Uninstall without uninstall args (#117)

* Uninstall without uninstall args

Windows adds registry keys for uninstalls. If uninstall args are not specified, use the uninstall string from the registry. Currently targeting MSI but leaving room for other formats.

system/system_windows.go

@@ -22,6 +22,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"runtime"
+	"strings"
 	"time"
 
 	"github.com/google/googet/v2/goolib"
@@ -69,6 +70,40 @@ func removeUninstallEntry(name string) error {
 	return registry.DeleteKey(registry.LOCAL_MACHINE, reg)
 }
 
+func uninstallString(installSource, extension string) string {
+	productroot := `SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\`
+	k, err := registry.OpenKey(registry.LOCAL_MACHINE, productroot, registry.ENUMERATE_SUB_KEYS)
+	if err != nil {
+		return ""
+	}
+	reg, _ := k.ReadSubKeyNames(-1)
+	defer k.Close()
+	for _, v := range reg {
+		q, err := registry.OpenKey(registry.LOCAL_MACHINE, fmt.Sprintf("%s%s", productroot, v), registry.ALL_ACCESS)
+		defer q.Close()
+		if err != nil {
+			continue
+		}
+		switch extension {
+		case "msi":
+			a, _, err := q.GetStringValue("InstallSource")
+			if err != nil {
+				// InstallSource not found, move on to next entry
+				continue
+			}
+			if strings.Contains(a, installSource) {
+				un, _, err := q.GetStringValue("UninstallString")
+				if err != nil {
+					// UninstallString not found, move on to next entry
+					continue
+				}
+				return un
+			}
+		}
+	}
+	return ""
+}
+
 // Install performs a system specfic install given a package extraction directory and a PkgSpec struct.
 func Install(dir string, ps *goolib.PkgSpec) error {
 	in := ps.Install
@@ -117,9 +152,23 @@ func Install(dir string, ps *goolib.PkgSpec) error {
 
 // Uninstall performs a system specfic uninstall given a packages PackageState.
 func Uninstall(dir string, ps *goolib.PkgSpec) error {
+	var filePath string
 	un := ps.Uninstall
+	// Automatically determine uninstall script if none is specified in spec.
 	if un.Path == "" {
-		return nil
+		switch filepath.Ext(ps.Install.Path) {
+		case ".msi":
+			u := uninstallString(dir, "msi")
+			u = strings.ReplaceAll(u, `/I`, `/X`)
+			commands := strings.Split(u, " ")
+			un.Path = commands[0]
+			un.Args = commands[1:]
+			un.Args = append([]string{"/qn", "/norestart"}, un.Args...)
+			filePath = un.Path
+		}
+		if un.Path == "" {
+			return nil
+		}
 	}
 
 	logger.Infof("Running uninstall command: %q", un.Path)
@@ -133,18 +182,20 @@ func Uninstall(dir string, ps *goolib.PkgSpec) error {
 			logger.Error(err)
 		}
 	}()
-	s := filepath.Join(dir, un.Path)
+	if filePath == "" {
+		filePath = filepath.Join(dir, un.Path)
+	}
 	ec := append(msiSuccessCodes, un.ExitCodes...)
-	switch filepath.Ext(s) {
+	switch filepath.Ext(filePath) {
 	case ".msi":
 		msiLog := filepath.Join(dir, "msi_uninstall.log")
-		args := append([]string{"/x", s, "/qn", "/norestart", "/log", msiLog}, un.Args...)
+		args := append([]string{"/x", filePath, "/qn", "/norestart", "/log", msiLog}, un.Args...)
 		err = goolib.Run(exec.Command("msiexec", args...), ec, out)
 	case ".msu":
-		args := append([]string{s, "/uninstall", "/quiet", "/norestart"}, un.Args...)
+		args := append([]string{filePath, "/uninstall", "/quiet", "/norestart"}, un.Args...)
 		err = goolib.Run(exec.Command("wusa", args...), ec, out)
 	case ".exe":
-		err = goolib.Run(exec.Command(s, un.Args...), ec, out)
+		err = goolib.Run(exec.Command(filePath, un.Args...), ec, out)
 	default:
 		err = goolib.Exec(filepath.Join(dir, un.Path), un.Args, un.ExitCodes, out)
 	}