mirror of
https://github.com/gohugoio/hugo.git
synced 2024-12-25 06:21:37 +00:00
379 lines
11 KiB
Go
379 lines
11 KiB
Go
// Copyright 2024 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package template
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import (
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"context"
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"io"
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"reflect"
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"github.com/gohugoio/hugo/common/hreflect"
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"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"
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)
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/*
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This files contains the Hugo related addons. All the other files in this
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package is auto generated.
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*/
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// Export it so we can populate Hugo's func map with it, which makes it faster.
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var GoFuncs = builtinFuncs()
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// Preparer prepares the template before execution.
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type Preparer interface {
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Prepare() (*Template, error)
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}
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// ExecHelper allows some custom eval hooks.
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type ExecHelper interface {
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Init(ctx context.Context, tmpl Preparer)
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GetFunc(ctx context.Context, tmpl Preparer, name string) (reflect.Value, reflect.Value, bool)
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GetMethod(ctx context.Context, tmpl Preparer, receiver reflect.Value, name string) (method reflect.Value, firstArg reflect.Value)
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GetMapValue(ctx context.Context, tmpl Preparer, receiver, key reflect.Value) (reflect.Value, bool)
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OnCalled(ctx context.Context, tmpl Preparer, name string, args []reflect.Value, result reflect.Value)
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}
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// Executer executes a given template.
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type Executer interface {
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ExecuteWithContext(ctx context.Context, p Preparer, wr io.Writer, data any) error
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}
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type executer struct {
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helper ExecHelper
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}
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func NewExecuter(helper ExecHelper) Executer {
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return &executer{helper: helper}
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}
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// Note: The context is currently not fully implemented in Hugo. This is a work in progress.
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func (t *executer) ExecuteWithContext(ctx context.Context, p Preparer, wr io.Writer, data any) error {
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if ctx == nil {
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panic("nil context")
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}
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tmpl, err := p.Prepare()
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if err != nil {
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return err
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}
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value, ok := data.(reflect.Value)
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if !ok {
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value = reflect.ValueOf(data)
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}
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state := &state{
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ctx: ctx,
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helper: t.helper,
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prep: p,
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tmpl: tmpl,
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wr: wr,
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vars: []variable{{"$", value}},
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}
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t.helper.Init(ctx, p)
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return tmpl.executeWithState(state, value)
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}
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// Prepare returns a template ready for execution.
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func (t *Template) Prepare() (*Template, error) {
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return t, nil
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}
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func (t *Template) executeWithState(state *state, value reflect.Value) (err error) {
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defer errRecover(&err)
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if t.Tree == nil || t.Root == nil {
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state.errorf("%q is an incomplete or empty template", t.Name())
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}
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state.walk(value, t.Root)
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return
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}
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// Below are modified structs etc. The changes are marked with "Added for Hugo."
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// state represents the state of an execution. It's not part of the
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// template so that multiple executions of the same template
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// can execute in parallel.
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type state struct {
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tmpl *Template
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ctx context.Context // Added for Hugo. The original data context.
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prep Preparer // Added for Hugo.
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helper ExecHelper // Added for Hugo.
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wr io.Writer
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node parse.Node // current node, for errors
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vars []variable // push-down stack of variable values.
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depth int // the height of the stack of executing templates.
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}
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func (s *state) evalFunction(dot reflect.Value, node *parse.IdentifierNode, cmd parse.Node, args []parse.Node, final reflect.Value) reflect.Value {
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s.at(node)
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name := node.Ident
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var function reflect.Value
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// Added for Hugo.
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var first reflect.Value
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var ok bool
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var isBuiltin bool
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if s.helper != nil {
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isBuiltin = name == "and" || name == "or"
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function, first, ok = s.helper.GetFunc(s.ctx, s.prep, name)
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}
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if !ok {
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function, isBuiltin, ok = findFunction(name, s.tmpl)
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}
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if !ok {
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s.errorf("%q is not a defined function", name)
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}
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if first != zero {
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return s.evalCall(dot, function, isBuiltin, cmd, name, args, final, first)
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}
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return s.evalCall(dot, function, isBuiltin, cmd, name, args, final)
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}
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// evalField evaluates an expression like (.Field) or (.Field arg1 arg2).
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// The 'final' argument represents the return value from the preceding
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// value of the pipeline, if any.
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func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, args []parse.Node, final, receiver reflect.Value) reflect.Value {
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if !receiver.IsValid() {
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if s.tmpl.option.missingKey == mapError { // Treat invalid value as missing map key.
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s.errorf("nil data; no entry for key %q", fieldName)
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}
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return zero
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}
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typ := receiver.Type()
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receiver, isNil := indirect(receiver)
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if receiver.Kind() == reflect.Interface && isNil {
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// Calling a method on a nil interface can't work. The
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// MethodByName method call below would panic.
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s.errorf("nil pointer evaluating %s.%s", typ, fieldName)
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return zero
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}
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// Unless it's an interface, need to get to a value of type *T to guarantee
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// we see all methods of T and *T.
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ptr := receiver
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if ptr.Kind() != reflect.Interface && ptr.Kind() != reflect.Pointer && ptr.CanAddr() {
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ptr = ptr.Addr()
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}
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// Added for Hugo.
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var first reflect.Value
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var method reflect.Value
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if s.helper != nil {
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method, first = s.helper.GetMethod(s.ctx, s.prep, ptr, fieldName)
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} else {
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method = ptr.MethodByName(fieldName)
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}
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if method.IsValid() {
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if first != zero {
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return s.evalCall(dot, method, false, node, fieldName, args, final, first)
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}
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return s.evalCall(dot, method, false, node, fieldName, args, final)
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}
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if method := ptr.MethodByName(fieldName); method.IsValid() {
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return s.evalCall(dot, method, false, node, fieldName, args, final)
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}
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hasArgs := len(args) > 1 || final != missingVal
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// It's not a method; must be a field of a struct or an element of a map.
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switch receiver.Kind() {
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case reflect.Struct:
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tField, ok := receiver.Type().FieldByName(fieldName)
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if ok {
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field, err := receiver.FieldByIndexErr(tField.Index)
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if !tField.IsExported() {
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s.errorf("%s is an unexported field of struct type %s", fieldName, typ)
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}
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if err != nil {
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s.errorf("%v", err)
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}
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// If it's a function, we must call it.
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if hasArgs {
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s.errorf("%s has arguments but cannot be invoked as function", fieldName)
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}
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return field
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}
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case reflect.Map:
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// If it's a map, attempt to use the field name as a key.
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nameVal := reflect.ValueOf(fieldName)
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if nameVal.Type().AssignableTo(receiver.Type().Key()) {
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if hasArgs {
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s.errorf("%s is not a method but has arguments", fieldName)
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}
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var result reflect.Value
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if s.helper != nil {
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// Added for Hugo.
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result, _ = s.helper.GetMapValue(s.ctx, s.prep, receiver, nameVal)
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} else {
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result = receiver.MapIndex(nameVal)
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}
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if !result.IsValid() {
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switch s.tmpl.option.missingKey {
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case mapInvalid:
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// Just use the invalid value.
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case mapZeroValue:
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result = reflect.Zero(receiver.Type().Elem())
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case mapError:
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s.errorf("map has no entry for key %q", fieldName)
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}
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}
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return result
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}
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case reflect.Pointer:
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etyp := receiver.Type().Elem()
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if etyp.Kind() == reflect.Struct {
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if _, ok := etyp.FieldByName(fieldName); !ok {
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// If there's no such field, say "can't evaluate"
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// instead of "nil pointer evaluating".
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break
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}
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}
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if isNil {
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s.errorf("nil pointer evaluating %s.%s", typ, fieldName)
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}
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}
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s.errorf("can't evaluate field %s in type %s", fieldName, typ)
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panic("not reached")
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}
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// evalCall executes a function or method call. If it's a method, fun already has the receiver bound, so
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// it looks just like a function call. The arg list, if non-nil, includes (in the manner of the shell), arg[0]
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// as the function itself.
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func (s *state) evalCall(dot, fun reflect.Value, isBuiltin bool, node parse.Node, name string, args []parse.Node, final reflect.Value, first ...reflect.Value) reflect.Value {
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if args != nil {
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args = args[1:] // Zeroth arg is function name/node; not passed to function.
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}
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typ := fun.Type()
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numFirst := len(first)
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numIn := len(args) + numFirst // Added for Hugo
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if final != missingVal {
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numIn++
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}
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numFixed := len(args) + len(first) // Adjusted for Hugo
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if typ.IsVariadic() {
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numFixed = typ.NumIn() - 1 // last arg is the variadic one.
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if numIn < numFixed {
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s.errorf("wrong number of args for %s: want at least %d got %d", name, typ.NumIn()-1, len(args))
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}
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} else if numIn != typ.NumIn() {
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s.errorf("wrong number of args for %s: want %d got %d", name, typ.NumIn(), numIn)
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}
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if err := goodFunc(name, typ); err != nil {
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s.errorf("%v", err)
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}
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unwrap := func(v reflect.Value) reflect.Value {
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if v.Type() == reflectValueType {
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v = v.Interface().(reflect.Value)
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}
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return v
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}
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// Special case for builtin and/or, which short-circuit.
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if isBuiltin && (name == "and" || name == "or") {
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argType := typ.In(0)
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var v reflect.Value
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for _, arg := range args {
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v = s.evalArg(dot, argType, arg).Interface().(reflect.Value)
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if truth(v) == (name == "or") {
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// This value was already unwrapped
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// by the .Interface().(reflect.Value).
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return v
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}
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}
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if final != missingVal {
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// The last argument to and/or is coming from
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// the pipeline. We didn't short circuit on an earlier
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// argument, so we are going to return this one.
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// We don't have to evaluate final, but we do
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// have to check its type. Then, since we are
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// going to return it, we have to unwrap it.
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v = unwrap(s.validateType(final, argType))
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}
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return v
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}
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// Build the arg list.
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argv := make([]reflect.Value, numIn)
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// Args must be evaluated. Fixed args first.
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i := len(first) // Adjusted for Hugo.
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for ; i < numFixed && i < len(args)+numFirst; i++ { // Adjusted for Hugo.
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argv[i] = s.evalArg(dot, typ.In(i), args[i-numFirst]) // Adjusted for Hugo.
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}
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// Now the ... args.
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if typ.IsVariadic() {
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argType := typ.In(typ.NumIn() - 1).Elem() // Argument is a slice.
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for ; i < len(args)+numFirst; i++ { // Adjusted for Hugo.
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argv[i] = s.evalArg(dot, argType, args[i-numFirst]) // Adjusted for Hugo.
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}
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}
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// Add final value if necessary.
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if final != missingVal {
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t := typ.In(typ.NumIn() - 1)
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if typ.IsVariadic() {
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if numIn-1 < numFixed {
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// The added final argument corresponds to a fixed parameter of the function.
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// Validate against the type of the actual parameter.
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t = typ.In(numIn - 1)
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} else {
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// The added final argument corresponds to the variadic part.
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// Validate against the type of the elements of the variadic slice.
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t = t.Elem()
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}
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}
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argv[i] = s.validateType(final, t)
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}
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// Special case for the "call" builtin.
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// Insert the name of the callee function as the first argument.
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if isBuiltin && name == "call" {
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calleeName := args[0].String()
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argv = append([]reflect.Value{reflect.ValueOf(calleeName)}, argv...)
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fun = reflect.ValueOf(call)
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}
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// Added for Hugo
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for i := 0; i < len(first); i++ {
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argv[i] = s.validateType(first[i], typ.In(i))
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}
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v, err := safeCall(fun, argv)
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// If we have an error that is not nil, stop execution and return that
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// error to the caller.
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if err != nil {
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s.at(node)
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s.errorf("error calling %s: %w", name, err)
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}
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vv := unwrap(v)
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// Added for Hugo
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if s.helper != nil {
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s.helper.OnCalled(s.ctx, s.prep, name, argv, vv)
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}
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return vv
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}
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func isTrue(val reflect.Value) (truth, ok bool) {
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return hreflect.IsTruthfulValue(val), true
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}
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