1 files changed, 97 insertions, 0 deletions
diff --git a/tools/tryselect/preset.py b/tools/tryselect/preset.py
new file mode 100644
index 0000000000..98d2849a71
--- /dev/null
+++ b/tools/tryselect/preset.py
@@ -0,0 +1,97 @@
+# 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/.
+
+
+import os
+import shlex
+import subprocess
+
+import yaml
+
+
+class PresetHandler:
+    def __init__(self, path):
+        self.path = path
+        self._presets = {}
+
+    @property
+    def presets(self):
+        if not self._presets and os.path.isfile(self.path):
+            with open(self.path) as fh:
+                self._presets = yaml.safe_load(fh) or {}
+
+        return self._presets
+
+    def __contains__(self, name):
+        return name in self.presets
+
+    def __getitem__(self, name):
+        return self.presets[name]
+
+    def __len__(self):
+        return len(self.presets)
+
+    def __str__(self):
+        if not self.presets:
+            return ""
+        return yaml.safe_dump(self.presets, default_flow_style=False)
+
+    def list(self):
+        if not self.presets:
+            print("no presets found")
+        else:
+            print(self)
+
+    def edit(self):
+        if "EDITOR" not in os.environ:
+            print(
+                "error: must set the $EDITOR environment variable to use --edit-presets"
+            )
+            return
+
+        subprocess.call(shlex.split(os.environ["EDITOR"]) + [self.path])
+
+    def save(self, name, **data):
+        self.presets[name] = data
+
+        with open(self.path, "w") as fh:
+            fh.write(str(self))
+
+
+class MergedHandler:
+    def __init__(self, *paths):
+        """Helper class for dealing with multiple preset files."""
+        self.handlers = [PresetHandler(p) for p in paths]
+
+    def __contains__(self, name):
+        return any(name in handler for handler in self.handlers)
+
+    def __getitem__(self, name):
+        for handler in self.handlers:
+            if name in handler:
+                return handler[name]
+        raise KeyError(name)
+
+    def __len__(self):
+        return sum(len(h) for h in self.handlers)
+
+    def __str__(self):
+        all_presets = {
+            k: v for handler in self.handlers for k, v in handler.presets.items()
+        }
+        return yaml.safe_dump(all_presets, default_flow_style=False)
+
+    def list(self):
+        if len(self) == 0:
+            print("no presets found")
+            return
+
+        for handler in self.handlers:
+            val = str(handler)
+            if val:
+                val = "\n  ".join(
+                    [""] + val.splitlines() + [""]
+                )  # indent all lines by 2 spaces
+                print("Presets from {}:".format(handler.path))
+                print(val)