Merge pull request #11738 from daizuozhuo/master

JSONPath template language

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

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
+}

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, "<map[string]int Value> 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)
+}

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())
+}

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)
+}

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)
+		}
+	}
+}

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 "<no value>", 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
+}

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("&#34;") // shorter than "&quot;"
+	htmlApos = []byte("&#39;") // shorter than "&apos;" and apos was not in HTML until HTML5
+	htmlAmp  = []byte("&amp;")
+	htmlLt   = []byte("&lt;")
+	htmlGt   = []byte("&gt;")
+)
+
+// 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
+}