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TiddlyWiki5/core/modules/indexers/back-indexer.js

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/*\
title: $:/core/modules/indexers/back-indexer.js
type: application/javascript
module-type: indexer
By parsing the tiddler text, indexes the tiddlers' back links, back transclusions, block level back links.
\*/
function BackIndexer(wiki) {
this.wiki = wiki;
}
BackIndexer.prototype.init = function() {
this.subIndexers = {
link: new BackSubIndexer(this,"extractLinks"),
transclude: new BackSubIndexer(this,"extractTranscludes"),
};
};
BackIndexer.prototype.rebuild = function() {
$tw.utils.each(this.subIndexers,function(subIndexer) {
subIndexer.rebuild();
});
};
BackIndexer.prototype.update = function(updateDescriptor) {
$tw.utils.each(this.subIndexers,function(subIndexer) {
subIndexer.update(updateDescriptor);
});
};
function BackSubIndexer(indexer,extractor) {
this.wiki = indexer.wiki;
this.indexer = indexer;
this.extractor = extractor;
/**
* {
* [target title, e.g. tiddler title being linked to]:
* {
* [source title, e.g. tiddler title that has link syntax in its text]: true
* }
* }
*/
this.index = null;
}
BackSubIndexer.prototype.init = function() {
// lazy init until first lookup
this.index = null;
}
BackSubIndexer.prototype._init = function() {
this.index = Object.create(null);
var self = this;
this.wiki.forEachTiddler(function(sourceTitle,tiddler) {
var newTargets = self._getTarget(tiddler);
$tw.utils.each(newTargets, function(target) {
if(!self.index[target]) {
self.index[target] = Object.create(null);
}
self.index[target][sourceTitle] = true;
});
});
}
BackSubIndexer.prototype.rebuild = function() {
this.index = null;
}
/*
* Get things that is being referenced in the text, e.g. tiddler names in the link syntax.
*/
BackSubIndexer.prototype._getTarget = function(tiddler) {
if(this.wiki.isBinaryTiddler(tiddler.fields.text)) {
return [];
}
var parser = this.wiki.parseText(tiddler.fields.type, tiddler.fields.text, {});
if(parser) {
return this.wiki[this.extractor](parser.tree);
}
return [];
}
BackSubIndexer.prototype.update = function(updateDescriptor) {
// lazy init/update until first lookup
if(!this.index) {
return;
}
var newTargets = [],
oldTargets = [],
self = this;
if(updateDescriptor.old.exists) {
oldTargets = this._getTarget(updateDescriptor.old.tiddler);
}
if(updateDescriptor.new.exists) {
newTargets = this._getTarget(updateDescriptor.new.tiddler);
}
$tw.utils.each(oldTargets,function(target) {
if(self.index[target]) {
delete self.index[target][updateDescriptor.old.tiddler.fields.title];
}
});
$tw.utils.each(newTargets,function(target) {
if(!self.index[target]) {
self.index[target] = Object.create(null);
}
self.index[target][updateDescriptor.new.tiddler.fields.title] = true;
});
}
BackSubIndexer.prototype.lookup = function(title) {
if(!this.index) {
this._init();
}
if(this.index[title]) {
return Object.keys(this.index[title]);
} else {
return [];
}
}
exports.BackIndexer = BackIndexer;