Fix an issue where the scroll stopped working.

Under certain conditions, it was possible to get stuck in a state where any
user-initiated scroll would be met with "Working around
vector-im/vector-web#528" and overridden. Fix this by removing the duplication
between _lastSetScroll and recentEventScroll, and using _lastSetScroll which is
more reliable.
pull/21833/head
Richard van der Hoff 2016-04-02 18:09:44 +01:00
parent 2d3a237101
commit 51fe77122b
4 changed files with 301 additions and 34 deletions

View File

@ -26,6 +26,9 @@ module.exports = function (config) {
// list of files / patterns to load in the browser
files: [
'test/tests.js',
// XXX this will break on npm 3
'node_modules/react-gemini-scrollbar/node_modules/gemini-scrollbar/gemini-scrollbar.css',
],
// list of files to exclude

View File

@ -20,6 +20,7 @@ var GeminiScrollbar = require('react-gemini-scrollbar');
var q = require("q");
var DEBUG_SCROLL = false;
// var DEBUG_SCROLL = true;
if (DEBUG_SCROLL) {
// using bind means that we get to keep useful line numbers in the console
@ -144,7 +145,8 @@ module.exports = React.createClass({
onScroll: function(ev) {
var sn = this._getScrollNode();
debuglog("Scroll event: offset now:", sn.scrollTop, "recentEventScroll:", this.recentEventScroll);
debuglog("Scroll event: offset now:", sn.scrollTop,
"_lastSetScroll:", this._lastSetScroll);
// Sometimes we see attempts to write to scrollTop essentially being
// ignored. (Or rather, it is successfully written, but on the next
@ -158,13 +160,10 @@ module.exports = React.createClass({
// By way of a workaround, we detect this situation and just keep
// resetting scrollTop until we see the scroll node have the right
// value.
if (this.recentEventScroll !== undefined) {
if(sn.scrollTop < this.recentEventScroll-200) {
console.log("Working around vector-im/vector-web#528");
this._restoreSavedScrollState();
return;
}
this.recentEventScroll = undefined;
if (this._lastSetScroll !== undefined && sn.scrollTop < this._lastSetScroll-200) {
console.log("Working around vector-im/vector-web#528");
this._restoreSavedScrollState();
return;
}
// If there weren't enough children to fill the viewport, the scroll we
@ -395,17 +394,14 @@ module.exports = React.createClass({
var wrapperRect = ReactDOM.findDOMNode(this).getBoundingClientRect();
var boundingRect = node.getBoundingClientRect();
var scrollDelta = boundingRect.bottom + pixelOffset - wrapperRect.bottom;
debuglog("Scrolling to token '" + node.dataset.scrollToken + "'+" +
pixelOffset + " (delta: "+scrollDelta+")");
if(scrollDelta != 0) {
this._setScrollTop(scrollNode.scrollTop + scrollDelta);
// see the comments in onScroll regarding recentEventScroll
this.recentEventScroll = scrollNode.scrollTop;
}
debuglog("Scrolled to token", node.dataset.scrollToken, "+",
pixelOffset+":", scrollNode.scrollTop,
"(delta: "+scrollDelta+")");
debuglog("recentEventScroll now "+this.recentEventScroll);
},
_saveScrollState: function() {

View File

@ -0,0 +1,275 @@
/*
Copyright 2016 OpenMarket Ltd
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.
*/
var React = require('react');
var ReactDOM = require("react-dom");
var ReactTestUtils = require('react-addons-test-utils');
var expect = require('expect');
var q = require('q');
var sdk = require('matrix-react-sdk');
var ScrollPanel = sdk.getComponent('structures.ScrollPanel');
var test_utils = require('test-utils');
var Tester = React.createClass({
getInitialState: function() {
return {
tileKeys: [],
};
},
componentWillMount: function() {
this.fillCounts = {'b': 0, 'f': 0};
this._fillHandlers = {'b': null, 'f': null};
this._fillDefers = {'b': null, 'f': null};
this._scrollDefer = null;
// scrollTop at the last scroll event
this.lastScrollEvent = null;
},
_onFillRequest: function(back) {
var dir = back ? 'b': 'f';
console.log("FillRequest: " + dir);
this.fillCounts[dir]++;
var handler = this._fillHandlers[dir];
var defer = this._fillDefers[dir];
// don't use the same handler twice
this._fillHandlers[dir] = null;
this._fillDefers[dir] = null;
var res;
if (handler) {
res = handler();
} else {
res = q(false);
}
if (defer) {
defer.resolve();
}
return res;
},
addFillHandler: function(dir, handler) {
this._fillHandlers[dir] = handler;
},
/* returns a promise which will resolve when the fill happens */
awaitFill: function(dir) {
var defer = q.defer();
this._fillDefers[dir] = defer;
return defer.promise;
},
_onScroll: function(ev) {
var st = ev.target.scrollTop;
console.log("Scroll event; scrollTop: " + st);
this.lastScrollEvent = st;
var d = this._scrollDefer;
if (d) {
this._scrollDefer = null;
d.resolve();
}
},
/* returns a promise which will resolve when a scroll event happens */
awaitScroll: function() {
console.log("Awaiting scroll");
this._scrollDefer = q.defer();
return this._scrollDefer.promise;
},
setTileKeys: function(keys) {
console.log("Updating keys: len=" + keys.length);
this.setState({tileKeys: keys.slice()});
},
scrollPanel: function() {
return this.refs.sp;
},
_mkTile: function(key) {
// each tile is 150 pixels high:
// 98 pixels of body
// 2 pixels of border
// 50 pixels of margin
//
// there is an extra 50 pixels of margin at the bottom.
return (
<li key={key} data-scroll-token={key}>
<div style={{height: '98px', margin: '50px', border: '1px solid black',
backgroundColor: '#fff8dc' }}>
{key}
</div>
</li>
);
},
render: function() {
var tiles = this.state.tileKeys.map(this._mkTile);
console.log("rendering with " + tiles.length + " tiles");
return (
<ScrollPanel ref="sp"
onScroll={ this._onScroll }
onFillRequest={ this._onFillRequest }>
{tiles}
</ScrollPanel>
);
},
});
describe('ScrollPanel', function() {
var parentDiv;
var tester;
var scrollingDiv;
beforeEach(function(done) {
test_utils.beforeEach(this);
// create a div of a useful size to put our panel in, and attach it to
// the document so that we can interact with it properly.
parentDiv = document.createElement('div');
parentDiv.style.width = '800px';
parentDiv.style.height = '600px';
parentDiv.style.overflow = 'hidden';
document.body.appendChild(parentDiv);
tester = ReactDOM.render(<Tester/>, parentDiv);
expect(tester.fillCounts.b).toEqual(1);
expect(tester.fillCounts.f).toEqual(1);
scrollingDiv = ReactTestUtils.findRenderedDOMComponentWithClass(
tester, "gm-scroll-view");
// wait for a browser tick to let the initial paginates complete
setTimeout(function() {
done();
}, 0);
});
afterEach(function() {
if (parentDiv) {
document.body.removeChild(parentDiv);
parentDiv = null;
}
});
it('should handle scrollEvent strangeness', function(done) {
var events = [];
q().then(() => {
// initialise with a few events
for (var i = 0; i < 10; i++) {
events.push(i+90);
}
tester.setTileKeys(events);
expect(tester.fillCounts.b).toEqual(1);
expect(tester.fillCounts.f).toEqual(2);
expect(scrollingDiv.scrollHeight).toEqual(1550) // 10*150 + 50
expect(scrollingDiv.scrollTop).toEqual(1550 - 600);
return tester.awaitScroll();
}).then(() => {
expect(tester.lastScrollEvent).toBe(950);
// we want to simulate back-filling as we scroll up
tester.addFillHandler('b', function() {
var newEvents = [];
for (var i = 0; i < 10; i++) {
newEvents.push(i+80);
}
events.unshift.apply(events, newEvents);
tester.setTileKeys(events);
return q(true);
});
// simulate scrolling up; this should trigger the backfill
scrollingDiv.scrollTop = 200;
return tester.awaitFill('b');
}).then(() => {
console.log('filled');
// at this point, ScrollPanel will have updated scrollTop, but
// the event hasn't fired. Stamp over the scrollTop.
expect(tester.lastScrollEvent).toEqual(200);
expect(scrollingDiv.scrollTop).toEqual(10*150 + 200);
scrollingDiv.scrollTop = 500;
return tester.awaitScroll();
}).then(() => {
expect(tester.lastScrollEvent).toBe(10*150 + 200);
expect(scrollingDiv.scrollTop).toEqual(10*150 + 200);
}).done(done);
});
it('should not get stuck in #528 workaround', function(done) {
var events = [];
q().then(() => {
// initialise with a bunch of events
for (var i = 0; i < 40; i++) {
events.push(i);
}
tester.setTileKeys(events);
expect(tester.fillCounts.b).toEqual(1);
expect(tester.fillCounts.f).toEqual(2);
expect(scrollingDiv.scrollHeight).toEqual(6050) // 40*150 + 50
expect(scrollingDiv.scrollTop).toEqual(6050 - 600);
// try to scroll up, to a non-integer offset.
tester.scrollPanel().scrollToToken("30", -101/3);
expect(scrollingDiv.scrollTop).toEqual(4616); // 31*150 - 34
// wait for the scroll event to land
return tester.awaitScroll(); // fails
}).then(() => {
expect(tester.lastScrollEvent).toEqual(4616);
// Now one more event; this will make it reset the scroll, but
// because the delta will be less than 1, will not trigger a
// scroll event, this leaving recentEventScroll defined.
console.log("Adding event 50");
events.push(50);
tester.setTileKeys(events);
// wait for the scrollpanel to stop trying to paginate
}).then(() => {
// Now, simulate hitting "scroll to bottom".
events = [];
for (var i = 100; i < 120; i++) {
events.push(i);
}
tester.setTileKeys(events);
tester.scrollPanel().scrollToBottom();
// wait for the scroll event to land
return tester.awaitScroll(); // fails
}).then(() => {
expect(scrollingDiv.scrollTop).toEqual(20*150 + 50 - 600);
// simulate a user-initiated scroll on the div
scrollingDiv.scrollTop = 1200;
return tester.awaitScroll();
}).then(() => {
expect(scrollingDiv.scrollTop).toEqual(1200);
}).done(done);
});
});

View File

@ -5,6 +5,18 @@ var jssdk = require('matrix-js-sdk');
var MatrixEvent = jssdk.MatrixEvent;
var sinon = require('sinon');
/**
* Perform common actions before each test case, e.g. printing the test case
* name to stdout.
* @param {Mocha.Context} context The test context
*/
module.exports.beforeEach = function(context) {
var desc = context.currentTest.fullTitle();
console.log();
console.log(desc);
console.log(new Array(1 + desc.length).join("="));
};
/**
* Stub out the MatrixClient, and configure the MatrixClientPeg object to
@ -128,22 +140,3 @@ module.exports.mkMessage = function(opts) {
};
return module.exports.mkEvent(opts);
};
/**
* make the test fail, with the given exception
*
* <p>This is useful for use with integration tests which use asyncronous
* methods: it can be added as a 'catch' handler in a promise chain.
*
* @param {Error} error exception to be reported
*
* @example
* it("should not throw", function(done) {
* asynchronousMethod().then(function() {
* // some tests
* }).catch(utils.failTest).done(done);
* });
*/
module.exports.failTest = function(error) {
expect(error.stack).toBe(null);
};