diff --git a/pkg/util/jsonpath/doc.go b/pkg/util/jsonpath/doc.go new file mode 100644 index 00000000000..6bdf4ac59a5 --- /dev/null +++ b/pkg/util/jsonpath/doc.go @@ -0,0 +1,20 @@ +/* +Copyright 2015 The Kubernetes Authors All rights reserved. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +// package jsonpath is a template engine using jsonpath syntax, +// which can be seen at http://goessner.net/articles/JsonPath/. +// In addition, it has {range} {end} function to iterate list and slice. +package jsonpath diff --git a/pkg/util/jsonpath/jsonpath.go b/pkg/util/jsonpath/jsonpath.go new file mode 100644 index 00000000000..af5d560e14c --- /dev/null +++ b/pkg/util/jsonpath/jsonpath.go @@ -0,0 +1,472 @@ +/* +Copyright 2015 The Kubernetes Authors All rights reserved. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package jsonpath + +import ( + "bytes" + "fmt" + "io" + "reflect" + "strconv" + + "github.com/GoogleCloudPlatform/kubernetes/third_party/golang/template" +) + +type JSONPath struct { + name string + parser *Parser + stack [][]reflect.Value //push and pop values in different scopes + cur []reflect.Value //current scope values + beginRange int + inRange int + endRange int +} + +func New(name string) *JSONPath { + return &JSONPath{ + name: name, + beginRange: 0, + inRange: 0, + endRange: 0, + } +} + +// Parse parse the given template, return error +func (j *JSONPath) Parse(text string) (err error) { + j.parser, err = Parse(j.name, text) + return +} + +// Execute bounds data into template and write the result +func (j *JSONPath) Execute(wr io.Writer, data interface{}) error { + if j.parser == nil { + return fmt.Errorf("%s is an incomplete jsonpath template", j.name) + } + + j.cur = []reflect.Value{reflect.ValueOf(data)} + nodes := j.parser.Root.Nodes + for i := 0; i < len(nodes); i++ { + node := nodes[i] + results, err := j.walk(j.cur, node) + if err != nil { + return err + } + + //encounter an end node, break the current block + if j.endRange > 0 && j.endRange <= j.inRange { + j.endRange -= 1 + break + } + //encounter a range node, start a range loop + if j.beginRange > 0 { + j.beginRange -= 1 + j.inRange += 1 + for k, value := range results { + j.parser.Root.Nodes = nodes[i+1:] + if k == len(results)-1 { + j.inRange -= 1 + } + err := j.Execute(wr, value.Interface()) + if err != nil { + return err + } + + } + break + } + err = j.PrintResults(wr, results) + if err != nil { + return err + } + } + return nil +} + +// PrintResults write the results into writer +func (j *JSONPath) PrintResults(wr io.Writer, results []reflect.Value) error { + for i, r := range results { + text, err := j.evalToText(r) + if err != nil { + return err + } + if i != len(results)-1 { + text = append(text, ' ') + } + if _, err = wr.Write(text); err != nil { + return err + } + } + return nil +} + +// walk visits tree rooted at the given node in DFS order +func (j *JSONPath) walk(value []reflect.Value, node Node) ([]reflect.Value, error) { + switch node := node.(type) { + case *ListNode: + return j.evalList(value, node) + case *TextNode: + return []reflect.Value{reflect.ValueOf(string(node.Text))}, nil + case *FieldNode: + return j.evalField(value, node) + case *ArrayNode: + return j.evalArray(value, node) + case *FilterNode: + return j.evalFilter(value, node) + case *IntNode: + return j.evalInt(value, node) + case *FloatNode: + return j.evalFloat(value, node) + case *WildcardNode: + return j.evalWildcard(value, node) + case *RecursiveNode: + return j.evalRecursive(value, node) + case *UnionNode: + return j.evalUnion(value, node) + case *IdentifierNode: + return j.evalIdentifier(value, node) + default: + return value, fmt.Errorf("unexpected Node %v", node) + } +} + +// evalInt evaluates IntNode +func (j *JSONPath) evalInt(input []reflect.Value, node *IntNode) ([]reflect.Value, error) { + result := make([]reflect.Value, len(input)) + for i := range input { + result[i] = reflect.ValueOf(node.Value) + } + return result, nil +} + +// evalFloat evaluates FloatNode +func (j *JSONPath) evalFloat(input []reflect.Value, node *FloatNode) ([]reflect.Value, error) { + result := make([]reflect.Value, len(input)) + for i := range input { + result[i] = reflect.ValueOf(node.Value) + } + return result, nil +} + +// evalList evaluates ListNode +func (j *JSONPath) evalList(value []reflect.Value, node *ListNode) ([]reflect.Value, error) { + var err error + curValue := value + for _, node := range node.Nodes { + curValue, err = j.walk(curValue, node) + if err != nil { + return curValue, err + } + } + return curValue, nil +} + +// evalIdentifier evaluates IdentifierNode +func (j *JSONPath) evalIdentifier(input []reflect.Value, node *IdentifierNode) ([]reflect.Value, error) { + results := []reflect.Value{} + switch node.Name { + case "range": + j.stack = append(j.stack, j.cur) + j.beginRange += 1 + results = input + case "end": + if j.endRange < j.inRange { //inside a loop, break the current block + j.endRange += 1 + break + } + // the loop is about to end, pop value and continue the following execution + if len(j.stack) > 0 { + j.cur, j.stack = j.stack[len(j.stack)-1], j.stack[:len(j.stack)-1] + } else { + return results, fmt.Errorf("not in range, nothing to end") + } + default: + return input, fmt.Errorf("unrecongnized identifier %v", node.Name) + } + return results, nil +} + +// evalArray evaluates ArrayNode +func (j *JSONPath) evalArray(input []reflect.Value, node *ArrayNode) ([]reflect.Value, error) { + result := []reflect.Value{} + for _, value := range input { + if value.Kind() == reflect.Interface { + value = reflect.ValueOf(value.Interface()) + } + if value.Kind() != reflect.Array && value.Kind() != reflect.Slice { + return input, fmt.Errorf("%v is not array or slice", value) + } + params := node.Params + if !params[0].Known { + params[0].Value = 0 + } + if params[0].Value < 0 { + params[0].Value += value.Len() + } + if !params[1].Known { + params[1].Value = value.Len() + } + + if params[1].Value < 0 { + params[1].Value += value.Len() + } + + if !params[2].Known { + value = value.Slice(params[0].Value, params[1].Value) + } else { + value = value.Slice3(params[0].Value, params[1].Value, params[2].Value) + } + for i := 0; i < value.Len(); i++ { + result = append(result, value.Index(i)) + } + } + return result, nil +} + +// evalUnion evaluates UnionNode +func (j *JSONPath) evalUnion(input []reflect.Value, node *UnionNode) ([]reflect.Value, error) { + result := []reflect.Value{} + for _, listNode := range node.Nodes { + temp, err := j.evalList(input, listNode) + if err != nil { + return input, err + } + result = append(result, temp...) + } + return result, nil +} + +// evalField evaluates filed of struct or key of map. +func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.Value, error) { + results := []reflect.Value{} + for _, value := range input { + var result reflect.Value + if value.Kind() == reflect.Interface { + value = reflect.ValueOf(value.Interface()) + } + if value.Kind() == reflect.Struct { + result = value.FieldByName(node.Value) + } else if value.Kind() == reflect.Map { + result = value.MapIndex(reflect.ValueOf(node.Value)) + } + if result.IsValid() { + results = append(results, result) + } + } + if len(results) == 0 { + return results, fmt.Errorf("%s is not found", node.Value) + } + return results, nil +} + +// evalWildcard extract all contents of the given value +func (j *JSONPath) evalWildcard(input []reflect.Value, node *WildcardNode) ([]reflect.Value, error) { + results := []reflect.Value{} + for _, value := range input { + kind := value.Kind() + if kind == reflect.Struct { + for i := 0; i < value.NumField(); i++ { + results = append(results, value.Field(i)) + } + } else if kind == reflect.Map { + for _, key := range value.MapKeys() { + results = append(results, value.MapIndex(key)) + } + } else if kind == reflect.Array || kind == reflect.Slice || kind == reflect.String { + for i := 0; i < value.Len(); i++ { + results = append(results, value.Index(i)) + } + } + } + return results, nil +} + +// evalRecursive visit the given value recursively and push all of them to result +func (j *JSONPath) evalRecursive(input []reflect.Value, node *RecursiveNode) ([]reflect.Value, error) { + result := []reflect.Value{} + for _, value := range input { + results := []reflect.Value{} + kind := value.Kind() + if kind == reflect.Struct { + for i := 0; i < value.NumField(); i++ { + results = append(results, value.Field(i)) + } + } else if kind == reflect.Map { + for _, key := range value.MapKeys() { + results = append(results, value.MapIndex(key)) + } + } else if kind == reflect.Array || kind == reflect.Slice || kind == reflect.String { + for i := 0; i < value.Len(); i++ { + results = append(results, value.Index(i)) + } + } + if len(results) != 0 { + result = append(result, value) + output, err := j.evalRecursive(results, node) + if err != nil { + return result, err + } + result = append(result, output...) + } + } + return result, nil +} + +// evalFilter filter array according to FilterNode +func (j *JSONPath) evalFilter(input []reflect.Value, node *FilterNode) ([]reflect.Value, error) { + results := []reflect.Value{} + for _, value := range input { + if value.Kind() == reflect.Interface { + value = reflect.ValueOf(value.Interface()) + } + if value.Kind() != reflect.Array && value.Kind() != reflect.Slice { + return input, fmt.Errorf("%v is not array or slice", value) + } + for i := 0; i < value.Len(); i++ { + temp := []reflect.Value{value.Index(i)} + lefts, err := j.evalList(temp, node.Left) + + //case exists + if node.Operator == "exists" { + if len(lefts) > 0 { + results = append(results, value.Index(i)) + } + continue + } + + if err != nil { + return input, err + } + + var left, right interface{} + if len(lefts) != 1 { + return input, fmt.Errorf("can only compare one element at a time") + } + left = lefts[0].Interface() + + rights, err := j.evalList(temp, node.Right) + if err != nil { + return input, err + } + if len(rights) != 1 { + return input, fmt.Errorf("can only compare one element at a time") + } + right = rights[0].Interface() + + pass := false + switch node.Operator { + case "<": + pass, err = template.Less(left, right) + case ">": + pass, err = template.Greater(left, right) + case "==": + pass, err = template.Equal(left, right) + case "!=": + pass, err = template.NotEqual(left, right) + case "<=": + pass, err = template.LessEqual(left, right) + case ">=": + pass, err = template.GreaterEqual(left, right) + default: + return results, fmt.Errorf("unrecognized filter operator %s", node.Operator) + } + if err != nil { + return results, err + } + if pass { + results = append(results, value.Index(i)) + } + } + } + return results, nil +} + +// evalToText translates reflect value to corresponding text +func (j *JSONPath) evalToText(v reflect.Value) ([]byte, error) { + if v.Kind() == reflect.Interface { + v = reflect.ValueOf(v.Interface()) + } + var buffer bytes.Buffer + switch v.Kind() { + case reflect.Invalid: + //pass + case reflect.Ptr: + text, err := j.evalToText(reflect.Indirect(v)) + if err != nil { + return nil, err + } + buffer.Write(text) + case reflect.Bool: + if variable := v.Bool(); variable { + buffer.WriteString("True") + } else { + buffer.WriteString("False") + } + case reflect.Float32: + buffer.WriteString(strconv.FormatFloat(v.Float(), 'f', -1, 32)) + case reflect.Float64: + buffer.WriteString(strconv.FormatFloat(v.Float(), 'f', -1, 64)) + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + buffer.WriteString(strconv.FormatInt(v.Int(), 10)) + case reflect.String: + buffer.WriteString(v.String()) + case reflect.Array, reflect.Slice: + buffer.WriteString("[") + for i := 0; i < v.Len(); i++ { + text, err := j.evalToText(v.Index(i)) + if err != nil { + return nil, err + } + buffer.Write(text) + if i != v.Len()-1 { + buffer.WriteString(", ") + } + } + buffer.WriteString("]") + case reflect.Struct: + buffer.WriteString("{") + for i := 0; i < v.NumField(); i++ { + text, err := j.evalToText(v.Field(i)) + if err != nil { + return nil, err + } + pair := fmt.Sprintf("%s: %s", v.Type().Field(i).Name, text) + buffer.WriteString(pair) + if i != v.NumField()-1 { + buffer.WriteString(", ") + } + } + buffer.WriteString("}") + case reflect.Map: + buffer.WriteString("{") + for i, key := range v.MapKeys() { + text, err := j.evalToText(v.MapIndex(key)) + if err != nil { + return nil, err + } + pair := fmt.Sprintf("%s: %s", key, text) + buffer.WriteString(pair) + if i != len(v.MapKeys())-1 { + buffer.WriteString(", ") + } + } + buffer.WriteString("}") + + default: + return nil, fmt.Errorf("%v is not printable", v.Kind()) + } + return buffer.Bytes(), nil +} diff --git a/pkg/util/jsonpath/jsonpath_test.go b/pkg/util/jsonpath/jsonpath_test.go new file mode 100644 index 00000000000..78cebc92f0c --- /dev/null +++ b/pkg/util/jsonpath/jsonpath_test.go @@ -0,0 +1,214 @@ +/* +Copyright 2015 The Kubernetes Authors All rights reserved. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package jsonpath + +import ( + "bytes" + "encoding/json" + "testing" +) + +type jsonpathTest struct { + name string + template string + input interface{} + expect string +} + +func testJSONPath(tests []jsonpathTest, t *testing.T) { + for _, test := range tests { + j := New(test.name) + err := j.Parse(test.template) + if err != nil { + t.Errorf("in %s, parse %s error %v", test.name, test.template, err) + } + buf := new(bytes.Buffer) + err = j.Execute(buf, test.input) + if err != nil { + t.Errorf("in %s, execute error %v", test.name, err) + } + out := buf.String() + if out != test.expect { + t.Errorf(`in %s, expect to get "%s", got "%s"`, test.name, test.expect, out) + } + } +} + +func testFailJSONPath(tests []jsonpathTest, t *testing.T) { + for _, test := range tests { + j := New(test.name) + err := j.Parse(test.template) + if err != nil { + t.Errorf("in %s, parse %s error %v", test.name, test.template, err) + } + buf := new(bytes.Buffer) + err = j.Execute(buf, test.input) + var out string + if err == nil { + out = "nil" + } else { + out = err.Error() + } + if out != test.expect { + t.Errorf("in %s, expect to get error %s, got %s", test.name, test.expect, out) + } + } +} + +func TestStructInput(t *testing.T) { + type book struct { + Category string + Author string + Title string + Price float32 + } + + type bicycle struct { + Color string + Price float32 + } + + type store struct { + Book []book + Bicycle bicycle + Name string + Labels map[string]int + } + + storeData := store{ + Name: "jsonpath", + Book: []book{ + {"reference", "Nigel Rees", "Sayings of the Centurey", 8.95}, + {"fiction", "Evelyn Waugh", "Sword of Honour", 12.99}, + {"fiction", "Herman Melville", "Moby Dick", 8.99}, + }, + Bicycle: bicycle{"red", 19.95}, + Labels: map[string]int{ + "engieer": 10, + "web/html": 15, + "k8s-app": 20, + }, + } + + storeTests := []jsonpathTest{ + {"plain", "hello jsonpath", nil, "hello jsonpath"}, + {"recursive", "{..}", []int{1, 2, 3}, "[1, 2, 3]"}, + {"filter", "{[?(@<5)]}", []int{2, 6, 3, 7}, "2 3"}, + {"quote", `{"{"}`, nil, "{"}, + {"union", "{[1,3,4]}", []int{0, 1, 2, 3, 4}, "1 3 4"}, + {"array", "{[0:2]}", []string{"Monday", "Tudesday"}, "Monday Tudesday"}, + {"variable", "hello {.Name}", storeData, "hello jsonpath"}, + {"dict/", "{.Labels.web/html}", storeData, "15"}, + {"dict-", "{.Labels.k8s-app}", storeData, "20"}, + {"nest", "{.Bicycle.Color}", storeData, "red"}, + {"allarray", "{.Book[*].Author}", storeData, "Nigel Rees Evelyn Waugh Herman Melville"}, + {"allfileds", "{.Bicycle.*}", storeData, "red 19.95"}, + {"recurfileds", "{..Price}", storeData, "8.95 12.99 8.99 19.95"}, + {"lastarray", "{.Book[-1:]}", storeData, + "{Category: fiction, Author: Herman Melville, Title: Moby Dick, Price: 8.99}"}, + {"recurarray", "{..Book[2]}", storeData, + "{Category: fiction, Author: Herman Melville, Title: Moby Dick, Price: 8.99}"}, + } + testJSONPath(storeTests, t) + + failStoreTests := []jsonpathTest{ + {"invalid identfier", "{hello}", storeData, "unrecongnized identifier hello"}, + {"nonexistent field", "{.hello}", storeData, "hello is not found"}, + {"invalid array", "{.Labels[0]}", storeData, " is not array or slice"}, + {"invalid filter operator", "{.Book[?(@.Price<>10)]}", storeData, "unrecognized filter operator <>"}, + {"redundent end", "{range .Labels.*}{@}{end}{end}", storeData, "not in range, nothing to end"}, + } + testFailJSONPath(failStoreTests, t) +} + +func TestJSONInput(t *testing.T) { + var pointsJSON = []byte(`[ + {"id": "i1", "x":4, "y":-5}, + {"id": "i2", "x":-2, "y":-5, "z":1}, + {"id": "i3", "x": 8, "y": 3 }, + {"id": "i4", "x": -6, "y": -1 }, + {"id": "i5", "x": 0, "y": 2, "z": 1 }, + {"id": "i6", "x": 1, "y": 4 } + ]`) + var pointsData interface{} + err := json.Unmarshal(pointsJSON, &pointsData) + if err != nil { + t.Error(err) + } + pointsTests := []jsonpathTest{ + {"exists filter", "{[?(@.z)].id}", pointsData, "i2 i5"}, + {"bracket key", "{[0]['id']}", pointsData, "i1"}, + } + testJSONPath(pointsTests, t) +} + +// TestKubenates tests some use cases from kubenates +func TestKubenates(t *testing.T) { + var input = []byte(`{ + "kind": "List", + "items":[ + { + "kind":"None", + "metadata":{"name":"127.0.0.1"}, + "status":{ + "capacity":{"cpu":"4"}, + "addresses":[{"type": "LegacyHostIP", "address":"127.0.0.1"}] + } + }, + { + "kind":"None", + "metadata":{"name":"127.0.0.2"}, + "status":{ + "capacity":{"cpu":"8"}, + "addresses":[ + {"type": "LegacyHostIP", "address":"127.0.0.2"}, + {"type": "another", "address":"127.0.0.3"} + ] + } + } + ], + "users":[ + { + "name": "myself", + "user": {} + }, + { + "name": "e2e", + "user": {"username": "admin", "password": "secret"} + } + ] + }`) + var nodesData interface{} + err := json.Unmarshal(input, &nodesData) + if err != nil { + t.Error(err) + } + nodesTests := []jsonpathTest{ + {"range item", "{range .items[*]}{.metadata.name}, {end}{.kind}", nodesData, `127.0.0.1, 127.0.0.2, List`}, + {"range addresss", "{.items[*].status.addresses[*].address}", nodesData, + `127.0.0.1 127.0.0.2 127.0.0.3`}, + {"double range", "{range .items[*]}{range .status.addresses[*]}{.address}, {end}{end}", nodesData, + `127.0.0.1, 127.0.0.2, 127.0.0.3, `}, + {"item name", "{.items[*].metadata.name}", nodesData, `127.0.0.1 127.0.0.2`}, + {"union nodes capacity", "{.items[*]['metadata.name', 'status.capacity']}", nodesData, + `127.0.0.1 127.0.0.2 {cpu: 4} {cpu: 8}`}, + {"range nodes capacity", "{range .items[*]}[{.metadata.name}, {.status.capacity}] {end}", nodesData, + `[127.0.0.1, {cpu: 4}] [127.0.0.2, {cpu: 8}] `}, + {"user password", `{.users[?(@.name=="e2e")].user.password}`, nodesData, "secret"}, + } + testJSONPath(nodesTests, t) +} diff --git a/pkg/util/jsonpath/node.go b/pkg/util/jsonpath/node.go new file mode 100644 index 00000000000..bdbf0d38d22 --- /dev/null +++ b/pkg/util/jsonpath/node.go @@ -0,0 +1,239 @@ +/* +Copyright 2015 The Kubernetes Authors All rights reserved. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package jsonpath + +import "fmt" + +// NodeType identifies the type of a parse tree node. +type NodeType int + +// Type returns itself and provides an easy default implementation +func (t NodeType) Type() NodeType { + return t +} + +func (t NodeType) String() string { + return NodeTypeName[t] +} + +const ( + NodeText NodeType = iota + NodeArray + NodeList + NodeField + NodeIdentifier + NodeFilter + NodeInt + NodeFloat + NodeWildcard + NodeRecursive + NodeUnion +) + +var NodeTypeName = map[NodeType]string{ + NodeText: "NodeText", + NodeArray: "NodeArray", + NodeList: "NodeList", + NodeField: "NodeField", + NodeIdentifier: "NodeIdentifier", + NodeFilter: "NodeFilter", + NodeInt: "NodeInt", + NodeFloat: "NodeFloat", + NodeWildcard: "NodeWildcard", + NodeRecursive: "NodeRecursive", + NodeUnion: "NodeUnion", +} + +type Node interface { + Type() NodeType + String() string +} + +// ListNode holds a sequence of nodes. +type ListNode struct { + NodeType + Nodes []Node // The element nodes in lexical order. +} + +func newList() *ListNode { + return &ListNode{NodeType: NodeList} +} + +func (l *ListNode) append(n Node) { + l.Nodes = append(l.Nodes, n) +} + +func (l *ListNode) String() string { + return fmt.Sprintf("%s", l.Type()) +} + +// TextNode holds plain text. +type TextNode struct { + NodeType + Text []byte // The text; may span newlines. +} + +func newText(text string) *TextNode { + return &TextNode{NodeType: NodeText, Text: []byte(text)} +} + +func (t *TextNode) String() string { + return fmt.Sprintf("%s: %s", t.Type(), t.Text) +} + +// FieldNode holds filed of struct +type FieldNode struct { + NodeType + Value string +} + +func newField(value string) *FieldNode { + return &FieldNode{NodeType: NodeField, Value: value} +} + +func (f *FieldNode) String() string { + return fmt.Sprintf("%s: %s", f.Type(), f.Value) +} + +// IdentifierNode holds an identifier +type IdentifierNode struct { + NodeType + Name string +} + +func newIdentifier(value string) *IdentifierNode { + return &IdentifierNode{ + NodeType: NodeIdentifier, + Name: value, + } +} + +func (f *IdentifierNode) String() string { + return fmt.Sprintf("%s: %s", f.Type(), f.Name) +} + +// ParamsEntry holds param information for ArrayNode +type ParamsEntry struct { + Value int + Known bool //whether the value is known when parse it +} + +// ArrayNode holds start, end, step information for array index selection +type ArrayNode struct { + NodeType + Params [3]ParamsEntry //start, end, step +} + +func newArray(params [3]ParamsEntry) *ArrayNode { + return &ArrayNode{ + NodeType: NodeArray, + Params: params, + } +} + +func (a *ArrayNode) String() string { + return fmt.Sprintf("%s: %v", a.Type(), a.Params) +} + +// FilterNode holds operand and operator information for filter +type FilterNode struct { + NodeType + Left *ListNode + Right *ListNode + Operator string +} + +func newFilter(left, right *ListNode, operator string) *FilterNode { + return &FilterNode{ + NodeType: NodeFilter, + Left: left, + Right: right, + Operator: operator, + } +} + +func (f *FilterNode) String() string { + return fmt.Sprintf("%s: %s %s %s", f.Type(), f.Left, f.Operator, f.Right) +} + +// IntNode holds integer value +type IntNode struct { + NodeType + Value int +} + +func newInt(num int) *IntNode { + return &IntNode{NodeType: NodeInt, Value: num} +} + +func (i *IntNode) String() string { + return fmt.Sprintf("%s: %d", i.Type(), i.Value) +} + +// FloatNode holds float value +type FloatNode struct { + NodeType + Value float64 +} + +func newFloat(num float64) *FloatNode { + return &FloatNode{NodeType: NodeFloat, Value: num} +} + +func (i *FloatNode) String() string { + return fmt.Sprintf("%s: %f", i.Type(), i.Value) +} + +// WildcardNode means a wildcard +type WildcardNode struct { + NodeType +} + +func newWildcard() *WildcardNode { + return &WildcardNode{NodeType: NodeWildcard} +} + +func (i *WildcardNode) String() string { + return fmt.Sprintf("%s", i.Type()) +} + +// RecursiveNode means a recursive descent operator +type RecursiveNode struct { + NodeType +} + +func newRecursive() *RecursiveNode { + return &RecursiveNode{NodeType: NodeRecursive} +} + +func (r *RecursiveNode) String() string { + return fmt.Sprintf("%s", r.Type()) +} + +// UnionNode is union of ListNode +type UnionNode struct { + NodeType + Nodes []*ListNode +} + +func newUnion(nodes []*ListNode) *UnionNode { + return &UnionNode{NodeType: NodeUnion, Nodes: nodes} +} + +func (u *UnionNode) String() string { + return fmt.Sprintf("%s", u.Type()) +} diff --git a/pkg/util/jsonpath/parser.go b/pkg/util/jsonpath/parser.go new file mode 100644 index 00000000000..e80034c5872 --- /dev/null +++ b/pkg/util/jsonpath/parser.go @@ -0,0 +1,419 @@ +/* +Copyright 2015 The Kubernetes Authors All rights reserved. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package jsonpath + +import ( + "fmt" + "regexp" + "strconv" + "strings" + "unicode" + "unicode/utf8" +) + +const eof = -1 + +const ( + leftDelim = "{" + rightDelim = "}" +) + +type Parser struct { + Name string + Root *ListNode + input string + cur *ListNode + pos int + start int + width int +} + +// Parse parsed the given text and return a node Parser. +// If an error is encountered, parsing stops and an empty +// Parser is returned with the error +func Parse(name, text string) (*Parser, error) { + p := NewParser(name) + err := p.Parse(text) + if err != nil { + p = nil + } + return p, err +} + +func NewParser(name string) *Parser { + return &Parser{ + Name: name, + } +} + +// parseAction parsed the expression inside delimiter +func parseAction(name, text string) (*Parser, error) { + p, err := Parse(name, fmt.Sprintf("%s%s%s", leftDelim, text, rightDelim)) + p.Root = p.Root.Nodes[0].(*ListNode) + return p, err +} + +func (p *Parser) Parse(text string) error { + p.input = text + p.Root = newList() + p.pos = 0 + return p.parseText(p.Root) +} + +// consumeText return the parsed text since last cosumeText +func (p *Parser) consumeText() string { + value := p.input[p.start:p.pos] + p.start = p.pos + return value +} + +// next returns the next rune in the input. +func (p *Parser) next() rune { + if int(p.pos) >= len(p.input) { + p.width = 0 + return eof + } + r, w := utf8.DecodeRuneInString(p.input[p.pos:]) + p.width = w + p.pos += p.width + return r +} + +// peek returns but does not consume the next rune in the input. +func (p *Parser) peek() rune { + r := p.next() + p.backup() + return r +} + +// backup steps back one rune. Can only be called once per call of next. +func (p *Parser) backup() { + p.pos -= p.width +} + +func (p *Parser) parseText(cur *ListNode) error { + for { + if strings.HasPrefix(p.input[p.pos:], leftDelim) { + if p.pos > p.start { + cur.append(newText(p.consumeText())) + } + return p.parseLeftDelim(cur) + } + if p.next() == eof { + break + } + } + // Correctly reached EOF. + if p.pos > p.start { + cur.append(newText(p.consumeText())) + } + return nil +} + +// parseLeftDelim scans the left delimiter, which is known to be present. +func (p *Parser) parseLeftDelim(cur *ListNode) error { + p.pos += len(leftDelim) + p.consumeText() + newNode := newList() + cur.append(newNode) + cur = newNode + return p.parseInsideAction(cur) +} + +func (p *Parser) parseInsideAction(cur *ListNode) error { + prefixMap := map[string]func(*ListNode) error{ + rightDelim: p.parseRightDelim, + "[?(": p.parseFilter, + "..": p.parseRecursive, + } + for prefix, parseFunc := range prefixMap { + if strings.HasPrefix(p.input[p.pos:], prefix) { + return parseFunc(cur) + } + } + + switch r := p.next(); { + case r == eof || isEndOfLine(r): + return fmt.Errorf("unclosed action") + case r == ' ': + p.consumeText() + case r == '@': //the current object, just pass it + p.consumeText() + case r == '[': + return p.parseArray(cur) + case r == '"': + return p.parseQuote(cur) + case r == '.': + return p.parseField(cur) + case r == '+' || r == '-' || unicode.IsDigit(r): + p.backup() + return p.parseNumber(cur) + case isAlphaNumeric(r): + p.backup() + return p.parseIdentifier(cur) + default: + return fmt.Errorf("unrecognized charactor in action: %#U", r) + } + return p.parseInsideAction(cur) +} + +// parseRightDelim scans the right delimiter, which is known to be present. +func (p *Parser) parseRightDelim(cur *ListNode) error { + p.pos += len(rightDelim) + p.consumeText() + cur = p.Root + return p.parseText(cur) +} + +// parseIdentifier scans build-in keywords, like "range" "end" +func (p *Parser) parseIdentifier(cur *ListNode) error { + var r rune + for { + r = p.next() + if isTerminator(r) { + p.backup() + break + } + } + value := p.consumeText() + cur.append(newIdentifier(value)) + return p.parseInsideAction(cur) +} + +// parseRecursive scans the recursive desent operator .. +func (p *Parser) parseRecursive(cur *ListNode) error { + p.pos += len("..") + p.consumeText() + cur.append(newRecursive()) + if r := p.peek(); isAlphaNumeric(r) { + return p.parseField(cur) + } + return p.parseInsideAction(cur) +} + +// parseNumber scans number +func (p *Parser) parseNumber(cur *ListNode) error { + r := p.peek() + if r == '+' || r == '-' { + r = p.next() + } + for { + r = p.next() + if r != '.' && !unicode.IsDigit(r) { + p.backup() + break + } + } + value := p.consumeText() + i, err := strconv.Atoi(value) + if err == nil { + cur.append(newInt(i)) + return p.parseInsideAction(cur) + } + d, err := strconv.ParseFloat(value, 64) + if err == nil { + cur.append(newFloat(d)) + return p.parseInsideAction(cur) + } + return fmt.Errorf("cannot parse number %s", value) +} + +// parseArray scans array index selection +func (p *Parser) parseArray(cur *ListNode) error { +Loop: + for { + switch p.next() { + case eof, '\n': + return fmt.Errorf("unterminated array") + case ']': + break Loop + } + } + text := p.consumeText() + text = string(text[1 : len(text)-1]) + if text == "*" { + text = ":" + } + + //union operator + strs := strings.Split(text, ",") + if len(strs) > 1 { + union := []*ListNode{} + for _, str := range strs { + parser, err := parseAction("union", fmt.Sprintf("[%s]", strings.Trim(str, " "))) + if err != nil { + return err + } + union = append(union, parser.Root) + } + cur.append(newUnion(union)) + return p.parseInsideAction(cur) + } + + // dict key + reg := regexp.MustCompile(`^'([^']*)'$`) + value := reg.FindStringSubmatch(text) + if value != nil { + parser, err := parseAction("arraydict", fmt.Sprintf(".%s", value[1])) + if err != nil { + return err + } + for _, node := range parser.Root.Nodes { + cur.append(node) + } + return p.parseInsideAction(cur) + } + + //slice operator + reg = regexp.MustCompile(`^(-?[\d]*)(:-?[\d]*)?(:[\d]*)?$`) + value = reg.FindStringSubmatch(text) + if value == nil { + return fmt.Errorf("invalid array index %s", text) + } + value = value[1:] + params := [3]ParamsEntry{} + for i := 0; i < 3; i++ { + if value[i] != "" { + if i > 0 { + value[i] = value[i][1:] + } + if i > 0 && value[i] == "" { + params[i].Known = false + } else { + var err error + params[i].Known = true + params[i].Value, err = strconv.Atoi(value[i]) + if err != nil { + return fmt.Errorf("array index %s is not a number", params[i].Value) + } + } + } else { + if i == 1 { + params[i].Known = true + params[i].Value = params[0].Value + 1 + } else { + params[i].Known = false + params[i].Value = 0 + } + } + } + cur.append(newArray(params)) + return p.parseInsideAction(cur) +} + +// parseFilter scans filter inside array selection +func (p *Parser) parseFilter(cur *ListNode) error { + p.pos += len("[?(") + p.consumeText() +Loop: + for { + switch p.next() { + case eof, '\n': + return fmt.Errorf("unterminated filter") + case ')': + break Loop + } + } + if p.next() != ']' { + return fmt.Errorf("unclosed array expect ]") + } + reg := regexp.MustCompile(`^([^!<>=]+)([!<>=]+)(.+?)$`) + text := p.consumeText() + text = string(text[:len(text)-2]) + value := reg.FindStringSubmatch(text) + if value == nil { + parser, err := parseAction("text", text) + if err != nil { + return err + } + cur.append(newFilter(parser.Root, newList(), "exists")) + } else { + leftParser, err := parseAction("left", value[1]) + if err != nil { + return err + } + rightParser, err := parseAction("right", value[3]) + if err != nil { + return err + } + cur.append(newFilter(leftParser.Root, rightParser.Root, value[2])) + } + return p.parseInsideAction(cur) +} + +// parseQuote scans array index selection +func (p *Parser) parseQuote(cur *ListNode) error { +Loop: + for { + switch p.next() { + case eof, '\n': + return fmt.Errorf("unterminated quoted string") + case '"': + break Loop + } + } + value := p.consumeText() + cur.append(newText(value[1 : len(value)-1])) + return p.parseInsideAction(cur) +} + +// parseField scans a field until a terminator +func (p *Parser) parseField(cur *ListNode) error { + p.consumeText() + var r rune + for { + r = p.next() + if isTerminator(r) { + p.backup() + break + } + } + value := p.consumeText() + if value == "*" { + cur.append(newWildcard()) + } else { + cur.append(newField(value)) + } + return p.parseInsideAction(cur) +} + +// isTerminator reports whether the input is at valid termination character to appear after an identifier. +func isTerminator(r rune) bool { + if isSpace(r) || isEndOfLine(r) { + return true + } + switch r { + case eof, '.', ',', '[', ']', '$', '@', '{', '}': + return true + } + return false +} + +// isSpace reports whether r is a space character. +func isSpace(r rune) bool { + return r == ' ' || r == '\t' +} + +// isEndOfLine reports whether r is an end-of-line character. +func isEndOfLine(r rune) bool { + return r == '\r' || r == '\n' +} + +// isAlphaNumeric reports whether r is an alphabetic, digit, or underscore. +func isAlphaNumeric(r rune) bool { + return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r) +} diff --git a/pkg/util/jsonpath/parser_test.go b/pkg/util/jsonpath/parser_test.go new file mode 100644 index 00000000000..29083dd6c44 --- /dev/null +++ b/pkg/util/jsonpath/parser_test.go @@ -0,0 +1,128 @@ +/* +Copyright 2015 The Kubernetes Authors All rights reserved. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package jsonpath + +import ( + "testing" +) + +type parserTest struct { + name string + text string + nodes []Node +} + +var parserTests = []parserTest{ + {"plain", `hello jsonpath`, []Node{newText("hello jsonpath")}}, + {"variable", `hello {.jsonpath}`, + []Node{newText("hello "), newList(), newField("jsonpath")}}, + {"arrayfiled", `hello {['jsonpath']}`, + []Node{newText("hello "), newList(), newField("jsonpath")}}, + {"quote", `{"{"}`, []Node{newList(), newText("{")}}, + {"array", `{[1:3]}`, []Node{newList(), + newArray([3]ParamsEntry{{1, true}, {3, true}, {0, false}})}}, + {"allarray", `{.book[*].author}`, + []Node{newList(), newField("book"), + newArray([3]ParamsEntry{{0, false}, {0, false}, {0, false}}), newField("author")}}, + {"wildcard", `{.bicycle.*}`, + []Node{newList(), newField("bicycle"), newWildcard()}}, + {"filter", `{[?(@.price<3)]}`, + []Node{newList(), newFilter(newList(), newList(), "<"), + newList(), newField("price"), newList(), newInt(3)}}, + {"recursive", `{..}`, []Node{newList(), newRecursive()}}, + {"recurField", `{..price}`, + []Node{newList(), newRecursive(), newField("price")}}, + {"arraydict", `{['book.price']}`, []Node{newList(), + newField("book"), newField("price"), + }}, + {"union", `{['bicycle.price', 3, 'book.price']}`, []Node{newList(), newUnion([]*ListNode{}), + newList(), newField("bicycle"), newField("price"), + newList(), newArray([3]ParamsEntry{{3, true}, {4, true}, {0, false}}), + newList(), newField("book"), newField("price"), + }}, + {"range", `{range .items}{.name},{end}`, []Node{ + newList(), newIdentifier("range"), newField("items"), + newList(), newField("name"), newText(","), + newList(), newIdentifier("end"), + }}, +} + +func collectNode(nodes []Node, cur Node) []Node { + nodes = append(nodes, cur) + switch cur.Type() { + case NodeList: + for _, node := range cur.(*ListNode).Nodes { + nodes = collectNode(nodes, node) + } + case NodeFilter: + nodes = collectNode(nodes, cur.(*FilterNode).Left) + nodes = collectNode(nodes, cur.(*FilterNode).Right) + case NodeUnion: + for _, node := range cur.(*UnionNode).Nodes { + nodes = collectNode(nodes, node) + } + } + return nodes +} + +func TestParser(t *testing.T) { + for _, test := range parserTests { + parser, err := Parse(test.name, test.text) + if err != nil { + t.Errorf("parse %s error %v", test.name, err) + } + result := collectNode([]Node{}, parser.Root)[1:] + if len(result) != len(test.nodes) { + t.Errorf("in %s, expect to get %d nodes, got %d nodes", test.name, len(test.nodes), len(result)) + t.Error(result) + } + for i, expect := range test.nodes { + if result[i].String() != expect.String() { + t.Errorf("in %s, %dth node, expect %v, got %v", test.name, i, expect, result[i]) + } + } + } +} + +type failParserTest struct { + name string + text string + err string +} + +func TestFailParser(t *testing.T) { + failParserTests := []failParserTest{ + {"unclosed action", "{.hello", "unclosed action"}, + {"unrecognized charactor", "{*}", "unrecognized charactor in action: U+002A '*'"}, + {"invalid number", "{+12.3.0}", "cannot parse number +12.3.0"}, + {"unterminated array", "{[1}", "unterminated array"}, + {"invalid index", "{[::-1]}", "invalid array index ::-1"}, + {"unterminated filter", "{[?(.price]}", "unterminated filter"}, + } + for _, test := range failParserTests { + _, err := Parse(test.name, test.text) + var out string + if err == nil { + out = "nil" + } else { + out = err.Error() + } + if out != test.err { + t.Errorf("in %s, expect to get error %v, got %v", test.name, test.err, out) + } + } +} diff --git a/third_party/golang/template/exec.go b/third_party/golang/template/exec.go new file mode 100644 index 00000000000..11fef63f486 --- /dev/null +++ b/third_party/golang/template/exec.go @@ -0,0 +1,89 @@ +package template +import ( + "reflect" + "fmt" +) + + +var ( + errorType = reflect.TypeOf((*error)(nil)).Elem() + fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem() +) + + +// indirect returns the item at the end of indirection, and a bool to indicate if it's nil. +// We indirect through pointers and empty interfaces (only) because +// non-empty interfaces have methods we might need. +func indirect(v reflect.Value) (rv reflect.Value, isNil bool) { + for ; v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface; v = v.Elem() { + if v.IsNil() { + return v, true + } + if v.Kind() == reflect.Interface && v.NumMethod() > 0 { + break + } + } + return v, false +} + +// printableValue returns the, possibly indirected, interface value inside v that +// is best for a call to formatted printer. +func printableValue(v reflect.Value) (interface{}, bool) { + if v.Kind() == reflect.Ptr { + v, _ = indirect(v) // fmt.Fprint handles nil. + } + if !v.IsValid() { + return "", true + } + + if !v.Type().Implements(errorType) && !v.Type().Implements(fmtStringerType) { + if v.CanAddr() && (reflect.PtrTo(v.Type()).Implements(errorType) || reflect.PtrTo(v.Type()).Implements(fmtStringerType)) { + v = v.Addr() + } else { + switch v.Kind() { + case reflect.Chan, reflect.Func: + return nil, false + } + } + } + return v.Interface(), true +} + +// canBeNil reports whether an untyped nil can be assigned to the type. See reflect.Zero. +func canBeNil(typ reflect.Type) bool { + switch typ.Kind() { + case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice: + return true + } + return false +} + +// isTrue reports whether the value is 'true', in the sense of not the zero of its type, +// and whether the value has a meaningful truth value. +func isTrue(val reflect.Value) (truth, ok bool) { + if !val.IsValid() { + // Something like var x interface{}, never set. It's a form of nil. + return false, true + } + switch val.Kind() { + case reflect.Array, reflect.Map, reflect.Slice, reflect.String: + truth = val.Len() > 0 + case reflect.Bool: + truth = val.Bool() + case reflect.Complex64, reflect.Complex128: + truth = val.Complex() != 0 + case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Interface: + truth = !val.IsNil() + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + truth = val.Int() != 0 + case reflect.Float32, reflect.Float64: + truth = val.Float() != 0 + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + truth = val.Uint() != 0 + case reflect.Struct: + truth = true // Struct values are always true. + default: + return + } + return truth, true +} \ No newline at end of file diff --git a/third_party/golang/template/funcs.go b/third_party/golang/template/funcs.go new file mode 100644 index 00000000000..27a008b0a7e --- /dev/null +++ b/third_party/golang/template/funcs.go @@ -0,0 +1,599 @@ +//This package is copied from Go library text/template. +//The original private functions eq, ge, gt, le, lt, and ne +//are exported as public functions. +package template + +import ( + "bytes" + "errors" + "fmt" + "io" + "net/url" + "reflect" + "strings" + "unicode" + "unicode/utf8" +) + +var Equal = eq +var GreaterEqual = ge +var Greater = gt +var LessEqual = le +var Less = lt +var NotEqual = ne + +// FuncMap is the type of the map defining the mapping from names to functions. +// Each function must have either a single return value, or two return values of +// which the second has type error. In that case, if the second (error) +// return value evaluates to non-nil during execution, execution terminates and +// Execute returns that error. +type FuncMap map[string]interface{} + +var builtins = FuncMap{ + "and": and, + "call": call, + "html": HTMLEscaper, + "index": index, + "js": JSEscaper, + "len": length, + "not": not, + "or": or, + "print": fmt.Sprint, + "printf": fmt.Sprintf, + "println": fmt.Sprintln, + "urlquery": URLQueryEscaper, + + // Comparisons + "eq": eq, // == + "ge": ge, // >= + "gt": gt, // > + "le": le, // <= + "lt": lt, // < + "ne": ne, // != +} + +var builtinFuncs = createValueFuncs(builtins) + +// createValueFuncs turns a FuncMap into a map[string]reflect.Value +func createValueFuncs(funcMap FuncMap) map[string]reflect.Value { + m := make(map[string]reflect.Value) + addValueFuncs(m, funcMap) + return m +} + +// addValueFuncs adds to values the functions in funcs, converting them to reflect.Values. +func addValueFuncs(out map[string]reflect.Value, in FuncMap) { + for name, fn := range in { + v := reflect.ValueOf(fn) + if v.Kind() != reflect.Func { + panic("value for " + name + " not a function") + } + if !goodFunc(v.Type()) { + panic(fmt.Errorf("can't install method/function %q with %d results", name, v.Type().NumOut())) + } + out[name] = v + } +} + +// AddFuncs adds to values the functions in funcs. It does no checking of the input - +// call addValueFuncs first. +func addFuncs(out, in FuncMap) { + for name, fn := range in { + out[name] = fn + } +} + +// goodFunc checks that the function or method has the right result signature. +func goodFunc(typ reflect.Type) bool { + // We allow functions with 1 result or 2 results where the second is an error. + switch { + case typ.NumOut() == 1: + return true + case typ.NumOut() == 2 && typ.Out(1) == errorType: + return true + } + return false +} + +// findFunction looks for a function in the template, and global map. +func findFunction(name string) (reflect.Value, bool) { + if fn := builtinFuncs[name]; fn.IsValid() { + return fn, true + } + return reflect.Value{}, false +} + +// Indexing. + +// index returns the result of indexing its first argument by the following +// arguments. Thus "index x 1 2 3" is, in Go syntax, x[1][2][3]. Each +// indexed item must be a map, slice, or array. +func index(item interface{}, indices ...interface{}) (interface{}, error) { + v := reflect.ValueOf(item) + for _, i := range indices { + index := reflect.ValueOf(i) + var isNil bool + if v, isNil = indirect(v); isNil { + return nil, fmt.Errorf("index of nil pointer") + } + switch v.Kind() { + case reflect.Array, reflect.Slice, reflect.String: + var x int64 + switch index.Kind() { + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + x = index.Int() + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + x = int64(index.Uint()) + default: + return nil, fmt.Errorf("cannot index slice/array with type %s", index.Type()) + } + if x < 0 || x >= int64(v.Len()) { + return nil, fmt.Errorf("index out of range: %d", x) + } + v = v.Index(int(x)) + case reflect.Map: + if !index.IsValid() { + index = reflect.Zero(v.Type().Key()) + } + if !index.Type().AssignableTo(v.Type().Key()) { + return nil, fmt.Errorf("%s is not index type for %s", index.Type(), v.Type()) + } + if x := v.MapIndex(index); x.IsValid() { + v = x + } else { + v = reflect.Zero(v.Type().Elem()) + } + default: + return nil, fmt.Errorf("can't index item of type %s", v.Type()) + } + } + return v.Interface(), nil +} + +// Length + +// length returns the length of the item, with an error if it has no defined length. +func length(item interface{}) (int, error) { + v, isNil := indirect(reflect.ValueOf(item)) + if isNil { + return 0, fmt.Errorf("len of nil pointer") + } + switch v.Kind() { + case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice, reflect.String: + return v.Len(), nil + } + return 0, fmt.Errorf("len of type %s", v.Type()) +} + +// Function invocation + +// call returns the result of evaluating the first argument as a function. +// The function must return 1 result, or 2 results, the second of which is an error. +func call(fn interface{}, args ...interface{}) (interface{}, error) { + v := reflect.ValueOf(fn) + typ := v.Type() + if typ.Kind() != reflect.Func { + return nil, fmt.Errorf("non-function of type %s", typ) + } + if !goodFunc(typ) { + return nil, fmt.Errorf("function called with %d args; should be 1 or 2", typ.NumOut()) + } + numIn := typ.NumIn() + var dddType reflect.Type + if typ.IsVariadic() { + if len(args) < numIn-1 { + return nil, fmt.Errorf("wrong number of args: got %d want at least %d", len(args), numIn-1) + } + dddType = typ.In(numIn - 1).Elem() + } else { + if len(args) != numIn { + return nil, fmt.Errorf("wrong number of args: got %d want %d", len(args), numIn) + } + } + argv := make([]reflect.Value, len(args)) + for i, arg := range args { + value := reflect.ValueOf(arg) + // Compute the expected type. Clumsy because of variadics. + var argType reflect.Type + if !typ.IsVariadic() || i < numIn-1 { + argType = typ.In(i) + } else { + argType = dddType + } + if !value.IsValid() && canBeNil(argType) { + value = reflect.Zero(argType) + } + if !value.Type().AssignableTo(argType) { + return nil, fmt.Errorf("arg %d has type %s; should be %s", i, value.Type(), argType) + } + argv[i] = value + } + result := v.Call(argv) + if len(result) == 2 && !result[1].IsNil() { + return result[0].Interface(), result[1].Interface().(error) + } + return result[0].Interface(), nil +} + +// Boolean logic. + +func truth(a interface{}) bool { + t, _ := isTrue(reflect.ValueOf(a)) + return t +} + +// and computes the Boolean AND of its arguments, returning +// the first false argument it encounters, or the last argument. +func and(arg0 interface{}, args ...interface{}) interface{} { + if !truth(arg0) { + return arg0 + } + for i := range args { + arg0 = args[i] + if !truth(arg0) { + break + } + } + return arg0 +} + +// or computes the Boolean OR of its arguments, returning +// the first true argument it encounters, or the last argument. +func or(arg0 interface{}, args ...interface{}) interface{} { + if truth(arg0) { + return arg0 + } + for i := range args { + arg0 = args[i] + if truth(arg0) { + break + } + } + return arg0 +} + +// not returns the Boolean negation of its argument. +func not(arg interface{}) (truth bool) { + truth, _ = isTrue(reflect.ValueOf(arg)) + return !truth +} + +// Comparison. + +// TODO: Perhaps allow comparison between signed and unsigned integers. + +var ( + errBadComparisonType = errors.New("invalid type for comparison") + errBadComparison = errors.New("incompatible types for comparison") + errNoComparison = errors.New("missing argument for comparison") +) + +type kind int + +const ( + invalidKind kind = iota + boolKind + complexKind + intKind + floatKind + integerKind + stringKind + uintKind +) + +func basicKind(v reflect.Value) (kind, error) { + switch v.Kind() { + case reflect.Bool: + return boolKind, nil + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + return intKind, nil + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + return uintKind, nil + case reflect.Float32, reflect.Float64: + return floatKind, nil + case reflect.Complex64, reflect.Complex128: + return complexKind, nil + case reflect.String: + return stringKind, nil + } + return invalidKind, errBadComparisonType +} + +// eq evaluates the comparison a == b || a == c || ... +func eq(arg1 interface{}, arg2 ...interface{}) (bool, error) { + v1 := reflect.ValueOf(arg1) + k1, err := basicKind(v1) + if err != nil { + return false, err + } + if len(arg2) == 0 { + return false, errNoComparison + } + for _, arg := range arg2 { + v2 := reflect.ValueOf(arg) + k2, err := basicKind(v2) + if err != nil { + return false, err + } + truth := false + if k1 != k2 { + // Special case: Can compare integer values regardless of type's sign. + switch { + case k1 == intKind && k2 == uintKind: + truth = v1.Int() >= 0 && uint64(v1.Int()) == v2.Uint() + case k1 == uintKind && k2 == intKind: + truth = v2.Int() >= 0 && v1.Uint() == uint64(v2.Int()) + default: + return false, errBadComparison + } + } else { + switch k1 { + case boolKind: + truth = v1.Bool() == v2.Bool() + case complexKind: + truth = v1.Complex() == v2.Complex() + case floatKind: + truth = v1.Float() == v2.Float() + case intKind: + truth = v1.Int() == v2.Int() + case stringKind: + truth = v1.String() == v2.String() + case uintKind: + truth = v1.Uint() == v2.Uint() + default: + panic("invalid kind") + } + } + if truth { + return true, nil + } + } + return false, nil +} + +// ne evaluates the comparison a != b. +func ne(arg1, arg2 interface{}) (bool, error) { + // != is the inverse of ==. + equal, err := eq(arg1, arg2) + return !equal, err +} + +// lt evaluates the comparison a < b. +func lt(arg1, arg2 interface{}) (bool, error) { + v1 := reflect.ValueOf(arg1) + k1, err := basicKind(v1) + if err != nil { + return false, err + } + v2 := reflect.ValueOf(arg2) + k2, err := basicKind(v2) + if err != nil { + return false, err + } + truth := false + if k1 != k2 { + // Special case: Can compare integer values regardless of type's sign. + switch { + case k1 == intKind && k2 == uintKind: + truth = v1.Int() < 0 || uint64(v1.Int()) < v2.Uint() + case k1 == uintKind && k2 == intKind: + truth = v2.Int() >= 0 && v1.Uint() < uint64(v2.Int()) + default: + return false, errBadComparison + } + } else { + switch k1 { + case boolKind, complexKind: + return false, errBadComparisonType + case floatKind: + truth = v1.Float() < v2.Float() + case intKind: + truth = v1.Int() < v2.Int() + case stringKind: + truth = v1.String() < v2.String() + case uintKind: + truth = v1.Uint() < v2.Uint() + default: + panic("invalid kind") + } + } + return truth, nil +} + +// le evaluates the comparison <= b. +func le(arg1, arg2 interface{}) (bool, error) { + // <= is < or ==. + lessThan, err := lt(arg1, arg2) + if lessThan || err != nil { + return lessThan, err + } + return eq(arg1, arg2) +} + +// gt evaluates the comparison a > b. +func gt(arg1, arg2 interface{}) (bool, error) { + // > is the inverse of <=. + lessOrEqual, err := le(arg1, arg2) + if err != nil { + return false, err + } + return !lessOrEqual, nil +} + +// ge evaluates the comparison a >= b. +func ge(arg1, arg2 interface{}) (bool, error) { + // >= is the inverse of <. + lessThan, err := lt(arg1, arg2) + if err != nil { + return false, err + } + return !lessThan, nil +} + +// HTML escaping. + +var ( + htmlQuot = []byte(""") // shorter than """ + htmlApos = []byte("'") // shorter than "'" and apos was not in HTML until HTML5 + htmlAmp = []byte("&") + htmlLt = []byte("<") + htmlGt = []byte(">") +) + +// HTMLEscape writes to w the escaped HTML equivalent of the plain text data b. +func HTMLEscape(w io.Writer, b []byte) { + last := 0 + for i, c := range b { + var html []byte + switch c { + case '"': + html = htmlQuot + case '\'': + html = htmlApos + case '&': + html = htmlAmp + case '<': + html = htmlLt + case '>': + html = htmlGt + default: + continue + } + w.Write(b[last:i]) + w.Write(html) + last = i + 1 + } + w.Write(b[last:]) +} + +// HTMLEscapeString returns the escaped HTML equivalent of the plain text data s. +func HTMLEscapeString(s string) string { + // Avoid allocation if we can. + if strings.IndexAny(s, `'"&<>`) < 0 { + return s + } + var b bytes.Buffer + HTMLEscape(&b, []byte(s)) + return b.String() +} + +// HTMLEscaper returns the escaped HTML equivalent of the textual +// representation of its arguments. +func HTMLEscaper(args ...interface{}) string { + return HTMLEscapeString(evalArgs(args)) +} + +// JavaScript escaping. + +var ( + jsLowUni = []byte(`\u00`) + hex = []byte("0123456789ABCDEF") + + jsBackslash = []byte(`\\`) + jsApos = []byte(`\'`) + jsQuot = []byte(`\"`) + jsLt = []byte(`\x3C`) + jsGt = []byte(`\x3E`) +) + +// JSEscape writes to w the escaped JavaScript equivalent of the plain text data b. +func JSEscape(w io.Writer, b []byte) { + last := 0 + for i := 0; i < len(b); i++ { + c := b[i] + + if !jsIsSpecial(rune(c)) { + // fast path: nothing to do + continue + } + w.Write(b[last:i]) + + if c < utf8.RuneSelf { + // Quotes, slashes and angle brackets get quoted. + // Control characters get written as \u00XX. + switch c { + case '\\': + w.Write(jsBackslash) + case '\'': + w.Write(jsApos) + case '"': + w.Write(jsQuot) + case '<': + w.Write(jsLt) + case '>': + w.Write(jsGt) + default: + w.Write(jsLowUni) + t, b := c>>4, c&0x0f + w.Write(hex[t : t+1]) + w.Write(hex[b : b+1]) + } + } else { + // Unicode rune. + r, size := utf8.DecodeRune(b[i:]) + if unicode.IsPrint(r) { + w.Write(b[i : i+size]) + } else { + fmt.Fprintf(w, "\\u%04X", r) + } + i += size - 1 + } + last = i + 1 + } + w.Write(b[last:]) +} + +// JSEscapeString returns the escaped JavaScript equivalent of the plain text data s. +func JSEscapeString(s string) string { + // Avoid allocation if we can. + if strings.IndexFunc(s, jsIsSpecial) < 0 { + return s + } + var b bytes.Buffer + JSEscape(&b, []byte(s)) + return b.String() +} + +func jsIsSpecial(r rune) bool { + switch r { + case '\\', '\'', '"', '<', '>': + return true + } + return r < ' ' || utf8.RuneSelf <= r +} + +// JSEscaper returns the escaped JavaScript equivalent of the textual +// representation of its arguments. +func JSEscaper(args ...interface{}) string { + return JSEscapeString(evalArgs(args)) +} + +// URLQueryEscaper returns the escaped value of the textual representation of +// its arguments in a form suitable for embedding in a URL query. +func URLQueryEscaper(args ...interface{}) string { + return url.QueryEscape(evalArgs(args)) +} + +// evalArgs formats the list of arguments into a string. It is therefore equivalent to +// fmt.Sprint(args...) +// except that each argument is indirected (if a pointer), as required, +// using the same rules as the default string evaluation during template +// execution. +func evalArgs(args []interface{}) string { + ok := false + var s string + // Fast path for simple common case. + if len(args) == 1 { + s, ok = args[0].(string) + } + if !ok { + for i, arg := range args { + a, ok := printableValue(reflect.ValueOf(arg)) + if ok { + args[i] = a + } // else left fmt do its thing + } + s = fmt.Sprint(args...) + } + return s +}