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Merge pull request #70 from matrix-org/rav/scrollpanel_promises

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Make ScrollPanel keep track of when fill requests are happening
This commit is contained in:
Richard van der Hoff 2016-01-05 13:52:04 +00:00
commit 355cabb7ee
2 changed files with 129 additions and 41 deletions
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56
src/components/structures/RoomView.js
View file

@ -43,6 +43,13 @@ var INITIAL_SIZE = 20;
var DEBUG_SCROLL = false;
if (DEBUG_SCROLL) {
// using bind means that we get to keep useful line numbers in the console
var debuglog = console.log.bind(console);
} else {
var debuglog = function () {};
}
module.exports = React.createClass({
displayName: 'RoomView',
propTypes: {
@ -330,8 +337,6 @@ module.exports = React.createClass({
this.scrollToBottom();
this.sendReadReceipt();
this.refs.messagePanel.checkFillState();
},
componentDidUpdate: function() {
@ -346,53 +351,48 @@ module.exports = React.createClass({
},
_paginateCompleted: function() {
if (DEBUG_SCROLL) console.log("paginate complete");
debuglog("paginate complete");
this.setState({
room: MatrixClientPeg.get().getRoom(this.props.roomId)
});
this.setState({paginating: false});
// we might not have got enough (or, indeed, any) results from the
// pagination request, so give the messagePanel a chance to set off
// another.
if (this.refs.messagePanel) {
this.refs.messagePanel.checkFillState();
}
},
onSearchResultsFillRequest: function(backwards) {
if (!backwards || this.state.searchInProgress)
return;
if (!backwards)
return q(false);
if (this.nextSearchBatch) {
if (DEBUG_SCROLL) console.log("requesting more search results");
this._getSearchBatch(this.state.searchTerm,
this.state.searchScope);
debuglog("requesting more search results");
return this._getSearchBatch(this.state.searchTerm,
this.state.searchScope).then(true);
} else {
if (DEBUG_SCROLL) console.log("no more search results");
debuglog("no more search results");
return q(false);
}
},
// set off a pagination request.
onMessageListFillRequest: function(backwards) {
if (!backwards || this.state.paginating)
return;
if (!backwards)
return q(false);
// Either wind back the message cap (if there are enough events in the
// timeline to do so), or fire off a pagination request.
if (this.state.messageCap < this.state.room.timeline.length) {
var cap = Math.min(this.state.messageCap + PAGINATE_SIZE, this.state.room.timeline.length);
if (DEBUG_SCROLL) console.log("winding back message cap to", cap);
debuglog("winding back message cap to", cap);
this.setState({messageCap: cap});
return q(true);
} else if(this.state.room.oldState.paginationToken) {
var cap = this.state.messageCap + PAGINATE_SIZE;
if (DEBUG_SCROLL) console.log("starting paginate to cap", cap);
debuglog("starting paginate to cap", cap);
this.setState({messageCap: cap, paginating: true});
MatrixClientPeg.get().scrollback(this.state.room, PAGINATE_SIZE).finally(this._paginateCompleted).done();
return MatrixClientPeg.get().scrollback(this.state.room, PAGINATE_SIZE).
finally(this._paginateCompleted).then(true);
}
},
@ -499,7 +499,7 @@ module.exports = React.createClass({
}
this.nextSearchBatch = null;
this._getSearchBatch(term, scope);
this._getSearchBatch(term, scope).done();
},
// fire off a request for a batch of search results
@ -516,11 +516,11 @@ module.exports = React.createClass({
var self = this;
if (DEBUG_SCROLL) console.log("sending search request");
MatrixClientPeg.get().search({ body: this._getSearchCondition(term, scope),
next_batch: this.nextSearchBatch })
debuglog("sending search request");
return MatrixClientPeg.get().search({ body: this._getSearchCondition(term, scope),
next_batch: this.nextSearchBatch })
.then(function(data) {
if (DEBUG_SCROLL) console.log("search complete");
debuglog("search complete");
if (!self.state.searching || self.searchId != searchId) {
console.error("Discarding stale search results");
return;
@ -566,7 +566,7 @@ module.exports = React.createClass({
self.setState({
searchInProgress: false
});
}).done();
});
},
_getSearchCondition: function(term, scope) {

114
src/components/structures/ScrollPanel.js
View file

@ -17,9 +17,17 @@ limitations under the License.
var React = require("react");
var ReactDOM = require("react-dom");
var GeminiScrollbar = require('react-gemini-scrollbar');
var q = require("q");
var DEBUG_SCROLL = false;
if (DEBUG_SCROLL) {
// using bind means that we get to keep useful line numbers in the console
var debuglog = console.log.bind(console);
} else {
var debuglog = function () {};
}
/* This component implements an intelligent scrolling list.
*
* It wraps a list of <li> children; when items are added to the start or end
@ -51,7 +59,16 @@ module.exports = React.createClass({
/* onFillRequest(backwards): a callback which is called on scroll when
* the user nears the start (backwards = true) or end (backwards =
* false) of the list
* false) of the list.
*
* This should return a promise; no more calls will be made until the
* promise completes.
*
* The promise should resolve to true if there is more data to be
* retrieved in this direction (in which case onFillRequest may be
* called again immediately), or false if there is no more data in this
* directon (at this time) - which will stop the pagination cycle until
* the user scrolls again.
*/
onFillRequest: React.PropTypes.func,
@ -71,25 +88,33 @@ module.exports = React.createClass({
getDefaultProps: function() {
return {
stickyBottom: true,
onFillRequest: function(backwards) {},
onFillRequest: function(backwards) { return q(false); },
onScroll: function() {},
};
},
componentWillMount: function() {
this._pendingFillRequests = {b: null, f: null};
this.resetScrollState();
},
componentDidMount: function() {
this.checkFillState();
},
componentDidUpdate: function() {
// after adding event tiles, we may need to tweak the scroll (either to
// keep at the bottom of the timeline, or to maintain the view after
// adding events to the top).
this._restoreSavedScrollState();
// we also re-check the fill state, in case the paginate was inadequate
this.checkFillState();
},
onScroll: function(ev) {
var sn = this._getScrollNode();
if (DEBUG_SCROLL) console.log("Scroll event: offset now:", sn.scrollTop, "recentEventScroll:", this.recentEventScroll);
debuglog("Scroll event: offset now:", sn.scrollTop, "recentEventScroll:", this.recentEventScroll);
// Sometimes we see attempts to write to scrollTop essentially being
// ignored. (Or rather, it is successfully written, but on the next
@ -113,7 +138,7 @@ module.exports = React.createClass({
}
this.scrollState = this._calculateScrollState();
if (DEBUG_SCROLL) console.log("Saved scroll state", this.scrollState);
debuglog("Saved scroll state", this.scrollState);
this.props.onScroll(ev);
@ -135,11 +160,74 @@ module.exports = React.createClass({
checkFillState: function() {
var sn = this._getScrollNode();
// if there is less than a screenful of messages above or below the
// viewport, try to get some more messages.
//
// scrollTop is the number of pixels between the top of the content and
// the top of the viewport.
//
// scrollHeight is the total height of the content.
//
// clientHeight is the height of the viewport (excluding borders,
// margins, and scrollbars).
//
//
// .---------. - -
// | | | scrollTop |
// .-+---------+-. - - |
// | | | | | |
// | | | | | clientHeight | scrollHeight
// | | | | | |
// `-+---------+-' - |
// | | |
// | | |
// `---------' -
//
if (sn.scrollTop < sn.clientHeight) {
// there's less than a screenful of messages left - try to get some
// more messages.
this.props.onFillRequest(true);
// need to back-fill
this._maybeFill(true);
}
if (sn.scrollTop > sn.scrollHeight - sn.clientHeight * 2) {
// need to forward-fill
this._maybeFill(false);
}
},
// check if there is already a pending fill request. If not, set one off.
_maybeFill: function(backwards) {
var dir = backwards ? 'b' : 'f';
if (this._pendingFillRequests[dir]) {
debuglog("ScrollPanel: Already a "+dir+" fill in progress - not starting another");
return;
}
debuglog("ScrollPanel: starting "+dir+" fill");
// onFillRequest can end up calling us recursively (via onScroll
// events) so make sure we set this before firing off the call. That
// does present the risk that we might not ever actually fire off the
// fill request, so wrap it in a try/catch.
this._pendingFillRequests[dir] = true;
var fillPromise;
try {
fillPromise = this.props.onFillRequest(backwards);
} catch (e) {
this._pendingFillRequests[dir] = false;
throw e;
}
q.finally(fillPromise, () => {
debuglog("ScrollPanel: "+dir+" fill complete");
this._pendingFillRequests[dir] = false;
}).then((hasMoreResults) => {
if (hasMoreResults) {
// further pagination requests have been disabled until now, so
// it's time to check the fill state again in case the pagination
// was insufficient.
this.checkFillState();
}
}).done();
},
// get the current scroll position of the room, so that it can be
@ -163,13 +251,13 @@ module.exports = React.createClass({
scrollToTop: function() {
this._getScrollNode().scrollTop = 0;
if (DEBUG_SCROLL) console.log("Scrolled to top");
debuglog("Scrolled to top");
},
scrollToBottom: function() {
var scrollNode = this._getScrollNode();
scrollNode.scrollTop = scrollNode.scrollHeight;
if (DEBUG_SCROLL) console.log("Scrolled to bottom; offset now", scrollNode.scrollTop);
debuglog("Scrolled to bottom; offset now", scrollNode.scrollTop);
},
// scroll the message list to the node with the given scrollToken. See
@ -206,10 +294,10 @@ module.exports = React.createClass({
this.recentEventScroll = scrollNode.scrollTop;
}
if (DEBUG_SCROLL) {
console.log("Scrolled to token", node.dataset.scrollToken, "+", pixelOffset+":", scrollNode.scrollTop, "(delta: "+scrollDelta+")");
console.log("recentEventScroll now "+this.recentEventScroll);
}
debuglog("Scrolled to token", node.dataset.scrollToken, "+",
pixelOffset+":", scrollNode.scrollTop,
"(delta: "+scrollDelta+")");
debuglog("recentEventScroll now "+this.recentEventScroll);
},
_calculateScrollState: function() {