private static final Pattern EXPRESSION_PROJECT_NAME_PATTERN = Pattern.compile("\\$\\{(project.+?)}");

    private static final String ILLEGAL_FS_CHARS = "\\/:\"<>|?*";

    private static final String ILLEGAL_VERSION_CHARS = ILLEGAL_FS_CHARS;

    private static final String ILLEGAL_REPO_ID_CHARS = ILLEGAL_FS_CHARS;

    private static final String EMPTY = "";

'\''         // rune literal containing single quote character
'aa'         // illegal: too many characters
'\k'         // illegal: k is not recognized after a backslash
'\xa'        // illegal: too few hexadecimal digits
'\0'         // illegal: too few octal digits
'\400'       // illegal: octal value over 255
'\uDFFF'     // illegal: surrogate half
'\U00110000' // illegal: invalid Unicode code point
</pre>

// descriptions for all the error responses.
var errorCodes = errorCodeMap{
	ErrInvalidCopyDest: {
		Code:           "InvalidRequest",
		Description:    "This copy request is illegal because it is trying to copy an object to itself without changing the object's metadata, storage class, website redirect location or encryption attributes.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidCopySource: {