Support importing an osmChange file

config/eslint.config.mjs

@@ -31,7 +31,6 @@ export default [
        'indent': ['off', 4],
        'keyword-spacing': 'error',
        'linebreak-style': ['error', 'unix'],
-       'no-await-in-loop': 'error',
        'no-caller': 'error',
        'no-catch-shadow': 'error',
        'no-console': 'warn',

css/80_app.css

@@ -135,19 +135,29 @@ em {
 strong {
     font-weight: bold;
 }
+
+.button-link,
 a,
 a:visited,
 a:active {
     color: #7092ff;
 }
+.button-link:focus,
 a:focus {
     color: #597be7;
 }
 @media (hover: hover) {
+    .button-link:hover,
     a:hover {
         color: #597be7;
     }
 }
+
+.button-link {
+    display: flex;
+    align-items: center;
+}
+
 kbd {
     display: inline-block;
     text-align: center;
@@ -405,6 +415,9 @@ button.secondary-action:focus,
 button.secondary-action:active {
     background: #cccccc;
 }
+button.secondary-action.small {
+    padding: 2px 5px;
+}
 
 button.action.disabled,
 button[disabled].action {

data/core.yaml

@@ -365,6 +365,14 @@ en:
           area: This feature can't follow the area because it is only connected at a single point. Add another point manually to continue.
           generic: This feature can't follow the other feature because they are only connected at a single point. Add another point manually to continue.
         unknown: This feature can't follow another feature.
+    import_from_file:
+      title: Load edits from file
+      tooltip: Import an osmChange file or osmPatch file into the editor.
+      loading: Importing file…
+      error: Failed to import file.
+      annotation:
+        osmChange: Imported an osmChange file
+        osmPatch: Imported an osmPatch file
     reflect:
       title:
         long: Flip Long

jsconfig.json

@@ -0,0 +1,6 @@
+{
+    "compilerOptions": {
+        "downlevelIteration": true,
+        "types": ["modules/global.d.ts"]
+    }
+}

modules/actions/import_osmChange.js

@@ -0,0 +1,156 @@
+// @ts-check
+/** @import * as Osm from 'osm-api' */
+import { osmNode, osmRelation, osmWay } from '../osm';
+import { actionAddEntity } from './add_entity';
+import { actionChangeTags } from './change_tags';
+import { actionDeleteNode } from './delete_node';
+import { actionDeleteRelation } from './delete_relation';
+import { actionDeleteWay } from './delete_way';
+import { actionMoveNode } from './move_node';
+import { actionReplaceRelationMembers } from './replace_relation_members';
+import { actionReplaceWayNodes } from './replace_way_nodes';
+
+/**
+ * A map of the IDs from the osmPatch file to the IDs in our graph.
+ * @typedef {Record<Osm.OsmFeatureType, Record<number, string>>} IDMap
+ */
+
+/**
+ * @param {Osm.OsmFeatureType} type
+ * @param {number} id
+ * @param {IDMap} idMap
+ */
+const getId = (type, id, idMap) => {
+  const mappedId = id > 0 ? type[0] + id : idMap[type][id];
+  if (mappedId === undefined) {
+    throw new Error(`No entry in idMap for ${type} ${id}`);
+  }
+  return mappedId;
+};
+
+/**
+ * @param {Osm.OsmChange} osmChange
+ * @param {boolean} allowConflicts
+ */
+export function actionImportOsmChange(osmChange, allowConflicts) {
+  /** @param {iD.Graph} graph */
+  return (graph) => {
+    /** @type {IDMap} */
+    const idMap = { node: {}, way: {}, relation: {} };
+
+    // check that the versions from the osmChange file match the
+    // versions in our graph. If not, there are conflicts.
+    if (!allowConflicts) {
+      for (const feature of [...osmChange.modify, ...osmChange.delete]) {
+        const entity = graph.entity(getId(feature.type, feature.id, idMap));
+        if (+entity.version !== feature.version) {
+          throw new Error('Conflicts');
+        }
+      }
+    }
+
+    // create placeholders in the graph for all new features, so
+    // that all new features are allocated an ID.
+    for (const feature of osmChange.create) {
+      switch (feature.type) {
+        case 'node': {
+          const entity = osmNode({
+            tags: feature.tags,
+            loc: [feature.lon, feature.lat],
+          });
+          idMap[feature.type][feature.id] = entity.id;
+          graph = actionAddEntity(entity)(graph);
+          break;
+        }
+
+        case 'way': {
+          const entity = osmWay({
+            tags: feature.tags,
+            // `nodes` are added later, once an ID has
+            // been allocated to all new features
+            nodes: [],
+          });
+          idMap[feature.type][feature.id] = entity.id;
+          graph = actionAddEntity(entity)(graph);
+          break;
+        }
+
+        case 'relation': {
+          const entity = osmRelation({
+            tags: feature.tags,
+            // `members` are added later, once an ID has
+            // been allocated to all new features
+            members: [],
+          });
+          idMap[feature.type][feature.id] = entity.id;
+          graph = actionAddEntity(entity)(graph);
+          break;
+        }
+
+        default:
+          // eslint-disable-next-line no-unused-expressions -- exhaustivity check
+          /** @satisfies {never} */ (feature);
+      }
+    }
+
+    // loop through the `create` features again, to set the loc/nodes/members
+    // we can also handle the `modify` features at the same time.
+    for (const feature of [...osmChange.create, ...osmChange.modify]) {
+      const entityId = getId(feature.type, feature.id, idMap);
+
+      // firstly, change tags
+      graph = actionChangeTags(entityId, feature.tags)(graph);
+
+      // secondly, change loc/nodes/members
+      switch (feature.type) {
+        case 'node':
+          graph = actionMoveNode(entityId, [feature.lon, feature.lat])(graph);
+          break;
+
+        case 'way': {
+          const newNodes = feature.nodes.map((id) => getId('node', id, idMap));
+          graph = actionReplaceWayNodes(entityId, newNodes)(graph);
+          break;
+        }
+
+        case 'relation': {
+          const newMembers = feature.members.map((member) => ({
+            id: getId(member.type, member.ref, idMap),
+            role: member.role,
+            type: member.type,
+          }));
+          graph = actionReplaceRelationMembers(entityId, newMembers)(graph);
+          break;
+        }
+
+        default:
+          // eslint-disable-next-line no-unused-expressions -- exhaustivity check
+          /** @satisfies {never} */ (feature);
+      }
+    }
+
+    // delete
+    for (const feature of osmChange.delete) {
+      const entityId = getId(feature.type, feature.id, idMap);
+      switch (feature.type) {
+        case 'node':
+          graph = actionDeleteNode(entityId)(graph);
+          break;
+
+        case 'way':
+          graph = actionDeleteWay(entityId)(graph);
+          break;
+
+        case 'relation':
+          graph = actionDeleteRelation(entityId)(graph);
+          break;
+
+        default:
+          // eslint-disable-next-line no-unused-expressions -- exhaustivity check
+          /** @satisfies {never} */ (feature);
+      }
+    }
+
+    return graph;
+  };
+}