Port calibredb clone

src/calibre/db/cli/cmd_clone.py

@@ -4,19 +4,60 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-readonly = False
+import os
+
+from calibre import patheq
+from calibre.constants import iswindows
+from calibre.db.legacy import LibraryDatabase
+
+readonly = True
 version = 0  # change this if you change signature of implementation()
 
 
-def implementation(db, notify_changes, *args):
-    is_remote = notify_changes is not None
-    is_remote
+def implementation(db, notify_changes):
+    return db.backend.prefs.copy(), db.backend.library_path
 
 
 def option_parser(get_parser, args):
-    pass
+    return get_parser(
+        _(
+            '''\
+%prog clone path/to/new/library
+
+Create a clone of the current library. This creates a new, empty library that has all the
+same custom columns, virtual libraries and other settings as the current library.
+
+The cloned library will contain no books. If you want to create a full duplicate, including
+all books, then simply use your filesystem tools to copy the library folder.
+    '''
+        )
+    )
 
 
 def main(opts, args, dbctx):
-    raise NotImplementedError('TODO: implement this')
+    if len(args) < 1:
+        raise SystemExit(_('Error: You must specify the path to the cloned library'))
+    prefs, library_path = dbctx.run('clone')
+    loc = os.path.abspath(args[0])
+    if not os.path.exists(loc):
+        os.makedirs(loc)
+
+    if patheq(loc, library_path):
+        raise SystemExit(
+            _('The location for the new library is the same as the current library')
+        )
+    empty = not os.listdir(loc)
+    if not empty:
+        raise SystemExit(
+            _(
+                '%s is not empty. You must choose an empty directory for the new library.'
+            ) % loc
+        )
+    if iswindows and len(loc) > LibraryDatabase.WINDOWS_LIBRARY_PATH_LIMIT:
+        raise SystemExit(
+            _('Path to library too long. Must be less than'
+              ' %d characters.') % LibraryDatabase.WINDOWS_LIBRARY_PATH_LIMIT
+        )
+    LibraryDatabase(loc, default_prefs=prefs)
+
     return 0

src/calibre/db/cli/main.py

@@ -22,8 +22,8 @@ COMMANDS = (
     'list', 'add', 'remove', 'add_format', 'remove_format', 'show_metadata',
     'set_metadata', 'export', 'catalog', 'saved_searches', 'add_custom_column',
     'custom_columns', 'remove_custom_column', 'set_custom', 'restore_database',
-    'check_library', 'list_categories', 'backup_metadata',
-    # 'clone', 'embed_metadata', 'search'
+    'check_library', 'list_categories', 'backup_metadata', 'clone',
+    # 'embed_metadata', 'search'
 )