1 files changed, 120 insertions, 0 deletions
diff --git a/dom/webgpu/tests/cts/checkout/src/common/framework/data_cache.ts b/dom/webgpu/tests/cts/checkout/src/common/framework/data_cache.ts
new file mode 100644
index 0000000000..6f6e80288a
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+++ b/dom/webgpu/tests/cts/checkout/src/common/framework/data_cache.ts
@@ -0,0 +1,120 @@
+/**
+ * Utilities to improve the performance of the CTS, by caching data that is
+ * expensive to build using a two-level cache (in-memory, pre-computed file).
+ */
+
+interface DataStore {
+  load(path: string): Promise<string>;
+}
+
+/** Logger is a basic debug logger function */
+export type Logger = (s: string) => void;
+
+/** DataCache is an interface to a data store used to hold cached data */
+export class DataCache {
+  /** setDataStore() sets the backing data store used by the data cache */
+  public setStore(dataStore: DataStore) {
+    this.dataStore = dataStore;
+  }
+
+  /** setDebugLogger() sets the verbose logger */
+  public setDebugLogger(logger: Logger) {
+    this.debugLogger = logger;
+  }
+
+  /**
+   * fetch() retrieves cacheable data from the data cache, first checking the
+   * in-memory cache, then the data store (if specified), then resorting to
+   * building the data and storing it in the cache.
+   */
+  public async fetch<Data>(cacheable: Cacheable<Data>): Promise<Data> {
+    // First check the in-memory cache
+    let data = this.cache.get(cacheable.path);
+    if (data !== undefined) {
+      this.log('in-memory cache hit');
+      return Promise.resolve(data as Data);
+    }
+    this.log('in-memory cache miss');
+    // In in-memory cache miss.
+    // Next, try the data store.
+    if (this.dataStore !== null && !this.unavailableFiles.has(cacheable.path)) {
+      let serialized: string | undefined;
+      try {
+        serialized = await this.dataStore.load(cacheable.path);
+        this.log('loaded serialized');
+      } catch (err) {
+        // not found in data store
+        this.log(`failed to load (${cacheable.path}): ${err}`);
+        this.unavailableFiles.add(cacheable.path);
+      }
+      if (serialized !== undefined) {
+        this.log(`deserializing`);
+        data = cacheable.deserialize(serialized);
+        this.cache.set(cacheable.path, data);
+        return data as Data;
+      }
+    }
+    // Not found anywhere. Build the data, and cache for future lookup.
+    this.log(`cache: building (${cacheable.path})`);
+    data = await cacheable.build();
+    this.cache.set(cacheable.path, data);
+    return data as Data;
+  }
+
+  private log(msg: string) {
+    if (this.debugLogger !== null) {
+      this.debugLogger(`DataCache: ${msg}`);
+    }
+  }
+
+  private cache = new Map<string, unknown>();
+  private unavailableFiles = new Set<string>();
+  private dataStore: DataStore | null = null;
+  private debugLogger: Logger | null = null;
+}
+
+/** The data cache */
+export const dataCache = new DataCache();
+
+/** true if the current process is building the cache */
+let isBuildingDataCache = false;
+
+/** @returns true if the data cache is currently being built */
+export function getIsBuildingDataCache() {
+  return isBuildingDataCache;
+}
+
+/** Sets whether the data cache is currently being built */
+export function setIsBuildingDataCache(value = true) {
+  isBuildingDataCache = value;
+}
+
+/**
+ * Cacheable is the interface to something that can be stored into the
+ * DataCache.
+ * The 'npm run gen_cache' tool will look for module-scope variables of this
+ * interface, with the name `d`.
+ */
+export interface Cacheable<Data> {
+  /** the globally unique path for the cacheable data */
+  readonly path: string;
+
+  /**
+   * build() builds the cacheable data.
+   * This is assumed to be an expensive operation and will only happen if the
+   * cache does not already contain the built data.
+   */
+  build(): Promise<Data>;
+
+  /**
+   * serialize() transforms `data` to a string (usually JSON encoded) so that it
+   * can be stored in a text cache file.
+   */
+  serialize(data: Data): string;
+
+  /**
+   * deserialize() is the inverse of serialize(), transforming the string back
+   * to the Data object.
+   */
+  deserialize(serialized: string): Data;
+}