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TiddlyWiki5/plugins/tiddlywiki/dynannotate/modules/textmap.js

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/*\
title: $:/plugins/tiddlywiki/dynannotate/textmap.js
type: application/javascript
module-type: library
Structure for modelling mapping between a string and its representation in the DOM
\*/
(function(){
/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";
var PREFIX_SUFFIX_LENGTH = 50;
/*
Build a map of the text content of a DOM node and its descendants:
string: concatenation of the text content of child nodes
metadata: array of {start,end,domNode} where start and end identify position in the string
*/
exports.TextMap = function(domNode) {
var self = this,
stringChunks = [],
p = 0;
this.metadata = [];
var processNode = function(domNode) {
// Check for text nodes
if(domNode.nodeType === 3) {
var text = domNode.textContent;
stringChunks.push(text);
self.metadata.push({
start: p,
end: p + text.length,
domNode: domNode
});
p += text.length;
} else {
// Otherwise look within the child nodes
if(domNode.childNodes) {
for(var t=0; t<domNode.childNodes.length; t++ ) {
processNode(domNode.childNodes[t]);
}
}
}
};
// Process our text nodes
processNode(domNode);
this.string = stringChunks.join("");
};
/*
Locate the metadata record corresponding to a given position in the string
*/
exports.TextMap.prototype.locateMetadata = function(position) {
return this.metadata.find(function(metadata) {
return position >= metadata.start && position < metadata.end;
});
};
/*
Search for the first occurrence of a target string within the textmap of a DOM node
Returns an object with the following properties:
startNode: node containing the start of the text
startOffset: offset of the start of the text within the node
endNode: node containing the end of the text
endOffset: offset of the end of the text within the node
*/
exports.TextMap.prototype.findText = function(targetString,targetPrefix,targetSuffix) {
if(!targetString) {
return null;
}
targetPrefix = targetPrefix || "";
targetSuffix = targetSuffix || "";
var startPos = this.string.indexOf(targetPrefix + targetString + targetSuffix);
if(startPos !== -1) {
startPos += targetPrefix.length;
var startMetadata = this.locateMetadata(startPos),
endMetadata = this.locateMetadata(startPos + targetString.length - 1);
if(startMetadata && endMetadata) {
return {
startNode: startMetadata.domNode,
startOffset: startPos - startMetadata.start,
endNode: endMetadata.domNode,
endOffset: (startPos + targetString.length) - endMetadata.start
}
}
}
return null;
};
/*
Search for all occurrences of a string within the textmap of a DOM node
Options include:
mode: "normal", "literal", "regexp", "whitespace", "some" or "words"
caseSensitive: true if the search should be case sensitive
Returns an array of objects with the following properties:
startPos: start position of the match within the string contained by this TextMap
startNode: node containing the start of the text
startOffset: offset of the start of the text within the node
endPos: end position of the match within the string contained by this TextMap
endNode: node containing the end of the text
endOffset: offset of the end of the text within the node
*/
exports.TextMap.prototype.search = function(searchString,options) {
if(!searchString) {
return [];
}
options = options || {};
// Compose the regexp
var regExpString,
flags = options.caseSensitive ? "g" : "gi";
if(options.mode === "regexp") {
regExpString = "(" + searchString + ")";
} else if(options.mode === "whitespace") {
// Normalise whitespace
regExpString = "(" + searchString.split(/\s+/g).filter(function(word) {
return !!word
}).map($tw.utils.escapeRegExp).join("\\s+") + ")";
} else if(options.mode === "words" || options.mode === "some") {
// Match any word separated by whitespace
regExpString = "(" + searchString.split(/\s+/g).filter(function(word) {
return !!word
}).map($tw.utils.escapeRegExp).join("|") + ")";
} else {
// Normal search
regExpString = "(" + $tw.utils.escapeRegExp(searchString) + ")";
}
// Compile the regular expression
var regExp;
try {
regExp = RegExp(regExpString,flags);
} catch(e) {
}
if(!regExp) {
return [];
}
// Find each match
var results = [],
match;
do {
match = regExp.exec(this.string);
if(match) {
var metadataStart = this.locateMetadata(match.index),
metadataEnd = this.locateMetadata(match.index + match[0].length);
if(metadataStart && metadataEnd) {
results.push({
startPos: match.index,
startNode: metadataStart.domNode,
startOffset: match.index - metadataStart.start,
endPos: match.index + match[0].length,
endNode: metadataEnd.domNode,
endOffset: match.index + match[0].length - metadataEnd.start
});
}
}
} while(match);
return results;
};
/*
Given a start container and offset and a search string, return a prefix and suffix to disambiguate the text
*/
exports.TextMap.prototype.extractContext = function(startContainer,startOffset,text) {
var startMetadata = this.metadata.find(function(metadata) {
return metadata.domNode === startContainer
});
if(!startMetadata) {
return null;
}
var startPos = startMetadata.start + startOffset;
return {
prefix: this.string.slice(Math.max(startPos - PREFIX_SUFFIX_LENGTH, 0), startPos),
suffix: this.string.slice(startPos + text.length, Math.min(startPos + text.length + PREFIX_SUFFIX_LENGTH, this.string.length))
};
};
})();