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-rw-r--r--libgo/go/template/exec.go673
1 files changed, 0 insertions, 673 deletions
diff --git a/libgo/go/template/exec.go b/libgo/go/template/exec.go
deleted file mode 100644
index 228477c..0000000
--- a/libgo/go/template/exec.go
+++ /dev/null
@@ -1,673 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package template
-
-import (
- "fmt"
- "io"
- "reflect"
- "runtime"
- "strings"
- "template/parse"
-)
-
-// state represents the state of an execution. It's not part of the
-// template so that multiple executions of the same template
-// can execute in parallel.
-type state struct {
- tmpl *Template
- wr io.Writer
- line int // line number for errors
- vars []variable // push-down stack of variable values.
-}
-
-// variable holds the dynamic value of a variable such as $, $x etc.
-type variable struct {
- name string
- value reflect.Value
-}
-
-// push pushes a new variable on the stack.
-func (s *state) push(name string, value reflect.Value) {
- s.vars = append(s.vars, variable{name, value})
-}
-
-// mark returns the length of the variable stack.
-func (s *state) mark() int {
- return len(s.vars)
-}
-
-// pop pops the variable stack up to the mark.
-func (s *state) pop(mark int) {
- s.vars = s.vars[0:mark]
-}
-
-// setVar overwrites the top-nth variable on the stack. Used by range iterations.
-func (s *state) setVar(n int, value reflect.Value) {
- s.vars[len(s.vars)-n].value = value
-}
-
-// varValue returns the value of the named variable.
-func (s *state) varValue(name string) reflect.Value {
- for i := s.mark() - 1; i >= 0; i-- {
- if s.vars[i].name == name {
- return s.vars[i].value
- }
- }
- s.errorf("undefined variable: %s", name)
- return zero
-}
-
-var zero reflect.Value
-
-// errorf formats the error and terminates processing.
-func (s *state) errorf(format string, args ...interface{}) {
- format = fmt.Sprintf("template: %s:%d: %s", s.tmpl.Name(), s.line, format)
- panic(fmt.Errorf(format, args...))
-}
-
-// error terminates processing.
-func (s *state) error(err error) {
- s.errorf("%s", err)
-}
-
-// errRecover is the handler that turns panics into returns from the top
-// level of Parse.
-func errRecover(errp *error) {
- e := recover()
- if e != nil {
- if _, ok := e.(runtime.Error); ok {
- panic(e)
- }
- *errp = e.(error)
- }
-}
-
-// Execute applies a parsed template to the specified data object,
-// writing the output to wr.
-func (t *Template) Execute(wr io.Writer, data interface{}) (err error) {
- defer errRecover(&err)
- value := reflect.ValueOf(data)
- state := &state{
- tmpl: t,
- wr: wr,
- line: 1,
- vars: []variable{{"$", value}},
- }
- if t.Tree == nil || t.Root == nil {
- state.errorf("must be parsed before execution")
- }
- state.walk(value, t.Root)
- return
-}
-
-// Walk functions step through the major pieces of the template structure,
-// generating output as they go.
-func (s *state) walk(dot reflect.Value, n parse.Node) {
- switch n := n.(type) {
- case *parse.ActionNode:
- s.line = n.Line
- // Do not pop variables so they persist until next end.
- // Also, if the action declares variables, don't print the result.
- val := s.evalPipeline(dot, n.Pipe)
- if len(n.Pipe.Decl) == 0 {
- s.printValue(n, val)
- }
- case *parse.IfNode:
- s.line = n.Line
- s.walkIfOrWith(parse.NodeIf, dot, n.Pipe, n.List, n.ElseList)
- case *parse.ListNode:
- for _, node := range n.Nodes {
- s.walk(dot, node)
- }
- case *parse.RangeNode:
- s.line = n.Line
- s.walkRange(dot, n)
- case *parse.TemplateNode:
- s.line = n.Line
- s.walkTemplate(dot, n)
- case *parse.TextNode:
- if _, err := s.wr.Write(n.Text); err != nil {
- s.error(err)
- }
- case *parse.WithNode:
- s.line = n.Line
- s.walkIfOrWith(parse.NodeWith, dot, n.Pipe, n.List, n.ElseList)
- default:
- s.errorf("unknown node: %s", n)
- }
-}
-
-// walkIfOrWith walks an 'if' or 'with' node. The two control structures
-// are identical in behavior except that 'with' sets dot.
-func (s *state) walkIfOrWith(typ parse.NodeType, dot reflect.Value, pipe *parse.PipeNode, list, elseList *parse.ListNode) {
- defer s.pop(s.mark())
- val := s.evalPipeline(dot, pipe)
- truth, ok := isTrue(val)
- if !ok {
- s.errorf("if/with can't use %v", val)
- }
- if truth {
- if typ == parse.NodeWith {
- s.walk(val, list)
- } else {
- s.walk(dot, list)
- }
- } else if elseList != nil {
- s.walk(dot, elseList)
- }
-}
-
-// isTrue returns 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
-}
-
-func (s *state) walkRange(dot reflect.Value, r *parse.RangeNode) {
- defer s.pop(s.mark())
- val, _ := indirect(s.evalPipeline(dot, r.Pipe))
- // mark top of stack before any variables in the body are pushed.
- mark := s.mark()
- oneIteration := func(index, elem reflect.Value) {
- // Set top var (lexically the second if there are two) to the element.
- if len(r.Pipe.Decl) > 0 {
- s.setVar(1, elem)
- }
- // Set next var (lexically the first if there are two) to the index.
- if len(r.Pipe.Decl) > 1 {
- s.setVar(2, index)
- }
- s.walk(elem, r.List)
- s.pop(mark)
- }
- switch val.Kind() {
- case reflect.Array, reflect.Slice:
- if val.Len() == 0 {
- break
- }
- for i := 0; i < val.Len(); i++ {
- oneIteration(reflect.ValueOf(i), val.Index(i))
- }
- return
- case reflect.Map:
- if val.Len() == 0 {
- break
- }
- for _, key := range val.MapKeys() {
- oneIteration(key, val.MapIndex(key))
- }
- return
- case reflect.Chan:
- if val.IsNil() {
- break
- }
- i := 0
- for ; ; i++ {
- elem, ok := val.Recv()
- if !ok {
- break
- }
- oneIteration(reflect.ValueOf(i), elem)
- }
- if i == 0 {
- break
- }
- return
- case reflect.Invalid:
- break // An invalid value is likely a nil map, etc. and acts like an empty map.
- default:
- s.errorf("range can't iterate over %v", val)
- }
- if r.ElseList != nil {
- s.walk(dot, r.ElseList)
- }
-}
-
-func (s *state) walkTemplate(dot reflect.Value, t *parse.TemplateNode) {
- set := s.tmpl.set
- if set == nil {
- s.errorf("no set defined in which to invoke template named %q", t.Name)
- }
- tmpl := set.tmpl[t.Name]
- if tmpl == nil {
- s.errorf("template %q not in set", t.Name)
- }
- // Variables declared by the pipeline persist.
- dot = s.evalPipeline(dot, t.Pipe)
- newState := *s
- newState.tmpl = tmpl
- // No dynamic scoping: template invocations inherit no variables.
- newState.vars = []variable{{"$", dot}}
- newState.walk(dot, tmpl.Root)
-}
-
-// Eval functions evaluate pipelines, commands, and their elements and extract
-// values from the data structure by examining fields, calling methods, and so on.
-// The printing of those values happens only through walk functions.
-
-// evalPipeline returns the value acquired by evaluating a pipeline. If the
-// pipeline has a variable declaration, the variable will be pushed on the
-// stack. Callers should therefore pop the stack after they are finished
-// executing commands depending on the pipeline value.
-func (s *state) evalPipeline(dot reflect.Value, pipe *parse.PipeNode) (value reflect.Value) {
- if pipe == nil {
- return
- }
- for _, cmd := range pipe.Cmds {
- value = s.evalCommand(dot, cmd, value) // previous value is this one's final arg.
- // If the object has type interface{}, dig down one level to the thing inside.
- if value.Kind() == reflect.Interface && value.Type().NumMethod() == 0 {
- value = reflect.ValueOf(value.Interface()) // lovely!
- }
- }
- for _, variable := range pipe.Decl {
- s.push(variable.Ident[0], value)
- }
- return value
-}
-
-func (s *state) notAFunction(args []parse.Node, final reflect.Value) {
- if len(args) > 1 || final.IsValid() {
- s.errorf("can't give argument to non-function %s", args[0])
- }
-}
-
-func (s *state) evalCommand(dot reflect.Value, cmd *parse.CommandNode, final reflect.Value) reflect.Value {
- firstWord := cmd.Args[0]
- switch n := firstWord.(type) {
- case *parse.FieldNode:
- return s.evalFieldNode(dot, n, cmd.Args, final)
- case *parse.IdentifierNode:
- // Must be a function.
- return s.evalFunction(dot, n.Ident, cmd.Args, final)
- case *parse.VariableNode:
- return s.evalVariableNode(dot, n, cmd.Args, final)
- }
- s.notAFunction(cmd.Args, final)
- switch word := firstWord.(type) {
- case *parse.BoolNode:
- return reflect.ValueOf(word.True)
- case *parse.DotNode:
- return dot
- case *parse.NumberNode:
- return s.idealConstant(word)
- case *parse.StringNode:
- return reflect.ValueOf(word.Text)
- }
- s.errorf("can't evaluate command %q", firstWord)
- panic("not reached")
-}
-
-// idealConstant is called to return the value of a number in a context where
-// we don't know the type. In that case, the syntax of the number tells us
-// its type, and we use Go rules to resolve. Note there is no such thing as
-// a uint ideal constant in this situation - the value must be of int type.
-func (s *state) idealConstant(constant *parse.NumberNode) reflect.Value {
- // These are ideal constants but we don't know the type
- // and we have no context. (If it was a method argument,
- // we'd know what we need.) The syntax guides us to some extent.
- switch {
- case constant.IsComplex:
- return reflect.ValueOf(constant.Complex128) // incontrovertible.
- case constant.IsFloat && strings.IndexAny(constant.Text, ".eE") >= 0:
- return reflect.ValueOf(constant.Float64)
- case constant.IsInt:
- n := int(constant.Int64)
- if int64(n) != constant.Int64 {
- s.errorf("%s overflows int", constant.Text)
- }
- return reflect.ValueOf(n)
- case constant.IsUint:
- s.errorf("%s overflows int", constant.Text)
- }
- return zero
-}
-
-func (s *state) evalFieldNode(dot reflect.Value, field *parse.FieldNode, args []parse.Node, final reflect.Value) reflect.Value {
- return s.evalFieldChain(dot, dot, field.Ident, args, final)
-}
-
-func (s *state) evalVariableNode(dot reflect.Value, v *parse.VariableNode, args []parse.Node, final reflect.Value) reflect.Value {
- // $x.Field has $x as the first ident, Field as the second. Eval the var, then the fields.
- value := s.varValue(v.Ident[0])
- if len(v.Ident) == 1 {
- return value
- }
- return s.evalFieldChain(dot, value, v.Ident[1:], args, final)
-}
-
-// evalFieldChain evaluates .X.Y.Z possibly followed by arguments.
-// dot is the environment in which to evaluate arguments, while
-// receiver is the value being walked along the chain.
-func (s *state) evalFieldChain(dot, receiver reflect.Value, ident []string, args []parse.Node, final reflect.Value) reflect.Value {
- n := len(ident)
- for i := 0; i < n-1; i++ {
- receiver = s.evalField(dot, ident[i], nil, zero, receiver)
- }
- // Now if it's a method, it gets the arguments.
- return s.evalField(dot, ident[n-1], args, final, receiver)
-}
-
-func (s *state) evalFunction(dot reflect.Value, name string, args []parse.Node, final reflect.Value) reflect.Value {
- function, ok := findFunction(name, s.tmpl, s.tmpl.set)
- if !ok {
- s.errorf("%q is not a defined function", name)
- }
- return s.evalCall(dot, function, name, args, final)
-}
-
-// evalField evaluates an expression like (.Field) or (.Field arg1 arg2).
-// The 'final' argument represents the return value from the preceding
-// value of the pipeline, if any.
-func (s *state) evalField(dot reflect.Value, fieldName string, args []parse.Node, final, receiver reflect.Value) reflect.Value {
- if !receiver.IsValid() {
- return zero
- }
- typ := receiver.Type()
- receiver, _ = indirect(receiver)
- // Unless it's an interface, need to get to a value of type *T to guarantee
- // we see all methods of T and *T.
- ptr := receiver
- if ptr.Kind() != reflect.Interface && ptr.CanAddr() {
- ptr = ptr.Addr()
- }
- if method, ok := methodByName(ptr, fieldName); ok {
- return s.evalCall(dot, method, fieldName, args, final)
- }
- hasArgs := len(args) > 1 || final.IsValid()
- // It's not a method; is it a field of a struct?
- receiver, isNil := indirect(receiver)
- if receiver.Kind() == reflect.Struct {
- tField, ok := receiver.Type().FieldByName(fieldName)
- if ok {
- field := receiver.FieldByIndex(tField.Index)
- if hasArgs {
- s.errorf("%s is not a method but has arguments", fieldName)
- }
- if tField.PkgPath == "" { // field is exported
- return field
- }
- }
- }
- // If it's a map, attempt to use the field name as a key.
- if receiver.Kind() == reflect.Map {
- nameVal := reflect.ValueOf(fieldName)
- if nameVal.Type().AssignableTo(receiver.Type().Key()) {
- if hasArgs {
- s.errorf("%s is not a method but has arguments", fieldName)
- }
- return receiver.MapIndex(nameVal)
- }
- }
- if isNil {
- s.errorf("nil pointer evaluating %s.%s", typ, fieldName)
- }
- s.errorf("can't evaluate field %s in type %s", fieldName, typ)
- panic("not reached")
-}
-
-// TODO: delete when reflect's own MethodByName is released.
-func methodByName(receiver reflect.Value, name string) (reflect.Value, bool) {
- typ := receiver.Type()
- for i := 0; i < typ.NumMethod(); i++ {
- if typ.Method(i).Name == name {
- return receiver.Method(i), true // This value includes the receiver.
- }
- }
- return zero, false
-}
-
-var (
- osErrorType = reflect.TypeOf((*error)(nil)).Elem()
- fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
-)
-
-// evalCall executes a function or method call. If it's a method, fun already has the receiver bound, so
-// it looks just like a function call. The arg list, if non-nil, includes (in the manner of the shell), arg[0]
-// as the function itself.
-func (s *state) evalCall(dot, fun reflect.Value, name string, args []parse.Node, final reflect.Value) reflect.Value {
- if args != nil {
- args = args[1:] // Zeroth arg is function name/node; not passed to function.
- }
- typ := fun.Type()
- numIn := len(args)
- if final.IsValid() {
- numIn++
- }
- numFixed := len(args)
- if typ.IsVariadic() {
- numFixed = typ.NumIn() - 1 // last arg is the variadic one.
- if numIn < numFixed {
- s.errorf("wrong number of args for %s: want at least %d got %d", name, typ.NumIn()-1, len(args))
- }
- } else if numIn < typ.NumIn()-1 || !typ.IsVariadic() && numIn != typ.NumIn() {
- s.errorf("wrong number of args for %s: want %d got %d", name, typ.NumIn(), len(args))
- }
- if !goodFunc(typ) {
- s.errorf("can't handle multiple results from method/function %q", name)
- }
- // Build the arg list.
- argv := make([]reflect.Value, numIn)
- // Args must be evaluated. Fixed args first.
- i := 0
- for ; i < numFixed; i++ {
- argv[i] = s.evalArg(dot, typ.In(i), args[i])
- }
- // Now the ... args.
- if typ.IsVariadic() {
- argType := typ.In(typ.NumIn() - 1).Elem() // Argument is a slice.
- for ; i < len(args); i++ {
- argv[i] = s.evalArg(dot, argType, args[i])
- }
- }
- // Add final value if necessary.
- if final.IsValid() {
- argv[i] = final
- }
- result := fun.Call(argv)
- // If we have an error that is not nil, stop execution and return that error to the caller.
- if len(result) == 2 && !result[1].IsNil() {
- s.errorf("error calling %s: %s", name, result[1].Interface().(error))
- }
- return result[0]
-}
-
-// validateType guarantees that the value is valid and assignable to the type.
-func (s *state) validateType(value reflect.Value, typ reflect.Type) reflect.Value {
- if !value.IsValid() {
- s.errorf("invalid value; expected %s", typ)
- }
- if !value.Type().AssignableTo(typ) {
- // Does one dereference or indirection work? We could do more, as we
- // do with method receivers, but that gets messy and method receivers
- // are much more constrained, so it makes more sense there than here.
- // Besides, one is almost always all you need.
- switch {
- case value.Kind() == reflect.Ptr && value.Type().Elem().AssignableTo(typ):
- value = value.Elem()
- case reflect.PtrTo(value.Type()).AssignableTo(typ) && value.CanAddr():
- value = value.Addr()
- default:
- s.errorf("wrong type for value; expected %s; got %s", typ, value.Type())
- }
- }
- return value
-}
-
-func (s *state) evalArg(dot reflect.Value, typ reflect.Type, n parse.Node) reflect.Value {
- switch arg := n.(type) {
- case *parse.DotNode:
- return s.validateType(dot, typ)
- case *parse.FieldNode:
- return s.validateType(s.evalFieldNode(dot, arg, []parse.Node{n}, zero), typ)
- case *parse.VariableNode:
- return s.validateType(s.evalVariableNode(dot, arg, nil, zero), typ)
- }
- switch typ.Kind() {
- case reflect.Bool:
- return s.evalBool(typ, n)
- case reflect.Complex64, reflect.Complex128:
- return s.evalComplex(typ, n)
- case reflect.Float32, reflect.Float64:
- return s.evalFloat(typ, n)
- case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
- return s.evalInteger(typ, n)
- case reflect.Interface:
- if typ.NumMethod() == 0 {
- return s.evalEmptyInterface(dot, n)
- }
- case reflect.String:
- return s.evalString(typ, n)
- case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
- return s.evalUnsignedInteger(typ, n)
- }
- s.errorf("can't handle %s for arg of type %s", n, typ)
- panic("not reached")
-}
-
-func (s *state) evalBool(typ reflect.Type, n parse.Node) reflect.Value {
- if n, ok := n.(*parse.BoolNode); ok {
- value := reflect.New(typ).Elem()
- value.SetBool(n.True)
- return value
- }
- s.errorf("expected bool; found %s", n)
- panic("not reached")
-}
-
-func (s *state) evalString(typ reflect.Type, n parse.Node) reflect.Value {
- if n, ok := n.(*parse.StringNode); ok {
- value := reflect.New(typ).Elem()
- value.SetString(n.Text)
- return value
- }
- s.errorf("expected string; found %s", n)
- panic("not reached")
-}
-
-func (s *state) evalInteger(typ reflect.Type, n parse.Node) reflect.Value {
- if n, ok := n.(*parse.NumberNode); ok && n.IsInt {
- value := reflect.New(typ).Elem()
- value.SetInt(n.Int64)
- return value
- }
- s.errorf("expected integer; found %s", n)
- panic("not reached")
-}
-
-func (s *state) evalUnsignedInteger(typ reflect.Type, n parse.Node) reflect.Value {
- if n, ok := n.(*parse.NumberNode); ok && n.IsUint {
- value := reflect.New(typ).Elem()
- value.SetUint(n.Uint64)
- return value
- }
- s.errorf("expected unsigned integer; found %s", n)
- panic("not reached")
-}
-
-func (s *state) evalFloat(typ reflect.Type, n parse.Node) reflect.Value {
- if n, ok := n.(*parse.NumberNode); ok && n.IsFloat {
- value := reflect.New(typ).Elem()
- value.SetFloat(n.Float64)
- return value
- }
- s.errorf("expected float; found %s", n)
- panic("not reached")
-}
-
-func (s *state) evalComplex(typ reflect.Type, n parse.Node) reflect.Value {
- if n, ok := n.(*parse.NumberNode); ok && n.IsComplex {
- value := reflect.New(typ).Elem()
- value.SetComplex(n.Complex128)
- return value
- }
- s.errorf("expected complex; found %s", n)
- panic("not reached")
-}
-
-func (s *state) evalEmptyInterface(dot reflect.Value, n parse.Node) reflect.Value {
- switch n := n.(type) {
- case *parse.BoolNode:
- return reflect.ValueOf(n.True)
- case *parse.DotNode:
- return dot
- case *parse.FieldNode:
- return s.evalFieldNode(dot, n, nil, zero)
- case *parse.IdentifierNode:
- return s.evalFunction(dot, n.Ident, nil, zero)
- case *parse.NumberNode:
- return s.idealConstant(n)
- case *parse.StringNode:
- return reflect.ValueOf(n.Text)
- case *parse.VariableNode:
- return s.evalVariableNode(dot, n, nil, zero)
- }
- s.errorf("can't handle assignment of %s to empty interface argument", n)
- panic("not reached")
-}
-
-// 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
-}
-
-// printValue writes the textual representation of the value to the output of
-// the template.
-func (s *state) printValue(n parse.Node, v reflect.Value) {
- if v.Kind() == reflect.Ptr {
- v, _ = indirect(v) // fmt.Fprint handles nil.
- }
- if !v.IsValid() {
- fmt.Fprint(s.wr, "<no value>")
- return
- }
-
- if !v.Type().Implements(fmtStringerType) {
- if v.CanAddr() && reflect.PtrTo(v.Type()).Implements(fmtStringerType) {
- v = v.Addr()
- } else {
- switch v.Kind() {
- case reflect.Chan, reflect.Func:
- s.errorf("can't print %s of type %s", n, v.Type())
- }
- }
- }
- fmt.Fprint(s.wr, v.Interface())
-}
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