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-rw-r--r--src/pkg/template/execute.go346
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diff --git a/src/pkg/template/execute.go b/src/pkg/template/execute.go
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--- a/src/pkg/template/execute.go
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@@ -1,346 +0,0 @@
-// Copyright 2009 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.
-
-// Code to execute a parsed template.
-
-package template
-
-import (
- "bytes"
- "io"
- "reflect"
- "strings"
-)
-
-// Internal state for executing a Template. As we evaluate the struct,
-// the data item descends into the fields associated with sections, etc.
-// Parent is used to walk upwards to find variables higher in the tree.
-type state struct {
- parent *state // parent in hierarchy
- data reflect.Value // the driver data for this section etc.
- wr io.Writer // where to send output
- buf [2]bytes.Buffer // alternating buffers used when chaining formatters
-}
-
-func (parent *state) clone(data reflect.Value) *state {
- return &state{parent: parent, data: data, wr: parent.wr}
-}
-
-// Evaluate interfaces and pointers looking for a value that can look up the name, via a
-// struct field, method, or map key, and return the result of the lookup.
-func (t *Template) lookup(st *state, v reflect.Value, name string) reflect.Value {
- for v.IsValid() {
- typ := v.Type()
- if n := v.Type().NumMethod(); n > 0 {
- for i := 0; i < n; i++ {
- m := typ.Method(i)
- mtyp := m.Type
- if m.Name == name && mtyp.NumIn() == 1 && mtyp.NumOut() == 1 {
- if !isExported(name) {
- t.execError(st, t.linenum, "name not exported: %s in type %s", name, st.data.Type())
- }
- return v.Method(i).Call(nil)[0]
- }
- }
- }
- switch av := v; av.Kind() {
- case reflect.Ptr:
- v = av.Elem()
- case reflect.Interface:
- v = av.Elem()
- case reflect.Struct:
- if !isExported(name) {
- t.execError(st, t.linenum, "name not exported: %s in type %s", name, st.data.Type())
- }
- return av.FieldByName(name)
- case reflect.Map:
- if v := av.MapIndex(reflect.ValueOf(name)); v.IsValid() {
- return v
- }
- return reflect.Zero(typ.Elem())
- default:
- return reflect.Value{}
- }
- }
- return v
-}
-
-// indirectPtr returns the item numLevels levels of indirection below the value.
-// It is forgiving: if the value is not a pointer, it returns it rather than giving
-// an error. If the pointer is nil, it is returned as is.
-func indirectPtr(v reflect.Value, numLevels int) reflect.Value {
- for i := numLevels; v.IsValid() && i > 0; i++ {
- if p := v; p.Kind() == reflect.Ptr {
- if p.IsNil() {
- return v
- }
- v = p.Elem()
- } else {
- break
- }
- }
- return v
-}
-
-// Walk v through pointers and interfaces, extracting the elements within.
-func indirect(v reflect.Value) reflect.Value {
-loop:
- for v.IsValid() {
- switch av := v; av.Kind() {
- case reflect.Ptr:
- v = av.Elem()
- case reflect.Interface:
- v = av.Elem()
- default:
- break loop
- }
- }
- return v
-}
-
-// If the data for this template is a struct, find the named variable.
-// Names of the form a.b.c are walked down the data tree.
-// The special name "@" (the "cursor") denotes the current data.
-// The value coming in (st.data) might need indirecting to reach
-// a struct while the return value is not indirected - that is,
-// it represents the actual named field. Leading stars indicate
-// levels of indirection to be applied to the value.
-func (t *Template) findVar(st *state, s string) reflect.Value {
- data := st.data
- flattenedName := strings.TrimLeft(s, "*")
- numStars := len(s) - len(flattenedName)
- s = flattenedName
- if s == "@" {
- return indirectPtr(data, numStars)
- }
- for _, elem := range strings.Split(s, ".") {
- // Look up field; data must be a struct or map.
- data = t.lookup(st, data, elem)
- if !data.IsValid() {
- return reflect.Value{}
- }
- }
- return indirectPtr(data, numStars)
-}
-
-// Is there no data to look at?
-func empty(v reflect.Value) bool {
- v = indirect(v)
- if !v.IsValid() {
- return true
- }
- switch v.Kind() {
- case reflect.Bool:
- return v.Bool() == false
- case reflect.String:
- return v.String() == ""
- case reflect.Struct:
- return false
- case reflect.Map:
- return false
- case reflect.Array:
- return v.Len() == 0
- case reflect.Slice:
- return v.Len() == 0
- }
- return false
-}
-
-// Look up a variable or method, up through the parent if necessary.
-func (t *Template) varValue(name string, st *state) reflect.Value {
- field := t.findVar(st, name)
- if !field.IsValid() {
- if st.parent == nil {
- t.execError(st, t.linenum, "name not found: %s in type %s", name, st.data.Type())
- }
- return t.varValue(name, st.parent)
- }
- return field
-}
-
-func (t *Template) format(wr io.Writer, fmt string, val []interface{}, v *variableElement, st *state) {
- fn := t.formatter(fmt)
- if fn == nil {
- t.execError(st, v.linenum, "missing formatter %s for variable", fmt)
- }
- fn(wr, fmt, val...)
-}
-
-// Evaluate a variable, looking up through the parent if necessary.
-// If it has a formatter attached ({var|formatter}) run that too.
-func (t *Template) writeVariable(v *variableElement, st *state) {
- // Resolve field names
- val := make([]interface{}, len(v.args))
- for i, arg := range v.args {
- if name, ok := arg.(fieldName); ok {
- val[i] = t.varValue(string(name), st).Interface()
- } else {
- val[i] = arg
- }
- }
- for i, fmt := range v.fmts[:len(v.fmts)-1] {
- b := &st.buf[i&1]
- b.Reset()
- t.format(b, fmt, val, v, st)
- val = val[0:1]
- val[0] = b.Bytes()
- }
- t.format(st.wr, v.fmts[len(v.fmts)-1], val, v, st)
-}
-
-// Execute element i. Return next index to execute.
-func (t *Template) executeElement(i int, st *state) int {
- switch elem := t.elems[i].(type) {
- case *textElement:
- st.wr.Write(elem.text)
- return i + 1
- case *literalElement:
- st.wr.Write(elem.text)
- return i + 1
- case *variableElement:
- t.writeVariable(elem, st)
- return i + 1
- case *sectionElement:
- t.executeSection(elem, st)
- return elem.end
- case *repeatedElement:
- t.executeRepeated(elem, st)
- return elem.end
- }
- e := t.elems[i]
- t.execError(st, 0, "internal error: bad directive in execute: %v %T\n", reflect.ValueOf(e).Interface(), e)
- return 0
-}
-
-// Execute the template.
-func (t *Template) execute(start, end int, st *state) {
- for i := start; i < end; {
- i = t.executeElement(i, st)
- }
-}
-
-// Execute a .section
-func (t *Template) executeSection(s *sectionElement, st *state) {
- // Find driver data for this section. It must be in the current struct.
- field := t.varValue(s.field, st)
- if !field.IsValid() {
- t.execError(st, s.linenum, ".section: cannot find field %s in %s", s.field, st.data.Type())
- }
- st = st.clone(field)
- start, end := s.start, s.or
- if !empty(field) {
- // Execute the normal block.
- if end < 0 {
- end = s.end
- }
- } else {
- // Execute the .or block. If it's missing, do nothing.
- start, end = s.or, s.end
- if start < 0 {
- return
- }
- }
- for i := start; i < end; {
- i = t.executeElement(i, st)
- }
-}
-
-// Return the result of calling the Iter method on v, or nil.
-func iter(v reflect.Value) reflect.Value {
- for j := 0; j < v.Type().NumMethod(); j++ {
- mth := v.Type().Method(j)
- fv := v.Method(j)
- ft := fv.Type()
- // TODO(rsc): NumIn() should return 0 here, because ft is from a curried FuncValue.
- if mth.Name != "Iter" || ft.NumIn() != 1 || ft.NumOut() != 1 {
- continue
- }
- ct := ft.Out(0)
- if ct.Kind() != reflect.Chan ||
- ct.ChanDir()&reflect.RecvDir == 0 {
- continue
- }
- return fv.Call(nil)[0]
- }
- return reflect.Value{}
-}
-
-// Execute a .repeated section
-func (t *Template) executeRepeated(r *repeatedElement, st *state) {
- // Find driver data for this section. It must be in the current struct.
- field := t.varValue(r.field, st)
- if !field.IsValid() {
- t.execError(st, r.linenum, ".repeated: cannot find field %s in %s", r.field, st.data.Type())
- }
- field = indirect(field)
-
- start, end := r.start, r.or
- if end < 0 {
- end = r.end
- }
- if r.altstart >= 0 {
- end = r.altstart
- }
- first := true
-
- // Code common to all the loops.
- loopBody := func(newst *state) {
- // .alternates between elements
- if !first && r.altstart >= 0 {
- for i := r.altstart; i < r.altend; {
- i = t.executeElement(i, newst)
- }
- }
- first = false
- for i := start; i < end; {
- i = t.executeElement(i, newst)
- }
- }
-
- if array := field; array.Kind() == reflect.Array || array.Kind() == reflect.Slice {
- for j := 0; j < array.Len(); j++ {
- loopBody(st.clone(array.Index(j)))
- }
- } else if m := field; m.Kind() == reflect.Map {
- for _, key := range m.MapKeys() {
- loopBody(st.clone(m.MapIndex(key)))
- }
- } else if ch := iter(field); ch.IsValid() {
- for {
- e, ok := ch.Recv()
- if !ok {
- break
- }
- loopBody(st.clone(e))
- }
- } else {
- t.execError(st, r.linenum, ".repeated: cannot repeat %s (type %s)",
- r.field, field.Type())
- }
-
- if first {
- // Empty. Execute the .or block, once. If it's missing, do nothing.
- start, end := r.or, r.end
- if start >= 0 {
- newst := st.clone(field)
- for i := start; i < end; {
- i = t.executeElement(i, newst)
- }
- }
- return
- }
-}
-
-// A valid delimiter must contain no space and be non-empty.
-func validDelim(d []byte) bool {
- if len(d) == 0 {
- return false
- }
- for _, c := range d {
- if isSpace(c) {
- return false
- }
- }
- return true
-}