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Change the room list algo to eagerly delete and carefully insert
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Previously it made some complicated assumptions about the contexts it was called in (it generally assumed it just had to shuffle rooms between tags and didn't really handle new rooms very well).

The algorithm now eagerly tries to drop rooms from tags and carefully inserts them. The actual insertion logic is mostly untouched: the only part changed is how it handles failure to insert into tag. It shouldn't be possible for this algorithm to completely skip a room unless the tag is empty, so we special case that.

There are several TODO comments to be addressed here. Namely, it doesn't handle manually ordered tags (favourites, custom, etc) and doesn't check if tags are even enabled. Changes in this area are waiting for #2686 to land to take advantage of monitoring the settings flag for tags.
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@turt2live
turt2live committed Feb 25, 2019
1 parent c12bea0 commit 5f760fb
Showing 1 changed file with 122 additions and 108 deletions.
230 changes: 122 additions & 108 deletions src/stores/RoomListStore.js
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Original file line number Diff line number Diff line change
Expand Up @@ -180,15 +180,15 @@ class RoomListStore extends Store {
break;
case 'MatrixActions.Room.myMembership': {
if (!logicallyReady) break;
this._roomUpdateTriggered(payload.room.roomId);
this._roomUpdateTriggered(payload.room.roomId, true);
}
break;
// This could be a new room that we've been invited to, joined or created
// we won't get a RoomMember.membership for these cases if we're not already
// a member.
case 'MatrixActions.Room': {
if (!logicallyReady) break;
this._roomUpdateTriggered(payload.room.roomId);
this._roomUpdateTriggered(payload.room.roomId, true);
}
break;
// TODO: Re-enable optimistic updates when we support dragging again
Expand Down Expand Up @@ -230,12 +230,12 @@ class RoomListStore extends Store {
}
}

_roomUpdateTriggered(roomId) {
_roomUpdateTriggered(roomId, ignoreSticky) {
// We don't calculate categories for sticky rooms because we have a moderate
// interest in trying to maintain the category that they were last in before
// being artificially flagged as IDLE. Also, this reduces the amount of time
// we spend in _setRoomCategory ever so slightly.
if (this._state.stickyRoomId !== roomId) {
if (this._state.stickyRoomId !== roomId || ignoreSticky) {
// Micro optimization: Only look up the room if we're confident we'll need it.
const room = this._matrixClient.getRoom(roomId);
if (!room) return;
Expand All @@ -245,6 +245,31 @@ class RoomListStore extends Store {
}
}

_getRecommendedTagsForRoom(room) {
const tags = [];

const myMembership = room.getMyMembership();
if (myMembership === 'join' || myMembership === 'invite') {
// Stack the user's tags on top
// TODO: Consider whether tags are enabled at all
tags.push(...(room.tags || []));

const dmRoomMap = DMRoomMap.shared();
if (dmRoomMap.getUserIdForRoomId(room.roomId)) {
tags.push("im.vector.fake.direct");
} else if (myMembership === 'invite') {
tags.push("im.vector.fake.invite");
} else if (tags.length === 0) {
tags.push("im.vector.fake.recent");
}
} else {
tags.push("im.vector.fake.archived");
}


return tags;
}

_setRoomCategory(room, category) {
if (!room) return; // This should only happen in tests

Expand All @@ -260,127 +285,116 @@ class RoomListStore extends Store {
return _targetTimestamp;
};

const myMembership = room.getMyMembership();
let doInsert = true;
const targetTags = [];
if (myMembership !== "join" && myMembership !== "invite") {
doInsert = false;
} else {
const dmRoomMap = DMRoomMap.shared();
if (dmRoomMap.getUserIdForRoomId(room.roomId)) {
targetTags.push('im.vector.fake.direct');
} else {
targetTags.push('im.vector.fake.recent');
}
}
const targetTags = this._getRecommendedTagsForRoom(room);
const insertedIntoTags = [];

// We need to update all instances of a room to ensure that they are correctly organized
// in the list. We do this by shallow-cloning the entire `lists` object using a single
// iterator. Within the loop, we also rebuild the list of rooms per tag (key) so that the
// updated room gets slotted into the right spot. This sacrifices code clarity for not
// iterating on potentially large collections multiple times.
// We need to make sure all the tags (lists) are updated with the room's new position. We
// generally only get called here when there's a new room to insert or a room has potentially
// changed positions within the list.
//
// We do all our checks by iterating over the rooms in the existing lists, trying to insert
// our room where we can. As a guiding principle, we should be removing the room from all
// tags, and insert the room into targetTags. We should perform the deletion before the addition
// where possible to keep a consistent state. By the end of this, targetTags should be the
// same as insertedIntoTags.

let inserted = false;
for (const key of Object.keys(this._state.lists)) {
const hasRoom = this._state.lists[key].some((e) => e.room.roomId === room.roomId);

// Speed optimization: Skip the loop below if we're not going to do anything productive
if (!hasRoom || LIST_ORDERS[key] !== 'recent') {
listsClone[key] = this._state.lists[key];
if (LIST_ORDERS[key] !== 'recent' && (hasRoom || targetTags.includes(key))) {
// Ensure that we don't try and sort the room into the tag
inserted = true;
doInsert = false;
}
continue;
const shouldHaveRoom = targetTags.includes(key);

// Speed optimization: Don't do complicated math if we don't have to.
if (!shouldHaveRoom) {
listsClone[key] = this._state.lists[key].filter((e) => e.room.roomId !== room.roomId);
} else {
listsClone[key] = [];
}

// We track where the boundary within listsClone[key] is just in case our timestamp
// ordering fails. If we can't stick the room in at the correct place in the category
// grouping based on timestamp, we'll stick it at the top of the group which will be
// the index we track here.
let desiredCategoryBoundaryIndex = 0;
let foundBoundary = false;
let pushedEntry = false;

for (const entry of this._state.lists[key]) {
// if the list is a recent list, and the room appears in this list, and we're not looking at a sticky
// room (sticky rooms have unreliable categories), try to slot the new room in
if (entry.room.roomId !== this._state.stickyRoomId) {
if (!pushedEntry && doInsert && (targetTags.length === 0 || targetTags.includes(key))) {
// Micro optimization: Support lazily loading the last timestamp in a room
let _entryTimestamp = null;
const entryTimestamp = () => {
if (_entryTimestamp === null) {
_entryTimestamp = this._tsOfNewestEvent(entry.room);
}
return _entryTimestamp;
};

const entryCategoryIndex = CATEGORY_ORDER.indexOf(entry.category);

// As per above, check if we're meeting that boundary we wanted to locate.
if (entryCategoryIndex >= targetCategoryIndex && !foundBoundary) {
desiredCategoryBoundaryIndex = listsClone[key].length - 1;
foundBoundary = true;
// Tags sorted by recents are more complicated than manually ordered tags, so hope
// for the best.
// TODO: Use the SettingsStore watcher to determine if tags are enabled or not
if (LIST_ORDERS[key] !== 'recent') {
// TODO: Actually insert the room
} else {
// We track where the boundary within listsClone[key] is just in case our timestamp
// ordering fails. If we can't stick the room in at the correct place in the category
// grouping based on timestamp, we'll stick it at the top of the group which will be
// the index we track here.
let desiredCategoryBoundaryIndex = 0;
let foundBoundary = false;
let pushedEntry = false;

for (const entry of this._state.lists[key]) {
// We insert our own record as needed, so don't let the old one through.
if (entry.room.roomId === room.roomId) {
continue;
}

// If we've hit the top of a boundary beyond our target category, insert at the top of
// the grouping to ensure the room isn't slotted incorrectly. Otherwise, try to insert
// based on most recent timestamp.
const changedBoundary = entryCategoryIndex > targetCategoryIndex;
const currentCategory = entryCategoryIndex === targetCategoryIndex;
if (changedBoundary || (currentCategory && targetTimestamp() >= entryTimestamp())) {
if (changedBoundary) {
// If we changed a boundary, then we've gone too far - go to the top of the last
// section instead.
listsClone[key].splice(desiredCategoryBoundaryIndex, 0, {room, category});
} else {
// If we're ordering by timestamp, just insert normally
listsClone[key].push({room, category});
// if the list is a recent list, and the room appears in this list, and we're
// not looking at a sticky room (sticky rooms have unreliable categories), try
// to slot the new room in
if (entry.room.roomId !== this._state.stickyRoomId) {
if (!pushedEntry && shouldHaveRoom) {
// Micro optimization: Support lazily loading the last timestamp in a room
let _entryTimestamp = null;
const entryTimestamp = () => {
if (_entryTimestamp === null) {
_entryTimestamp = this._tsOfNewestEvent(entry.room);
}
return _entryTimestamp;
};

const entryCategoryIndex = CATEGORY_ORDER.indexOf(entry.category);

// As per above, check if we're meeting that boundary we wanted to locate.
if (entryCategoryIndex >= targetCategoryIndex && !foundBoundary) {
desiredCategoryBoundaryIndex = listsClone[key].length - 1;
foundBoundary = true;
}

// If we've hit the top of a boundary beyond our target category, insert at the top of
// the grouping to ensure the room isn't slotted incorrectly. Otherwise, try to insert
// based on most recent timestamp.
const changedBoundary = entryCategoryIndex > targetCategoryIndex;
const currentCategory = entryCategoryIndex === targetCategoryIndex;
if (changedBoundary || (currentCategory && targetTimestamp() >= entryTimestamp())) {
if (changedBoundary) {
// If we changed a boundary, then we've gone too far - go to the top of the last
// section instead.
listsClone[key].splice(desiredCategoryBoundaryIndex, 0, {room, category});
} else {
// If we're ordering by timestamp, just insert normally
listsClone[key].push({room, category});
}
pushedEntry = true;
insertedIntoTags.push(key);
}
}
pushedEntry = true;
inserted = true;
}

// Fall through and clone the list.
listsClone[key].push(entry);
}

// We insert our own record as needed, so don't let the old one through.
if (entry.room.roomId === room.roomId) {
continue;
if (!pushedEntry) {
if (listsClone[key].length === 0) {
listsClone[key].push({room, category});
insertedIntoTags.push(key);
} else {
// In theory, this should never happen
console.warn(`!! Room ${room.roomId} lost: No position available`);
}
}
}

// Fall through and clone the list.
listsClone[key].push(entry);
}
}

if (!inserted) {
// There's a good chance that we just joined the room, so we need to organize it
// We also could have left it...
let tags = [];
if (doInsert) {
tags = Object.keys(room.tags);
if (tags.length === 0) {
tags = targetTags;
}
if (tags.length === 0) {
tags = [myMembership === 'join' ? 'im.vector.fake.recent' : 'im.vector.fake.invite'];
}
} else {
tags = ['im.vector.fake.archived'];
// Double check that we inserted the room in the right places
for (const targetTag of targetTags) {
let count = 0;
for (const insertedTag of insertedIntoTags) {
if (insertedTag === targetTag) count++;
}
for (const tag of tags) {
for (let i = 0; i < listsClone[tag].length; i++) {
// Just find the top of our category grouping and insert it there.
const catIdxAtPosition = CATEGORY_ORDER.indexOf(listsClone[tag][i].category);
if (catIdxAtPosition >= targetCategoryIndex) {
listsClone[tag].splice(i, 0, {room: room, category: category});
break;
}
}

if (count !== 1) {
console.warn(`!! Room ${room.roomId} inserted ${count} times`);
}
}

Expand Down Expand Up @@ -574,7 +588,7 @@ class RoomListStore extends Store {
return -1;
}

return a === b ? this._lexicographicalComparator(roomA, roomB) : ( a > b ? 1 : -1);
return a === b ? this._lexicographicalComparator(roomA, roomB) : (a > b ? 1 : -1);
};
}

Expand Down

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