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authorDimitri Staessens <[email protected]>2019-10-06 21:37:45 +0200
committerDimitri Staessens <[email protected]>2019-10-06 21:37:45 +0200
commit3c51c3be85bb0d1bdb87ea0d6632f1c256912f27 (patch)
treec7ccc8279b12c4f7bdbbb4270d617e48f51722e4 /node_modules/dependency-graph/lib/dep_graph.js
parent412c104bebc507bea9c94fd53b5bdc4b64cbfe31 (diff)
downloadwebsite-3c51c3be85bb0d1bdb87ea0d6632f1c256912f27.tar.gz
website-3c51c3be85bb0d1bdb87ea0d6632f1c256912f27.zip
build: Add some required modules for node
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+/**
+ * A simple dependency graph
+ */
+
+/**
+ * Helper for creating a Depth-First-Search on
+ * a set of edges.
+ *
+ * Detects cycles and throws an Error if one is detected.
+ *
+ * @param edges The set of edges to DFS through
+ * @param leavesOnly Whether to only return "leaf" nodes (ones who have no edges)
+ * @param result An array in which the results will be populated
+ * @param circular A boolean to allow circular dependencies
+ */
+function createDFS(edges, leavesOnly, result, circular) {
+ var currentPath = [];
+ var visited = {};
+ return function DFS(currentNode) {
+ visited[currentNode] = true;
+ currentPath.push(currentNode);
+ edges[currentNode].forEach(function (node) {
+ if (!visited[node]) {
+ DFS(node);
+ } else if (currentPath.indexOf(node) >= 0) {
+ currentPath.push(node);
+ if (!circular) {
+ throw new Error('Dependency Cycle Found: ' + currentPath.join(' -> '));
+ }
+ }
+ });
+ currentPath.pop();
+ if ((!leavesOnly || edges[currentNode].length === 0) && result.indexOf(currentNode) === -1) {
+ result.push(currentNode);
+ }
+ };
+}
+
+/**
+ * Simple Dependency Graph
+ */
+var DepGraph = exports.DepGraph = function DepGraph(opts) {
+ this.nodes = {}; // Node -> Node/Data (treated like a Set)
+ this.outgoingEdges = {}; // Node -> [Dependency Node]
+ this.incomingEdges = {}; // Node -> [Dependant Node]
+ this.circular = opts && !!opts.circular; // Allows circular deps
+};
+DepGraph.prototype = {
+ /**
+ * The number of nodes in the graph.
+ */
+ size:function () {
+ return Object.keys(this.nodes).length;
+ },
+ /**
+ * Add a node to the dependency graph. If a node already exists, this method will do nothing.
+ */
+ addNode:function (node, data) {
+ if (!this.hasNode(node)) {
+ // Checking the arguments length allows the user to add a node with undefined data
+ if (arguments.length === 2) {
+ this.nodes[node] = data;
+ } else {
+ this.nodes[node] = node;
+ }
+ this.outgoingEdges[node] = [];
+ this.incomingEdges[node] = [];
+ }
+ },
+ /**
+ * Remove a node from the dependency graph. If a node does not exist, this method will do nothing.
+ */
+ removeNode:function (node) {
+ if (this.hasNode(node)) {
+ delete this.nodes[node];
+ delete this.outgoingEdges[node];
+ delete this.incomingEdges[node];
+ [this.incomingEdges, this.outgoingEdges].forEach(function (edgeList) {
+ Object.keys(edgeList).forEach(function (key) {
+ var idx = edgeList[key].indexOf(node);
+ if (idx >= 0) {
+ edgeList[key].splice(idx, 1);
+ }
+ }, this);
+ });
+ }
+ },
+ /**
+ * Check if a node exists in the graph
+ */
+ hasNode:function (node) {
+ return this.nodes.hasOwnProperty(node);
+ },
+ /**
+ * Get the data associated with a node name
+ */
+ getNodeData:function (node) {
+ if (this.hasNode(node)) {
+ return this.nodes[node];
+ } else {
+ throw new Error('Node does not exist: ' + node);
+ }
+ },
+ /**
+ * Set the associated data for a given node name. If the node does not exist, this method will throw an error
+ */
+ setNodeData:function (node, data) {
+ if (this.hasNode(node)) {
+ this.nodes[node] = data;
+ } else {
+ throw new Error('Node does not exist: ' + node);
+ }
+ },
+ /**
+ * Add a dependency between two nodes. If either of the nodes does not exist,
+ * an Error will be thrown.
+ */
+ addDependency:function (from, to) {
+ if (!this.hasNode(from)) {
+ throw new Error('Node does not exist: ' + from);
+ }
+ if (!this.hasNode(to)) {
+ throw new Error('Node does not exist: ' + to);
+ }
+ if (this.outgoingEdges[from].indexOf(to) === -1) {
+ this.outgoingEdges[from].push(to);
+ }
+ if (this.incomingEdges[to].indexOf(from) === -1) {
+ this.incomingEdges[to].push(from);
+ }
+ return true;
+ },
+ /**
+ * Remove a dependency between two nodes.
+ */
+ removeDependency:function (from, to) {
+ var idx;
+ if (this.hasNode(from)) {
+ idx = this.outgoingEdges[from].indexOf(to);
+ if (idx >= 0) {
+ this.outgoingEdges[from].splice(idx, 1);
+ }
+ }
+
+ if (this.hasNode(to)) {
+ idx = this.incomingEdges[to].indexOf(from);
+ if (idx >= 0) {
+ this.incomingEdges[to].splice(idx, 1);
+ }
+ }
+ },
+ /**
+ * Return a clone of the dependency graph. If any custom data is attached
+ * to the nodes, it will only be shallow copied.
+ */
+ clone:function () {
+ var source = this;
+ var result = new DepGraph();
+ var keys = Object.keys(source.nodes);
+ keys.forEach(function (n) {
+ result.nodes[n] = source.nodes[n];
+ result.outgoingEdges[n] = source.outgoingEdges[n].slice(0);
+ result.incomingEdges[n] = source.incomingEdges[n].slice(0);
+ });
+ return result;
+ },
+ /**
+ * Get an array containing the nodes that the specified node depends on (transitively).
+ *
+ * Throws an Error if the graph has a cycle, or the specified node does not exist.
+ *
+ * If `leavesOnly` is true, only nodes that do not depend on any other nodes will be returned
+ * in the array.
+ */
+ dependenciesOf:function (node, leavesOnly) {
+ if (this.hasNode(node)) {
+ var result = [];
+ var DFS = createDFS(this.outgoingEdges, leavesOnly, result, this.circular);
+ DFS(node);
+ var idx = result.indexOf(node);
+ if (idx >= 0) {
+ result.splice(idx, 1);
+ }
+ return result;
+ }
+ else {
+ throw new Error('Node does not exist: ' + node);
+ }
+ },
+ /**
+ * get an array containing the nodes that depend on the specified node (transitively).
+ *
+ * Throws an Error if the graph has a cycle, or the specified node does not exist.
+ *
+ * If `leavesOnly` is true, only nodes that do not have any dependants will be returned in the array.
+ */
+ dependantsOf:function (node, leavesOnly) {
+ if (this.hasNode(node)) {
+ var result = [];
+ var DFS = createDFS(this.incomingEdges, leavesOnly, result, this.circular);
+ DFS(node);
+ var idx = result.indexOf(node);
+ if (idx >= 0) {
+ result.splice(idx, 1);
+ }
+ return result;
+ } else {
+ throw new Error('Node does not exist: ' + node);
+ }
+ },
+ /**
+ * Construct the overall processing order for the dependency graph.
+ *
+ * Throws an Error if the graph has a cycle.
+ *
+ * If `leavesOnly` is true, only nodes that do not depend on any other nodes will be returned.
+ */
+ overallOrder:function (leavesOnly) {
+ var self = this;
+ var result = [];
+ var keys = Object.keys(this.nodes);
+ if (keys.length === 0) {
+ return result; // Empty graph
+ } else {
+ // Look for cycles - we run the DFS starting at all the nodes in case there
+ // are several disconnected subgraphs inside this dependency graph.
+ var CycleDFS = createDFS(this.outgoingEdges, false, [], this.circular);
+ keys.forEach(function(n) {
+ CycleDFS(n);
+ });
+
+ var DFS = createDFS(this.outgoingEdges, leavesOnly, result, this.circular);
+ // Find all potential starting points (nodes with nothing depending on them) an
+ // run a DFS starting at these points to get the order
+ keys.filter(function (node) {
+ return self.incomingEdges[node].length === 0;
+ }).forEach(function (n) {
+ DFS(n);
+ });
+
+ return result;
+ }
+ }
+};