lib/network/dotparser.js
/**
* Parse a text source containing data in DOT language into a JSON object.
* The object contains two lists: one with nodes and one with edges.
*
* DOT language reference: http://www.graphviz.org/doc/info/lang.html
*
* DOT language attributes: http://graphviz.org/content/attrs
*
* @param {string} data Text containing a graph in DOT-notation
* @return {Object} graph An object containing two parameters:
* {Object[]} nodes
* {Object[]} edges
*
* -------------------------------------------
* TODO
* ====
*
* For label handling, this is an incomplete implementation. From docs (quote #3015):
*
* > the escape sequences "\n", "\l" and "\r" divide the label into lines, centered,
* > left-justified, and right-justified, respectively.
*
* Source: http://www.graphviz.org/content/attrs#kescString
*
* > As another aid for readability, dot allows double-quoted strings to span multiple physical
* > lines using the standard C convention of a backslash immediately preceding a newline
* > character
* > In addition, double-quoted strings can be concatenated using a '+' operator.
* > As HTML strings can contain newline characters, which are used solely for formatting,
* > the language does not allow escaped newlines or concatenation operators to be used
* > within them.
*
* - Currently, only '\\n' is handled
* - Note that text explicitly says 'labels'; the dot parser currently handles escape
* sequences in **all** strings.
*/
function parseDOT (data) {
dot = data;
return parseGraph();
}
// mapping of attributes from DOT (the keys) to vis.js (the values)
var NODE_ATTR_MAPPING = {
'fontsize': 'font.size',
'fontcolor': 'font.color',
'labelfontcolor': 'font.color',
'fontname': 'font.face',
'color': ['color.border', 'color.background'],
'fillcolor': 'color.background',
'tooltip': 'title',
'labeltooltip': 'title'
};
var EDGE_ATTR_MAPPING = Object.create(NODE_ATTR_MAPPING);
EDGE_ATTR_MAPPING.color = 'color.color';
EDGE_ATTR_MAPPING.style = 'dashes';
// token types enumeration
var TOKENTYPE = {
NULL : 0,
DELIMITER : 1,
IDENTIFIER: 2,
UNKNOWN : 3
};
// map with all delimiters
var DELIMITERS = {
'{': true,
'}': true,
'[': true,
']': true,
';': true,
'=': true,
',': true,
'->': true,
'--': true
};
var dot = ''; // current dot file
var index = 0; // current index in dot file
var c = ''; // current token character in expr
var token = ''; // current token
var tokenType = TOKENTYPE.NULL; // type of the token
/**
* Get the first character from the dot file.
* The character is stored into the char c. If the end of the dot file is
* reached, the function puts an empty string in c.
*/
function first() {
index = 0;
c = dot.charAt(0);
}
/**
* Get the next character from the dot file.
* The character is stored into the char c. If the end of the dot file is
* reached, the function puts an empty string in c.
*/
function next() {
index++;
c = dot.charAt(index);
}
/**
* Preview the next character from the dot file.
* @return {string} cNext
*/
function nextPreview() {
return dot.charAt(index + 1);
}
var regexAlphaNumeric = /[a-zA-Z_0-9.:#]/;
/**
* Test whether given character is alphabetic or numeric
* @param {string} c
* @return {Boolean} isAlphaNumeric
*/
function isAlphaNumeric(c) {
return regexAlphaNumeric.test(c);
}
/**
* Merge all options of object b into object b
* @param {Object} a
* @param {Object} b
* @return {Object} a
*/
function merge (a, b) {
if (!a) {
a = {};
}
if (b) {
for (var name in b) {
if (b.hasOwnProperty(name)) {
a[name] = b[name];
}
}
}
return a;
}
/**
* Set a value in an object, where the provided parameter name can be a
* path with nested parameters. For example:
*
* var obj = {a: 2};
* setValue(obj, 'b.c', 3); // obj = {a: 2, b: {c: 3}}
*
* @param {Object} obj
* @param {string} path A parameter name or dot-separated parameter path,
* like "color.highlight.border".
* @param {*} value
*/
function setValue(obj, path, value) {
var keys = path.split('.');
var o = obj;
while (keys.length) {
var key = keys.shift();
if (keys.length) {
// this isn't the end point
if (!o[key]) {
o[key] = {};
}
o = o[key];
}
else {
// this is the end point
o[key] = value;
}
}
}
/**
* Add a node to a graph object. If there is already a node with
* the same id, their attributes will be merged.
* @param {Object} graph
* @param {Object} node
*/
function addNode(graph, node) {
var i, len;
var current = null;
// find root graph (in case of subgraph)
var graphs = [graph]; // list with all graphs from current graph to root graph
var root = graph;
while (root.parent) {
graphs.push(root.parent);
root = root.parent;
}
// find existing node (at root level) by its id
if (root.nodes) {
for (i = 0, len = root.nodes.length; i < len; i++) {
if (node.id === root.nodes[i].id) {
current = root.nodes[i];
break;
}
}
}
if (!current) {
// this is a new node
current = {
id: node.id
};
if (graph.node) {
// clone default attributes
current.attr = merge(current.attr, graph.node);
}
}
// add node to this (sub)graph and all its parent graphs
for (i = graphs.length - 1; i >= 0; i--) {
var g = graphs[i];
if (!g.nodes) {
g.nodes = [];
}
if (g.nodes.indexOf(current) === -1) {
g.nodes.push(current);
}
}
// merge attributes
if (node.attr) {
current.attr = merge(current.attr, node.attr);
}
}
/**
* Add an edge to a graph object
* @param {Object} graph
* @param {Object} edge
*/
function addEdge(graph, edge) {
if (!graph.edges) {
graph.edges = [];
}
graph.edges.push(edge);
if (graph.edge) {
var attr = merge({}, graph.edge); // clone default attributes
edge.attr = merge(attr, edge.attr); // merge attributes
}
}
/**
* Create an edge to a graph object
* @param {Object} graph
* @param {string | number | Object} from
* @param {string | number | Object} to
* @param {string} type
* @param {Object | null} attr
* @return {Object} edge
*/
function createEdge(graph, from, to, type, attr) {
var edge = {
from: from,
to: to,
type: type
};
if (graph.edge) {
edge.attr = merge({}, graph.edge); // clone default attributes
}
edge.attr = merge(edge.attr || {}, attr); // merge attributes
return edge;
}
/**
* Get next token in the current dot file.
* The token and token type are available as token and tokenType
*/
function getToken() {
tokenType = TOKENTYPE.NULL;
token = '';
// skip over whitespaces
while (c === ' ' || c === '\t' || c === '\n' || c === '\r') { // space, tab, enter
next();
}
do {
var isComment = false;
// skip comment
if (c === '#') {
// find the previous non-space character
var i = index - 1;
while (dot.charAt(i) === ' ' || dot.charAt(i) === '\t') {
i--;
}
if (dot.charAt(i) === '\n' || dot.charAt(i) === '') {
// the # is at the start of a line, this is indeed a line comment
while (c != '' && c != '\n') {
next();
}
isComment = true;
}
}
if (c === '/' && nextPreview() === '/') {
// skip line comment
while (c != '' && c != '\n') {
next();
}
isComment = true;
}
if (c === '/' && nextPreview() === '*') {
// skip block comment
while (c != '') {
if (c === '*' && nextPreview() === '/') {
// end of block comment found. skip these last two characters
next();
next();
break;
}
else {
next();
}
}
isComment = true;
}
// skip over whitespaces
while (c === ' ' || c === '\t' || c === '\n' || c === '\r') { // space, tab, enter
next();
}
}
while (isComment);
// check for end of dot file
if (c === '') {
// token is still empty
tokenType = TOKENTYPE.DELIMITER;
return;
}
// check for delimiters consisting of 2 characters
var c2 = c + nextPreview();
if (DELIMITERS[c2]) {
tokenType = TOKENTYPE.DELIMITER;
token = c2;
next();
next();
return;
}
// check for delimiters consisting of 1 character
if (DELIMITERS[c]) {
tokenType = TOKENTYPE.DELIMITER;
token = c;
next();
return;
}
// check for an identifier (number or string)
// TODO: more precise parsing of numbers/strings (and the port separator ':')
if (isAlphaNumeric(c) || c === '-') {
token += c;
next();
while (isAlphaNumeric(c)) {
token += c;
next();
}
if (token === 'false') {
token = false; // convert to boolean
}
else if (token === 'true') {
token = true; // convert to boolean
}
else if (!isNaN(Number(token))) {
token = Number(token); // convert to number
}
tokenType = TOKENTYPE.IDENTIFIER;
return;
}
// check for a string enclosed by double quotes
if (c === '"') {
next();
while (c != '' && (c != '"' || (c === '"' && nextPreview() === '"'))) {
if (c === '"') { // skip the escape character
token += c;
next();
} else if (c === '\\' && nextPreview() === 'n') { // Honor a newline escape sequence
token += '\n';
next();
} else {
token += c;
}
next();
}
if (c != '"') {
throw newSyntaxError('End of string " expected');
}
next();
tokenType = TOKENTYPE.IDENTIFIER;
return;
}
// something unknown is found, wrong characters, a syntax error
tokenType = TOKENTYPE.UNKNOWN;
while (c != '') {
token += c;
next();
}
throw new SyntaxError('Syntax error in part "' + chop(token, 30) + '"');
}
/**
* Parse a graph.
* @returns {Object} graph
*/
function parseGraph() {
var graph = {};
first();
getToken();
// optional strict keyword
if (token === 'strict') {
graph.strict = true;
getToken();
}
// graph or digraph keyword
if (token === 'graph' || token === 'digraph') {
graph.type = token;
getToken();
}
// optional graph id
if (tokenType === TOKENTYPE.IDENTIFIER) {
graph.id = token;
getToken();
}
// open angle bracket
if (token != '{') {
throw newSyntaxError('Angle bracket { expected');
}
getToken();
// statements
parseStatements(graph);
// close angle bracket
if (token != '}') {
throw newSyntaxError('Angle bracket } expected');
}
getToken();
// end of file
if (token !== '') {
throw newSyntaxError('End of file expected');
}
getToken();
// remove temporary default options
delete graph.node;
delete graph.edge;
delete graph.graph;
return graph;
}
/**
* Parse a list with statements.
* @param {Object} graph
*/
function parseStatements (graph) {
while (token !== '' && token != '}') {
parseStatement(graph);
if (token === ';') {
getToken();
}
}
}
/**
* Parse a single statement. Can be a an attribute statement, node
* statement, a series of node statements and edge statements, or a
* parameter.
* @param {Object} graph
*/
function parseStatement(graph) {
// parse subgraph
var subgraph = parseSubgraph(graph);
if (subgraph) {
// edge statements
parseEdge(graph, subgraph);
return;
}
// parse an attribute statement
var attr = parseAttributeStatement(graph);
if (attr) {
return;
}
// parse node
if (tokenType != TOKENTYPE.IDENTIFIER) {
throw newSyntaxError('Identifier expected');
}
var id = token; // id can be a string or a number
getToken();
if (token === '=') {
// id statement
getToken();
if (tokenType != TOKENTYPE.IDENTIFIER) {
throw newSyntaxError('Identifier expected');
}
graph[id] = token;
getToken();
// TODO: implement comma separated list with "a_list: ID=ID [','] [a_list] "
}
else {
parseNodeStatement(graph, id);
}
}
/**
* Parse a subgraph
* @param {Object} graph parent graph object
* @return {Object | null} subgraph
*/
function parseSubgraph (graph) {
var subgraph = null;
// optional subgraph keyword
if (token === 'subgraph') {
subgraph = {};
subgraph.type = 'subgraph';
getToken();
// optional graph id
if (tokenType === TOKENTYPE.IDENTIFIER) {
subgraph.id = token;
getToken();
}
}
// open angle bracket
if (token === '{') {
getToken();
if (!subgraph) {
subgraph = {};
}
subgraph.parent = graph;
subgraph.node = graph.node;
subgraph.edge = graph.edge;
subgraph.graph = graph.graph;
// statements
parseStatements(subgraph);
// close angle bracket
if (token != '}') {
throw newSyntaxError('Angle bracket } expected');
}
getToken();
// remove temporary default options
delete subgraph.node;
delete subgraph.edge;
delete subgraph.graph;
delete subgraph.parent;
// register at the parent graph
if (!graph.subgraphs) {
graph.subgraphs = [];
}
graph.subgraphs.push(subgraph);
}
return subgraph;
}
/**
* parse an attribute statement like "node [shape=circle fontSize=16]".
* Available keywords are 'node', 'edge', 'graph'.
* The previous list with default attributes will be replaced
* @param {Object} graph
* @returns {String | null} keyword Returns the name of the parsed attribute
* (node, edge, graph), or null if nothing
* is parsed.
*/
function parseAttributeStatement (graph) {
// attribute statements
if (token === 'node') {
getToken();
// node attributes
graph.node = parseAttributeList();
return 'node';
}
else if (token === 'edge') {
getToken();
// edge attributes
graph.edge = parseAttributeList();
return 'edge';
}
else if (token === 'graph') {
getToken();
// graph attributes
graph.graph = parseAttributeList();
return 'graph';
}
return null;
}
/**
* parse a node statement
* @param {Object} graph
* @param {string | number} id
*/
function parseNodeStatement(graph, id) {
// node statement
var node = {
id: id
};
var attr = parseAttributeList();
if (attr) {
node.attr = attr;
}
addNode(graph, node);
// edge statements
parseEdge(graph, id);
}
/**
* Parse an edge or a series of edges
* @param {Object} graph
* @param {string | number} from Id of the from node
*/
function parseEdge(graph, from) {
while (token === '->' || token === '--') {
var to;
var type = token;
getToken();
var subgraph = parseSubgraph(graph);
if (subgraph) {
to = subgraph;
}
else {
if (tokenType != TOKENTYPE.IDENTIFIER) {
throw newSyntaxError('Identifier or subgraph expected');
}
to = token;
addNode(graph, {
id: to
});
getToken();
}
// parse edge attributes
var attr = parseAttributeList();
// create edge
var edge = createEdge(graph, from, to, type, attr);
addEdge(graph, edge);
from = to;
}
}
/**
* Parse a set with attributes,
* for example [label="1.000", shape=solid]
* @return {Object | null} attr
*/
function parseAttributeList() {
var attr = null;
// edge styles of dot and vis
var edgeStyles = {
'dashed': true,
'solid': false,
'dotted': [1, 5]
};
while (token === '[') {
getToken();
attr = {};
while (token !== '' && token != ']') {
if (tokenType != TOKENTYPE.IDENTIFIER) {
throw newSyntaxError('Attribute name expected');
}
var name = token;
getToken();
if (token != '=') {
throw newSyntaxError('Equal sign = expected');
}
getToken();
if (tokenType != TOKENTYPE.IDENTIFIER) {
throw newSyntaxError('Attribute value expected');
}
var value = token;
// convert from dot style to vis
if (name === 'style') {
value = edgeStyles[value];
}
setValue(attr, name, value); // name can be a path
getToken();
if (token ==',') {
getToken();
}
}
if (token != ']') {
throw newSyntaxError('Bracket ] expected');
}
getToken();
}
return attr;
}
/**
* Create a syntax error with extra information on current token and index.
* @param {string} message
* @returns {SyntaxError} err
*/
function newSyntaxError(message) {
return new SyntaxError(message + ', got "' + chop(token, 30) + '" (char ' + index + ')');
}
/**
* Chop off text after a maximum length
* @param {string} text
* @param {number} maxLength
* @returns {String}
*/
function chop (text, maxLength) {
return (text.length <= maxLength) ? text : (text.substr(0, 27) + '...');
}
/**
* Execute a function fn for each pair of elements in two arrays
* @param {Array | *} array1
* @param {Array | *} array2
* @param {function} fn
*/
function forEach2(array1, array2, fn) {
if (Array.isArray(array1)) {
array1.forEach(function (elem1) {
if (Array.isArray(array2)) {
array2.forEach(function (elem2) {
fn(elem1, elem2);
});
}
else {
fn(elem1, array2);
}
});
}
else {
if (Array.isArray(array2)) {
array2.forEach(function (elem2) {
fn(array1, elem2);
});
}
else {
fn(array1, array2);
}
}
}
/**
* Set a nested property on an object
* When nested objects are missing, they will be created.
* For example setProp({}, 'font.color', 'red') will return {font: {color: 'red'}}
* @param {Object} object
* @param {string} path A dot separated string like 'font.color'
* @param {*} value Value for the property
* @return {Object} Returns the original object, allows for chaining.
*/
function setProp(object, path, value) {
var names = path.split('.');
var prop = names.pop();
// traverse over the nested objects
var obj = object;
for (var i = 0; i < names.length; i++) {
var name = names[i];
if (!(name in obj)) {
obj[name] = {};
}
obj = obj[name];
}
// set the property value
obj[prop] = value;
return object;
}
/**
* Convert an object with DOT attributes to their vis.js equivalents.
* @param {Object} attr Object with DOT attributes
* @param {Object} mapping
* @return {Object} Returns an object with vis.js attributes
*/
function convertAttr (attr, mapping) {
var converted = {};
for (var prop in attr) {
if (attr.hasOwnProperty(prop)) {
var visProp = mapping[prop];
if (Array.isArray(visProp)) {
visProp.forEach(function (visPropI) {
setProp(converted, visPropI, attr[prop]);
})
}
else if (typeof visProp === 'string') {
setProp(converted, visProp, attr[prop]);
}
else {
setProp(converted, prop, attr[prop]);
}
}
}
return converted;
}
/**
* Convert a string containing a graph in DOT language into a map containing
* with nodes and edges in the format of graph.
* @param {string} data Text containing a graph in DOT-notation
* @return {Object} graphData
*/
function DOTToGraph (data) {
// parse the DOT file
var dotData = parseDOT(data);
var graphData = {
nodes: [],
edges: [],
options: {}
};
// copy the nodes
if (dotData.nodes) {
dotData.nodes.forEach(function (dotNode) {
var graphNode = {
id: dotNode.id,
label: String(dotNode.label || dotNode.id)
};
merge(graphNode, convertAttr(dotNode.attr, NODE_ATTR_MAPPING));
if (graphNode.image) {
graphNode.shape = 'image';
}
graphData.nodes.push(graphNode);
});
}
// copy the edges
if (dotData.edges) {
/**
* Convert an edge in DOT format to an edge with VisGraph format
* @param {Object} dotEdge
* @returns {Object} graphEdge
*/
var convertEdge = function (dotEdge) {
var graphEdge = {
from: dotEdge.from,
to: dotEdge.to
};
merge(graphEdge, convertAttr(dotEdge.attr, EDGE_ATTR_MAPPING));
graphEdge.arrows = (dotEdge.type === '->') ? 'to' : undefined;
return graphEdge;
};
dotData.edges.forEach(function (dotEdge) {
var from, to;
if (dotEdge.from instanceof Object) {
from = dotEdge.from.nodes;
}
else {
from = {
id: dotEdge.from
}
}
// TODO: support for attributes 'dir' and 'arrowhead' (edge arrows)
if (dotEdge.to instanceof Object) {
to = dotEdge.to.nodes;
}
else {
to = {
id: dotEdge.to
}
}
if (dotEdge.from instanceof Object && dotEdge.from.edges) {
dotEdge.from.edges.forEach(function (subEdge) {
var graphEdge = convertEdge(subEdge);
graphData.edges.push(graphEdge);
});
}
forEach2(from, to, function (from, to) {
var subEdge = createEdge(graphData, from.id, to.id, dotEdge.type, dotEdge.attr);
var graphEdge = convertEdge(subEdge);
graphData.edges.push(graphEdge);
});
if (dotEdge.to instanceof Object && dotEdge.to.edges) {
dotEdge.to.edges.forEach(function (subEdge) {
var graphEdge = convertEdge(subEdge);
graphData.edges.push(graphEdge);
});
}
});
}
// copy the options
if (dotData.attr) {
graphData.options = dotData.attr;
}
return graphData;
}
// exports
exports.parseDOT = parseDOT;
exports.DOTToGraph = DOTToGraph;