Add support for Dockerfile CMD options

This adds support for Dockerfile commands to have options - e.g:
   COPY --user=john foo /tmp/
   COPY --ignore-mtime foo /tmp/

Supports both booleans and strings.

Signed-off-by: Doug Davis <dug@us.ibm.com>

builder/parser/parser.go

@@ -29,6 +29,7 @@ type Node struct {
 	Children   []*Node         // the children of this sexp
 	Attributes map[string]bool // special attributes for this node
 	Original   string          // original line used before parsing
+	Flags      []string        // only top Node should have this set
 }
 
 var (
@@ -75,7 +76,7 @@ func parseLine(line string) (string, *Node, error) {
 		return line, nil, nil
 	}
 
-	cmd, args, err := splitCommand(line)
+	cmd, flags, args, err := splitCommand(line)
 	if err != nil {
 		return "", nil, err
 	}
@@ -91,6 +92,7 @@ func parseLine(line string) (string, *Node, error) {
 	node.Next = sexp
 	node.Attributes = attrs
 	node.Original = line
+	node.Flags = flags
 
 	return "", node, nil
 }

builder/parser/testfiles/flags/Dockerfile

@@ -0,0 +1,10 @@
+FROM scratch
+COPY foo /tmp/
+COPY --user=me foo /tmp/
+COPY --doit=true foo /tmp/
+COPY --user=me --doit=true foo /tmp/
+COPY --doit=true -- foo /tmp/
+COPY -- foo /tmp/
+CMD --doit [ "a", "b" ]
+CMD --doit=true -- [ "a", "b" ]
+CMD --doit -- [ ]

builder/parser/testfiles/flags/result

@@ -0,0 +1,10 @@
+(from "scratch")
+(copy "foo" "/tmp/")
+(copy ["--user=me"] "foo" "/tmp/")
+(copy ["--doit=true"] "foo" "/tmp/")
+(copy ["--user=me" "--doit=true"] "foo" "/tmp/")
+(copy ["--doit=true"] "foo" "/tmp/")
+(copy "foo" "/tmp/")
+(cmd ["--doit"] "a" "b")
+(cmd ["--doit=true"] "a" "b")
+(cmd ["--doit"])

builder/parser/utils.go

@@ -1,8 +1,10 @@
 package parser
 
 import (
+	"fmt"
 	"strconv"
 	"strings"
+	"unicode"
 )
 
 // dumps the AST defined by `node` as a list of sexps. Returns a string
@@ -11,6 +13,10 @@ func (node *Node) Dump() string {
 	str := ""
 	str += node.Value
 
+	if len(node.Flags) > 0 {
+		str += fmt.Sprintf(" %q", node.Flags)
+	}
+
 	for _, n := range node.Children {
 		str += "(" + n.Dump() + ")\n"
 	}
@@ -48,20 +54,23 @@ func fullDispatch(cmd, args string) (*Node, map[string]bool, error) {
 
 // splitCommand takes a single line of text and parses out the cmd and args,
 // which are used for dispatching to more exact parsing functions.
-func splitCommand(line string) (string, string, error) {
+func splitCommand(line string) (string, []string, string, error) {
 	var args string
+	var flags []string
 
 	// Make sure we get the same results irrespective of leading/trailing spaces
 	cmdline := TOKEN_WHITESPACE.Split(strings.TrimSpace(line), 2)
 	cmd := strings.ToLower(cmdline[0])
 
 	if len(cmdline) == 2 {
-		args = strings.TrimSpace(cmdline[1])
+		var err error
+		args, flags, err = extractBuilderFlags(cmdline[1])
+		if err != nil {
+			return "", nil, "", err
+		}
 	}
 
-	// the cmd should never have whitespace, but it's possible for the args to
-	// have trailing whitespace.
-	return cmd, args, nil
+	return cmd, flags, strings.TrimSpace(args), nil
 }
 
 // covers comments and empty lines. Lines should be trimmed before passing to
@@ -74,3 +83,94 @@ func stripComments(line string) string {
 
 	return line
 }
+
+func extractBuilderFlags(line string) (string, []string, error) {
+	// Parses the BuilderFlags and returns the remaining part of the line
+
+	const (
+		inSpaces = iota // looking for start of a word
+		inWord
+		inQuote
+	)
+
+	words := []string{}
+	phase := inSpaces
+	word := ""
+	quote := '\000'
+	blankOK := false
+	var ch rune
+
+	for pos := 0; pos <= len(line); pos++ {
+		if pos != len(line) {
+			ch = rune(line[pos])
+		}
+
+		if phase == inSpaces { // Looking for start of word
+			if pos == len(line) { // end of input
+				break
+			}
+			if unicode.IsSpace(ch) { // skip spaces
+				continue
+			}
+
+			// Only keep going if the next word starts with --
+			if ch != '-' || pos+1 == len(line) || rune(line[pos+1]) != '-' {
+				return line[pos:], words, nil
+			}
+
+			phase = inWord // found someting with "--", fall thru
+		}
+		if (phase == inWord || phase == inQuote) && (pos == len(line)) {
+			if word != "--" && (blankOK || len(word) > 0) {
+				words = append(words, word)
+			}
+			break
+		}
+		if phase == inWord {
+			if unicode.IsSpace(ch) {
+				phase = inSpaces
+				if word == "--" {
+					return line[pos:], words, nil
+				}
+				if blankOK || len(word) > 0 {
+					words = append(words, word)
+				}
+				word = ""
+				blankOK = false
+				continue
+			}
+			if ch == '\'' || ch == '"' {
+				quote = ch
+				blankOK = true
+				phase = inQuote
+				continue
+			}
+			if ch == '\\' {
+				if pos+1 == len(line) {
+					continue // just skip \ at end
+				}
+				pos++
+				ch = rune(line[pos])
+			}
+			word += string(ch)
+			continue
+		}
+		if phase == inQuote {
+			if ch == quote {
+				phase = inWord
+				continue
+			}
+			if ch == '\\' {
+				if pos+1 == len(line) {
+					phase = inWord
+					continue // just skip \ at end
+				}
+				pos++
+				ch = rune(line[pos])
+			}
+			word += string(ch)
+		}
+	}
+
+	return "", words, nil
+}