Add existing to tracked

node_modules/@cesium/engine/Source/Scene/preprocess3DTileContent.js

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+import defined from "../Core/defined.js";
+import getJsonFromTypedArray from "../Core/getJsonFromTypedArray.js";
+import getMagic from "../Core/getMagic.js";
+import RuntimeError from "../Core/RuntimeError.js";
+import Cesium3DTileContentType from "./Cesium3DTileContentType.js";
+
+/**
+ * Results of the preprocess3DTileContent() function. This includes the
+ * {@link Cesium3DTileContentType} and the payload. The payload is either
+ * binary or JSON depending on the content type.
+ *
+ * @typedef {object} PreprocessedContent
+ * @property {Cesium3DTileContentType} contentType The type of the content
+ * @property {Uint8Array} [binaryPayload] For binary files, the payload is returned as a typed array with byteOffset of 0
+ * @property {object} [jsonPayload] For JSON files, the results are returned as a JSON object.
+ * @private
+ */
+
+/**
+ * Preprocess a {@link Cesium3DTileContent}, to determine the type of content
+ * and to parse JSON files into objects.
+ *
+ * @param {ArrayBuffer} arrayBuffer The raw binary payload
+ * @return {PreprocessedContent}
+ * @private
+ */
+function preprocess3DTileContent(arrayBuffer) {
+  const uint8Array = new Uint8Array(arrayBuffer);
+  let contentType = getMagic(uint8Array);
+
+  // We use glTF for JSON glTF files. For binary glTF, we rename this
+  // to glb to disambiguate
+  if (contentType === "glTF") {
+    contentType = "glb";
+  }
+
+  if (Cesium3DTileContentType.isBinaryFormat(contentType)) {
+    return {
+      // For binary files, the enum value is the magic number
+      contentType: contentType,
+      binaryPayload: uint8Array,
+    };
+  }
+
+  const json = getJsonContent(uint8Array);
+  if (defined(json.root)) {
+    // Most likely a tileset JSON
+    return {
+      contentType: Cesium3DTileContentType.EXTERNAL_TILESET,
+      jsonPayload: json,
+    };
+  }
+
+  if (defined(json.asset)) {
+    // Most likely a glTF. Tileset JSON also has an "asset" property
+    // so this check needs to happen second
+    return {
+      contentType: Cesium3DTileContentType.GLTF,
+      jsonPayload: json,
+    };
+  }
+
+  if (defined(json.tileAvailability)) {
+    // Most likely a subtree JSON.
+    return {
+      contentType: Cesium3DTileContentType.IMPLICIT_SUBTREE_JSON,
+      jsonPayload: json,
+    };
+  }
+
+  if (defined(json.type)) {
+    // Most likely a GeoJSON
+    return {
+      contentType: Cesium3DTileContentType.GEOJSON,
+      jsonPayload: json,
+    };
+  }
+
+  if (defined(json.voxelTable)) {
+    // Most likely a voxel JSON
+    return {
+      contentType: Cesium3DTileContentType.VOXEL_JSON,
+      jsonPayload: json,
+    };
+  }
+
+  throw new RuntimeError("Invalid tile content.");
+}
+
+function getJsonContent(uint8Array) {
+  let json;
+
+  try {
+    json = getJsonFromTypedArray(uint8Array);
+  } catch (error) {
+    throw new RuntimeError("Invalid tile content.");
+  }
+
+  return json;
+}
+
+export default preprocess3DTileContent;