Create a cached template() function

We were previously doing calls to Template() directly, sometimes in a
loop. This caused the same template to be recompiled over and over. This
commit introduces a function template() which caches the results, so
that multiple calls with the same template string does not require
recompilation.

beets/dbcore/db.py

@@ -25,7 +25,7 @@ import sqlite3
 import contextlib
 
 import beets
-from beets.util.functemplate import Template
+from beets.util import functemplate
 from beets.util import py3_path
 from beets.dbcore import types
 from .query import MatchQuery, NullSort, TrueQuery
@@ -597,7 +597,7 @@ class Model(object):
         """
         # Perform substitution.
         if isinstance(template, six.string_types):
-            template = Template(template)
+            template = functemplate.template(template)
         return template.substitute(self.formatted(for_path),
                                    self._template_funcs())
 

beets/library.py

@@ -31,7 +31,7 @@ from beets import plugins
 from beets import util
 from beets.util import bytestring_path, syspath, normpath, samefile, \
     MoveOperation
-from beets.util.functemplate import Template
+from beets.util.functemplate import template, Template
 from beets import dbcore
 from beets.dbcore import types
 import beets
@@ -855,7 +855,7 @@ class Item(LibModel):
         if isinstance(path_format, Template):
             subpath_tmpl = path_format
         else:
-            subpath_tmpl = Template(path_format)
+            subpath_tmpl = template(path_format)
 
         # Evaluate the selected template.
         subpath = self.evaluate_template(subpath_tmpl, True)
@@ -1134,7 +1134,7 @@ class Album(LibModel):
         image = bytestring_path(image)
         item_dir = item_dir or self.item_dir()
 
-        filename_tmpl = Template(
+        filename_tmpl = template(
             beets.config['art_filename'].as_str())
         subpath = self.evaluate_template(filename_tmpl, True)
         if beets.config['asciify_paths']:

beets/ui/__init__.py

@@ -36,7 +36,7 @@ from beets import logging
 from beets import library
 from beets import plugins
 from beets import util
-from beets.util.functemplate import Template
+from beets.util.functemplate import template
 from beets import config
 from beets.util import confit, as_string
 from beets.autotag import mb
@@ -616,7 +616,7 @@ def get_path_formats(subview=None):
     subview = subview or config['paths']
     for query, view in subview.items():
         query = PF_KEY_QUERIES.get(query, query)  # Expand common queries.
-        path_formats.append((query, Template(view.as_str())))
+        path_formats.append((query, template(view.as_str())))
     return path_formats
 
 

beets/util/functemplate.py

@@ -35,6 +35,7 @@ import dis
 import types
 import sys
 import six
+import functools
 
 SYMBOL_DELIM = u'$'
 FUNC_DELIM = u'%'
@@ -552,6 +553,9 @@ def _parse(template):
         parts.append(remainder)
     return Expression(parts)
 
+@functools.lru_cache(maxsize=128)
+def template(fmt):
+    return Template(fmt)
 
 # External interface.
 

docs/changelog.rst

@@ -117,6 +117,9 @@ Some improvements have been focused on improving beets' performance:
   to be displayed.
   Thanks to :user:`pprkut`.
   :bug:`3089`
+* Querying the library was further improved by reusing compiled teamplates
+  instead of compiling them over and over again.
+  Thanks to :user:`SimonPersson`.
 * :doc:`/plugins/absubmit`, :doc:`/plugins/badfiles`: Analysis now works in
   parallel (on Python 3 only).
   Thanks to :user:`bemeurer`.