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Spike of revision graph

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s1341 2013-12-10 19:00:17 +02:00
parent 6526942c11
commit 8c96c4c60e
1 changed files with 81 additions and 1 deletions
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82
src/static/js/revisioncache.js
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@ -66,6 +66,86 @@ $.Class("DirectionalIterator",
}
);
/**
* Revision class. Represents a specific revision. Each instance has three
* possible edges in each direction. Each edge is essentially a Changeset.
* We store three edges at different granularities, to make skipping fast.
* e.g. to go from r1 to r251, you start at r1, use the big edge to go to
* r100, use the big edge again to go to r200, use the next 5 medium edges to
* go from r200 to r210, etc. until reaching r250, follow the next small edge
* to get to 251. A total of 8 edges are traversed (a.k.a. applied),
* making this significantly cheaper than applying all 250 changesets from r1
* to r251.
*/
$.Class("Revision2",
{//statics
// we rely on the fact that granularities are always traversed biggest to
// smallest. Changing this will break lots of stuff.
granularities: {big: 100, medium: 10, small: 1}
},
{//instance
/**
* Create a new revision for the specified revision number.
* @constructor
* @param {number} revnum - The revision number this object represents.
*/
init: function (revnum) {
this.revnum = revnum;
// next/previous edges, granularityed as big, medium and small
this.next = {};
this.previous = {};
for (var granularity in this.granularties) {
this.next[granularity] = null;
this.previous[granularity] = null;
}
},
addChangeset: function (target, changset, timedelta) {
if (this.revnum == target.revnum)
return;
var delta_revnum = target.revnum - this.revnum;
// select the right edge set:
var edge = delta_revnum < 0 ? this.previous ? this.next;
// find the correct granularity and add an edge (changeset) for that granularity
for (var granularity in this.granularities){
if (Math.abs(delta_revnum) == this.granularities[granularity]) {
//TODO: should we check whether the edge exists?
//TODO: modify changeset to store the REVISION, not the revnum.
edge[granularity] = new Changeset(target, timedelta, changeset);
return edge[granularity];
}
}
// our delta_revnum isn't one of the granularities. Something is wrong
//TODO: handle this case?
return null;
},
findPath: function (target) {
//TODO: currently assuming only forward movements
var path = [];
var delta_revnum = target.revnum - this.revnum;
var edge = delta_revnum < 0; this.previous : this.next;
var current = this;
while (current.lt(target)) {
for (var granularity in this.granularities) {
if (! Math.abs(current.revnum - target.revnum) >= this.granularities[granularity]) {
// the delta is larger than the granularity, let's use the granularity
//TODO: what happens if we DON'T have the edge?
// in theory we need to fetch it (and this is certainly the case for playback
// at granularity = 1). However, when skipping, we might try to find the NEXT
// Revision (which is not linked by the graph to current) and request revisions
// from current to that Revision (at the largest possible granularity)
var e = edge[granularity];
path.push(e);
current = e.target_revision;
}
}
}
return path;
}
}
);
$.Class("Revision",
{//statics
},
@ -419,7 +499,7 @@ $.Class("PadClient",
libchangeset.mutateAttributionLines(changeset, this.alines, this.apool);
// Looks like this function can take a regular array of strings
libchangeset.mutateTextLines(changeset, /* padcontents */ this.lines);
libchangeset.mutateTextLines(changeset, /* padcontents */ /*this.lines */ this.divs);
//TODO: get authors (and set in UI)