feat(keymap-upgrader): Upgrade encoder resolution

Added an upgrade function to the keymap upgrader to replace the encoder
"resolution" property with "steps" and (if it is not already present)
"triggers-per-rotation".

docs/src/keymap-upgrade/encoder.ts

@@ -0,0 +1,101 @@
+import type { SyntaxNode, Tree } from "web-tree-sitter";
+
+import {
+  getContainingDevicetreeNode,
+  getDevicetreeNodePath,
+  findDevicetreeProperty,
+} from "./parser";
+import { TextEdit } from "./textedit";
+
+const ALPS_EC11_COMPATIBLE = '"alps,ec11"';
+const DEFAULT_RESOLUTION = 4;
+const TRIGGERS_PER_ROTATION = 20;
+const TRIGGERS_PER_ROTATION_DT = `
+
+&sensors {
+    // Change this to your encoder's number of detents.
+    // If you have multiple encoders with different detents, see
+    // https://zmk.dev/docs/config/encoders#keymap-sensor-config
+    triggers-per-rotation = <${TRIGGERS_PER_ROTATION}>;
+};`;
+
+export function upgradeEncoderResolution(tree: Tree) {
+  const edits: TextEdit[] = [];
+
+  const resolutionProps = findEncoderResolution(tree);
+  edits.push(...resolutionProps.flatMap(upgradeResolutionProperty));
+
+  if (resolutionProps.length > 0) {
+    edits.push(...addTriggersPerRotation(tree));
+  }
+
+  return edits;
+}
+
+function findEncoderResolution(tree: Tree): SyntaxNode[] {
+  const props = findDevicetreeProperty(tree.rootNode, "resolution", {
+    recursive: true,
+  });
+
+  return props.filter((prop) => {
+    const node = getContainingDevicetreeNode(prop);
+    return node && isEncoderNode(node);
+  });
+}
+
+function isEncoderNode(node: SyntaxNode) {
+  // If a compatible property is set, then we know for sure if this is an encoder.
+  const compatible = findDevicetreeProperty(node, "compatible");
+  if (compatible) {
+    return compatible.childForFieldName("value")?.text === ALPS_EC11_COMPATIBLE;
+  }
+
+  // Compatible properties rarely appear in a keymap though, so just guess based
+  // on the node path/reference otherwise.
+  return getDevicetreeNodePath(node).toLowerCase().includes("encoder");
+}
+
+function upgradeResolutionProperty(prop: SyntaxNode): TextEdit[] {
+  const name = prop.childForFieldName("name");
+  const value = prop.childForFieldName("value");
+
+  if (!name || !value) {
+    return [];
+  }
+
+  // Try to set the new steps to be triggers-per-rotation * resolution, but fall
+  // back to a default if the value is something more complex than a single int.
+  const resolution = value.text.trim().replaceAll(/^<|>$/g, "");
+  const steps =
+    (parseInt(resolution) || DEFAULT_RESOLUTION) * TRIGGERS_PER_ROTATION;
+
+  const hint = `/* Change this to your encoder's number of detents times ${resolution} */`;
+
+  return [
+    TextEdit.fromNode(name, "steps"),
+    TextEdit.fromNode(value, `<${steps}> ${hint}`),
+  ];
+}
+
+function addTriggersPerRotation(tree: Tree): TextEdit[] {
+  // The keymap might already contain "triggers-per-rotation" for example if the
+  // user already upgraded some but not all "resolution" properties. Don't add
+  // another one if it already exists.
+  if (keymapHasTriggersPerRotation(tree)) {
+    return [];
+  }
+
+  // Inserting a new property into an existing node while keeping the code
+  // readable in all cases is hard, so just append a new &sensors node to the
+  // end of the keymap.
+  const end = tree.rootNode.endIndex;
+  return [new TextEdit(end, end, TRIGGERS_PER_ROTATION_DT)];
+}
+
+function keymapHasTriggersPerRotation(tree: Tree) {
+  const props = findDevicetreeProperty(tree.rootNode, "triggers-per-rotation", {
+    recursive: true,
+  });
+
+  return props.length > 0;
+}

docs/src/keymap-upgrade/index.ts

@@ -2,6 +2,7 @@ import { createParser } from "./parser";
 import { applyEdits, Range } from "./textedit";
 
 import { upgradeBehaviors } from "./behaviors";
+import { upgradeEncoderResolution } from "./encoder";
 import { upgradeHeaders } from "./headers";
 import { upgradeKeycodes } from "./keycodes";
 import { upgradeNodeNames } from "./nodes";
@@ -11,6 +12,7 @@ export { initParser } from "./parser";
 
 const upgradeFunctions = [
   upgradeBehaviors,
+  upgradeEncoderResolution,
   upgradeHeaders,
   upgradeKeycodes,
   upgradeNodeNames,

docs/src/keymap-upgrade/parser.ts

@@ -57,9 +57,15 @@ export function captureHasText(
 
 /**
  * Get a list of SyntaxNodes representing a devicetree node with the given path.
- * (The same node may be listed multiple times within a file.)
+ * The same node may be listed multiple times within a file.
  *
- * @param path Absolute path to the node (must start with "/")
+ * This function does not evaluate which node a reference points to, so given
+ * a file containing "/ { foo: bar {}; }; &foo {};" searching for "&foo" will
+ * return the "&foo {}" node but not "foo: bar {}".
+ *
+ * @param path Path to the node to find. May be an absolute path such as
+ * "/foo/bar", a node reference such as "&foo", or a node reference followed by
+ * a relative path such as "&foo/bar".
  */
 export function findDevicetreeNode(
   tree: Parser.Tree,
@@ -81,6 +87,64 @@ export function findDevicetreeNode(
   return result;
 }
 
+export interface FindPropertyOptions {
+  /** Search in children of the given node as well */
+  recursive?: boolean;
+}
+
+/**
+ * Find all instances of a devicetree property with the given name which are
+ * descendants of the given syntax node.
+ *
+ * @param node Any syntax node
+ */
+export function findDevicetreeProperty(
+  node: Parser.SyntaxNode,
+  name: string,
+  options: FindPropertyOptions & { recursive: true }
+): Parser.SyntaxNode[];
+
+/**
+ * Find a devicetree node's property with the given name, or null if it doesn't
+ * have one.
+ *
+ * @note If the node contains multiple instances of the same property, this
+ * returns the last once, since that is the one that will actually be applied.
+ *
+ * @param node A syntax node for a devicetree node
+ */
+export function findDevicetreeProperty(
+  node: Parser.SyntaxNode,
+  name: string,
+  options?: FindPropertyOptions
+): Parser.SyntaxNode | null;
+
+export function findDevicetreeProperty(
+  node: Parser.SyntaxNode,
+  name: string,
+  options?: FindPropertyOptions
+): Parser.SyntaxNode[] | Parser.SyntaxNode | null {
+  const query = Devicetree.query(
+    `(property name: (identifier) @name (#eq? @name "${name}")) @prop`
+  );
+  const matches = query.matches(node);
+  const props = matches.map(({ captures }) => findCapture("prop", captures)!);
+
+  if (options?.recursive) {
+    return props;
+  }
+
+  // The query finds all descendants. Filter to just the properties that belong
+  // to the given devicetree node.
+  const childProps = props.filter((prop) =>
+    getContainingDevicetreeNode(prop)?.equals(node)
+  );
+
+  // Sort in descending order to select the last instance of the property.
+  childProps.sort((a, b) => b.startIndex - a.startIndex);
+  return childProps[0] ?? null;
+}
+
 export function getDevicetreeNodePath(node: Parser.SyntaxNode | null) {
   const parts = getDevicetreeNodePathParts(node);
 
@@ -99,9 +163,7 @@ export function getDevicetreeNodePath(node: Parser.SyntaxNode | null) {
   return parts[0] === "/" ? path.substring(1) : path;
 }
 
-export function getDevicetreeNodePathParts(
-  node: Parser.SyntaxNode | null
-): string[] {
+function getDevicetreeNodePathParts(node: Parser.SyntaxNode | null): string[] {
   // There may be intermediate syntax nodes between devicetree nodes, such as
   // #if blocks, so if we aren't currently on a "node" node, traverse up the
   // tree until we find one.
@@ -115,7 +177,7 @@ export function getDevicetreeNodePathParts(
   return [...getDevicetreeNodePathParts(dtnode.parent), name];
 }
 
-function getContainingDevicetreeNode(node: Parser.SyntaxNode | null) {
+export function getContainingDevicetreeNode(node: Parser.SyntaxNode | null) {
   while (node && node.type !== "node") {
     node = node.parent;
   }