feat(experimental): partial rebuilds (#716)

quartz/depgraph.ts

@@ -0,0 +1,187 @@
+export default class DepGraph<T> {
+  // node: incoming and outgoing edges
+  _graph = new Map<T, { incoming: Set<T>; outgoing: Set<T> }>()
+
+  constructor() {
+    this._graph = new Map()
+  }
+
+  export(): Object {
+    return {
+      nodes: this.nodes,
+      edges: this.edges,
+    }
+  }
+
+  toString(): string {
+    return JSON.stringify(this.export(), null, 2)
+  }
+
+  // BASIC GRAPH OPERATIONS
+
+  get nodes(): T[] {
+    return Array.from(this._graph.keys())
+  }
+
+  get edges(): [T, T][] {
+    let edges: [T, T][] = []
+    this.forEachEdge((edge) => edges.push(edge))
+    return edges
+  }
+
+  hasNode(node: T): boolean {
+    return this._graph.has(node)
+  }
+
+  addNode(node: T): void {
+    if (!this._graph.has(node)) {
+      this._graph.set(node, { incoming: new Set(), outgoing: new Set() })
+    }
+  }
+
+  removeNode(node: T): void {
+    if (this._graph.has(node)) {
+      this._graph.delete(node)
+    }
+  }
+
+  hasEdge(from: T, to: T): boolean {
+    return Boolean(this._graph.get(from)?.outgoing.has(to))
+  }
+
+  addEdge(from: T, to: T): void {
+    this.addNode(from)
+    this.addNode(to)
+
+    this._graph.get(from)!.outgoing.add(to)
+    this._graph.get(to)!.incoming.add(from)
+  }
+
+  removeEdge(from: T, to: T): void {
+    if (this._graph.has(from) && this._graph.has(to)) {
+      this._graph.get(from)!.outgoing.delete(to)
+      this._graph.get(to)!.incoming.delete(from)
+    }
+  }
+
+  // returns -1 if node does not exist
+  outDegree(node: T): number {
+    return this.hasNode(node) ? this._graph.get(node)!.outgoing.size : -1
+  }
+
+  // returns -1 if node does not exist
+  inDegree(node: T): number {
+    return this.hasNode(node) ? this._graph.get(node)!.incoming.size : -1
+  }
+
+  forEachOutNeighbor(node: T, callback: (neighbor: T) => void): void {
+    this._graph.get(node)?.outgoing.forEach(callback)
+  }
+
+  forEachInNeighbor(node: T, callback: (neighbor: T) => void): void {
+    this._graph.get(node)?.incoming.forEach(callback)
+  }
+
+  forEachEdge(callback: (edge: [T, T]) => void): void {
+    for (const [source, { outgoing }] of this._graph.entries()) {
+      for (const target of outgoing) {
+        callback([source, target])
+      }
+    }
+  }
+
+  // DEPENDENCY ALGORITHMS
+
+  // For the node provided:
+  // If node does not exist, add it
+  // If an incoming edge was added in other, it is added in this graph
+  // If an incoming edge was deleted in other, it is deleted in this graph
+  updateIncomingEdgesForNode(other: DepGraph<T>, node: T): void {
+    this.addNode(node)
+
+    // Add edge if it is present in other
+    other.forEachInNeighbor(node, (neighbor) => {
+      this.addEdge(neighbor, node)
+    })
+
+    // For node provided, remove incoming edge if it is absent in other
+    this.forEachEdge(([source, target]) => {
+      if (target === node && !other.hasEdge(source, target)) {
+        this.removeEdge(source, target)
+      }
+    })
+  }
+
+  // Get all leaf nodes (i.e. destination paths) reachable from the node provided
+  // Eg. if the graph is A -> B -> C
+  //                     D ---^
+  // and the node is B, this function returns [C]
+  getLeafNodes(node: T): Set<T> {
+    let stack: T[] = [node]
+    let visited = new Set<T>()
+    let leafNodes = new Set<T>()
+
+    // DFS
+    while (stack.length > 0) {
+      let node = stack.pop()!
+
+      // If the node is already visited, skip it
+      if (visited.has(node)) {
+        continue
+      }
+      visited.add(node)
+
+      // Check if the node is a leaf node (i.e. destination path)
+      if (this.outDegree(node) === 0) {
+        leafNodes.add(node)
+      }
+
+      // Add all unvisited neighbors to the stack
+      this.forEachOutNeighbor(node, (neighbor) => {
+        if (!visited.has(neighbor)) {
+          stack.push(neighbor)
+        }
+      })
+    }
+
+    return leafNodes
+  }
+
+  // Get all ancestors of the leaf nodes reachable from the node provided
+  // Eg. if the graph is A -> B -> C
+  //                     D ---^
+  // and the node is B, this function returns [A, B, D]
+  getLeafNodeAncestors(node: T): Set<T> {
+    const leafNodes = this.getLeafNodes(node)
+    let visited = new Set<T>()
+    let upstreamNodes = new Set<T>()
+
+    // Backwards DFS for each leaf node
+    leafNodes.forEach((leafNode) => {
+      let stack: T[] = [leafNode]
+
+      while (stack.length > 0) {
+        let node = stack.pop()!
+
+        if (visited.has(node)) {
+          continue
+        }
+        visited.add(node)
+        // Add node if it's not a leaf node (i.e. destination path)
+        // Assumes destination file cannot depend on another destination file
+        if (this.outDegree(node) !== 0) {
+          upstreamNodes.add(node)
+        }
+
+        // Add all unvisited parents to the stack
+        this.forEachInNeighbor(node, (parentNode) => {
+          if (!visited.has(parentNode)) {
+            stack.push(parentNode)
+          }
+        })
+      }
+    })
+
+    return upstreamNodes
+  }
+}