String toFilePath({bool windows})

Returns the file path from a file URI.

The returned path has either Windows or non-Windows semantics.

For non-Windows semantics the slash ("/") is used to separate path segments.

For Windows semantics the backslash ("\") separator is used to separate path segments.

If the URI is absolute the path starts with a path separator unless Windows semantics is used and the first path segment is a drive letter. When Windows semantics is used a host component in the uri in interpreted as a file server and a UNC path is returned.

The default for whether to use Windows or non-Windows semantics determined from the platform Dart is running on. When running in the standalone VM this is detected by the VM based on the operating system. When running in a browser non-Windows semantics is always used.

To override the automatic detection of which semantics to use pass a value for windows. Passing true will use Windows semantics and passing false will use non-Windows semantics.

If the URI ends with a slash (i.e. the last path component is empty) the returned file path will also end with a slash.

With Windows semantics URIs starting with a drive letter cannot be relative to the current drive on the designated drive. That is for the URI file:///c:abc calling toFilePath will throw as a path segment cannot contain colon on Windows.

Examples using non-Windows semantics (resulting of calling toFilePath in comment):

Uri.parse("xxx/yyy");  // xxx/yyy
Uri.parse("xxx/yyy/");  // xxx/yyy/
Uri.parse("file:///xxx/yyy");  // /xxx/yyy
Uri.parse("file:///xxx/yyy/");  // /xxx/yyy/
Uri.parse("file:///C:");  // /C:
Uri.parse("file:///C:a");  // /C:a

Examples using Windows semantics (resulting URI in comment):

Uri.parse("xxx/yyy");  // xxx\yyy
Uri.parse("xxx/yyy/");  // xxx\yyy\
Uri.parse("file:///xxx/yyy");  // \xxx\yyy
Uri.parse("file:///xxx/yyy/");  // \xxx\yyy/
Uri.parse("file:///C:/xxx/yyy");  // C:\xxx\yyy
Uri.parse("file:C:xxx/yyy");  // Throws as a path segment
                              // cannot contain colon on Windows.
Uri.parse("file://server/share/file");  // \\server\share\file

If the URI is not a file URI calling this throws UnsupportedError.

If the URI cannot be converted to a file path calling this throws UnsupportedError.

Source 

String toFilePath({bool windows}) {
  if (scheme != "" && scheme != "file") {
    throw new UnsupportedError(
        "Cannot extract a file path from a $scheme URI");
  }
  if (query != "") {
    throw new UnsupportedError(
        "Cannot extract a file path from a URI with a query component");
  }
  if (fragment != "") {
    throw new UnsupportedError(
        "Cannot extract a file path from a URI with a fragment component");
  }
  if (windows == null) windows = _isWindows;
  return windows ? _toWindowsFilePath() : _toFilePath();
}