Add FilesSample type with filesSample and totalFileCount, use when fe…

…tching files

Summary:
Use a dedicated type with a subset of all files, combined with the count of all files. This way, the UI can know the total number of files but only render or use a subset, and also know when it's using a subset or if it knows all the files.

This matches what already exists in `CommitInfo`, but we can use this when fetching just files without the rest of the CommitInfo.

Reviewed By: quark-zju

Differential Revision: D57458042

fbshipit-source-id: 8bde18f0ce6de7d550a901d59d831b2ed678a791

addons/isl-server/src/ServerToClientAPI.ts

@@ -627,8 +627,9 @@ export default class ServerToClientAPI {
             this.postMessage({
               type: 'fetchedCommitChangedFiles',
               hash: data.hash,
-              result: {value: files.slice(0, data.limit)},
-              totalFileCount: files.length,
+              result: {
+                value: {filesSample: files.slice(0, data.limit), totalFileCount: files.length},
+              },
             });
           })
           .catch(err => {

addons/isl/src/ChangedFilesWithFetching.tsx

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import type {Hash, Result, ChangedFile, CommitInfo} from './types';
+import type {Hash, Result, CommitInfo, FilesSample} from './types';
 
 import serverAPI from './ClientToServerAPI';
 import {ChangedFiles} from './UncommittedChanges';
@@ -14,7 +14,7 @@ import {ComparisonType} from 'shared/Comparison';
 import {LRU} from 'shared/LRU';
 
 // Cache fetches in progress so we don't double fetch
-const commitFilesCache = new LRU<Hash, Promise<Result<Array<ChangedFile>>>>(10);
+const commitFilesCache = new LRU<Hash, Promise<Result<FilesSample>>>(10);
 
 /**
  * The basic CommitInfo we fetch in bulk only contains the first 25 files.
@@ -23,7 +23,7 @@ const commitFilesCache = new LRU<Hash, Promise<Result<Array<ChangedFile>>>>(10);
  * to augment the subset we already have.
  */
 export function ChangedFilesWithFetching({commit}: {commit: CommitInfo}) {
-  const [fetchedAllFiles, setFetchedAllFiles] = useState<Array<ChangedFile> | undefined>(undefined);
+  const [fetchedAllFiles, setFetchedAllFiles] = useState<FilesSample | undefined>(undefined);
 
   const hasAllFilesAlready = commit.filesSample.length === commit.totalFileCount;
   useEffect(() => {
@@ -40,8 +40,8 @@ export function ChangedFilesWithFetching({commit}: {commit: CommitInfo}) {
 
   return (
     <ChangedFiles
-      filesSubset={fetchedAllFiles ?? commit.filesSample}
-      totalFiles={commit.totalFileCount}
+      filesSubset={fetchedAllFiles?.filesSample ?? commit.filesSample}
+      totalFiles={fetchedAllFiles?.totalFileCount ?? commit.totalFileCount}
       comparison={
         commit.isDot
           ? {type: ComparisonType.HeadChanges}
@@ -58,10 +58,7 @@ export function ChangedFilesWithFetching({commit}: {commit: CommitInfo}) {
  * Get changed files in a given commit.
  * A small subset of the files may have already been fetched,
  * or in some cases no files may be cached yet and all files need to be fetched asynchronously. */
-export function getChangedFilesForHash(
-  hash: Hash,
-  limit = 1000,
-): Promise<Result<Array<ChangedFile>>> {
+export function getChangedFilesForHash(hash: Hash, limit = 1000): Promise<Result<FilesSample>> {
   const foundPromise = commitFilesCache.get(hash);
   if (foundPromise != null) {
     return foundPromise;

addons/isl/src/__tests__/ChangedFilesWithFetching.test.tsx

@@ -81,7 +81,7 @@ describe('ChangedFilesWithFetching', () => {
       simulateMessageFromServer({
         type: 'fetchedCommitChangedFiles',
         hash: 'b',
-        result: {value: makeFiles(510)},
+        result: {value: {filesSample: makeFiles(510), totalFileCount: 510}},
       });
     });
 

addons/isl/src/types.ts

@@ -275,6 +275,10 @@ export type ChangedFile = {
    * */
   copy?: RepoRelativePath;
 };
+export type FilesSample = {
+  filesSample: Array<ChangedFile>;
+  totalFileCount: number;
+};
 
 export type SucceedableRevset = {type: 'succeedable-revset'; revset: Revset};
 export type ExactRevset = {type: 'exact-revset'; revset: Revset};
@@ -725,8 +729,7 @@ export type ServerToClientMessage =
   | {
       type: 'fetchedCommitChangedFiles';
       hash: Hash;
-      result: Result<Array<ChangedFile>>;
-      totalFileCount?: number;
+      result: Result<FilesSample>;
     }
   | {type: 'typeaheadResult'; id: string; result: Array<TypeaheadResult>}
   | {type: 'applicationInfo'; info: ApplicationInfo}