metro-cache: make Flow-private class members JS-private, misc fixes

Summary:
Prefer actually-private class field/method syntax (`#` prefix) over private-by-convention (`_` prefix).

Flow will already error on use of `_`-private fields, but they will generate TypeScript types as if part of the public API.

Also cleans up some inconsistent headers and a stray self-import of a type. This prepares `metro-cache` for fully auto-generated TypeScript types.

Changelog: Internal

Reviewed By: huntie

Differential Revision: D81879389

fbshipit-source-id: 6c2d0071da02db4a9bc2b79a205486b61d270069

Author: robhogan

packages/metro-cache/src/Cache.js

@@ -9,7 +9,7 @@
  * @oncall react_native
  */
 
-import type {CacheStore} from 'metro-cache';
+import type {CacheStore} from './types';
 
 import {Logger} from 'metro-core';
 
@@ -21,17 +21,15 @@ import {Logger} from 'metro-core';
  * All get/set operations are logged via Metro's logger.
  */
 export default class Cache<T> {
-  _stores: $ReadOnlyArray<CacheStore<T>>;
-
-  _hits: WeakMap<Buffer, CacheStore<T>>;
+  +#stores: $ReadOnlyArray<CacheStore<T>>;
+  +#hits: WeakMap<Buffer, CacheStore<T>> = new WeakMap();
 
   constructor(stores: $ReadOnlyArray<CacheStore<T>>) {
-    this._hits = new WeakMap();
-    this._stores = stores;
+    this.#stores = stores;
   }
 
   async get(key: Buffer): Promise<?T> {
-    const stores = this._stores;
+    const stores = this.#stores;
     const length = stores.length;
 
     for (let i = 0; i < length; i++) {
@@ -74,7 +72,7 @@ export default class Cache<T> {
         );
 
         if (value != null) {
-          this._hits.set(key, store);
+          this.#hits.set(key, store);
 
           return value;
         }
@@ -85,8 +83,8 @@ export default class Cache<T> {
   }
 
   async set(key: Buffer, value: T): Promise<void> {
-    const stores = this._stores;
-    const stop = this._hits.get(key);
+    const stores = this.#stores;
+    const stop = this.#hits.get(key);
     const length = stores.length;
     const promises = [];
     const writeErrors = [];
@@ -133,6 +131,6 @@ export default class Cache<T> {
   // writing to the cache is a no-op and reading from the cache will always
   // return null.
   get isDisabled(): boolean {
-    return this._stores.length === 0;
+    return this.#stores.length === 0;
   }
 }

packages/metro-cache/src/index.js

@@ -29,6 +29,15 @@ export {
   stableHash,
 };
 
+export interface MetroCache {
+  +AutoCleanFileStore: typeof AutoCleanFileStore;
+  +Cache: typeof Cache;
+  +FileStore: typeof FileStore;
+  +HttpGetStore: typeof HttpGetStore;
+  +HttpStore: typeof HttpStore;
+  +stableHash: typeof stableHash;
+}
+
 /**
  * Backwards-compatibility with CommonJS consumers using interopRequireDefault.
  * Do not add to this list.
@@ -42,4 +51,4 @@ export default {
   HttpGetStore,
   HttpStore,
   stableHash,
-};
+} as MetroCache;

packages/metro-cache/src/stores/AutoCleanFileStore.js

@@ -6,6 +6,7 @@
  *
  * @flow strict-local
  * @format
+ * @oncall react_native
  */
 
 import type {Options} from './FileStore';

packages/metro-cache/src/stores/FileStore.js

@@ -6,6 +6,7 @@
  *
  * @flow
  * @format
+ * @oncall react_native
  */
 
 import fs from 'fs';

packages/metro-cache/src/stores/HttpError.js

@@ -4,8 +4,8 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @format
  * @flow strict
+ * @format
  */
 
 export default class HttpError extends Error {

packages/metro-cache/src/stores/HttpGetStore.js

@@ -4,24 +4,25 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @format
  * @flow strict-local
+ * @format
+ * @oncall react_native
  */
 
 import type HttpError from './HttpError';
+import type {Options as HttpOptions} from './HttpStore';
 import type NetworkError from './NetworkError';
-import type {HttpOptions} from 'metro-cache';
 
 import HttpStore from './HttpStore';
 import {Logger} from 'metro-core';
 
 export default class HttpGetStore<T> extends HttpStore<T> {
-  _warned: boolean;
+  #warned: boolean;
 
   constructor(options: HttpOptions) {
     super(options);
 
-    this._warned = false;
+    this.#warned = false;
   }
 
   async get(key: Buffer): Promise<?T> {
@@ -35,18 +36,16 @@ export default class HttpGetStore<T> extends HttpStore<T> {
         throw err;
       }
 
-      this._warn(err);
+      this.#warn(err);
 
       return null;
     }
   }
 
-  set(): Promise<void> {
-    return Promise.resolve(undefined);
-  }
+  async set(_key: Buffer, _value: T): Promise<void> {}
 
-  _warn(err: HttpError | NetworkError) {
-    if (!this._warned) {
+  #warn(err: HttpError | NetworkError) {
+    if (!this.#warned) {
       process.emitWarning(
         [
           'Could not connect to the HTTP cache.',
@@ -60,7 +59,7 @@ export default class HttpGetStore<T> extends HttpStore<T> {
           log_entry_label: `${err.message} (${err.code})`,
         }),
       );
-      this._warned = true;
+      this.#warned = true;
     }
   }
 }

packages/metro-cache/src/stores/HttpStore.js

@@ -4,8 +4,9 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @format
  * @flow
+ * @format
+ * @oncall react_native
  */
 
 import type {HttpsProxyAgentOptions} from 'https-proxy-agent';
@@ -78,19 +79,19 @@ export default class HttpStore<T> {
   static HttpError: typeof HttpError = HttpError;
   static NetworkError: typeof NetworkError = NetworkError;
 
-  _getEndpoint: Endpoint;
-  _setEndpoint: Endpoint;
+  #getEndpoint: Endpoint;
+  #setEndpoint: Endpoint;
 
   constructor(options: Options) {
-    this._getEndpoint = this.createEndpointConfig(
+    this.#getEndpoint = this.#createEndpointConfig(
       options.getOptions != null ? options.getOptions : options,
     );
-    this._setEndpoint = this.createEndpointConfig(
+    this.#setEndpoint = this.#createEndpointConfig(
       options.setOptions != null ? options.setOptions : options,
     );
   }
 
-  createEndpointConfig(options: EndpointOptions): Endpoint {
+  #createEndpointConfig(options: EndpointOptions): Endpoint {
     const agentConfig: http$agentOptions & HttpsProxyAgentOptions = {
       family: options.family,
       keepAlive: true,
@@ -151,32 +152,32 @@ export default class HttpStore<T> {
   }
 
   get(key: Buffer): Promise<?T> {
-    return this.#withRetries(() => this.#getOnce(key), this._getEndpoint);
+    return this.#withRetries(() => this.#getOnce(key), this.#getEndpoint);
   }
 
   #getOnce(key: Buffer): Promise<?T> {
     return new Promise((resolve, reject) => {
-      let searchParamsString = this._getEndpoint.params.toString();
+      let searchParamsString = this.#getEndpoint.params.toString();
       if (searchParamsString != '') {
         searchParamsString = '?' + searchParamsString;
       }
       const options = {
-        agent: this._getEndpoint.agent,
-        headers: this._getEndpoint.headers,
-        host: this._getEndpoint.host,
+        agent: this.#getEndpoint.agent,
+        headers: this.#getEndpoint.headers,
+        host: this.#getEndpoint.host,
         method: 'GET',
-        path: `${this._getEndpoint.path}/${key.toString(
+        path: `${this.#getEndpoint.path}/${key.toString(
           'hex',
         )}${searchParamsString}`,
-        port: this._getEndpoint.port,
-        timeout: this._getEndpoint.timeout,
+        port: this.#getEndpoint.port,
+        timeout: this.#getEndpoint.timeout,
       };
 
       // $FlowFixMe[incompatible-type]
       /* $FlowFixMe[missing-local-annot](>=0.101.0 site=react_native_fb) This comment suppresses an
        * error found when Flow v0.101 was deployed. To see the error, delete
        * this comment and run Flow. */
-      const req = this._getEndpoint.module.request(options, res => {
+      const req = this.#getEndpoint.module.request(options, res => {
         const code = res.statusCode;
         const data = [];
 
@@ -187,9 +188,9 @@ export default class HttpStore<T> {
           return;
         } else if (
           code !== 200 &&
-          !this._getEndpoint.additionalSuccessStatuses.has(code)
+          !this.#getEndpoint.additionalSuccessStatuses.has(code)
         ) {
-          if (this._getEndpoint.debug) {
+          if (this.#getEndpoint.debug) {
             res.on('data', chunk => {
               data.push(chunk);
             });
@@ -275,43 +276,43 @@ export default class HttpStore<T> {
   set(key: Buffer, value: T): Promise<void> {
     return this.#withRetries(
       () => this.#setOnce(key, value),
-      this._setEndpoint,
+      this.#setEndpoint,
     );
   }
 
   #setOnce(key: Buffer, value: T): Promise<void> {
     return new Promise((resolve, reject) => {
       const gzip = zlib.createGzip(ZLIB_OPTIONS);
 
-      let searchParamsString = this._setEndpoint.params.toString();
+      let searchParamsString = this.#setEndpoint.params.toString();
       if (searchParamsString != '') {
         searchParamsString = '?' + searchParamsString;
       }
 
       const options = {
-        agent: this._setEndpoint.agent,
-        headers: this._setEndpoint.headers,
-        host: this._setEndpoint.host,
+        agent: this.#setEndpoint.agent,
+        headers: this.#setEndpoint.headers,
+        host: this.#setEndpoint.host,
         method: 'PUT',
-        path: `${this._setEndpoint.path}/${key.toString(
+        path: `${this.#setEndpoint.path}/${key.toString(
           'hex',
         )}${searchParamsString}`,
-        port: this._setEndpoint.port,
-        timeout: this._setEndpoint.timeout,
+        port: this.#setEndpoint.port,
+        timeout: this.#setEndpoint.timeout,
       };
 
       // $FlowFixMe[incompatible-type]
       /* $FlowFixMe[missing-local-annot](>=0.101.0 site=react_native_fb) This comment suppresses an
        * error found when Flow v0.101 was deployed. To see the error, delete
        * this comment and run Flow. */
-      const req = this._setEndpoint.module.request(options, res => {
+      const req = this.#setEndpoint.module.request(options, res => {
         const code = res.statusCode;
 
         if (
           (code < 200 || code > 299) &&
-          !this._setEndpoint.additionalSuccessStatuses.has(code)
+          !this.#setEndpoint.additionalSuccessStatuses.has(code)
         ) {
-          if (this._setEndpoint.debug) {
+          if (this.#setEndpoint.debug) {
             const data = [];
             res.on('data', chunk => {
               data.push(chunk);
@@ -395,13 +396,13 @@ export default class HttpStore<T> {
     return backOff(fn, {
       jitter: 'full',
       maxDelay: 30000,
-      numOfAttempts: this._getEndpoint.maxAttempts || Number.POSITIVE_INFINITY,
+      numOfAttempts: this.#getEndpoint.maxAttempts || Number.POSITIVE_INFINITY,
       retry: (e: Error) => {
         if (e instanceof HttpError) {
-          return this._getEndpoint.retryStatuses.has(e.code);
+          return this.#getEndpoint.retryStatuses.has(e.code);
         }
         return (
-          e instanceof NetworkError && this._getEndpoint.retryNetworkErrors
+          e instanceof NetworkError && this.#getEndpoint.retryNetworkErrors
         );
       },
     });

packages/metro-cache/src/stores/NetworkError.js

@@ -4,8 +4,8 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @format
  * @flow strict
+ * @format
  */
 
 export default class NetworkError extends Error {

packages/metro-config/src/types.js

@@ -10,8 +10,7 @@
  */
 
 import type {HandleFunction, Server} from 'connect';
-import type {CacheStore} from 'metro-cache';
-import typeof * as MetroCache from 'metro-cache';
+import type {CacheStore, MetroCache} from 'metro-cache';
 import type {CacheManagerFactory} from 'metro-file-map';
 import type {CustomResolver} from 'metro-resolver';
 import type {JsTransformerConfig} from 'metro-transform-worker';