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Make ScrollPanel keep track of when fill requests are happening

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The dance to avoid doing repeated fill requests on every update is common, so
add it to ScrollPanel. Let onFillRequest return a promise, which prevents any
updates until it completes.
This commit is contained in:
Richard van der Hoff 2015-12-24 00:10:21 +00:00
parent 103b0a03b1
commit f2a24521dc
2 changed files with 72 additions and 18 deletions
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27
src/components/structures/RoomView.js
View file

@ -330,8 +330,6 @@ module.exports = React.createClass({
this.scrollToBottom();
this.sendReadReceipt();
this.refs.messagePanel.checkFillState();
},
componentDidUpdate: function() {
@ -353,30 +351,25 @@ module.exports = React.createClass({
});
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.
this.refs.messagePanel.checkFillState();
},
onSearchResultsFillRequest: function(backwards) {
if (!backwards || this.state.searchInProgress)
return;
if (!backwards)
return false;
if (this.nextSearchBatch) {
if (DEBUG_SCROLL) console.log("requesting more search results");
this._getSearchBatch(this.state.searchTerm,
this.state.searchScope);
return this._getSearchBatch(this.state.searchTerm,
this.state.searchScope).then(true);
} else {
if (DEBUG_SCROLL) console.log("no more search results");
return false;
}
},
// set off a pagination request.
onMessageListFillRequest: function(backwards) {
if (!backwards || this.state.paginating)
if (!backwards)
return;
// Either wind back the message cap (if there are enough events in the
@ -386,11 +379,13 @@ module.exports = React.createClass({
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);
this.setState({messageCap: cap});
return 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);
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);
}
},
@ -515,8 +510,8 @@ 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 })
return MatrixClientPeg.get().search({ body: this._getSearchCondition(term, scope),
next_batch: this.nextSearchBatch })
.then(function(data) {
if (DEBUG_SCROLL) console.log("search complete");
if (!self.state.searching || self.searchId != searchId) {

63
src/components/structures/ScrollPanel.js
View file

@ -17,6 +17,7 @@ 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;
@ -51,7 +52,15 @@ 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 true if the pagination was successful, 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.
*
* This can return a promise; if it does, no more calls will be made
* until the promise completes. The promise should resolve to true or
* false as above.
*/
onFillRequest: React.PropTypes.func,
@ -77,14 +86,22 @@ module.exports = React.createClass({
},
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) {
@ -131,10 +148,52 @@ module.exports = React.createClass({
if (sn.scrollTop < sn.clientHeight) {
// there's less than a screenful of messages left - try to get some
// more messages.
this.props.onFillRequest(true);
this._maybeFill(true);
}
},
// 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]) {
if (DEBUG_SCROLL) {
console.log("ScrollPanel: Already a "+dir+" fill in progress - not starting another");
}
return;
}
if (DEBUG_SCROLL) {
console.log("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 r;
try {
r = this.props.onFillRequest(backwards);
} catch (e) {
this._pendingFillRequests[dir] = false;
throw e;
}
q.finally(r, () => {
if (DEBUG_SCROLL) {
console.log("ScrollPanel: "+dir+" fill complete");
}
this._pendingFillRequests[dir] = false;
}).then((res) => {
if (res) {
// 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
// restored later
getScrollState: function() {