Do a large chunk of the move to go

This commit moves a huge chunk of the code to go. The TODO.md document
indicates what is left to be done.

internal/config/file.go

@@ -0,0 +1,76 @@
+package config
+
+import (
+	"bufio"
+	"io"
+	"strings"
+)
+
+// Scanner scans an io.Reader for a source file
+type Scanner struct {
+	src *bufio.Scanner
+
+	key   string
+	value string
+}
+
+func NewScanner(r io.Reader) *Scanner {
+	return &Scanner{
+		src: bufio.NewScanner(r),
+	}
+}
+
+// Scanner advances the scanner to the next variable
+func (scanner *Scanner) Scan() bool {
+	for scanner.src.Scan() {
+		// check that we don't have an empty or comment only line
+		tokens := strings.TrimSpace(scanner.src.Text())
+		if len(tokens) == 0 || tokens[0] == '#' || strings.HasPrefix(tokens, "//") {
+			continue
+		}
+
+		// check that we have a 'key=value' pair
+		values := strings.SplitN(tokens, "=", 2)
+		if len(values) != 2 {
+			continue
+		}
+
+		// got a key = value
+		scanner.key = strings.TrimSpace(values[0])
+		scanner.value = strings.TrimSpace(values[1])
+		return true
+	}
+	scanner.key = ""
+	scanner.value = ""
+	return false
+}
+
+// Data reads the current value from the scanner.
+// When Scan() has not been called, or returned false, returns two empty strings.
+func (scanner Scanner) Data() (key, value string) {
+	return scanner.key, scanner.value
+}
+
+// Error returns an error (if any)
+func (scanner Scanner) Error() error {
+	return scanner.src.Err()
+}
+
+// ReadAll reads all key-value pairs from r.
+// If a key occurs more than once, a later occurance overwrites a previous one.
+func ReadAll(r io.Reader) (values map[string]string, err error) {
+	scanner := NewScanner(r)
+
+	// read and store all values
+	values = make(map[string]string)
+	for scanner.Scan() {
+		key, value := scanner.Data()
+		values[key] = value
+	}
+
+	// check if there was an error!
+	if err := scanner.Error(); err != nil {
+		return nil, err
+	}
+	return values, nil
+}