Stabilize keyval module

We have experimented with the module for about a year in a qemu
branch (https://wiki.qemu.org/Features/Meson), and we would like to
start moving the build system to meson. For that, keyval should have
the stability guarantees.

Cc: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/mesonbuild/modules/keyval.py b/mesonbuild/modules/keyval.py
new file mode 100644
index 0000000..3da2992
--- /dev/null
+++ b/mesonbuild/modules/keyval.py
@@ -0,0 +1,71 @@
+# Copyright 2017, 2019 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from . import ExtensionModule
+
+from .. import mesonlib
+from ..mesonlib import typeslistify
+from ..interpreterbase import FeatureNew, noKwargs
+from ..interpreter import InvalidCode
+
+import os
+
+class KeyvalModule(ExtensionModule):
+
+    @FeatureNew('Keyval Module', '0.55.0')
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.snippets.add('load')
+
+    def _load_file(self, path_to_config):
+        result = dict()
+        try:
+            with open(path_to_config) as f:
+                for line in f:
+                    if '#' in line:
+                        comment_idx = line.index('#')
+                        line = line[:comment_idx]
+                    line = line.strip()
+                    try:
+                        name, val = line.split('=', 1)
+                    except ValueError:
+                        continue
+                    result[name.strip()] = val.strip()
+        except IOError as e:
+            raise mesonlib.MesonException('Failed to load {}: {}'.format(path_to_config, e))
+
+        return result
+
+    @noKwargs
+    def load(self, interpreter, state, args, kwargs):
+        sources = typeslistify(args, (str, mesonlib.File))
+        if len(sources) != 1:
+            raise InvalidCode('load takes only one file input.')
+
+        s = sources[0]
+        is_built = False
+        if isinstance(s, mesonlib.File):
+            is_built = is_built or s.is_built
+            s = s.absolute_path(interpreter.environment.source_dir, interpreter.environment.build_dir)
+        else:
+            s = os.path.join(interpreter.environment.source_dir, s)
+
+        if s not in interpreter.build_def_files and not is_built:
+            interpreter.build_def_files.append(s)
+
+        return self._load_file(s)
+
+
+def initialize(*args, **kwargs):
+    return KeyvalModule(*args, **kwargs)