ui/code-owners-service.js - plugins/code-owners - Git at Google

 /**
  * @license
  * Copyright (C) 2020 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /**
  * All statuses returned for owner status.
  *
  * @enum
  */
 export const OwnerStatus = {
   INSUFFICIENT_REVIEWERS: 'INSUFFICIENT_REVIEWERS',
   PENDING: 'PENDING',
   APPROVED: 'APPROVED',
 };

 /**
  * @enum
  */
 const FetchStatus = {
   NOT_STARTED: 0,
   FETCHING: 1,
   FINISHED: 2,
   ABORT: 3,
 };

 /**
  * Specifies status for a change. The same as ChangeStatus enum in gerrit
  *
  * @enum
  */
 const ChangeStatus = {
   ABANDONED: 'ABANDONED',
   MERGED: 'MERGED',
   NEW: 'NEW',
 };

 /**
  * @enum
  */
 const UserRole = {
   ANONYMOUS: 'ANONYMOUS',
   AUTHOR: 'AUTHOR',
   CHANGE_OWNER: 'CHANGE_OWNER',
   REVIEWER: 'REVIEWER',
   CC: 'CC',
   REMOVED_REVIEWER: 'REMOVED_REVIEWER',
   OTHER: 'OTHER',
 };

 /**
  * Responsible for communicating with the rest-api
  *
  * @see resources/Documentation/rest-api.md
  */
 class CodeOwnerApi {
   constructor(restApi) {
     this.restApi = restApi;
   }

   /**
    * Returns a promise fetching the owner statuses for all files within the change.
    *
    * @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#change-endpoints
    * @param {string} changeId
    */
   listOwnerStatus(changeId) {
     return this.restApi.get(`/changes/${changeId}/code_owners.status`);
   }

   /**
    * Returns a promise fetching the owners for a given path.
    *
    * @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#list-code-owners-for-path-in-branch
    * @param {string} changeId
    * @param {string} path
    */
   listOwnersForPath(changeId, path) {
     return this.restApi.get(
         `/changes/${changeId}/revisions/current/code_owners` +
         `/${encodeURIComponent(path)}?limit=5&o=DETAILS`
     );
   }

   /**
    * Returns a promise fetching the owners config for a given path.
    *
    * @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#branch-endpoints
    * @param {string} project
    * @param {string} branch
    * @param {string} path
    */
   getConfigForPath(project, branch, path) {
     return this.restApi.get(
         `/projects/${encodeURIComponent(project)}/` +
         `branches/${encodeURIComponent(branch)}/` +
         `code_owners.config/${encodeURIComponent(path)}`
     );
   }

   /**
    * Returns a promise fetching project_config for code owners.
    *
    * @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#get-code-owner-project-config
    * @param {string} project
    */
   getProjectConfig(project) {
     return this.restApi.get(
         `/projects/${encodeURIComponent(project)}/code_owners.project_config`
     );
   }

   /**
    * Returns a promise fetching the owners config for a given branch.
    *
    * @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#branch-endpoints
    * @param {string} project
    * @param {string} branch
    */
   getBranchConfig(project, branch) {
     return this.restApi.get(
         `/projects/${encodeURIComponent(project)}/` +
         `branches/${encodeURIComponent(branch)}/` +
         `code_owners.branch_config`
     );
   }
 }

 /**
  * Service for the data layer used in the plugin UI.
  */
 export class CodeOwnerService {
   constructor(restApi, change, options = {}) {
     this.restApi = restApi;
     this.change = change;
     this.options = {maxConcurrentRequests: 10, ...options};
     this.codeOwnerApi = new CodeOwnerApi(restApi);

     // fetched files and fetching status
     this._fetchedOwners = new Map();
     this._fetchStatus = FetchStatus.NOT_STARTED;
     this._totalFetchCount = 0;

     this.init();
   }

   /**
    * Initial fetches.
    */
   init() {
     this.accountPromise = this.restApi.getLoggedIn().then(loggedIn => {
       if (!loggedIn) {
         return undefined;
       }
       return this.restApi.getAccount();
     });

     this.statusPromise = this.isCodeOwnerEnabled().then(enabled => {
       if (!enabled) {
         return {
           patchsetNumber: 0,
           enabled: false,
           codeOwnerStatusMap: new Map(),
           rawStatuses: [],
         };
       }
       return this.codeOwnerApi
           .listOwnerStatus(this.change._number)
           .then(res => {
             return {
               enabled: true,
               patchsetNumber: res.patch_set_number,
               codeOwnerStatusMap: this._formatStatuses(
                   res.file_code_owner_statuses
               ),
               rawStatuses: res.file_code_owner_statuses,
             };
           });
     });
   }

   /**
    * Returns the role of the current user. The returned value reflects the
    * role of the user at the time when the change is loaded.
    * For example, if a user removes themselves as a reviewer, the returned
    * role 'REVIEWER' remains unchanged until the change view is reloaded.
    */
   getLoggedInUserInitialRole() {
     return this.accountPromise.then(account => {
       if (!account) {
         return UserRole.ANONYMOUS;
       }
       const change = this.change;
       if (
         change.revisions &&
         change.current_revision &&
         change.revisions[change.current_revision]
       ) {
         const commit = change.revisions[change.current_revision].commit;
         if (
           commit &&
           commit.author &&
           account.email &&
           commit.author.email === account.email
         ) {
           return UserRole.AUTHOR;
         }
       }
       if (change.owner._account_id === account._account_id) {
         return UserRole.CHANGE_OWNER;
       }
       if (change.reviewers) {
         if (this._accountInReviewers(change.reviewers.REVIEWER, account)) {
           return UserRole.REVIEWER;
         } else if (this._accountInReviewers(change.reviewers.CC, account)) {
           return UserRole.CC;
         } else if (this._accountInReviewers(change.reviewers.REMOVED, account)) {
           return UserRole.REMOVED_REVIEWER;
         }
       }
       return UserRole.OTHER;
     })
   }

   _accountInReviewers(reviewers, account) {
     if (!reviewers) {
       return false;
     }
     return reviewers.some(reviewer => reviewer._account_id === account._account_id);
   }

   getStatus() {
     return this.statusPromise.then(res => {
       if (res.enabled && !this.isOnLatestPatchset(res.patchsetNumber)) {
         // status is outdated, abort and re-init
         this.abort();
         this.init();
         return this.statusPromise;
       }
       return res;
     });
   }

   areAllFilesApproved() {
     return this.getStatus().then(({rawStatuses}) => {
       return !rawStatuses.some(status => {
         const oldPathStatus = status.old_path_status;
         const newPathStatus = status.new_path_status;
         // For deleted files, no new_path_status exists
         return (newPathStatus && newPathStatus.status !== OwnerStatus.APPROVED)
           || (oldPathStatus && oldPathStatus.status !== OwnerStatus.APPROVED);
       });
     });
   }

   /**
    * Gets owner suggestions.
    *
    * @returns {{
    *  finished?: boolean,
    *  progress?: string,
    *  suggestions: Array<{
    *    groupName: {
    *      name: string,
    *      prefix: string
    *    },
    *    error?: Error,
    *    owners?: Array,
    *    files: Array,
    *  }>
    * }}
    */
   getSuggestedOwners() {
     // In case its aborted due to outdated patches
     // should kick start the fetching again
     // Note: we currently are not reusing the instance when switching changes,
     // so if its `abort` due to different changes, the whole instance will be
     // outdated and not used.
     if (this._fetchStatus === FetchStatus.NOT_STARTED
       || this._fetchStatus === FetchStatus.ABORT) {
       this._fetchSuggestedOwners().then(() => {
         this._fetchStatus = FetchStatus.FINISHED;
       });
     }

     return this.getStatus().then(({codeOwnerStatusMap}) => {
       return {
         finished: this._fetchStatus === FetchStatus.FINISHED,
         status: this._fetchStatus,
         progress: this._totalFetchCount === 0 ?
           `Loading suggested owners ...` :
           `${this._fetchedOwners.size} out of ${this._totalFetchCount} files have returned suggested owners.`,
         suggestions: this._groupFilesByOwners(codeOwnerStatusMap),
       };
     });
   }

   _fetchSuggestedOwners() {
     // reset existing temporary storage
     this._fetchedOwners = new Map();
     this._fetchStatus = FetchStatus.FETCHING;
     this._totalFetchCount = 0;

     return this.getStatus()
         .then(({codeOwnerStatusMap}) => {
           // only fetch those not approved yet
           const filesGroupByStatus = [...codeOwnerStatusMap.keys()].reduce(
               (list, file) => {
                 const status = codeOwnerStatusMap
                     .get(file).status;
                 if (status === OwnerStatus.INSUFFICIENT_REVIEWERS) {
                   list.missing.push(file);
                 } else if (status === OwnerStatus.PENDING) {
                   list.pending.push(file);
                 }
                 return list;
               }
               , {pending: [], missing: []});
           // always fetch INSUFFICIENT_REVIEWERS first and then pending
           const filesToFetch = filesGroupByStatus.missing.concat(filesGroupByStatus.pending);
           this._totalFetchCount = filesToFetch.length;
           return this._batchFetchCodeOwners(filesToFetch);
         });
   }

   _formatStatuses(statuses) {
     // convert the array of statuses to map between file path -> status
     return statuses.reduce((prev, cur) => {
       const newPathStatus = cur.new_path_status;
       const oldPathStatus = cur.old_path_status;
       if (oldPathStatus) {
         prev.set(oldPathStatus.path, {
           changeType: cur.change_type,
           status: oldPathStatus.status,
           newPath: newPathStatus ? newPathStatus.path : null,
         });
       }
       if (newPathStatus) {
         prev.set(newPathStatus.path, {
           changeType: cur.change_type,
           status: newPathStatus.status,
           oldPath: oldPathStatus ? oldPathStatus.path : null,
         });
       }
       return prev;
     }, new Map());
   }

   _computeFileStatus(fileStatusMap, path) {
     // empty for modified files and old-name files
     // Show `Renamed` for renamed file
     const status = fileStatusMap.get(path);
     if (status.oldPath) {
       return 'Renamed';
     }
     return;
   }

   _groupFilesByOwners(codeOwnerStatusMap) {
     // Note: for renamed or moved files, they will have two entries in the map
     // we will treat them as two entries when group as well
     const allFiles = [...this._fetchedOwners.keys()];
     const ownersFilesMap = new Map();
     const failedToFetchFiles = new Set();
     for (let i = 0; i < allFiles.length; i++) {
       const fileInfo = {
         path: allFiles[i],
         status: this._computeFileStatus(codeOwnerStatusMap, allFiles[i]),
       };
       // for files failed to fetch, add them to the special group
       if (this._fetchedOwners.get(fileInfo.path).error) {
         failedToFetchFiles.add(fileInfo);
         continue;
       }

       // do not include files still in fetching
       if (!this._fetchedOwners.get(fileInfo.path).owners) {
         continue;
       }
       const owners = [...this._fetchedOwners.get(fileInfo.path).owners];
       const ownersKey = owners
           .map(owner => owner.account._account_id)
           .sort()
           .join(',');
       ownersFilesMap.set(
           ownersKey,
           ownersFilesMap.get(ownersKey) || {files: [], owners}
       );
       ownersFilesMap.get(ownersKey).files.push(fileInfo);
     }
     const groupedItems = [];
     for (const ownersKey of ownersFilesMap.keys()) {
       const groupName = this.getGroupName(ownersFilesMap.get(ownersKey).files);
       groupedItems.push({
         groupName,
         files: ownersFilesMap.get(ownersKey).files,
         owners: ownersFilesMap.get(ownersKey).owners,
       });
     }

     if (failedToFetchFiles.size > 0) {
       const failedFiles = [...failedToFetchFiles];
       groupedItems.push({
         groupName: this.getGroupName(failedFiles),
         files: failedFiles,
         error: new Error('Failed to fetch code owner info. Try to refresh the page.'),
       });
     }

     return groupedItems;
   }

   getGroupName(files) {
     const fileName = files[0].path.split('/').pop();
     return {
       name: fileName,
       prefix: files.length > 1 ? `+ ${files.length - 1} more` : '',
     };
   }

   isOnLatestPatchset(patchsetId) {
     const latestRevision = this.change.revisions[this.change.current_revision];
     return `${latestRevision._number}` === `${patchsetId}`;
   }

   /**
    * Recursively fetches code owners for all files until finished.
    *
    * @param {!Array<string>} files
    */
   _batchFetchCodeOwners(files) {
     if (this._fetchStatus === FetchStatus.ABORT) {
       return Promise.resolve(this._fetchedOwners);
     }

     const batchRequests = [];
     const maxConcurrentRequests = this.options.maxConcurrentRequests;
     for (let i = 0; i < maxConcurrentRequests; i++) {
       const filePath = files[i];
       if (filePath) {
         this._fetchedOwners.set(filePath, {});
         batchRequests.push(
             this.codeOwnerApi
                 .listOwnersForPath(
                     this.change.id,
                     filePath
                 )
                 .then(owners => {
                   // use Set to de-dup
                   this._fetchedOwners.get(filePath).owners = new Set(owners);
                 })
                 .catch(e => {
                   this._fetchedOwners.get(filePath).error = e;
                 })
         );
       }
     }
     const resPromise = Promise.all(batchRequests);
     if (files.length > maxConcurrentRequests) {
       return resPromise.then(() => {
         return this._batchFetchCodeOwners(files.slice(maxConcurrentRequests));
       });
     }
     return resPromise.then(() => this._fetchedOwners);
   }

   abort() {
     this._fetchStatus = FetchStatus.ABORT;
     this._fetchedOwners = new Map();
     this._totalFetchCount = 0;
   }

   getProjectConfig() {
     if (!this.getProjectConfigPromise) {
       this.getProjectConfigPromise =
           this.codeOwnerApi.getProjectConfig(this.change.project);
     }
     return this.getProjectConfigPromise;
   }

   getBranchConfig() {
     if (!this.getBranchConfigPromise) {
       this.getBranchConfigPromise =
           this.codeOwnerApi.getBranchConfig(this.change.project,
               this.change.branch);
     }
     return this.getBranchConfigPromise;
   }

   isCodeOwnerEnabled() {
     if (this.change.status === ChangeStatus.ABANDONED ||
         this.change.status === ChangeStatus.MERGED) {
       return Promise.resolve(false);
     }
     return this.getBranchConfig().then(config => {
       return !(config.status && config.status.disabled);
     });
   }

   static getOwnerService(restApi, change) {
     if (!this.ownerService || this.ownerService.change !== change) {
       this.ownerService = new CodeOwnerService(restApi, change, {
         // Chrome has a limit of 6 connections per host name, and a max of 10 connections.
         maxConcurrentRequests: 6,
       });
     }
     return this.ownerService;
   }
 }
	/**
	* @license
	* Copyright (C) 2020 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/**
	* All statuses returned for owner status.
	*
	* @enum
	*/
	export const OwnerStatus = {
	INSUFFICIENT_REVIEWERS: 'INSUFFICIENT_REVIEWERS',
	PENDING: 'PENDING',
	APPROVED: 'APPROVED',
	};

	/**
	* @enum
	*/
	const FetchStatus = {
	NOT_STARTED: 0,
	FETCHING: 1,
	FINISHED: 2,
	ABORT: 3,
	};

	/**
	* Specifies status for a change. The same as ChangeStatus enum in gerrit
	*
	* @enum
	*/
	const ChangeStatus = {
	ABANDONED: 'ABANDONED',
	MERGED: 'MERGED',
	NEW: 'NEW',
	};

	/**
	* @enum
	*/
	const UserRole = {
	ANONYMOUS: 'ANONYMOUS',
	AUTHOR: 'AUTHOR',
	CHANGE_OWNER: 'CHANGE_OWNER',
	REVIEWER: 'REVIEWER',
	CC: 'CC',
	REMOVED_REVIEWER: 'REMOVED_REVIEWER',
	OTHER: 'OTHER',
	};

	/**
	* Responsible for communicating with the rest-api
	*
	* @see resources/Documentation/rest-api.md
	*/
	class CodeOwnerApi {
	constructor(restApi) {
	this.restApi = restApi;
	}

	/**
	* Returns a promise fetching the owner statuses for all files within the change.
	*
	* @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#change-endpoints
	* @param {string} changeId
	*/
	listOwnerStatus(changeId) {
	return this.restApi.get(`/changes/${changeId}/code_owners.status`);
	}

	/**
	* Returns a promise fetching the owners for a given path.
	*
	* @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#list-code-owners-for-path-in-branch
	* @param {string} changeId
	* @param {string} path
	*/
	listOwnersForPath(changeId, path) {
	return this.restApi.get(
	`/changes/${changeId}/revisions/current/code_owners` +
	`/${encodeURIComponent(path)}?limit=5&o=DETAILS`
	);
	}

	/**
	* Returns a promise fetching the owners config for a given path.
	*
	* @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#branch-endpoints
	* @param {string} project
	* @param {string} branch
	* @param {string} path
	*/
	getConfigForPath(project, branch, path) {
	return this.restApi.get(
	`/projects/${encodeURIComponent(project)}/` +
	`branches/${encodeURIComponent(branch)}/` +
	`code_owners.config/${encodeURIComponent(path)}`
	);
	}

	/**
	* Returns a promise fetching project_config for code owners.
	*
	* @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#get-code-owner-project-config
	* @param {string} project
	*/
	getProjectConfig(project) {
	return this.restApi.get(
	`/projects/${encodeURIComponent(project)}/code_owners.project_config`
	);
	}

	/**
	* Returns a promise fetching the owners config for a given branch.
	*
	* @doc https://gerrit.googlesource.com/plugins/code-owners/+/refs/heads/master/resources/Documentation/rest-api.md#branch-endpoints
	* @param {string} project
	* @param {string} branch
	*/
	getBranchConfig(project, branch) {
	return this.restApi.get(
	`/projects/${encodeURIComponent(project)}/` +
	`branches/${encodeURIComponent(branch)}/` +
	`code_owners.branch_config`
	);
	}
	}

	/**
	* Service for the data layer used in the plugin UI.
	*/
	export class CodeOwnerService {
	constructor(restApi, change, options = {}) {
	this.restApi = restApi;
	this.change = change;
	this.options = {maxConcurrentRequests: 10, ...options};
	this.codeOwnerApi = new CodeOwnerApi(restApi);

	// fetched files and fetching status
	this._fetchedOwners = new Map();
	this._fetchStatus = FetchStatus.NOT_STARTED;
	this._totalFetchCount = 0;

	this.init();
	}

	/**
	* Initial fetches.
	*/
	init() {
	this.accountPromise = this.restApi.getLoggedIn().then(loggedIn => {
	if (!loggedIn) {
	return undefined;
	}
	return this.restApi.getAccount();
	});

	this.statusPromise = this.isCodeOwnerEnabled().then(enabled => {
	if (!enabled) {
	return {
	patchsetNumber: 0,
	enabled: false,
	codeOwnerStatusMap: new Map(),
	rawStatuses: [],
	};
	}
	return this.codeOwnerApi
	.listOwnerStatus(this.change._number)
	.then(res => {
	return {
	enabled: true,
	patchsetNumber: res.patch_set_number,
	codeOwnerStatusMap: this._formatStatuses(
	res.file_code_owner_statuses
	),
	rawStatuses: res.file_code_owner_statuses,
	};
	});
	});
	}

	/**
	* Returns the role of the current user. The returned value reflects the
	* role of the user at the time when the change is loaded.
	* For example, if a user removes themselves as a reviewer, the returned
	* role 'REVIEWER' remains unchanged until the change view is reloaded.
	*/
	getLoggedInUserInitialRole() {
	return this.accountPromise.then(account => {
	if (!account) {
	return UserRole.ANONYMOUS;
	}
	const change = this.change;
	if (
	change.revisions &&
	change.current_revision &&
	change.revisions[change.current_revision]
	) {
	const commit = change.revisions[change.current_revision].commit;
	if (
	commit &&
	commit.author &&
	account.email &&
	commit.author.email === account.email
	) {
	return UserRole.AUTHOR;
	}
	}
	if (change.owner._account_id === account._account_id) {
	return UserRole.CHANGE_OWNER;
	}
	if (change.reviewers) {
	if (this._accountInReviewers(change.reviewers.REVIEWER, account)) {
	return UserRole.REVIEWER;
	} else if (this._accountInReviewers(change.reviewers.CC, account)) {
	return UserRole.CC;
	} else if (this._accountInReviewers(change.reviewers.REMOVED, account)) {
	return UserRole.REMOVED_REVIEWER;
	}
	}
	return UserRole.OTHER;
	})
	}

	_accountInReviewers(reviewers, account) {
	if (!reviewers) {
	return false;
	}
	return reviewers.some(reviewer => reviewer._account_id === account._account_id);
	}

	getStatus() {
	return this.statusPromise.then(res => {
	if (res.enabled && !this.isOnLatestPatchset(res.patchsetNumber)) {
	// status is outdated, abort and re-init
	this.abort();
	this.init();
	return this.statusPromise;
	}
	return res;
	});
	}

	areAllFilesApproved() {
	return this.getStatus().then(({rawStatuses}) => {
	return !rawStatuses.some(status => {
	const oldPathStatus = status.old_path_status;
	const newPathStatus = status.new_path_status;
	// For deleted files, no new_path_status exists
	return (newPathStatus && newPathStatus.status !== OwnerStatus.APPROVED)
	\|\| (oldPathStatus && oldPathStatus.status !== OwnerStatus.APPROVED);
	});
	});
	}

	/**
	* Gets owner suggestions.
	*
	* @returns {{
	* finished?: boolean,
	* progress?: string,
	* suggestions: Array<{
	* groupName: {
	* name: string,
	* prefix: string
	* },
	* error?: Error,
	* owners?: Array,
	* files: Array,
	* }>
	* }}
	*/
	getSuggestedOwners() {
	// In case its aborted due to outdated patches
	// should kick start the fetching again
	// Note: we currently are not reusing the instance when switching changes,
	// so if its `abort` due to different changes, the whole instance will be
	// outdated and not used.
	if (this._fetchStatus === FetchStatus.NOT_STARTED
	\|\| this._fetchStatus === FetchStatus.ABORT) {
	this._fetchSuggestedOwners().then(() => {
	this._fetchStatus = FetchStatus.FINISHED;
	});
	}

	return this.getStatus().then(({codeOwnerStatusMap}) => {
	return {
	finished: this._fetchStatus === FetchStatus.FINISHED,
	status: this._fetchStatus,
	progress: this._totalFetchCount === 0 ?
	`Loading suggested owners ...` :
	`${this._fetchedOwners.size} out of ${this._totalFetchCount} files have returned suggested owners.`,
	suggestions: this._groupFilesByOwners(codeOwnerStatusMap),
	};
	});
	}

	_fetchSuggestedOwners() {
	// reset existing temporary storage
	this._fetchedOwners = new Map();
	this._fetchStatus = FetchStatus.FETCHING;
	this._totalFetchCount = 0;

	return this.getStatus()
	.then(({codeOwnerStatusMap}) => {
	// only fetch those not approved yet
	const filesGroupByStatus = [...codeOwnerStatusMap.keys()].reduce(
	(list, file) => {
	const status = codeOwnerStatusMap
	.get(file).status;
	if (status === OwnerStatus.INSUFFICIENT_REVIEWERS) {
	list.missing.push(file);
	} else if (status === OwnerStatus.PENDING) {
	list.pending.push(file);
	}
	return list;
	}
	, {pending: [], missing: []});
	// always fetch INSUFFICIENT_REVIEWERS first and then pending
	const filesToFetch = filesGroupByStatus.missing.concat(filesGroupByStatus.pending);
	this._totalFetchCount = filesToFetch.length;
	return this._batchFetchCodeOwners(filesToFetch);
	});
	}

	_formatStatuses(statuses) {
	// convert the array of statuses to map between file path -> status
	return statuses.reduce((prev, cur) => {
	const newPathStatus = cur.new_path_status;
	const oldPathStatus = cur.old_path_status;
	if (oldPathStatus) {
	prev.set(oldPathStatus.path, {
	changeType: cur.change_type,
	status: oldPathStatus.status,
	newPath: newPathStatus ? newPathStatus.path : null,
	});
	}
	if (newPathStatus) {
	prev.set(newPathStatus.path, {
	changeType: cur.change_type,
	status: newPathStatus.status,
	oldPath: oldPathStatus ? oldPathStatus.path : null,
	});
	}
	return prev;
	}, new Map());
	}

	_computeFileStatus(fileStatusMap, path) {
	// empty for modified files and old-name files
	// Show `Renamed` for renamed file
	const status = fileStatusMap.get(path);
	if (status.oldPath) {
	return 'Renamed';
	}
	return;
	}

	_groupFilesByOwners(codeOwnerStatusMap) {
	// Note: for renamed or moved files, they will have two entries in the map
	// we will treat them as two entries when group as well
	const allFiles = [...this._fetchedOwners.keys()];
	const ownersFilesMap = new Map();
	const failedToFetchFiles = new Set();
	for (let i = 0; i < allFiles.length; i++) {
	const fileInfo = {
	path: allFiles[i],
	status: this._computeFileStatus(codeOwnerStatusMap, allFiles[i]),
	};
	// for files failed to fetch, add them to the special group
	if (this._fetchedOwners.get(fileInfo.path).error) {
	failedToFetchFiles.add(fileInfo);
	continue;
	}

	// do not include files still in fetching
	if (!this._fetchedOwners.get(fileInfo.path).owners) {
	continue;
	}
	const owners = [...this._fetchedOwners.get(fileInfo.path).owners];
	const ownersKey = owners
	.map(owner => owner.account._account_id)
	.sort()
	.join(',');
	ownersFilesMap.set(
	ownersKey,
	ownersFilesMap.get(ownersKey) \|\| {files: [], owners}
	);
	ownersFilesMap.get(ownersKey).files.push(fileInfo);
	}
	const groupedItems = [];
	for (const ownersKey of ownersFilesMap.keys()) {
	const groupName = this.getGroupName(ownersFilesMap.get(ownersKey).files);
	groupedItems.push({
	groupName,
	files: ownersFilesMap.get(ownersKey).files,
	owners: ownersFilesMap.get(ownersKey).owners,
	});
	}

	if (failedToFetchFiles.size > 0) {
	const failedFiles = [...failedToFetchFiles];
	groupedItems.push({
	groupName: this.getGroupName(failedFiles),
	files: failedFiles,
	error: new Error('Failed to fetch code owner info. Try to refresh the page.'),
	});
	}

	return groupedItems;
	}

	getGroupName(files) {
	const fileName = files[0].path.split('/').pop();
	return {
	name: fileName,
	prefix: files.length > 1 ? `+ ${files.length - 1} more` : '',
	};
	}

	isOnLatestPatchset(patchsetId) {
	const latestRevision = this.change.revisions[this.change.current_revision];
	return `${latestRevision._number}` === `${patchsetId}`;
	}

	/**
	* Recursively fetches code owners for all files until finished.
	*
	* @param {!Array<string>} files
	*/
	_batchFetchCodeOwners(files) {
	if (this._fetchStatus === FetchStatus.ABORT) {
	return Promise.resolve(this._fetchedOwners);
	}

	const batchRequests = [];
	const maxConcurrentRequests = this.options.maxConcurrentRequests;
	for (let i = 0; i < maxConcurrentRequests; i++) {
	const filePath = files[i];
	if (filePath) {
	this._fetchedOwners.set(filePath, {});
	batchRequests.push(
	this.codeOwnerApi
	.listOwnersForPath(
	this.change.id,
	filePath
	)
	.then(owners => {
	// use Set to de-dup
	this._fetchedOwners.get(filePath).owners = new Set(owners);
	})
	.catch(e => {
	this._fetchedOwners.get(filePath).error = e;
	})
	);
	}
	}
	const resPromise = Promise.all(batchRequests);
	if (files.length > maxConcurrentRequests) {
	return resPromise.then(() => {
	return this._batchFetchCodeOwners(files.slice(maxConcurrentRequests));
	});
	}
	return resPromise.then(() => this._fetchedOwners);
	}

	abort() {
	this._fetchStatus = FetchStatus.ABORT;
	this._fetchedOwners = new Map();
	this._totalFetchCount = 0;
	}

	getProjectConfig() {
	if (!this.getProjectConfigPromise) {
	this.getProjectConfigPromise =
	this.codeOwnerApi.getProjectConfig(this.change.project);
	}
	return this.getProjectConfigPromise;
	}

	getBranchConfig() {
	if (!this.getBranchConfigPromise) {
	this.getBranchConfigPromise =
	this.codeOwnerApi.getBranchConfig(this.change.project,
	this.change.branch);
	}
	return this.getBranchConfigPromise;
	}

	isCodeOwnerEnabled() {
	if (this.change.status === ChangeStatus.ABANDONED \|\|
	this.change.status === ChangeStatus.MERGED) {
	return Promise.resolve(false);
	}
	return this.getBranchConfig().then(config => {
	return !(config.status && config.status.disabled);
	});
	}

	static getOwnerService(restApi, change) {
	if (!this.ownerService \|\| this.ownerService.change !== change) {
	this.ownerService = new CodeOwnerService(restApi, change, {
	// Chrome has a limit of 6 connections per host name, and a max of 10 connections.
	maxConcurrentRequests: 6,
	});
	}
	return this.ownerService;
	}
	}