Move git protocol detection into seperate util

- the git protocol detection is required by buildx, and should reside in
a seperate exported gitutil package.

Signed-off-by: Alex Couture-Beil <alex@earthly.dev>

client/llb/source.go

@@ -11,6 +11,7 @@ import (
 	"github.com/docker/distribution/reference"
 	"github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/util/apicaps"
+	"github.com/moby/buildkit/util/gitutil"
 	"github.com/moby/buildkit/util/sshutil"
 	digest "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
@@ -198,52 +199,14 @@ type ImageInfo struct {
 	RecordType    string
 }
 
-const (
-	gitProtocolHTTP = iota + 1
-	gitProtocolHTTPS
-	gitProtocolSSH
-	gitProtocolGit
-	gitProtocolUnknown
-)
-
-func getGitProtocol(remote string) (string, int) {
-	prefixes := map[string]int{
-		"http://":  gitProtocolHTTP,
-		"https://": gitProtocolHTTPS,
-		"git://":   gitProtocolGit,
-		"ssh://":   gitProtocolSSH,
-	}
-	protocolType := gitProtocolUnknown
-	for prefix, potentialType := range prefixes {
-		if strings.HasPrefix(remote, prefix) {
-			remote = strings.TrimPrefix(remote, prefix)
-			protocolType = potentialType
-		}
-	}
-
-	if protocolType == gitProtocolUnknown && sshutil.IsImplicitSSHTransport(remote) {
-		protocolType = gitProtocolSSH
-	}
-
-	// remove name from ssh
-	if protocolType == gitProtocolSSH {
-		parts := strings.SplitN(remote, "@", 2)
-		if len(parts) == 2 {
-			remote = parts[1]
-		}
-	}
-
-	return remote, protocolType
-}
-
 func Git(remote, ref string, opts ...GitOption) State {
 	url := strings.Split(remote, "#")[0]
 
 	var protocolType int
-	remote, protocolType = getGitProtocol(remote)
+	remote, protocolType = gitutil.ParseProtocol(remote)
 
 	var sshHost string
-	if protocolType == gitProtocolSSH {
+	if protocolType == gitutil.SSHProtocol {
 		parts := strings.SplitN(remote, ":", 2)
 		if len(parts) == 2 {
 			sshHost = parts[0]
@@ -251,7 +214,7 @@ func Git(remote, ref string, opts ...GitOption) State {
 			remote = parts[0] + "/" + parts[1]
 		}
 	}
-	if protocolType == gitProtocolUnknown {
+	if protocolType == gitutil.UnknownProtocol {
 		url = "https://" + url
 	}
 
@@ -289,7 +252,7 @@ func Git(remote, ref string, opts ...GitOption) State {
 			addCap(&gi.Constraints, pb.CapSourceGitHTTPAuth)
 		}
 	}
-	if protocolType == gitProtocolSSH {
+	if protocolType == gitutil.SSHProtocol {
 		if gi.KnownSSHHosts != "" {
 			attrs[pb.AttrKnownSSHHosts] = gi.KnownSSHHosts
 		} else if sshHost != "" {

util/gitutil/git_protocol.go

@@ -0,0 +1,46 @@
+package gitutil
+
+import (
+	"strings"
+
+	"github.com/moby/buildkit/util/sshutil"
+)
+
+const (
+	HTTPProtocol = iota + 1
+	HTTPSProtocol
+	SSHProtocol
+	GitProtocol
+	UnknownProtocol
+)
+
+// ParseProtocol parses a git URL and returns the remote url and protocol type
+func ParseProtocol(remote string) (string, int) {
+	prefixes := map[string]int{
+		"http://":  HTTPProtocol,
+		"https://": HTTPSProtocol,
+		"git://":   GitProtocol,
+		"ssh://":   SSHProtocol,
+	}
+	protocolType := UnknownProtocol
+	for prefix, potentialType := range prefixes {
+		if strings.HasPrefix(remote, prefix) {
+			remote = strings.TrimPrefix(remote, prefix)
+			protocolType = potentialType
+		}
+	}
+
+	if protocolType == UnknownProtocol && sshutil.IsImplicitSSHTransport(remote) {
+		protocolType = SSHProtocol
+	}
+
+	// remove name from ssh
+	if protocolType == SSHProtocol {
+		parts := strings.SplitN(remote, "@", 2)
+		if len(parts) == 2 {
+			remote = parts[1]
+		}
+	}
+
+	return remote, protocolType
+}

util/gitutil/git_protocol_test.go

@@ -0,0 +1,51 @@
+package gitutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseProtocol(t *testing.T) {
+	tests := []struct {
+		url      string
+		protocol int
+		remote   string
+	}{
+		{
+			url:      "http://github.com/moby/buildkit",
+			protocol: HTTPProtocol,
+			remote:   "github.com/moby/buildkit",
+		},
+		{
+			url:      "https://github.com/moby/buildkit",
+			protocol: HTTPSProtocol,
+			remote:   "github.com/moby/buildkit",
+		},
+		{
+			url:      "git@github.com:moby/buildkit.git",
+			protocol: SSHProtocol,
+			remote:   "github.com:moby/buildkit.git",
+		},
+		{
+			url:      "nonstandarduser@example.com:/srv/repos/weird/project.git",
+			protocol: SSHProtocol,
+			remote:   "example.com:/srv/repos/weird/project.git",
+		},
+		{
+			url:      "ssh://root@subdomain.example.hostname:2222/root/my/really/weird/path/foo.git",
+			protocol: SSHProtocol,
+			remote:   "subdomain.example.hostname:2222/root/my/really/weird/path/foo.git",
+		},
+		{
+			url:      "git://host.xz:1234/path/to/repo.git",
+			protocol: GitProtocol,
+			remote:   "host.xz:1234/path/to/repo.git",
+		},
+	}
+	for _, test := range tests {
+		remote, protocol := ParseProtocol(test.url)
+		require.Equal(t, remote, test.remote)
+		require.Equal(t, protocol, test.protocol)
+	}
+}