Merge branch 'master' of https://github.com/cbhaley/calibre

Fixes #2003712 [Enhancement Request: URL scheme: 'virtual_library' for show-book](https://bugs.launchpad.net/calibre/+bug/2003712)

manual/url_scheme.rst

@@ -56,6 +56,18 @@ brackets at the end of the path to the book folder.
 You can copy a link to the current book displayed in calibre by right clicking
 the :guilabel:`Book details` panel and choosing :guilabel:`Copy link to book`.
 
+If a Virtual library is selected, calibre will use it when showing the book. If
+the book isn't found in that virtual library then the virtual library is cleared.
+
+If you want to switch to a particular Virtual library when showing the book, use::
+
+    calibre://show-book/Library_Name/book_id?virtual_library=Library%20Name
+    or
+    calibre://show-book/Library_Name/book_id?encoded_virtual_library=hex_encoded_virtual_library_name
+
+replacing spaces in the Virtual library name by ``%20``. If the book isn't in that
+virtual library then it is ignored.
+
 
 Open a specific book in the E-book viewer at a specific position
 -------------------------------------------------------------------

src/calibre/gui2/ui.py

@@ -675,6 +675,16 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
                 return bytes.fromhex(x[6:]).decode('utf-8')
             return x
 
+        def get_virtual_library(query):
+            vl = None
+            if query.get('encoded_virtual_library'):
+                vl = bytes.fromhex(query.get('encoded_virtual_library')[0]).decode('utf-8')
+            elif query.get('virtual_library'):
+                vl = query.get('virtual_library')[0]
+            if vl == '-':
+                vl = None
+            return vl
+
         if action == 'switch-library':
             library_id = decode_library_id(posixpath.basename(path))
             library_path = self.library_broker.path_for_library_id(library_id)
@@ -694,8 +704,12 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
             library_path = self.library_broker.path_for_library_id(library_id)
             if library_path is None:
                 return
+            vl = get_virtual_library(query)
 
             def doit():
+                # To maintain compatibility, don't change the VL if it isn't specified.
+                if vl is not None and vl != '_':
+                    self.apply_virtual_library(vl)
                 rows = self.library_view.select_rows((book_id,))
                 db = self.current_db
                 if not rows and (db.data.get_base_restriction_name() or db.data.get_search_restriction_name()):
@@ -743,13 +757,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
                 if sq:
                     sq = sq[0]
             sq = sq or ''
-            vl = None
+            vl = get_virtual_library(query)
-            if query.get('encoded_virtual_library'):
-                vl = bytes.fromhex(query.get('encoded_virtual_library')[0]).decode('utf-8')
-            elif query.get('virtual_library'):
-                vl = query.get('virtual_library')[0]
-            if vl == '-':
-                vl = None
 
             def doit():
                 if vl != '_':