Added some comments and basic write support

Crx/patchbuilder.py

@@ -0,0 +1,64 @@
+from typing import Dict, List, Union
+from logging import Logger
+import json
+
+if False:
+    from .connection import Connection
+    from .simplenode import SimpleNode
+
+
+LOGGER = Logger(__name__)
+
+
+def _build_patch_set(change: dict) -> str:
+    line = ['^', change['path'], ' : ']
+    if change['type'] in ('Long', 'Float', 'Boolean', 'String'):
+        line.append(json.dumps(change['value']))
+    else:
+        raise ValueError(f'Type {change["type"]!r} is currently not supported!')
+
+    return ''.join(line)
+
+
+_patch_builders = {
+    'set': _build_patch_set
+}
+
+
+class PatchBuilder:
+    changes: List[Dict]
+
+    def __init__(self, connection: 'Connection'):
+        self.connection = connection
+        self.changes = []
+        self.saved = False
+
+    def set_value(self, path: str, value: Union[str, int, float], value_type: str):
+        self.changes.append({
+            'action': 'set',
+            'path': path,
+            'value': value,
+            'type': value_type
+        })
+
+    def save(self):
+        patch = []
+        for entry in self.changes:
+            patch.append(_patch_builders[entry['action']](entry))
+        patch = list(filter(None, patch))
+        if len(patch) == 0:
+            LOGGER.warning("No patch to submit")
+            return
+
+        self.connection.apply_diff('\n'.join(patch))
+        self.saved = True
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        if not self.saved:
+            LOGGER.warning("Patch not saved")
+
+        if self.connection:
+            self.connection._patch_builder = None