Merge "Optimize out empty path components" into main (c012b631) · Commits · e / os / android_build_soong

android/paths.go

+18 −2

Original line number	Diff line number	Diff line
		@@ -1915,7 +1915,9 @@ func (p InstallPaths) Strings() []string {
		// validatePathInternal ensures that a path does not leave its component, and
		// optionally doesn't contain Ninja variables.
		func validatePathInternal(allowNinjaVariables bool, pathComponents ...string) (string, error) {
		for _, path := range pathComponents {
		initialEmpty := 0
		finalEmpty := 0
		for i, path := range pathComponents {
		if !allowNinjaVariables && strings.Contains(path, "$") {
		return "", fmt.Errorf("Path contains invalid character($): %s", path)
		}
		@@ -1924,11 +1926,25 @@ func validatePathInternal(allowNinjaVariables bool, pathComponents ...string) (s
		if path == ".." \|\| strings.HasPrefix(path, "../") \|\| strings.HasPrefix(path, "/") {
		return "", fmt.Errorf("Path is outside directory: %s", path)
		}

		if i == initialEmpty && pathComponents[i] == "" {
		initialEmpty++
		}
		if i == finalEmpty && pathComponents[len(pathComponents)-1-i] == "" {
		finalEmpty++
		}
		}
		// Optimization: filepath.Join("foo", "") returns a newly allocated copy
		// of "foo", while filepath.Join("foo") does not. Strip out any empty
		// path components.
		if initialEmpty == len(pathComponents) {
		return "", nil
		}
		nonEmptyPathComponents := pathComponents[initialEmpty : len(pathComponents)-finalEmpty]
		// TODO: filepath.Join isn't necessarily correct with embedded ninja
		// variables. '..' may remove the entire ninja variable, even if it
		// will be expanded to multiple nested directories.
		return filepath.Join(pathComponents...), nil
		return filepath.Join(nonEmptyPathComponents...), nil
		}

		// validateSafePath validates a path that we trust (may contain ninja

android/paths_test.go

+16 −0

Original line number	Diff line number	Diff line
		@@ -36,6 +36,22 @@ var commonValidatePathTestCases = []strsTestCase{
		in: []string{""},
		out: "",
		},
		{
		in: []string{"", ""},
		out: "",
		},
		{
		in: []string{"a", ""},
		out: "a",
		},
		{
		in: []string{"", "a"},
		out: "a",
		},
		{
		in: []string{"", "a", ""},
		out: "a",
		},
		{
		in: []string{"a/b"},
		out: "a/b",