shelve: drop pickle usage Pickle was used to the `shelvedstate` file. However the content of the file is very simple and we can handle serialisation ourself. Not using pickle is a net win. Note incrementing the format version as no releases have been done so far.

store: use "vfs.exists()" instead of "os.path.exists()"

context: use "vfs.lstat()" to examine target path instead of "os.path.*" This patch gets stat object of target path by "vfs.lstat()", and examines stat object to know the type of it. This follows the way in "workingctx.add()". This should be cheaper than original implementation invoking "lexists()", "isfile()" and "islink()".

context: use "vfs.lstat()" instead of "os.lstat()"

context: use "vfs.lstat()" instead of "os.lstat()" This patch also changes paths added to "rejected" list from full path (referred by "p") to relative one (referred by "f"), when type of target path is neither file nor symlink. This change should be reasonable, because the path added to "rejected" list is relative one, when "OSError" is raised at "lstat()".

changelog: use "vfs.fstat()" instead of "util.fstat()" Just invoking "os.fstat()" with "file.fileno()" doesn't require non ANSI file API, because filename is not used for invocation of "os.fstat()". But "util.fstat()" should invoke "os.stat()" with "fp.name", if file object doesn't have "fileno()" method for portability, and "fp.name" may cause invocation of non ANSI file API. So, this patch makes the constructor of appender class invoke "util.fstat()" via vfs, to encapsulate filename handling.

changelog: use "vfs.rename()" instead of "util.rename()"

vfs: add "open()" for newly added code paths which open files via vfs This patch replaces "open()" by own "__call__()" defined in derived classes at the first invocation, for efficiency of succeeding invocations.

bookmarks: use "vfs.utime()" instead of "os.utime()"

bookmarks: use "vfs.unlink()" instead of "util.unlink()"