3 files changed, 231 insertions, 0 deletions

diff --git a/bitbake/bin/bitbake-selftest b/bitbake/bin/bitbake-selftest
index 1b7a783fdc..d45c2d406d 100755
--- a/bitbake/bin/bitbake-selftest
+++ b/bitbake/bin/bitbake-selftest
@@ -32,6 +32,7 @@ tests = ["bb.tests.codeparser",
          "bb.tests.siggen",
          "bb.tests.utils",
          "bb.tests.compression",
+         "bb.tests.filter",
          "hashserv.tests",
          "prserv.tests",
          "layerindexlib.tests.layerindexobj",
diff --git a/bitbake/lib/bb/filter.py b/bitbake/lib/bb/filter.py
new file mode 100644
index 0000000000..0b5b5d92ca
--- /dev/null
+++ b/bitbake/lib/bb/filter.py
@@ -0,0 +1,142 @@
+#
+# Copyright (C) 2025 Garmin Ltd. or its subsidiaries
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import builtins
+
+# Purposely blank out __builtins__ which prevents users from
+# calling any normal builtin python functions
+FILTERS = {
+    "__builtins__": {},
+}
+
+CACHE = {}
+
+
+def apply_filters(val, expressions):
+    g = FILTERS.copy()
+
+    for e in expressions:
+        e = e.strip()
+        if not e:
+            continue
+
+        k = (val, e)
+        if k not in CACHE:
+            # Set val as a local so it can be cleared out while keeping the
+            # globals
+            l = {"val": val}
+
+            CACHE[k] = eval(e, g, l)
+
+        val = CACHE[k]
+
+    return val
+
+
+class Namespace(object):
+    """
+    Helper class to simulate a python namespace. The object properties can be
+    set as if it were a dictionary. Properties cannot be changed or deleted
+    through the object interface
+    """
+
+    def __getitem__(self, name):
+        return self.__dict__[name]
+
+    def __setitem__(self, name, value):
+        self.__dict__[name] = value
+
+    def __contains__(self, name):
+        return name in self.__dict__
+
+    def __setattr__(self, name, value):
+        raise AttributeError(f"Attribute {name!r} cannot be changed")
+
+    def __delattr__(self, name):
+        raise AttributeError(f"Attribute {name!r} cannot be deleted")
+
+
+def filter_proc(*, name=None):
+    """
+    Decorator to mark a function that can be called in `apply_filters`, either
+    directly in a filter expression, or indirectly. The `name` argument can be
+    used to specify an alternate name for the function if the actual name is
+    not desired. The `name` can be a fully qualified namespace if desired.
+
+    All functions must be "pure" in that they do not depend on global state and
+    have no global side effects (e.g. the output only depends on the input
+    arguments); the results of filter expressions are cached to optimize
+    repeated calls.
+    """
+
+    def inner(func):
+        global FILTERS
+        nonlocal name
+
+        if name is None:
+            name = func.__name__
+
+        ns = name.split(".")
+        o = FILTERS
+        for n in ns[:-1]:
+            if not n in o:
+                o[n] = Namespace()
+            o = o[n]
+
+        o[ns[-1]] = func
+
+        return func
+
+    return inner
+
+
+# A select set of builtins that are supported in filter expressions
+filter_proc()(all)
+filter_proc()(all)
+filter_proc()(any)
+filter_proc()(bin)
+filter_proc()(bool)
+filter_proc()(chr)
+filter_proc()(enumerate)
+filter_proc()(float)
+filter_proc()(format)
+filter_proc()(hex)
+filter_proc()(int)
+filter_proc()(len)
+filter_proc()(map)
+filter_proc()(max)
+filter_proc()(min)
+filter_proc()(oct)
+filter_proc()(ord)
+filter_proc()(pow)
+filter_proc()(str)
+filter_proc()(sum)
+
+
+@filter_proc()
+def suffix(val, suffix):
+    return " ".join(v + suffix for v in val.split())
+
+
+@filter_proc()
+def prefix(val, prefix):
+    return " ".join(prefix + v for v in val.split())
+
+
+@filter_proc()
+def sort(val):
+    return " ".join(sorted(val.split()))
+
+
+@filter_proc()
+def remove(val, remove, sep=None):
+    if isinstance(remove, str):
+        remove = remove.split(sep)
+    new = [i for i in val.split(sep) if not i in remove]
+
+    if not sep:
+        return " ".join(new)
+    return sep.join(new)
diff --git a/bitbake/lib/bb/tests/filter.py b/bitbake/lib/bb/tests/filter.py
new file mode 100644
index 0000000000..245df7b22b
--- /dev/null
+++ b/bitbake/lib/bb/tests/filter.py
@@ -0,0 +1,88 @@
+#
+# Copyright (C) 2025 Garmin Ltd. or its subsidiaries
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import unittest
+import bb.filter
+
+
+class BuiltinFilterTest(unittest.TestCase):
+    def test_disallowed_builtins(self):
+        with self.assertRaises(NameError):
+            val = bb.filter.apply_filters("1", ["open('foo.txt', 'rb')"])
+
+    def test_prefix(self):
+        val = bb.filter.apply_filters("1 2 3", ["prefix(val, 'a')"])
+        self.assertEqual(val, "a1 a2 a3")
+
+        val = bb.filter.apply_filters("", ["prefix(val, 'a')"])
+        self.assertEqual(val, "")
+
+    def test_suffix(self):
+        val = bb.filter.apply_filters("1 2 3", ["suffix(val, 'b')"])
+        self.assertEqual(val, "1b 2b 3b")
+
+        val = bb.filter.apply_filters("", ["suffix(val, 'b')"])
+        self.assertEqual(val, "")
+
+    def test_sort(self):
+        val = bb.filter.apply_filters("z y x", ["sort(val)"])
+        self.assertEqual(val, "x y z")
+
+        val = bb.filter.apply_filters("", ["sort(val)"])
+        self.assertEqual(val, "")
+
+    def test_identity(self):
+        val = bb.filter.apply_filters("1 2 3", ["val"])
+        self.assertEqual(val, "1 2 3")
+
+        val = bb.filter.apply_filters("123", ["val"])
+        self.assertEqual(val, "123")
+
+    def test_empty(self):
+        val = bb.filter.apply_filters("1 2 3", ["", "prefix(val, 'a')", ""])
+        self.assertEqual(val, "a1 a2 a3")
+
+    def test_nested(self):
+        val = bb.filter.apply_filters("1 2 3", ["prefix(prefix(val, 'a'), 'b')"])
+        self.assertEqual(val, "ba1 ba2 ba3")
+
+        val = bb.filter.apply_filters("1 2 3", ["prefix(prefix(val, 'b'), 'a')"])
+        self.assertEqual(val, "ab1 ab2 ab3")
+
+    def test_filter_order(self):
+        val = bb.filter.apply_filters("1 2 3", ["prefix(val, 'a')", "prefix(val, 'b')"])
+        self.assertEqual(val, "ba1 ba2 ba3")
+
+        val = bb.filter.apply_filters("1 2 3", ["prefix(val, 'b')", "prefix(val, 'a')"])
+        self.assertEqual(val, "ab1 ab2 ab3")
+
+        val = bb.filter.apply_filters("1 2 3", ["prefix(val, 'a')", "suffix(val, 'b')"])
+        self.assertEqual(val, "a1b a2b a3b")
+
+        val = bb.filter.apply_filters("1 2 3", ["suffix(val, 'b')", "prefix(val, 'a')"])
+        self.assertEqual(val, "a1b a2b a3b")
+
+    def test_remove(self):
+        val = bb.filter.apply_filters("1 2 3", ["remove(val, ['2'])"])
+        self.assertEqual(val, "1 3")
+
+        val = bb.filter.apply_filters("1,2,3", ["remove(val, ['2'], ',')"])
+        self.assertEqual(val, "1,3")
+
+        val = bb.filter.apply_filters("1 2 3", ["remove(val, ['4'])"])
+        self.assertEqual(val, "1 2 3")
+
+        val = bb.filter.apply_filters("1 2 3", ["remove(val, ['1', '2'])"])
+        self.assertEqual(val, "3")
+
+        val = bb.filter.apply_filters("1 2 3", ["remove(val, '2')"])
+        self.assertEqual(val, "1 3")
+
+        val = bb.filter.apply_filters("1 2 3", ["remove(val, '4')"])
+        self.assertEqual(val, "1 2 3")
+
+        val = bb.filter.apply_filters("1 2 3", ["remove(val, '1 2')"])
+        self.assertEqual(val, "3")