Refactor Caddyfile adapter and module registration

Use piles from which to draw config values.

Module values can return their name, so now we can do two-way mapping
from value to name and name to value; whereas before we could only map
name to value. This was problematic with the Caddyfile adapter since
it receives values and needs to know the name to put in the config.

1 files changed, 19 insertions, 11 deletions

diff --git a/caddyconfig/caddyfile/dispenser.go b/caddyconfig/caddyfile/dispenser.go
index 1cf5d04..0d2c789 100755
--- a/caddyconfig/caddyfile/dispenser.go
+++ b/caddyconfig/caddyfile/dispenser.go
@@ -31,6 +31,7 @@ type Dispenser struct {
 }
 
 // NewDispenser returns a Dispenser filled with the given tokens.
+// TODO: Get rid of the filename argument; it seems pointless here
 func NewDispenser(filename string, tokens []Token) *Dispenser {
 	return &Dispenser{
 		filename: filename,
@@ -51,15 +52,15 @@ func (d *Dispenser) Next() bool {
 }
 
 // Prev moves to the previous token. It does the inverse
-// of Next(). Generally, this should only be used in
-// special cases such as deleting a token from the slice
-// that d is iterating. In that case, without using Prev(),
-// the dispenser would be pointing at the wrong token since
-// deleting a token implicitly advances the cursor.
+// of Next(), except this function may decrement the cursor
+// to -1 so that the next call to Next() points to the
+// first token; this allows dispensing to "start over". This
+// method returns true if the cursor ends up pointing to a
+// valid token.
 func (d *Dispenser) Prev() bool {
-	if d.cursor > 0 {
+	if d.cursor > -1 {
 		d.cursor--
-		return true
+		return d.cursor > -1
 	}
 	return false
 }
@@ -223,8 +224,7 @@ func (d *Dispenser) RemainingArgs() []string {
 // "directive" whether that be to the end of the line or
 // the end of a block that starts at the end of the line.
 func (d *Dispenser) NewFromNextTokens() *Dispenser {
-	var tkns []Token
-	tkns = append(tkns, d.Token())
+	tkns := []Token{d.Token()}
 	for d.NextArg() {
 		tkns = append(tkns, d.Token())
 	}
@@ -245,10 +245,14 @@ func (d *Dispenser) NewFromNextTokens() *Dispenser {
 
 // Token returns the current token.
 func (d *Dispenser) Token() Token {
-	if d.cursor < 0 || d.cursor >= len(d.tokens) {
+	return d.TokenAt(d.cursor)
+}
+
+func (d *Dispenser) TokenAt(cursor int) Token {
+	if cursor < 0 || cursor >= len(d.tokens) {
 		return Token{}
 	}
-	return d.tokens[d.cursor]
+	return d.tokens[cursor]
 }
 
 // Cursor returns the current cursor (token index).
@@ -256,6 +260,10 @@ func (d *Dispenser) Cursor() int {
 	return d.cursor
 }
 
+func (d *Dispenser) Reset() {
+	d.cursor = -1
+}
+
 // ArgErr returns an argument error, meaning that another
 // argument was expected but not found. In other words,
 // a line break or open curly brace was encountered instead of