config: support insteadOf for remotes' URLs (#79)

1 files changed, 81 insertions, 0 deletions

diff --git a/config/url.go b/config/url.go
new file mode 100644
index 0000000..114d6b2
--- /dev/null
+++ b/config/url.go
@@ -0,0 +1,81 @@
+package config
+
+import (
+	"errors"
+	"strings"
+
+	format "github.com/go-git/go-git/v5/plumbing/format/config"
+)
+
+var (
+	errURLEmptyInsteadOf = errors.New("url config: empty insteadOf")
+)
+
+// Url defines Url rewrite rules
+type URL struct {
+	// Name new base url
+	Name string
+	// Any URL that starts with this value will be rewritten to start, instead, with <base>.
+	// When more than one insteadOf strings match a given URL, the longest match is used.
+	InsteadOf string
+
+	// raw representation of the subsection, filled by marshal or unmarshal are
+	// called.
+	raw *format.Subsection
+}
+
+// Validate validates fields of branch
+func (b *URL) Validate() error {
+	if b.InsteadOf == "" {
+		return errURLEmptyInsteadOf
+	}
+
+	return nil
+}
+
+const (
+	insteadOfKey = "insteadOf"
+)
+
+func (u *URL) unmarshal(s *format.Subsection) error {
+	u.raw = s
+
+	u.Name = s.Name
+	u.InsteadOf = u.raw.Option(insteadOfKey)
+	return nil
+}
+
+func (u *URL) marshal() *format.Subsection {
+	if u.raw == nil {
+		u.raw = &format.Subsection{}
+	}
+
+	u.raw.Name = u.Name
+	u.raw.SetOption(insteadOfKey, u.InsteadOf)
+
+	return u.raw
+}
+
+func findLongestInsteadOfMatch(remoteURL string, urls map[string]*URL) *URL {
+	var longestMatch *URL
+	for _, u := range urls {
+		if !strings.HasPrefix(remoteURL, u.InsteadOf) {
+			continue
+		}
+
+		// according to spec if there is more than one match, take the logest
+		if longestMatch == nil || len(longestMatch.InsteadOf) < len(u.InsteadOf) {
+			longestMatch = u
+		}
+	}
+
+	return longestMatch
+}
+
+func (u *URL) ApplyInsteadOf(url string) string {
+	if !strings.HasPrefix(url, u.InsteadOf) {
+		return url
+	}
+
+	return u.Name + url[len(u.InsteadOf):]
+}