src/main/resources/static/find-owners.js - plugins/find-owners - Git at Google

 // Copyright (C) 2017 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.

 Gerrit.install(function(self) {
   if (window.Polymer) {
     // Install deprecated APIs to mimic GWT UI API.
     self.deprecated.install();
   }

   // If context.popup API exists and popup content is small,
   // use the API and set useContextPopup,
   // otherwise, use pageDiv and set its visibility.
   var useContextPopup = false;
   var pageDiv = document.createElement('div');
   document.body.appendChild(pageDiv);
   function hideFindOwnersPage() {
     pageDiv.style.visibility = 'hidden';
   }
   function popupFindOwnersPage(context, change, revision, onSubmit) {
     const PADDING = 5;
     const LARGE_PAGE_STYLE = Gerrit.css(
         'visibility: hidden;' +
         'background: rgba(200, 200, 200, 0.95);' +
         'border: 3px solid;' +
         'border-color: #c8c8c8;' +
         'border-radius: 3px;' +
         'position: fixed;' +
         'z-index: 100;' +
         'overflow: auto;' +
         'padding: ' + PADDING + 'px;'
         );
     const BUTTON_STYLE = Gerrit.css(
         'background-color: #4d90fe;' +
         'border: 2px solid;' +
         'border-color: #4d90fe;' +
         'margin: 2px 10px 2px 10px;' +
         'text-align: center;' +
         'font-size: 8pt;' +
         'font-weight: bold;' +
         'color: #fff;' +
         '-webkit-border-radius: 2px;' +
         'cursor: pointer;'
         );
     const HTML_BULLET = '<small>&#x2605;</small>'; // a Black Star
     const HTML_HAS_APPROVAL_HEADER =
         '<hr><b>Files with +1 or +2 Code-Review vote from owners:</b><br>';
     const HTML_IS_EXEMPTED =
         '<b>This change is Exempt-From-Owner-Approval.</b>';
     const HTML_NEED_REVIEWER_HEADER =
         '<hr><b>Files without owner reviewer:</b><br>';
     const HTML_NEED_APPROVAL_HEADER =
         '<hr><b>Files without Code-Review vote from an owner:</b><br>';
     const HTML_NO_OWNER =
         '<b>No owner was found for changed files.</b>';
     const HTML_ONSUBMIT_HEADER =
         '<b>WARNING: Need owner approval vote before submit.</b><hr>';
     const HTML_OWNERS_HEADER = '<hr><b>Owners in alphabetical order:</b><br>';
     const HTML_SELECT_REVIEWERS =
         '<b>Check the box before owner names to select reviewers, ' +
         'then click the "Apply" button.' +
         '</b><br><small>If owner-approval requirement is enabled, ' +
         'each file needs at least one Code-Review +1 vote from an owner. ' +
         'Owners listed after a file are ordered by their importance. ' +
         '(Or declare "<b><span style="font-size:80%;">' +
         'Exempt-From-Owner-Approval:</span></b> ' +
         '<i>reasons...</i>" in the Commit Message.)</small><br>';

     const APPLY_BUTTON_ID = 'FindOwners:Apply';
     const CHECKBOX_ID = 'FindOwners:CheckBox';
     const HEADER_DIV_ID = 'FindOwners:Header';
     const OWNERS_DIV_ID = 'FindOwners:Owners';
     const HAS_APPROVAL_DIV_ID = 'FindOwners:HasApproval';
     const NEED_APPROVAL_DIV_ID = 'FindOwners:NeedApproval';
     const NEED_REVIEWER_DIV_ID = 'FindOwners:NeedReviewer';

     // Aliases to values in the context.
     const branch = change.branch;
     const changeId = change._number;
     const changeOwner = change.owner;
     const message = revision.commit.message;
     const project = change.project;

     var minVoteLevel = 1; // could be changed by server returned results.
     var reviewerId = {}; // map from a reviewer's email to account id.
     var reviewerVote = {}; // map from a reviewer's email to Code-Review vote.

     // addList and removeList are used only under applySelections.
     var addList = []; // remain emails to add to reviewers
     var removeList = []; // remain emails to remove from reviewers
     var needRefresh = false; // true if to refresh after checkAddRemoveLists

     function getElement(id) {
       return document.getElementById(id);
     }
     function httpGet(url, callback) {
       var xhr = new XMLHttpRequest();
       xhr.open('GET', url);
       xhr.onreadystatechange = function() {
         if (xhr.readyState == XMLHttpRequest.DONE) {
           // skip special characters ")]}'\n"
           callback(!!xhr.responseText ?
                    JSON.parse(xhr.responseText.substring(5)) : {});
         }
       };
       xhr.send();
     }
     function httpError(msg, callback) {
       console.log('UNIMPLEMENTED: ' + msg);
       callback();
     }
     function gerritGet(url, callback) {
       (!!Gerrit.get) ? Gerrit.get(url, callback) :
           ((!!self.get) ? self.get('/../..' + url, callback) :
               httpGet(url, callback));
     }
     function gerritPost(url, data, callback) {
       (!!Gerrit.post) ? Gerrit.post(url, data, callback) :
           ((!!self.post) ? self.post('/../..' + url, data, callback) :
               httpError('POST ' + url, callback));
     }
     function gerritDelete(url, callback) {
       (!!Gerrit.delete) ? Gerrit.delete(url, callback) :
           ((!!self.delete) ? self.delete('/../..' + url, callback) :
               httpError('DELETE ' + url, callback));
     }
     function getReviewers(change, callBack) {
       gerritGet('/changes/' + change + '/reviewers', callBack);
     }
     function setupReviewersMap(reviewerList) {
       reviewerId = {};
       reviewerVote = {};
       reviewerList.forEach(function(reviewer) {
         if ('email' in reviewer && '_account_id' in reviewer) {
           reviewerId[reviewer.email] = reviewer._account_id;
           reviewerVote[reviewer.email] = 0;
           if ('approvals' in reviewer && 'Code-Review' in reviewer.approvals) {
             reviewerVote[reviewer.email] =
                 parseInt(reviewer.approvals['Code-Review']);
             // The 'Code-Review' values could be "-2", "-1", " 0", "+1", "+2"
           }
         }
       });
       // Give CL author a default minVoteLevel vote.
       if (changeOwner != null &&
           'email' in changeOwner && '_account_id' in changeOwner &&
           (!(changeOwner.email in reviewerId) ||
            reviewerVote[changeOwner.email] == 0)) {
         reviewerId[changeOwner.email] = changeOwner._account_id;
         reviewerVote[changeOwner.email] = minVoteLevel;
       }
     }
     function checkAddRemoveLists() {
       // Gerrit.post and delete are asynchronous.
       // Do one at a time, with checkAddRemoveLists as callBack.
       for (var i = 0; i < addList.length; i++) {
         var email = addList[i];
         if (!(email in reviewerId)) {
           addList = addList.slice(i + 1, addList.length);
           // A post request can fail if given reviewer email is invalid.
           // Gerrit core UI shows the error dialog and does not provide
           // a way for plugins to handle the error yet.
           needRefresh = true;
           gerritPost('/changes/' + changeId + '/reviewers',
                      {'reviewer': email},
                      checkAddRemoveLists);
           return;
         }
       }
       for (var i = 0; i < removeList.length; i++) {
         var email = removeList[i];
         if (email in reviewerId) {
           removeList = removeList.slice(i + 1, removeList.length);
           needRefresh = true;
           gerritDelete('/changes/' + changeId +
                        '/reviewers/' + reviewerId[email],
                        checkAddRemoveLists);
           return;
         }
       }
       hideFindOwnersPage();
       if (needRefresh) {
         needRefresh = false;
         (!!Gerrit.refresh) ? Gerrit.refresh() : location.reload();
       }
       callServer(showFindOwnersResults);
     }
     function applyGetReviewers(reviewerList) {
       setupReviewersMap(reviewerList);
       checkAddRemoveLists(); // update and pop up window at the end
     }
     function hasOwnerReviewer(reviewers, owners) {
       return owners.some(function(owner) {
         return (owner in reviewers || owner == '*');
       });
     }
     function hasOwnerApproval(votes, owners) {
       var foundApproval = false;
       for (var j = 0; j < owners.length; j++) {
         if (owners[j] in votes) {
           var v = votes[owners[j]];
           if (v < 0) {
             return false; // cannot have any negative vote
           }
           foundApproval |= v >= minVoteLevel;
         }
       }
       return foundApproval;
     }
     function isExemptedFromOwnerApproval() {
       return message.match(/(Exempted|Exempt)-From-Owner-Approval:/);
     }
     function showDiv(div, text) {
       div.style.display = 'inline';
       div.innerHTML = text;
     }
     function strElement(s) {
       var e = document.createElement('span');
       e.innerHTML = s;
       return e;
     }
     function br() {
       return document.createElement('br');
     }
     function hr() {
       return document.createElement('hr');
     }
     function newButton(name, action) {
       var b = document.createElement('button');
       b.appendChild(document.createTextNode(name));
       b.className = BUTTON_STYLE;
       b.onclick = action;
       return b;
     }
     function showJsonLines(args, key, obj) {
       showBoldKeyValueLines(args, key, JSON.stringify(obj, null, 2));
     }
     function showBoldKeyValueLines(args, key, value) {
       args.push(hr(), strElement('<b>' + key + '</b>:'), br());
       value.split('\n').forEach(function(line) {
         args.push(strElement(line), br());
       });
     }
     function showDebugMessages(result, args) {
       function addKeyValue(key, value) {
         args.push(strElement('<b>' + key + '</b>: ' + value + '<br>'));
       }
       args.push(hr());
       addKeyValue('changeId', changeId);
       addKeyValue('project', project);
       addKeyValue('branch', branch);
       addKeyValue('changeOwner.email', changeOwner.email);
       addKeyValue('Gerrit.url', Gerrit.url());
       addKeyValue('self.url', self.url());
       showJsonLines(args, 'changeOwner', change.owner);
       showBoldKeyValueLines(args, 'commit.message', message);
       showJsonLines(args, 'Client reviewers Ids', reviewerId);
       showJsonLines(args, 'Client reviewers Votes', reviewerVote);
       Object.keys(result).forEach(function(k) {
         showJsonLines(args, 'Server.' + k, result[k]);
       });
     }
     function showFilesAndOwners(result, args) {
       var sortedOwners = result.owners.map(
           function(ownerInfo) { return ownerInfo.email; });
       var groups = {};
       // group name ==> {needReviewer, needApproval, owners}
       var groupSize = {};
       // group name ==> number of files in group
       var header = emptyDiv(HEADER_DIV_ID);
       var needReviewerDiv = emptyDiv(NEED_REVIEWER_DIV_ID);
       var needApprovalDiv = emptyDiv(NEED_APPROVAL_DIV_ID);
       var hasApprovalDiv = emptyDiv(HAS_APPROVAL_DIV_ID);
       addApplyButton();
       args.push(newButton('Cancel', hideFindOwnersPage));
       var ownersDiv = emptyDiv(OWNERS_DIV_ID);
       var numCheckBoxes = 0;
       var owner2boxes = {}; // owner name ==> array of checkbox id
       var owner2email = {}; // owner name ==> email address
       minVoteLevel =
           ('minOwnerVoteLevel' in result ? result.minOwnerVoteLevel : 1);

       function addApplyButton() {
         var apply = newButton('Apply', doApplyButton);
         apply.id = APPLY_BUTTON_ID;
         apply.style.display = 'none';
         args.push(apply);
       }
       function emptyDiv(id) {
         var e = document.createElement('div');
         e.id = id;
         e.style.display = 'none';
         args.push(e);
         return e;
       }
       function doApplyButton() {
         addList = [];
         removeList = [];
         // add each owner's email address to addList or removeList
         Object.keys(owner2boxes).forEach(function(owner) {
           (getElement(owner2boxes[owner][0]).checked ?
               addList : removeList).push(owner2email[owner]);
         });
         getReviewers(changeId, applyGetReviewers);
       }
       function clickBox(event) {
         var name = event.target.value;
         var checked = event.target.checked;
         var others = owner2boxes[name];
         others.forEach(function(id) { getElement(id).checked = checked; });
         getElement(APPLY_BUTTON_ID).style.display = 'inline';
       }
       function addGroupsToDiv(div, keys, title) {
         if (keys.length <= 0) {
           div.style.display = 'none';
           return;
         }
         div.innerHTML = '';
         div.style.display = 'inline';
         div.appendChild(strElement(title));
         function addOwner(ownerEmail) {
           numCheckBoxes++;
           var name = ownerEmail.replace(/@[^ ]*/g, '');
           owner2email[name] = ownerEmail;
           var id = CHECKBOX_ID + ':' + numCheckBoxes;
           if (!(name in owner2boxes)) {
             owner2boxes[name] = [];
           }
           owner2boxes[name].push(id);
           var box = document.createElement('input');
           box.type = 'checkbox';
           box.checked = (ownerEmail in reviewerId);
           box.id = id;
           box.value = name;
           box.onclick = clickBox;
           div.appendChild(strElement('&nbsp;&nbsp; '));
           var nobr = document.createElement('nobr');
           nobr.appendChild(box);
           nobr.appendChild(strElement(name));
           div.appendChild(nobr);
         }
         keys.forEach(function(key) {
           var owners = groups[key].owners; // string of owner emails
           var numFiles = groupSize[key];
           var item = HTML_BULLET + '&nbsp;<b>' + key + '</b>' +
               ((numFiles > 1) ? (' (' + numFiles + ' files):') : ':');
           var setOfOwners = new Set(owners.split(' '));
           function add2list(list, email) {
             if (setOfOwners.has(email)) {
               list.push(email);
             }
             return list;
           }
           div.appendChild(strElement(item));
           sortedOwners.reduce(add2list, []).forEach(addOwner);
           div.appendChild(br());
         });
       }
       function addOwnersDiv(div, title) {
         div.innerHTML = '';
         div.style.display = 'inline';
         div.appendChild(strElement(title));
         function compareOwnerInfo(o1, o2) {
           return o1.email.localeCompare(o2.email);
         }
         result.owners.sort(compareOwnerInfo).forEach(function(ownerInfo) {
           var email = ownerInfo.email;
           var vote = reviewerVote[email];
           if ((email in reviewerVote) && vote != 0) {
             email += ' <font color="' +
                 ((vote > 0) ? 'green">(+' : 'red">(') + vote + ')</font>';
           }
           div.appendChild(strElement('&nbsp;&nbsp;' + email + '<br>'));
         });
       }
       function updateDivContent() {
         var groupNeedReviewer = [];
         var groupNeedApproval = [];
         var groupHasApproval = [];
         numCheckBoxes = 0;
         owner2boxes = {};
         Object.keys(groups).sort().forEach(function(key) {
           var g = groups[key];
           if (g.needReviewer) {
             groupNeedReviewer.push(key);
           } else if (g.needApproval) {
             groupNeedApproval.push(key);
           } else {
             groupHasApproval.push(key);
           }
         });
         showDiv(header,
                 (onSubmit ? HTML_ONSUBMIT_HEADER : '') + HTML_SELECT_REVIEWERS);
         addGroupsToDiv(needReviewerDiv, groupNeedReviewer,
                        HTML_NEED_REVIEWER_HEADER);
         addGroupsToDiv(needApprovalDiv, groupNeedApproval,
                        HTML_NEED_APPROVAL_HEADER);
         addGroupsToDiv(hasApprovalDiv, groupHasApproval,
                        HTML_HAS_APPROVAL_HEADER);
         addOwnersDiv(ownersDiv, HTML_OWNERS_HEADER);
       }
       function createGroups() {
         var owners2group = {}; // owner list to group name
         Object.keys(result.file2owners).sort().forEach(function(name) {
           var splitOwners = result.file2owners[name];
           var owners = splitOwners.join(' ');
           if (owners in owners2group) {
             groupSize[owners2group[owners]] += 1;
           } else {
             owners2group[owners] = name;
             groupSize[name] = 1;
             var needReviewer = !hasOwnerReviewer(reviewerId, splitOwners);
             var needApproval = !needReviewer &&
                 !hasOwnerApproval(reviewerVote, splitOwners);
             groups[name] = {
               'needReviewer': needReviewer,
               'needApproval': needApproval,
               'owners': owners};
           }
         });
       }
       createGroups();
       updateDivContent();
     }
     function showFindOwnersResults(result) {
       function prepareElements() {
         var elems = [];
         var text = isExemptedFromOwnerApproval() ? HTML_IS_EXEMPTED :
             (Object.keys(result.file2owners).length <= 0 ?
                 HTML_NO_OWNER : null);
         useContextPopup = !!context && !!text && !!context.popup;
         if (!!text) {
           if (useContextPopup) {
             elems.push(hr(), strElement(text), hr());
             var onClick = function() { context.hide(); };
             elems.push(context.button('OK', {onclick: onClick}), hr());
           } else {
             elems.push(strElement(text), newButton('OK', hideFindOwnersPage));
           }
         } else {
           showFilesAndOwners(result, elems);
           if (result.addDebugMsg) {
             showDebugMessages(result, elems);
           }
         }
         return elems;
       }
       function popupWindow(reviewerList) {
         setupReviewersMap(reviewerList);
         var elems = prepareElements();
         if (useContextPopup) {
           context.popup(context.div.apply(this, elems));
         } else {
           while (pageDiv.firstChild) {
             pageDiv.removeChild(pageDiv.firstChild);
           }
           elems.forEach(function(e) { pageDiv.appendChild(e); });
           pageDiv.className = LARGE_PAGE_STYLE;
           // Calculate required height, limited to 85% of window height,
           // and required width, limited to 75% of window width.
           var maxHeight = Math.round(window.innerHeight * 0.85);
           var maxWidth = Math.round(window.innerWidth * 0.75);
           pageDiv.style.top = '5%';
           pageDiv.style.height = 'auto';
           pageDiv.style.left = '10%';
           pageDiv.style.width = 'auto';
           var rect = pageDiv.getBoundingClientRect();
           if (rect.width > maxWidth) {
             pageDiv.style.width = maxWidth + 'px';
             rect = pageDiv.getBoundingClientRect();
           }
           pageDiv.style.left = Math.round((window.innerWidth - rect.width) / 2) + 'px';
           if (rect.height > maxHeight) {
             pageDiv.style.height = maxHeight + 'px';
             rect = pageDiv.getBoundingClientRect();
           }
           pageDiv.style.top = Math.round((window.innerHeight - rect.height) / 2) + 'px';
           pageDiv.style.visibility = 'visible';
         }
       }
       getReviewers(changeId, popupWindow);
     }
     function callServer(callBack) {
       // Use the plugin REST API; pass only changeId;
       // let server get current patch set, project and branch info.
       gerritGet('/changes/' + changeId + '/owners', showFindOwnersResults);
     }
     event.stopPropagation();
     callServer(showFindOwnersResults);
   }
   function onFindOwners(context) {
     popupFindOwnersPage(context, context.change, context.revision, false);
   }
   function onSubmit(change, revision) {
     const OWNER_REVIEW_LABEL = 'Owner-Review-Vote';
     if (change.labels.hasOwnProperty(OWNER_REVIEW_LABEL)) {
       // Pop up Find Owners page; do not submit.
       popupFindOwnersPage(null, change, revision, true);
       return false;
     }
     return true; // Okay to submit.
   }
   var actionKey = null;
   function onShowChangePolyGerrit(change, revision) {
     var changeActions = self.changeActions();
     // Hide previous 'Find Owners' button under 'MORE'.
     changeActions.setActionHidden('revision', 'find-owners~find-owners', true);
     if (!!actionKey) {
       changeActions.removeTapListener(actionKey);
       changeActions.remove(actionKey);
     }
     actionKey = changeActions.add('revision', '[Find Owners]');
     changeActions.setIcon(actionKey, 'robot');
     changeActions.setTitle(actionKey, 'Find owners of changed files');
     changeActions.addTapListener(actionKey,
         () => popupFindOwnersPage(null, change, revision, false));
   }
   function onClick(e) {
     if (pageDiv.style.visibility != 'hidden' && !useContextPopup) {
       var x = event.clientX;
       var y = event.clientY;
       var rect = pageDiv.getBoundingClientRect();
       if (x < rect.left || x >= rect.left + rect.width ||
           y < rect.top || y >= rect.top + rect.height) {
         hideFindOwnersPage();
       }
     }
   }
   // When the "Find Owners" button is clicked, call onFindOwners.
   if (!!self.onAction) { // PolyGerrit does not have self.onAction
     self.onAction('revision', 'find-owners', onFindOwners);
   } else {
     console.log('WARNING, no handler for the Find Owners button');
   }
   // When using PolyGerrit, move "Find Owners" button out of the 'MORE' list.
   if (window.Polymer) {
     self.on('showchange', onShowChangePolyGerrit);
   }
   // When the "Submit" button is clicked, call onSubmit.
   self.on('submitchange', onSubmit);
   // Clicks outside the pop up window should close the window.
   document.body.addEventListener('click', onClick);
 });
	// Copyright (C) 2017 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.

	Gerrit.install(function(self) {
	if (window.Polymer) {
	// Install deprecated APIs to mimic GWT UI API.
	self.deprecated.install();
	}

	// If context.popup API exists and popup content is small,
	// use the API and set useContextPopup,
	// otherwise, use pageDiv and set its visibility.
	var useContextPopup = false;
	var pageDiv = document.createElement('div');
	document.body.appendChild(pageDiv);
	function hideFindOwnersPage() {
	pageDiv.style.visibility = 'hidden';
	}
	function popupFindOwnersPage(context, change, revision, onSubmit) {
	const PADDING = 5;
	const LARGE_PAGE_STYLE = Gerrit.css(
	'visibility: hidden;' +
	'background: rgba(200, 200, 200, 0.95);' +
	'border: 3px solid;' +
	'border-color: #c8c8c8;' +
	'border-radius: 3px;' +
	'position: fixed;' +
	'z-index: 100;' +
	'overflow: auto;' +
	'padding: ' + PADDING + 'px;'
	);
	const BUTTON_STYLE = Gerrit.css(
	'background-color: #4d90fe;' +
	'border: 2px solid;' +
	'border-color: #4d90fe;' +
	'margin: 2px 10px 2px 10px;' +
	'text-align: center;' +
	'font-size: 8pt;' +
	'font-weight: bold;' +
	'color: #fff;' +
	'-webkit-border-radius: 2px;' +
	'cursor: pointer;'
	);
	const HTML_BULLET = '<small>★</small>'; // a Black Star
	const HTML_HAS_APPROVAL_HEADER =
	'<hr><b>Files with +1 or +2 Code-Review vote from owners:</b><br>';
	const HTML_IS_EXEMPTED =
	'<b>This change is Exempt-From-Owner-Approval.</b>';
	const HTML_NEED_REVIEWER_HEADER =
	'<hr><b>Files without owner reviewer:</b><br>';
	const HTML_NEED_APPROVAL_HEADER =
	'<hr><b>Files without Code-Review vote from an owner:</b><br>';
	const HTML_NO_OWNER =
	'<b>No owner was found for changed files.</b>';
	const HTML_ONSUBMIT_HEADER =
	'<b>WARNING: Need owner approval vote before submit.</b><hr>';
	const HTML_OWNERS_HEADER = '<hr><b>Owners in alphabetical order:</b><br>';
	const HTML_SELECT_REVIEWERS =
	'<b>Check the box before owner names to select reviewers, ' +
	'then click the "Apply" button.' +
	'</b><br><small>If owner-approval requirement is enabled, ' +
	'each file needs at least one Code-Review +1 vote from an owner. ' +
	'Owners listed after a file are ordered by their importance. ' +
	'(Or declare "<b><span style="font-size:80%;">' +
	'Exempt-From-Owner-Approval:</span></b> ' +
	'<i>reasons...</i>" in the Commit Message.)</small><br>';

	const APPLY_BUTTON_ID = 'FindOwners:Apply';
	const CHECKBOX_ID = 'FindOwners:CheckBox';
	const HEADER_DIV_ID = 'FindOwners:Header';
	const OWNERS_DIV_ID = 'FindOwners:Owners';
	const HAS_APPROVAL_DIV_ID = 'FindOwners:HasApproval';
	const NEED_APPROVAL_DIV_ID = 'FindOwners:NeedApproval';
	const NEED_REVIEWER_DIV_ID = 'FindOwners:NeedReviewer';

	// Aliases to values in the context.
	const branch = change.branch;
	const changeId = change._number;
	const changeOwner = change.owner;
	const message = revision.commit.message;
	const project = change.project;

	var minVoteLevel = 1; // could be changed by server returned results.
	var reviewerId = {}; // map from a reviewer's email to account id.
	var reviewerVote = {}; // map from a reviewer's email to Code-Review vote.

	// addList and removeList are used only under applySelections.
	var addList = []; // remain emails to add to reviewers
	var removeList = []; // remain emails to remove from reviewers
	var needRefresh = false; // true if to refresh after checkAddRemoveLists

	function getElement(id) {
	return document.getElementById(id);
	}
	function httpGet(url, callback) {
	var xhr = new XMLHttpRequest();
	xhr.open('GET', url);
	xhr.onreadystatechange = function() {
	if (xhr.readyState == XMLHttpRequest.DONE) {
	// skip special characters ")]}'\n"
	callback(!!xhr.responseText ?
	JSON.parse(xhr.responseText.substring(5)) : {});
	}
	};
	xhr.send();
	}
	function httpError(msg, callback) {
	console.log('UNIMPLEMENTED: ' + msg);
	callback();
	}
	function gerritGet(url, callback) {
	(!!Gerrit.get) ? Gerrit.get(url, callback) :
	((!!self.get) ? self.get('/../..' + url, callback) :
	httpGet(url, callback));
	}
	function gerritPost(url, data, callback) {
	(!!Gerrit.post) ? Gerrit.post(url, data, callback) :
	((!!self.post) ? self.post('/../..' + url, data, callback) :
	httpError('POST ' + url, callback));
	}
	function gerritDelete(url, callback) {
	(!!Gerrit.delete) ? Gerrit.delete(url, callback) :
	((!!self.delete) ? self.delete('/../..' + url, callback) :
	httpError('DELETE ' + url, callback));
	}
	function getReviewers(change, callBack) {
	gerritGet('/changes/' + change + '/reviewers', callBack);
	}
	function setupReviewersMap(reviewerList) {
	reviewerId = {};
	reviewerVote = {};
	reviewerList.forEach(function(reviewer) {
	if ('email' in reviewer && '_account_id' in reviewer) {
	reviewerId[reviewer.email] = reviewer._account_id;
	reviewerVote[reviewer.email] = 0;
	if ('approvals' in reviewer && 'Code-Review' in reviewer.approvals) {
	reviewerVote[reviewer.email] =
	parseInt(reviewer.approvals['Code-Review']);
	// The 'Code-Review' values could be "-2", "-1", " 0", "+1", "+2"
	}
	}
	});
	// Give CL author a default minVoteLevel vote.
	if (changeOwner != null &&
	'email' in changeOwner && '_account_id' in changeOwner &&
	(!(changeOwner.email in reviewerId) \|\|
	reviewerVote[changeOwner.email] == 0)) {
	reviewerId[changeOwner.email] = changeOwner._account_id;
	reviewerVote[changeOwner.email] = minVoteLevel;
	}
	}
	function checkAddRemoveLists() {
	// Gerrit.post and delete are asynchronous.
	// Do one at a time, with checkAddRemoveLists as callBack.
	for (var i = 0; i < addList.length; i++) {
	var email = addList[i];
	if (!(email in reviewerId)) {
	addList = addList.slice(i + 1, addList.length);
	// A post request can fail if given reviewer email is invalid.
	// Gerrit core UI shows the error dialog and does not provide
	// a way for plugins to handle the error yet.
	needRefresh = true;
	gerritPost('/changes/' + changeId + '/reviewers',
	{'reviewer': email},
	checkAddRemoveLists);
	return;
	}
	}
	for (var i = 0; i < removeList.length; i++) {
	var email = removeList[i];
	if (email in reviewerId) {
	removeList = removeList.slice(i + 1, removeList.length);
	needRefresh = true;
	gerritDelete('/changes/' + changeId +
	'/reviewers/' + reviewerId[email],
	checkAddRemoveLists);
	return;
	}
	}
	hideFindOwnersPage();
	if (needRefresh) {
	needRefresh = false;
	(!!Gerrit.refresh) ? Gerrit.refresh() : location.reload();
	}
	callServer(showFindOwnersResults);
	}
	function applyGetReviewers(reviewerList) {
	setupReviewersMap(reviewerList);
	checkAddRemoveLists(); // update and pop up window at the end
	}
	function hasOwnerReviewer(reviewers, owners) {
	return owners.some(function(owner) {
	return (owner in reviewers \|\| owner == '*');
	});
	}
	function hasOwnerApproval(votes, owners) {
	var foundApproval = false;
	for (var j = 0; j < owners.length; j++) {
	if (owners[j] in votes) {
	var v = votes[owners[j]];
	if (v < 0) {
	return false; // cannot have any negative vote
	}
	foundApproval \|= v >= minVoteLevel;
	}
	}
	return foundApproval;
	}
	function isExemptedFromOwnerApproval() {
	return message.match(/(Exempted\|Exempt)-From-Owner-Approval:/);
	}
	function showDiv(div, text) {
	div.style.display = 'inline';
	div.innerHTML = text;
	}
	function strElement(s) {
	var e = document.createElement('span');
	e.innerHTML = s;
	return e;
	}
	function br() {
	return document.createElement('br');
	}
	function hr() {
	return document.createElement('hr');
	}
	function newButton(name, action) {
	var b = document.createElement('button');
	b.appendChild(document.createTextNode(name));
	b.className = BUTTON_STYLE;
	b.onclick = action;
	return b;
	}
	function showJsonLines(args, key, obj) {
	showBoldKeyValueLines(args, key, JSON.stringify(obj, null, 2));
	}
	function showBoldKeyValueLines(args, key, value) {
	args.push(hr(), strElement('<b>' + key + '</b>:'), br());
	value.split('\n').forEach(function(line) {
	args.push(strElement(line), br());
	});
	}
	function showDebugMessages(result, args) {
	function addKeyValue(key, value) {
	args.push(strElement('<b>' + key + '</b>: ' + value + '<br>'));
	}
	args.push(hr());
	addKeyValue('changeId', changeId);
	addKeyValue('project', project);
	addKeyValue('branch', branch);
	addKeyValue('changeOwner.email', changeOwner.email);
	addKeyValue('Gerrit.url', Gerrit.url());
	addKeyValue('self.url', self.url());
	showJsonLines(args, 'changeOwner', change.owner);
	showBoldKeyValueLines(args, 'commit.message', message);
	showJsonLines(args, 'Client reviewers Ids', reviewerId);
	showJsonLines(args, 'Client reviewers Votes', reviewerVote);
	Object.keys(result).forEach(function(k) {
	showJsonLines(args, 'Server.' + k, result[k]);
	});
	}
	function showFilesAndOwners(result, args) {
	var sortedOwners = result.owners.map(
	function(ownerInfo) { return ownerInfo.email; });
	var groups = {};
	// group name ==> {needReviewer, needApproval, owners}
	var groupSize = {};
	// group name ==> number of files in group
	var header = emptyDiv(HEADER_DIV_ID);
	var needReviewerDiv = emptyDiv(NEED_REVIEWER_DIV_ID);
	var needApprovalDiv = emptyDiv(NEED_APPROVAL_DIV_ID);
	var hasApprovalDiv = emptyDiv(HAS_APPROVAL_DIV_ID);
	addApplyButton();
	args.push(newButton('Cancel', hideFindOwnersPage));
	var ownersDiv = emptyDiv(OWNERS_DIV_ID);
	var numCheckBoxes = 0;
	var owner2boxes = {}; // owner name ==> array of checkbox id
	var owner2email = {}; // owner name ==> email address
	minVoteLevel =
	('minOwnerVoteLevel' in result ? result.minOwnerVoteLevel : 1);

	function addApplyButton() {
	var apply = newButton('Apply', doApplyButton);
	apply.id = APPLY_BUTTON_ID;
	apply.style.display = 'none';
	args.push(apply);
	}
	function emptyDiv(id) {
	var e = document.createElement('div');
	e.id = id;
	e.style.display = 'none';
	args.push(e);
	return e;
	}
	function doApplyButton() {
	addList = [];
	removeList = [];
	// add each owner's email address to addList or removeList
	Object.keys(owner2boxes).forEach(function(owner) {
	(getElement(owner2boxes[owner][0]).checked ?
	addList : removeList).push(owner2email[owner]);
	});
	getReviewers(changeId, applyGetReviewers);
	}
	function clickBox(event) {
	var name = event.target.value;
	var checked = event.target.checked;
	var others = owner2boxes[name];
	others.forEach(function(id) { getElement(id).checked = checked; });
	getElement(APPLY_BUTTON_ID).style.display = 'inline';
	}
	function addGroupsToDiv(div, keys, title) {
	if (keys.length <= 0) {
	div.style.display = 'none';
	return;
	}
	div.innerHTML = '';
	div.style.display = 'inline';
	div.appendChild(strElement(title));
	function addOwner(ownerEmail) {
	numCheckBoxes++;
	var name = ownerEmail.replace(/@[^ ]*/g, '');
	owner2email[name] = ownerEmail;
	var id = CHECKBOX_ID + ':' + numCheckBoxes;
	if (!(name in owner2boxes)) {
	owner2boxes[name] = [];
	}
	owner2boxes[name].push(id);
	var box = document.createElement('input');
	box.type = 'checkbox';
	box.checked = (ownerEmail in reviewerId);
	box.id = id;
	box.value = name;
	box.onclick = clickBox;
	div.appendChild(strElement('   '));
	var nobr = document.createElement('nobr');
	nobr.appendChild(box);
	nobr.appendChild(strElement(name));
	div.appendChild(nobr);
	}
	keys.forEach(function(key) {
	var owners = groups[key].owners; // string of owner emails
	var numFiles = groupSize[key];
	var item = HTML_BULLET + ' <b>' + key + '</b>' +
	((numFiles > 1) ? (' (' + numFiles + ' files):') : ':');
	var setOfOwners = new Set(owners.split(' '));
	function add2list(list, email) {
	if (setOfOwners.has(email)) {
	list.push(email);
	}
	return list;
	}
	div.appendChild(strElement(item));
	sortedOwners.reduce(add2list, []).forEach(addOwner);
	div.appendChild(br());
	});
	}
	function addOwnersDiv(div, title) {
	div.innerHTML = '';
	div.style.display = 'inline';
	div.appendChild(strElement(title));
	function compareOwnerInfo(o1, o2) {
	return o1.email.localeCompare(o2.email);
	}
	result.owners.sort(compareOwnerInfo).forEach(function(ownerInfo) {
	var email = ownerInfo.email;
	var vote = reviewerVote[email];
	if ((email in reviewerVote) && vote != 0) {
	email += ' <font color="' +
	((vote > 0) ? 'green">(+' : 'red">(') + vote + ')</font>';
	}
	div.appendChild(strElement('  ' + email + '<br>'));
	});
	}
	function updateDivContent() {
	var groupNeedReviewer = [];
	var groupNeedApproval = [];
	var groupHasApproval = [];
	numCheckBoxes = 0;
	owner2boxes = {};
	Object.keys(groups).sort().forEach(function(key) {
	var g = groups[key];
	if (g.needReviewer) {
	groupNeedReviewer.push(key);
	} else if (g.needApproval) {
	groupNeedApproval.push(key);
	} else {
	groupHasApproval.push(key);
	}
	});
	showDiv(header,
	(onSubmit ? HTML_ONSUBMIT_HEADER : '') + HTML_SELECT_REVIEWERS);
	addGroupsToDiv(needReviewerDiv, groupNeedReviewer,
	HTML_NEED_REVIEWER_HEADER);
	addGroupsToDiv(needApprovalDiv, groupNeedApproval,
	HTML_NEED_APPROVAL_HEADER);
	addGroupsToDiv(hasApprovalDiv, groupHasApproval,
	HTML_HAS_APPROVAL_HEADER);
	addOwnersDiv(ownersDiv, HTML_OWNERS_HEADER);
	}
	function createGroups() {
	var owners2group = {}; // owner list to group name
	Object.keys(result.file2owners).sort().forEach(function(name) {
	var splitOwners = result.file2owners[name];
	var owners = splitOwners.join(' ');
	if (owners in owners2group) {
	groupSize[owners2group[owners]] += 1;
	} else {
	owners2group[owners] = name;
	groupSize[name] = 1;
	var needReviewer = !hasOwnerReviewer(reviewerId, splitOwners);
	var needApproval = !needReviewer &&
	!hasOwnerApproval(reviewerVote, splitOwners);
	groups[name] = {
	'needReviewer': needReviewer,
	'needApproval': needApproval,
	'owners': owners};
	}
	});
	}
	createGroups();
	updateDivContent();
	}
	function showFindOwnersResults(result) {
	function prepareElements() {
	var elems = [];
	var text = isExemptedFromOwnerApproval() ? HTML_IS_EXEMPTED :
	(Object.keys(result.file2owners).length <= 0 ?
	HTML_NO_OWNER : null);
	useContextPopup = !!context && !!text && !!context.popup;
	if (!!text) {
	if (useContextPopup) {
	elems.push(hr(), strElement(text), hr());
	var onClick = function() { context.hide(); };
	elems.push(context.button('OK', {onclick: onClick}), hr());
	} else {
	elems.push(strElement(text), newButton('OK', hideFindOwnersPage));
	}
	} else {
	showFilesAndOwners(result, elems);
	if (result.addDebugMsg) {
	showDebugMessages(result, elems);
	}
	}
	return elems;
	}
	function popupWindow(reviewerList) {
	setupReviewersMap(reviewerList);
	var elems = prepareElements();
	if (useContextPopup) {
	context.popup(context.div.apply(this, elems));
	} else {
	while (pageDiv.firstChild) {
	pageDiv.removeChild(pageDiv.firstChild);
	}
	elems.forEach(function(e) { pageDiv.appendChild(e); });
	pageDiv.className = LARGE_PAGE_STYLE;
	// Calculate required height, limited to 85% of window height,
	// and required width, limited to 75% of window width.
	var maxHeight = Math.round(window.innerHeight * 0.85);
	var maxWidth = Math.round(window.innerWidth * 0.75);
	pageDiv.style.top = '5%';
	pageDiv.style.height = 'auto';
	pageDiv.style.left = '10%';
	pageDiv.style.width = 'auto';
	var rect = pageDiv.getBoundingClientRect();
	if (rect.width > maxWidth) {
	pageDiv.style.width = maxWidth + 'px';
	rect = pageDiv.getBoundingClientRect();
	}
	pageDiv.style.left = Math.round((window.innerWidth - rect.width) / 2) + 'px';
	if (rect.height > maxHeight) {
	pageDiv.style.height = maxHeight + 'px';
	rect = pageDiv.getBoundingClientRect();
	}
	pageDiv.style.top = Math.round((window.innerHeight - rect.height) / 2) + 'px';
	pageDiv.style.visibility = 'visible';
	}
	}
	getReviewers(changeId, popupWindow);
	}
	function callServer(callBack) {
	// Use the plugin REST API; pass only changeId;
	// let server get current patch set, project and branch info.
	gerritGet('/changes/' + changeId + '/owners', showFindOwnersResults);
	}
	event.stopPropagation();
	callServer(showFindOwnersResults);
	}
	function onFindOwners(context) {
	popupFindOwnersPage(context, context.change, context.revision, false);
	}
	function onSubmit(change, revision) {
	const OWNER_REVIEW_LABEL = 'Owner-Review-Vote';
	if (change.labels.hasOwnProperty(OWNER_REVIEW_LABEL)) {
	// Pop up Find Owners page; do not submit.
	popupFindOwnersPage(null, change, revision, true);
	return false;
	}
	return true; // Okay to submit.
	}
	var actionKey = null;
	function onShowChangePolyGerrit(change, revision) {
	var changeActions = self.changeActions();
	// Hide previous 'Find Owners' button under 'MORE'.
	changeActions.setActionHidden('revision', 'find-owners~find-owners', true);
	if (!!actionKey) {
	changeActions.removeTapListener(actionKey);
	changeActions.remove(actionKey);
	}
	actionKey = changeActions.add('revision', '[Find Owners]');
	changeActions.setIcon(actionKey, 'robot');
	changeActions.setTitle(actionKey, 'Find owners of changed files');
	changeActions.addTapListener(actionKey,
	() => popupFindOwnersPage(null, change, revision, false));
	}
	function onClick(e) {
	if (pageDiv.style.visibility != 'hidden' && !useContextPopup) {
	var x = event.clientX;
	var y = event.clientY;
	var rect = pageDiv.getBoundingClientRect();
	if (x < rect.left \|\| x >= rect.left + rect.width \|\|
	y < rect.top \|\| y >= rect.top + rect.height) {
	hideFindOwnersPage();
	}
	}
	}
	// When the "Find Owners" button is clicked, call onFindOwners.
	if (!!self.onAction) { // PolyGerrit does not have self.onAction
	self.onAction('revision', 'find-owners', onFindOwners);
	} else {
	console.log('WARNING, no handler for the Find Owners button');
	}
	// When using PolyGerrit, move "Find Owners" button out of the 'MORE' list.
	if (window.Polymer) {
	self.on('showchange', onShowChangePolyGerrit);
	}
	// When the "Submit" button is clicked, call onSubmit.
	self.on('submitchange', onSubmit);
	// Clicks outside the pop up window should close the window.
	document.body.addEventListener('click', onClick);
	});