mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
137 lines
3.4 KiB
Go
137 lines
3.4 KiB
Go
package parser
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// line parsers are dispatch calls that parse a single unit of text into a
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// Node object which contains the whole statement. Dockerfiles have varied
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// (but not usually unique, see ONBUILD for a unique example) parsing rules
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// per-command, and these unify the processing in a way that makes it
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// manageable.
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import (
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"encoding/json"
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"errors"
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"fmt"
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"strconv"
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"strings"
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)
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var (
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errDockerfileJSONNesting = errors.New("You may not nest arrays in Dockerfile statements.")
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)
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// ignore the current argument. This will still leave a command parsed, but
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// will not incorporate the arguments into the ast.
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func parseIgnore(rest string) (*Node, map[string]bool, error) {
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return &Node{}, nil, nil
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}
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// used for onbuild. Could potentially be used for anything that represents a
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// statement with sub-statements.
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//
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// ONBUILD RUN foo bar -> (onbuild (run foo bar))
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//
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func parseSubCommand(rest string) (*Node, map[string]bool, error) {
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_, child, err := parseLine(rest)
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if err != nil {
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return nil, nil, err
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}
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return &Node{Children: []*Node{child}}, nil, nil
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}
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// parse environment like statements. Note that this does *not* handle
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// variable interpolation, which will be handled in the evaluator.
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func parseEnv(rest string) (*Node, map[string]bool, error) {
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node := &Node{}
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rootnode := node
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strs := TOKEN_WHITESPACE.Split(rest, 2)
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if len(strs) < 2 {
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return nil, nil, fmt.Errorf("ENV must have two arguments")
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}
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node.Value = strs[0]
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node.Next = &Node{}
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node.Next.Value = strs[1]
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return rootnode, nil, nil
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}
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// parses a whitespace-delimited set of arguments. The result is effectively a
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// linked list of string arguments.
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func parseStringsWhitespaceDelimited(rest string) (*Node, map[string]bool, error) {
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node := &Node{}
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rootnode := node
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prevnode := node
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for _, str := range TOKEN_WHITESPACE.Split(rest, -1) { // use regexp
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prevnode = node
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node.Value = str
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node.Next = &Node{}
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node = node.Next
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}
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// XXX to get around regexp.Split *always* providing an empty string at the
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// end due to how our loop is constructed, nil out the last node in the
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// chain.
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prevnode.Next = nil
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return rootnode, nil, nil
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}
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// parsestring just wraps the string in quotes and returns a working node.
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func parseString(rest string) (*Node, map[string]bool, error) {
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n := &Node{}
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n.Value = rest
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return n, nil, nil
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}
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// parseJSON converts JSON arrays to an AST.
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func parseJSON(rest string) (*Node, map[string]bool, error) {
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var (
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myJson []interface{}
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next = &Node{}
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orignext = next
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prevnode = next
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)
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if err := json.Unmarshal([]byte(rest), &myJson); err != nil {
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return nil, nil, err
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}
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for _, str := range myJson {
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switch str.(type) {
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case string:
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case float64:
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str = strconv.FormatFloat(str.(float64), 'G', -1, 64)
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default:
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return nil, nil, errDockerfileJSONNesting
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}
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next.Value = str.(string)
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next.Next = &Node{}
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prevnode = next
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next = next.Next
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}
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prevnode.Next = nil
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return orignext, map[string]bool{"json": true}, nil
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}
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// parseMaybeJSON determines if the argument appears to be a JSON array. If
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// so, passes to parseJSON; if not, quotes the result and returns a single
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// node.
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func parseMaybeJSON(rest string) (*Node, map[string]bool, error) {
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rest = strings.TrimSpace(rest)
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node, attrs, err := parseJSON(rest)
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if err == nil {
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return node, attrs, nil
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}
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if err == errDockerfileJSONNesting {
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return nil, nil, err
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}
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node = &Node{}
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node.Value = rest
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return node, nil, nil
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}
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