From 303a5cca6afd2c4046dbb37677b64f575ba0ea6e Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 23 Apr 2017 12:00:13 +0530
Subject: [PATCH] API to easily get books in a virtual library

Uses the search cache for maximum performance
---
 src/calibre/db/cache.py         |  8 ++++++++
 src/calibre/db/tests/reading.py | 19 ++++++++++++-------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/src/calibre/db/cache.py b/src/calibre/db/cache.py
index 2a273f5bef..d90dc96e1e 100644
--- a/src/calibre/db/cache.py
+++ b/src/calibre/db/cache.py
@@ -981,6 +981,14 @@ class Cache(object):
         '''
         return self._search_api(self, query, restriction, virtual_fields=virtual_fields, book_ids=book_ids)
 
+    @read_api
+    def books_in_virtual_library(self, vl):
+        ' Return the set of books in the specified virtual library '
+        vl = self._pref('virtual_libraries', {}).get(vl) if vl else None
+        if vl is None:
+            return self.all_book_ids()
+        return frozenset(self._search('', vl))
+
     @api
     def get_categories(self, sort='name', book_ids=None, already_fixed=None,
                        first_letter_sort=False):
diff --git a/src/calibre/db/tests/reading.py b/src/calibre/db/tests/reading.py
index 0886680414..f1bcc4b220 100644
--- a/src/calibre/db/tests/reading.py
+++ b/src/calibre/db/tests/reading.py
@@ -483,13 +483,18 @@ class ReadingTest(BaseTest):
     def test_restrictions(self):  # {{{
         ' Test searching with and without restrictions '
         cache = self.init_cache()
-        self.assertSetEqual(cache.all_book_ids(), cache.search(''))
-        self.assertSetEqual({1, 2}, cache.search('', 'not authors:=Unknown'))
-        self.assertSetEqual(set(), cache.search('authors:=Unknown', 'not authors:=Unknown'))
-        self.assertSetEqual({2}, cache.search('not authors:"=Author Two"', 'not authors:=Unknown'))
-        self.assertSetEqual({2}, cache.search('not authors:"=Author Two"', book_ids={1, 2}))
-        self.assertSetEqual({2}, cache.search('not authors:"=Author Two"', 'not authors:=Unknown', book_ids={1,2,3}))
-        self.assertSetEqual(set(), cache.search('authors:=Unknown', 'not authors:=Unknown', book_ids={1,2,3}))
+        se = self.assertSetEqual
+        se(cache.all_book_ids(), cache.search(''))
+        se({1, 2}, cache.search('', 'not authors:=Unknown'))
+        se(set(), cache.search('authors:=Unknown', 'not authors:=Unknown'))
+        se({2}, cache.search('not authors:"=Author Two"', 'not authors:=Unknown'))
+        se({2}, cache.search('not authors:"=Author Two"', book_ids={1, 2}))
+        se({2}, cache.search('not authors:"=Author Two"', 'not authors:=Unknown', book_ids={1,2,3}))
+        se(set(), cache.search('authors:=Unknown', 'not authors:=Unknown', book_ids={1,2,3}))
+        se(cache.all_book_ids(), cache.books_in_virtual_library(''))
+        se(cache.all_book_ids(), cache.books_in_virtual_library('does not exist'))
+        cache.set_pref('virtual_libraries', {'1':'title:"=Title One"'})
+        se({2}, cache.books_in_virtual_library('1'))
     # }}}
 
     def test_search_caching(self):  # {{{