13 | 14 | // SetFilter matches nodes whose names are in the specified set of names. 15 | type SetFilter struct { 16 | // Names is a set of names that match the filter 17 | Names []string 18 | 19 | // Type is the type of AST node to filter for 20 | Type reflect.Type 21 | } 22 | 23 | func (f SetFilter) Filter(node ast.Node) bool { 24 | nodeName, exists := GetName(node) 25 | if !exists { 26 | return false 27 | } 28 | 29 | matched := false 30 | for _, name := range f.Names { 31 | if name == nodeName { 32 | matched = true 33 | break 34 | } 35 | } 36 | return reflect.TypeOf(node) == f.Type && matched 37 | } 38 | 39 | // RegexpFilter matches nodes whose names match a regular expression. 40 | type RegexpFilter struct { 41 | // Pattern is a regular expression matching AST node names 42 | Pattern *regexp.Regexp 43 | 44 | // Type is the type of AST node to filter for 45 | Type reflect.Type 46 | } 47 | 48 | func (s RegexpFilter) Filter(node ast.Node) bool { 49 | nodeName, exists := GetName(node) 50 | if !exists { 51 | return false 52 | } 53 | return reflect.TypeOf(node) == s.Type && s.Pattern.MatchString(nodeName) 54 | } 55 | 56 | // MethodFilter matches method declaration nodes that have the specified receiver type. 57 | type MethodFilter struct { 58 | // ReceiverType is the name of the receiver's type (without the '*' if a pointer). 59 | ReceiverType string 60 | 61 | // ExportedOnly is if the filter should select only exported methods. 62 | ExportedOnly bool 63 | } 64 | 65 | func (f MethodFilter) Filter(node ast.Node) bool { 66 | switch node := node.(type) { 67 | case *ast.FuncDecl: 68 | recv := node.Recv 69 | if recv == nil || len(recv.List) != 1 { 70 | return false // not a method 71 | } 72 | recvType, _ := typeName(recv.List[0].Type) 73 | if recvType != f.ReceiverType { 74 | return false // receiver doesn't match 75 | } 76 | if f.ExportedOnly && !node.Name.IsExported() { 77 | return false // not exported 78 | } 79 | return true 80 | default: 81 | return false 82 | } 83 | } 84 | 85 | // FilterFunc lets you specify a function for custom filtering logic. 86 | type FilterFunc func(node ast.Node) bool 87 | 88 | func (f FilterFunc) Filter(node ast.Node) bool { return f(node) } 89 | 90 | // Find recursively searches the AST nodes passed as the first argument and returns all 91 | // AST nodes that match the filter. It does not descend into matching nodes for additional 92 | // matching nodes. 93 | func Find(nodes []ast.Node, filter Filter) []ast.Node { 94 | var found []ast.Node 95 | for _, node := range nodes { 96 | found = append(found, find(node, filter)...) 97 | } 98 | return found 99 | } 100 | 101 | func find(node ast.Node, filter Filter) []ast.Node { 102 | var found []ast.Node 103 | ast.Walk(visitFunc(func(node ast.Node) bool { 104 | if filter.Filter(node) { 105 | found = append(found, node) 106 | return false 107 | } 108 | return true 109 | }), node) 110 | return found 111 | } 112 | 113 | // visitFunc is a wrapper for traversing nodes in the AST 114 | type visitFunc func(node ast.Node) (descend bool) 115 | 116 | func (v visitFunc) Visit(node ast.Node) ast.Visitor { 117 | descend := v(node) 118 | if descend { 119 | return v 120 | } else { 121 | return nil 122 | } 123 | } 124 | 125 | // GetName gets the name of a node's identifier. For TypeSpecs and FuncDecls, it looks at the .Name field. For 126 | // SelectorExpr's, it looks at the Sel field. 127 | func GetName(n ast.Node) (name string, exists bool) { 128 | var ident_ interface{} 129 | if idt, exists := getStructField(n, "Name"); exists { 130 | ident_ = idt 131 | } else if idt, exists := getStructField(n, "Sel"); exists { 132 | ident_ = idt 133 | } 134 | if ident_ == nil { 135 | return "", false 136 | } 137 | 138 | nodeName, isIdent := ident_.(*ast.Ident) 139 | if !isIdent { 140 | return "", false 141 | } 142 | return nodeName.Name, true 143 | } 144 | 145 | // getStructField returns the value of v's field with the given name 146 | // if it exists. v must be a struct or a pointer to a struct. 147 | func getStructField(v interface{}, field string) (fieldVal interface{}, exists bool) { 148 | vv := reflect.ValueOf(v) 149 | if !vv.IsValid() { 150 | return nil, false 151 | } 152 | if vv.Kind() == reflect.Ptr { 153 | vv = vv.Elem() 154 | } 155 | fv := vv.FieldByName(field) 156 | if !fv.IsValid() { 157 | return nil, false 158 | } 159 | return fv.Interface(), true 160 | } 161 | 162 | // typeName returns the name of the type referenced by typeExpr. 163 | func typeName(typeExpr ast.Expr) (string, error) { 164 | switch typeExpr := typeExpr.(type) { 165 | case *ast.StarExpr: 166 | return typeName(typeExpr.X) 167 | case *ast.Ident: 168 | return typeExpr.Name, nil 169 | default: 170 | return "", fmt.Errorf("expr %+v is not a type expression", typeExpr) 171 | } 172 | } 173 | -------------------------------------------------------------------------------- /ast_test.go: -------------------------------------------------------------------------------- 1 | package astquery 2 | 3 | import ( 4 | "go/ast" 5 | "go/build" 6 | "go/parser" 7 | "go/token" 8 | "reflect" 9 | "regexp" 10 | "testing" 11 | ) 12 | 13 | type nodeInfo struct { 14 | Name string 15 | Type reflect.Type 16 | } 17 | 18 | func TestSetFilter(t *testing.T) { 19 | servicePkg := getTestPkg(t) 20 | 21 | serviceTypes := Find([]ast.Node{servicePkg}, SetFilter{ 22 | Names: []string{"ServiceOne", "ServiceTwo"}, 23 | Type: reflect.TypeOf((*ast.TypeSpec)(nil)), 24 | }) 25 | expServiceTypes := []nodeInfo{ 26 | {Name: "ServiceOne", Type: reflect.TypeOf((*ast.TypeSpec)(nil))}, 27 | {Name: "ServiceTwo", Type: reflect.TypeOf((*ast.TypeSpec)(nil))}, 28 | } 29 | checkNodesExpected(t, expServiceTypes, serviceTypes) 30 | } 31 | 32 | func TestRegexpFilter(t *testing.T) { 33 | servicePkg := getTestPkg(t) 34 | 35 | serviceTypes := Find([]ast.Node{servicePkg}, RegexpFilter{ 36 | Pattern: regexp.MustCompile(`^Service[A-Za-z]*$`), 37 | Type: reflect.TypeOf((*ast.TypeSpec)(nil)), 38 | }) 39 | expServiceTypes := []nodeInfo{ 40 | {Name: "ServiceOne", Type: reflect.TypeOf((*ast.TypeSpec)(nil))}, 41 | {Name: "ServiceTwo", Type: reflect.TypeOf((*ast.TypeSpec)(nil))}, 42 | } 43 | checkNodesExpected(t, expServiceTypes, serviceTypes) 44 | } 45 | 46 | func TestNestedFilters(t *testing.T) { 47 | servicePkg := getTestPkg(t) 48 | 49 | type expMethodInfo struct { 50 | method nodeInfo 51 | calls []nodeInfo 52 | } 53 | type expServiceInfo struct { 54 | service nodeInfo 55 | methods []expMethodInfo 56 | } 57 | testcases := []expServiceInfo{{ 58 | service: nodeInfo{Name: "ServiceOne", Type: reflect.TypeOf((*ast.TypeSpec)(nil))}, 59 | methods: []expMethodInfo{{ 60 | method: nodeInfo{Name: "Get", Type: reflect.TypeOf((*ast.FuncDecl)(nil))}, 61 | calls: []nodeInfo{{Name: "Check", Type: reflect.TypeOf((*ast.SelectorExpr)(nil))}}, 62 | }, { 63 | method: nodeInfo{Name: "List", Type: reflect.TypeOf((*ast.FuncDecl)(nil))}, 64 | calls: []nodeInfo{{Name: "Check", Type: reflect.TypeOf((*ast.SelectorExpr)(nil))}}, 65 | }}, 66 | }, { 67 | service: nodeInfo{Name: "ServiceTwo", Type: reflect.TypeOf((*ast.TypeSpec)(nil))}, 68 | methods: []expMethodInfo{{ 69 | method: nodeInfo{Name: "Get", Type: reflect.TypeOf((*ast.FuncDecl)(nil))}, 70 | calls: []nodeInfo{{Name: "Check", Type: reflect.TypeOf((*ast.SelectorExpr)(nil))}}, 71 | }, { 72 | method: nodeInfo{Name: "List", Type: reflect.TypeOf((*ast.FuncDecl)(nil))}, 73 | calls: []nodeInfo{{Name: "Check", Type: reflect.TypeOf((*ast.SelectorExpr)(nil))}}, 74 | }, { 75 | method: nodeInfo{Name: "UncheckedMeth", Type: reflect.TypeOf((*ast.FuncDecl)(nil))}, 76 | calls: []nodeInfo{}, 77 | }}, 78 | }} 79 | 80 | for _, test := range testcases { 81 | service_ := Find([]ast.Node{servicePkg}, 82 | SetFilter{Names: []string{test.service.Name}, Type: reflect.TypeOf((*ast.TypeSpec)(nil))}) 83 | if len(service_) != 1 { 84 | t.Fatalf("expected to get 1 AST node back, but got %d: %v", len(service_), service_) 85 | } 86 | service := service_[0] 87 | serviceName, _ := GetName(service) 88 | 89 | expMethods := make([]nodeInfo, len(test.methods)) 90 | for i, m := range test.methods { 91 | expMethods[i] = m.method 92 | } 93 | actMethods := Find([]ast.Node{servicePkg}, MethodFilter{ 94 | ReceiverType: serviceName, 95 | ExportedOnly: true, 96 | }) 97 | checkNodesExpected(t, expMethods, actMethods) 98 | 99 | for _, method := range actMethods { 100 | methodInfo := nodeInfoFromNode(method) 101 | var expCalls []nodeInfo 102 | for _, expMethodInfo := range test.methods { 103 | if expMethodInfo.method == methodInfo { 104 | expCalls = expMethodInfo.calls 105 | } 106 | } 107 | 108 | calls := Find([]ast.Node{method}, RegexpFilter{Pattern: regexp.MustCompile(`.*`), Type: reflect.TypeOf((*ast.SelectorExpr)(nil))}) 109 | checkNodesExpected(t, expCalls, calls) 110 | } 111 | } 112 | } 113 | 114 | // 115 | // Helpers 116 | // 117 | 118 | func nodeInfoFromNode(node ast.Node) nodeInfo { 119 | var info nodeInfo 120 | if name, nameExists := GetName(node); nameExists { 121 | info.Name = name 122 | } 123 | info.Type = reflect.TypeOf(node) 124 | return info 125 | } 126 | 127 | func checkNodesExpected(t *testing.T, exp []nodeInfo, actual []ast.Node) { 128 | exp_ := make(map[nodeInfo]bool) 129 | for _, e := range exp { 130 | exp_[e] = true 131 | } 132 | 133 | actual_ := make(map[nodeInfo]bool) 134 | for _, node := range actual { 135 | actual_[nodeInfoFromNode(node)] = true 136 | } 137 | if !reflect.DeepEqual(exp_, actual_) { 138 | t.Errorf("expected nodes %+v, but got %+v", exp_, actual_) 139 | } 140 | } 141 | 142 | func getTestPkg(t *testing.T) *ast.Package { 143 | pkg, err := build.Import("github.com/beyang/go-astquery/testpkg", "", build.FindOnly) 144 | if err != nil { 145 | t.Fatal(err) 146 | } 147 | pkgs, err := parser.ParseDir(token.NewFileSet(), pkg.Dir, nil, parser.AllErrors) 148 | if err != nil { 149 | t.Fatal(err) 150 | } 151 | servicePkg, in := pkgs["service"] 152 | if !in { 153 | t.Fatal("service package not found") 154 | } 155 | return servicePkg 156 | } 157 | -------------------------------------------------------------------------------- /testpkg/check.go: -------------------------------------------------------------------------------- 1 | package service 2 | 3 | var DefaultChecker = Checker{} 4 | 5 | type Checker struct{} 6 | 7 | // Checker.check should be called in each service method 8 | func (c *Checker) Check() {} 9 | -------------------------------------------------------------------------------- /testpkg/service1.go: -------------------------------------------------------------------------------- 1 | // +build testdata 2 | 3 | package service 4 | 5 | type ServiceOne struct { 6 | } 7 | 8 | func (s *ServiceOne) Get(id string) string { 9 | DefaultChecker.Check() 10 | return "" 11 | } 12 | 13 | func (s *ServiceOne) List() []string { 14 | DefaultChecker.Check() 15 | return nil 16 | } 17 | -------------------------------------------------------------------------------- /testpkg/service2.go: -------------------------------------------------------------------------------- 1 | // +build testdata 2 | 3 | package service 4 | 5 | type ServiceTwo struct { 6 | } 7 | 8 | func (s *ServiceTwo) Get(id string) string { 9 | DefaultChecker.Check() 10 | return "" 11 | } 12 | 13 | func (s *ServiceTwo) List() []string { 14 | DefaultChecker.Check() 15 | return nil 16 | } 17 | 18 | func (s *ServiceTwo) UncheckedMeth() {} 19 | -------------------------------------------------------------------------------- /testpkg/uncheckedservice.go: -------------------------------------------------------------------------------- 1 | package service 2 | 3 | type UncheckedService struct { 4 | } 5 | --------------------------------------------------------------------------------