1 files changed, 40 insertions, 0 deletions
diff --git a/third_party/python/taskcluster_taskgraph/taskgraph/util/memoize.py b/third_party/python/taskcluster_taskgraph/taskgraph/util/memoize.py
new file mode 100644
index 0000000000..56b513e74c
--- /dev/null
+++ b/third_party/python/taskcluster_taskgraph/taskgraph/util/memoize.py
@@ -0,0 +1,40 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Imported from
+# https://searchfox.org/mozilla-central/rev/c3ebaf6de2d481c262c04bb9657eaf76bf47e2ac/python/mozbuild/mozbuild/util.py#923-949
+
+
+import functools
+
+
+class memoize(dict):
+    """A decorator to memoize the results of function calls depending
+    on its arguments.
+    Both functions and instance methods are handled, although in the
+    instance method case, the results are cache in the instance itself.
+    """
+
+    def __init__(self, func):
+        self.func = func
+        functools.update_wrapper(self, func)
+
+    def __call__(self, *args):
+        if args not in self:
+            self[args] = self.func(*args)
+        return self[args]
+
+    def method_call(self, instance, *args):
+        name = "_%s" % self.func.__name__
+        if not hasattr(instance, name):
+            setattr(instance, name, {})
+        cache = getattr(instance, name)
+        if args not in cache:
+            cache[args] = self.func(instance, *args)
+        return cache[args]
+
+    def __get__(self, instance, cls):
+        return functools.update_wrapper(
+            functools.partial(self.method_call, instance), self.func
+        )