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+/**
+ * A simple dependency graph
+ */
+
+/**
+ * Helper for creating a Topological Sort using Depth-First-Search on a set of edges.
+ *
+ * Detects cycles and throws an Error if one is detected (unless the "circular"
+ * parameter is "true" in which case it ignores them).
+ *
+ * @param edges The edges to DFS through (this is a Map of node to Array of nodes)
+ * @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 visited = new Set();
+ return function (start) {
+ if (visited.has(start)) {
+ return;
+ }
+ var inCurrentPath = new Set();
+ var currentPath = [];
+ var todo = []; // used as a stack
+ todo.push({ node: start, processed: false });
+ while (todo.length > 0) {
+ var current = todo[todo.length - 1]; // peek at the todo stack
+ var processed = current.processed;
+ var node = current.node;
+ if (!processed) {
+ // Haven't visited edges yet (visiting phase)
+ if (visited.has(node)) {
+ todo.pop();
+ continue;
+ } else if (inCurrentPath.has(node)) {
+ // It's not a DAG
+ if (circular) {
+ todo.pop();
+ // If we're tolerating cycles, don't revisit the node
+ continue;
+ }
+ currentPath.push(node);
+ throw new DepGraphCycleError(currentPath);
+ }
+
+ inCurrentPath.add(node);
+ currentPath.push(node);
+ var nodeEdges = edges.get(node);
+ // (push edges onto the todo stack in reverse order to be order-compatible with the old DFS implementation)
+ for (var i = nodeEdges.length - 1; i >= 0; i--) {
+ todo.push({ node: nodeEdges[i], processed: false });
+ }
+ current.processed = true;
+ } else {
+ // Have visited edges (stack unrolling phase)
+ todo.pop();
+ currentPath.pop();
+ inCurrentPath.delete(node);
+ visited.add(node);
+ if (!leavesOnly || edges.get(node).length === 0) {
+ result.push(node);
+ }
+ }
+ }
+ };
+}
+
+/**
+ * Simple Dependency Graph
+ */
+var DepGraph = (exports.DepGraph = function DepGraph(opts) {
+ this.nodes = new Map(); // Node -> Node/Data
+ this.outgoingEdges = new Map(); // Node -> [Dependency Node]
+ this.incomingEdges = new Map(); // Node -> [Dependant Node]
+ this.circular = opts && !!opts.circular; // Allows circular deps
+});
+DepGraph.prototype = {
+ /**
+ * The number of nodes in the graph.
+ */
+ size: function () {
+ return this.nodes.size;
+ },
+ /**
+ * 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.set(node, data);
+ } else {
+ this.nodes.set(node, node);
+ }
+ this.outgoingEdges.set(node, []);
+ this.incomingEdges.set(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)) {
+ this.nodes.delete(node);
+ this.outgoingEdges.delete(node);
+ this.incomingEdges.delete(node);
+ [this.incomingEdges, this.outgoingEdges].forEach(function (edgeList) {
+ edgeList.forEach(function (v) {
+ var idx = v.indexOf(node);
+ if (idx >= 0) {
+ v.splice(idx, 1);
+ }
+ });
+ });
+ }
+ },
+ /**
+ * Check if a node exists in the graph
+ */
+ hasNode: function (node) {
+ return this.nodes.has(node);
+ },
+ /**
+ * Get the data associated with a node name
+ */
+ getNodeData: function (node) {
+ if (this.hasNode(node)) {
+ return this.nodes.get(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.set(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.get(from).indexOf(to) === -1) {
+ this.outgoingEdges.get(from).push(to);
+ }
+ if (this.incomingEdges.get(to).indexOf(from) === -1) {
+ this.incomingEdges.get(to).push(from);
+ }
+ return true;
+ },
+ /**
+ * Remove a dependency between two nodes.
+ */
+ removeDependency: function (from, to) {
+ var idx;
+ if (this.hasNode(from)) {
+ idx = this.outgoingEdges.get(from).indexOf(to);
+ if (idx >= 0) {
+ this.outgoingEdges.get(from).splice(idx, 1);
+ }
+ }
+
+ if (this.hasNode(to)) {
+ idx = this.incomingEdges.get(to).indexOf(from);
+ if (idx >= 0) {
+ this.incomingEdges.get(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();
+ source.nodes.forEach(function (v, n) {
+ result.nodes.set(n, v);
+ result.outgoingEdges.set(n, source.outgoingEdges.get(n).slice(0));
+ result.incomingEdges.set(n, source.incomingEdges.get(n).slice(0));
+ });
+ result.circular = source.circular;
+ return result;
+ },
+ /**
+ * Get an array containing the direct dependencies of the specified node.
+ *
+ * Throws an Error if the specified node does not exist.
+ */
+ directDependenciesOf: function (node) {
+ if (this.hasNode(node)) {
+ return this.outgoingEdges.get(node).slice(0);
+ } else {
+ throw new Error("Node does not exist: " + node);
+ }
+ },
+ /**
+ * Get an array containing the nodes that directly depend on the specified node.
+ *
+ * Throws an Error if the specified node does not exist.
+ */
+ directDependantsOf: function (node) {
+ if (this.hasNode(node)) {
+ return this.incomingEdges.get(node).slice(0);
+ } else {
+ throw new Error("Node does not exist: " + node);
+ }
+ },
+ /**
+ * 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 = Array.from(this.nodes.keys());
+ if (keys.length === 0) {
+ return result; // Empty graph
+ } else {
+ if (!this.circular) {
+ // 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.get(node).length === 0;
+ })
+ .forEach(function (n) {
+ DFS(n);
+ });
+
+ // If we're allowing cycles - we need to run the DFS against any remaining
+ // nodes that did not end up in the initial result (as they are part of a
+ // subgraph that does not have a clear starting point)
+ if (this.circular) {
+ keys
+ .filter(function (node) {
+ return result.indexOf(node) === -1;
+ })
+ .forEach(function (n) {
+ DFS(n);
+ });
+ }
+
+ return result;
+ }
+ },
+ /**
+ * Get an array of nodes that have no dependants (i.e. nothing depends on them).
+ */
+ entryNodes: function () {
+ var self = this;
+ return Array.from(this.nodes.keys()).filter(function (node) {
+ return self.incomingEdges.get(node).length === 0;
+ });
+ },
+};
+
+// Create some aliases
+DepGraph.prototype.directDependentsOf = DepGraph.prototype.directDependantsOf;
+DepGraph.prototype.dependentsOf = DepGraph.prototype.dependantsOf;
+
+/**
+ * Cycle error, including the path of the cycle.
+ */
+var DepGraphCycleError = (exports.DepGraphCycleError = function (cyclePath) {
+ var message = "Dependency Cycle Found: " + cyclePath.join(" -> ");
+ var instance = new Error(message);
+ instance.cyclePath = cyclePath;
+ Object.setPrototypeOf(instance, Object.getPrototypeOf(this));
+ if (Error.captureStackTrace) {
+ Error.captureStackTrace(instance, DepGraphCycleError);
+ }
+ return instance;
+});
+DepGraphCycleError.prototype = Object.create(Error.prototype, {
+ constructor: {
+ value: Error,
+ enumerable: false,
+ writable: true,
+ configurable: true,
+ },
+});
+Object.setPrototypeOf(DepGraphCycleError, Error);