1 files changed, 266 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/hil/walk.go b/vendor/github.com/hashicorp/hil/walk.go
new file mode 100644
index 00000000..0ace8306
--- /dev/null
+++ b/vendor/github.com/hashicorp/hil/walk.go
@@ -0,0 +1,266 @@
+package hil
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/hashicorp/hil/ast"
+	"github.com/mitchellh/reflectwalk"
+)
+
+// WalkFn is the type of function to pass to Walk. Modify fields within
+// WalkData to control whether replacement happens.
+type WalkFn func(*WalkData) error
+
+// WalkData is the structure passed to the callback of the Walk function.
+//
+// This structure contains data passed in as well as fields that are expected
+// to be written by the caller as a result. Please see the documentation for
+// each field for more information.
+type WalkData struct {
+	// Root is the parsed root of this HIL program
+	Root ast.Node
+
+	// Location is the location within the structure where this
+	// value was found. This can be used to modify behavior within
+	// slices and so on.
+	Location reflectwalk.Location
+
+	// The below two values must be set by the callback to have any effect.
+	//
+	// Replace, if true, will replace the value in the structure with
+	// ReplaceValue. It is up to the caller to make sure this is a string.
+	Replace      bool
+	ReplaceValue string
+}
+
+// Walk will walk an arbitrary Go structure and parse any string as an
+// HIL program and call the callback cb to determine what to replace it
+// with.
+//
+// This function is very useful for arbitrary HIL program interpolation
+// across a complex configuration structure. Due to the heavy use of
+// reflection in this function, it is recommend to write many unit tests
+// with your typical configuration structures to hilp mitigate the risk
+// of panics.
+func Walk(v interface{}, cb WalkFn) error {
+	walker := &interpolationWalker{F: cb}
+	return reflectwalk.Walk(v, walker)
+}
+
+// interpolationWalker implements interfaces for the reflectwalk package
+// (github.com/mitchellh/reflectwalk) that can be used to automatically
+// execute a callback for an interpolation.
+type interpolationWalker struct {
+	F WalkFn
+
+	key         []string
+	lastValue   reflect.Value
+	loc         reflectwalk.Location
+	cs          []reflect.Value
+	csKey       []reflect.Value
+	csData      interface{}
+	sliceIndex  int
+	unknownKeys []string
+}
+
+func (w *interpolationWalker) Enter(loc reflectwalk.Location) error {
+	w.loc = loc
+	return nil
+}
+
+func (w *interpolationWalker) Exit(loc reflectwalk.Location) error {
+	w.loc = reflectwalk.None
+
+	switch loc {
+	case reflectwalk.Map:
+		w.cs = w.cs[:len(w.cs)-1]
+	case reflectwalk.MapValue:
+		w.key = w.key[:len(w.key)-1]
+		w.csKey = w.csKey[:len(w.csKey)-1]
+	case reflectwalk.Slice:
+		// Split any values that need to be split
+		w.splitSlice()
+		w.cs = w.cs[:len(w.cs)-1]
+	case reflectwalk.SliceElem:
+		w.csKey = w.csKey[:len(w.csKey)-1]
+	}
+
+	return nil
+}
+
+func (w *interpolationWalker) Map(m reflect.Value) error {
+	w.cs = append(w.cs, m)
+	return nil
+}
+
+func (w *interpolationWalker) MapElem(m, k, v reflect.Value) error {
+	w.csData = k
+	w.csKey = append(w.csKey, k)
+	w.key = append(w.key, k.String())
+	w.lastValue = v
+	return nil
+}
+
+func (w *interpolationWalker) Slice(s reflect.Value) error {
+	w.cs = append(w.cs, s)
+	return nil
+}
+
+func (w *interpolationWalker) SliceElem(i int, elem reflect.Value) error {
+	w.csKey = append(w.csKey, reflect.ValueOf(i))
+	w.sliceIndex = i
+	return nil
+}
+
+func (w *interpolationWalker) Primitive(v reflect.Value) error {
+	setV := v
+
+	// We only care about strings
+	if v.Kind() == reflect.Interface {
+		setV = v
+		v = v.Elem()
+	}
+	if v.Kind() != reflect.String {
+		return nil
+	}
+
+	astRoot, err := Parse(v.String())
+	if err != nil {
+		return err
+	}
+
+	// If the AST we got is just a literal string value with the same
+	// value then we ignore it. We have to check if its the same value
+	// because it is possible to input a string, get out a string, and
+	// have it be different. For example: "foo-$${bar}" turns into
+	// "foo-${bar}"
+	if n, ok := astRoot.(*ast.LiteralNode); ok {
+		if s, ok := n.Value.(string); ok && s == v.String() {
+			return nil
+		}
+	}
+
+	if w.F == nil {
+		return nil
+	}
+
+	data := WalkData{Root: astRoot, Location: w.loc}
+	if err := w.F(&data); err != nil {
+		return fmt.Errorf(
+			"%s in:\n\n%s",
+			err, v.String())
+	}
+
+	if data.Replace {
+		/*
+			if remove {
+				w.removeCurrent()
+				return nil
+			}
+		*/
+
+		resultVal := reflect.ValueOf(data.ReplaceValue)
+		switch w.loc {
+		case reflectwalk.MapKey:
+			m := w.cs[len(w.cs)-1]
+
+			// Delete the old value
+			var zero reflect.Value
+			m.SetMapIndex(w.csData.(reflect.Value), zero)
+
+			// Set the new key with the existing value
+			m.SetMapIndex(resultVal, w.lastValue)
+
+			// Set the key to be the new key
+			w.csData = resultVal
+		case reflectwalk.MapValue:
+			// If we're in a map, then the only way to set a map value is
+			// to set it directly.
+			m := w.cs[len(w.cs)-1]
+			mk := w.csData.(reflect.Value)
+			m.SetMapIndex(mk, resultVal)
+		default:
+			// Otherwise, we should be addressable
+			setV.Set(resultVal)
+		}
+	}
+
+	return nil
+}
+
+func (w *interpolationWalker) removeCurrent() {
+	// Append the key to the unknown keys
+	w.unknownKeys = append(w.unknownKeys, strings.Join(w.key, "."))
+
+	for i := 1; i <= len(w.cs); i++ {
+		c := w.cs[len(w.cs)-i]
+		switch c.Kind() {
+		case reflect.Map:
+			// Zero value so that we delete the map key
+			var val reflect.Value
+
+			// Get the key and delete it
+			k := w.csData.(reflect.Value)
+			c.SetMapIndex(k, val)
+			return
+		}
+	}
+
+	panic("No container found for removeCurrent")
+}
+
+func (w *interpolationWalker) replaceCurrent(v reflect.Value) {
+	c := w.cs[len(w.cs)-2]
+	switch c.Kind() {
+	case reflect.Map:
+		// Get the key and delete it
+		k := w.csKey[len(w.csKey)-1]
+		c.SetMapIndex(k, v)
+	}
+}
+
+func (w *interpolationWalker) splitSlice() {
+	// Get the []interface{} slice so we can do some operations on
+	// it without dealing with reflection. We'll document each step
+	// here to be clear.
+	var s []interface{}
+	raw := w.cs[len(w.cs)-1]
+	switch v := raw.Interface().(type) {
+	case []interface{}:
+		s = v
+	case []map[string]interface{}:
+		return
+	default:
+		panic("Unknown kind: " + raw.Kind().String())
+	}
+
+	// Check if we have any elements that we need to split. If not, then
+	// just return since we're done.
+	split := false
+	if !split {
+		return
+	}
+
+	// Make a new result slice that is twice the capacity to fit our growth.
+	result := make([]interface{}, 0, len(s)*2)
+
+	// Go over each element of the original slice and start building up
+	// the resulting slice by splitting where we have to.
+	for _, v := range s {
+		sv, ok := v.(string)
+		if !ok {
+			// Not a string, so just set it
+			result = append(result, v)
+			continue
+		}
+
+		// Not a string list, so just set it
+		result = append(result, sv)
+	}
+
+	// Our slice is now done, we have to replace the slice now
+	// with this new one that we have.
+	w.replaceCurrent(reflect.ValueOf(result))
+}