automatically detect path queries containing / (finishes #146)

NEWS

@@ -9,6 +9,11 @@
   now matches the entire phrase. To match in specified fields, use
   a construction like this:
     beet ls "artist:the knife"
+* Queries can match items from the library by directory. A 'path:'
+  prefix is optional; any query containing a path separator (/ on
+  POSIX systems) is assumed to be a path query. Running
+  "beet ls path/to/music" will show all the music in your library
+  under the specified directory.
 * Album art is now automatically discovered and copied from the
   imported directories when available.
 * The release label for albums and tracks is now fetched from

beets/library.py

@@ -420,8 +420,14 @@ class CollectionQuery(Query):
             if not res:
                 continue
             key, pattern = res
-            if key is None: # no key specified; match any field
-                subqueries.append(AnySubstringQuery(pattern, default_fields))
+            if key is None: # No key specified.
+                if os.sep in pattern:
+                    # This looks like a path.
+                    subqueries.append(PathQuery(pattern))
+                else:
+                    # Match any field.
+                    subqueries.append(AnySubstringQuery(pattern,
+                                                        default_fields))
             elif key.lower() == 'comp': # a boolean field
                 subqueries.append(BooleanQuery(key.lower(), pattern))
             elif key.lower() == 'path':

test/test_query.py

@@ -258,6 +258,22 @@ class PathQueryTest(unittest.TestCase, AssertsMixin):
         self.assert_matched(results, 'path item')
         self.assert_done(results)
 
+    def test_slashed_query_matches_path(self):
+        q = '/a/b'
+        results = self.lib.items(q)
+        self.assert_matched(results, 'path item')
+        self.assert_done(results)
+
+    def test_non_slashed_does_not_match_path(self):
+        q = 'c.mp3'
+        results = self.lib.items(q)
+        self.assert_done(results)
+
+    def test_slashes_in_explicit_field_does_not_match_path(self):
+        q = 'title:/a/b'
+        results = self.lib.items(q)
+        self.assert_done(results)
+
 class BrowseTest(unittest.TestCase, AssertsMixin):
     def setUp(self):
         self.lib = beets.library.Library(