From f56d4308af3380e0f238794a0ac76c2399e2b526 Mon Sep 17 00:00:00 2001
From: Oleg Tsarev <ot@project-plato.com>
Date: Sun, 30 Jul 2017 16:48:06 +0200
Subject: [PATCH] Prototype for 'purge' command (#16)

---
 main.go  |  1 +
 purge.go | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 purge.go

diff --git a/main.go b/main.go
index 15d5bbe..f8fa716 100644
--- a/main.go
+++ b/main.go
@@ -31,6 +31,7 @@ var commands = []*Command{
 	cmdUpdate,
 	cmdList,
 	cmdDelete,
+	cmdPurge,
 }
 
 func main() {
diff --git a/purge.go b/purge.go
new file mode 100644
index 0000000..a562dd2
--- /dev/null
+++ b/purge.go
@@ -0,0 +1,62 @@
+package main
+
+import (
+	"path/filepath"
+	errors "github.com/pkg/errors"
+	"strings"
+
+	fileutils "github.com/FiloSottile/gvt/fileutils"
+	gbvendor "github.com/FiloSottile/gvt/gbvendor"
+	"path"
+)
+
+var cmdPurge = &Command{
+	Name:      "purge",
+	UsageLine: "purge",
+	Short:     "purges all unreferenced dependencies",
+	Long: `gb vendor purge will remove all unreferenced dependencies
+
+`,
+	Run: func(args []string) error {
+		m, err := gbvendor.ReadManifest(manifestFile)
+		if err != nil {
+			return errors.Wrap(err, "could not load manifest")
+		}
+		root := path.Dir(vendorDir)
+		imports, err := gbvendor.ParseImports(root, root, "", true, true)
+		if err != nil {
+			return errors.Wrap(err, "import could not be parsed")
+		}
+
+		var hasImportWithPrefix = func(d string) bool {
+			for i := range imports {
+				if strings.HasPrefix(i, d) {
+					return true
+				}
+			}
+			return false
+		}
+
+		dependencies := make([]gbvendor.Dependency, len(m.Dependencies))
+		copy(dependencies, m.Dependencies)
+
+		for _, d := range dependencies {
+			if !hasImportWithPrefix(d.Importpath) {
+				dep, err := m.GetDependencyForImportpath(d.Importpath)
+				if err != nil {
+					return errors.Wrap(err, "could not get get dependency")
+				}
+
+				if err := m.RemoveDependency(dep); err != nil {
+					return errors.Wrap(err, "dependency could not be removed")
+				}
+				if err := fileutils.RemoveAll(filepath.Join(root, "vendor", "src", filepath.FromSlash(d.Importpath))); err != nil {
+					// TODO(dfc) need to apply vendor.cleanpath here to remove intermediate directories.
+					return errors.Wrap(err, "dependency could not be deleted")
+				}
+			}
+		}
+
+		return gbvendor.WriteManifest(manifestFile, m)
+	},
+}