feat(engine): Implement STEM (#91)

* feat: implement Stem

* feat: change implicit branch stem naming

* test: add test for HEAD

* chore: set off the eslint no-continue rule

* refactor: 리뷰 반영

* feat: queue 생성 시, constructor에 정렬 비교 함수 파라미터 추가

* chore: edit test name

packages/analysis-engine/.eslintrc.json

@@ -31,6 +31,7 @@
         "object-shorthand": "off",
         "class-methods-use-this": "off",
         "import/extensions": "off",
-        "import/no-unresolved": "off"
+        "import/no-unresolved": "off",
+        "no-continue": "off"
     }
 }

packages/analysis-engine/src/commit.util.ts

@@ -0,0 +1,18 @@
+import { CommitNode } from "./types/CommitNode";
+import { CommitRaw } from "./types/CommitRaw";
+
+type CommitDict = Map<string, CommitNode>;
+
+export function generateCommitNodeDict(commits: CommitRaw[]): CommitDict {
+  return new Map(
+    commits.map((commit) => [commit.id, { commit } as CommitNode])
+  );
+}
+
+export function getLeafNodes(commitDict: CommitDict): CommitNode[] {
+  const leafNodes: CommitNode[] = [];
+  commitDict.forEach(
+    (node) => node.commit.branches.length && leafNodes.push(node)
+  );
+  return leafNodes;
+}

packages/analysis-engine/src/queue.ts

@@ -0,0 +1,30 @@
+export default class Queue<T> {
+  private queue: Array<T> = [];
+
+  private readonly compareFn: (a: T, b: T) => number;
+
+  constructor(compareFn: (a: T, b: T) => number) {
+    this.compareFn = compareFn;
+  }
+
+  push(node: T): void {
+    this.queue.push(node);
+    this.queue.sort(this.compareFn);
+  }
+
+  pop(): T | undefined {
+    return this.queue.shift();
+  }
+
+  isEmpty(): boolean {
+    return this.queue.length === 0;
+  }
+
+  pushFront(node: T): void {
+    this.queue.unshift(node);
+  }
+
+  pushBack(node: T): void {
+    this.queue.push(node);
+  }
+}

packages/analysis-engine/src/stem.spec.ts

@@ -1,7 +1,201 @@
-import stem from "./stem";
+import { generateCommitNodeDict, getLeafNodes } from "./commit.util";
+import { buildStemDict } from "./stem";
+import { CommitNode } from "./types/CommitNode";
+import { CommitRaw } from "./types/CommitRaw";
+
+type FakeCommitData = Pick<
+  CommitRaw,
+  "id" | "parents" | "branches" | "committerDate"
+>;
+
+const dummy: FakeCommitData[] = [
+  // 1
+  {
+    id: "a1a605b38df7462e14503a2a0bb8d7453df7c8ae",
+    parents: [],
+    branches: [],
+    committerDate: "Sat Sep 3 19:30:40 2022 +0900",
+  },
+  // 2
+  {
+    id: "10d086ff54073d5e9b634ffb378a3da4c15b05a9",
+    parents: ["a1a605b38df7462e14503a2a0bb8d7453df7c8ae"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:30:58 2022 +0900",
+  },
+  // 3
+  {
+    id: "f72a762bd84cae2da0933e637f800a30d6a1840c",
+    parents: [
+      "10d086ff54073d5e9b634ffb378a3da4c15b05a9",
+      "718352fcc051c2a8691d3d96e968d76f7bc6d846",
+    ],
+    branches: [],
+    committerDate: "Sat Sep 3 19:32:44 2022 +0900",
+  },
+  // 4
+  {
+    id: "699116bdd4e2de914e5f5df76cd5aac3e4b5babe",
+    parents: ["f72a762bd84cae2da0933e637f800a30d6a1840c"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:32:55 2022 +0900",
+  },
+  // 5
+  {
+    id: "421fb1cbabae99dc314f3076ea17c0bfd16457cb",
+    parents: [
+      "699116bdd4e2de914e5f5df76cd5aac3e4b5babe",
+      "704ba519d85c2d78914a1b7e5100bae19d36814b",
+    ],
+    branches: [],
+    committerDate: "Sat Sep 3 19:33:50 2022 +0900",
+  },
+  // 6
+  {
+    id: "d5fd016fac43cef3d270736cb169753495f58282",
+    parents: ["421fb1cbabae99dc314f3076ea17c0bfd16457cb"],
+    branches: ["main"],
+    committerDate: "Sat Sep 3 19:34:04 2022 +0900",
+  },
+  // 8
+  {
+    id: "718352fcc051c2a8691d3d96e968d76f7bc6d846",
+    parents: ["a1a605b38df7462e14503a2a0bb8d7453df7c8ae"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:31:25 2022 +0900",
+  },
+  // 9
+  {
+    id: "e40da20d4c80677f272b6ed104c55b237ecaa601",
+    parents: ["718352fcc051c2a8691d3d96e968d76f7bc6d846"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:33:10 2022 +0900",
+  },
+  // 10
+  {
+    id: "704ba519d85c2d78914a1b7e5100bae19d36814b",
+    parents: ["e40da20d4c80677f272b6ed104c55b237ecaa601"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:33:14 2022 +0900",
+  },
+  // 11
+  {
+    id: "6f77d7232b08e9444791e3931acd3b1aa59abe32",
+    parents: ["f72a762bd84cae2da0933e637f800a30d6a1840c"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:34:24 2022 +0900",
+  },
+  // 12
+  {
+    id: "48f1d4f2a1b7b0ac21095f3aa43f35f2cb733918",
+    parents: ["6f77d7232b08e9444791e3931acd3b1aa59abe32"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:34:44 2022 +0900",
+  },
+  // 13
+  {
+    id: "0beb987c722838f5d4bfadfa631c0792cd83849b",
+    parents: ["48f1d4f2a1b7b0ac21095f3aa43f35f2cb733918"],
+    branches: [],
+    committerDate: "Sat Sep 3 19:34:45 2022 +0900",
+  },
+  // 14
+  {
+    id: "b6d5e7979c71e7e7e7b537838c0d249ec5e63375",
+    parents: ["0beb987c722838f5d4bfadfa631c0792cd83849b"],
+    branches: ["dev"],
+    committerDate: "Sat Sep 3 19:34:57 2022 +0900",
+  },
+  // 15
+  {
+    id: "dcb3b0752a99d5c9449710f7f781dc2b5bc22cd9",
+    parents: [
+      "0beb987c722838f5d4bfadfa631c0792cd83849b",
+      "704ba519d85c2d78914a1b7e5100bae19d36814b",
+    ],
+    branches: [],
+    committerDate: "Sat Sep 3 19:37:35 2022 +0900",
+  },
+  // 16
+  {
+    id: "04b02e3efb9e432e3ce91f1b36bbdeb284fddcf5",
+    parents: ["dcb3b0752a99d5c9449710f7f781dc2b5bc22cd9"],
+    branches: ["HEAD"],
+    committerDate: "Sat Sep 3 19:37:53 2022 +0900",
+  },
+];
+
+function createTestCommit(fakeCommitData: FakeCommitData): CommitRaw {
+  return {
+    tags: [],
+    author: {
+      name: "",
+      email: "",
+    },
+    authorDate: "",
+    committer: {
+      name: "",
+      email: "",
+    },
+    message: "",
+    differenceStatistic: {
+      totalInsertionCount: 0,
+      totalDeletionCount: 0,
+      fileDictionary: {},
+    },
+    ...fakeCommitData,
+  } as CommitRaw;
+}
 
 describe("stem", () => {
-  it("temp test", () => {
-    expect(stem()).toBe("stem");
+  let commits: CommitRaw[] = [];
+  let commitDict: Map<string, CommitNode>;
+
+  beforeEach(() => {
+    commits = dummy.map(createTestCommit);
+    commitDict = generateCommitNodeDict(commits);
+  });
+
+  it("should make instance of Map", () => {
+    const stemDict = buildStemDict(commitDict);
+    expect(stemDict).toBeInstanceOf(Map);
+  });
+
+  it("should get leaf nodes", () => {
+    const leafNodes = getLeafNodes(commitDict);
+    expect(leafNodes.map((node) => node.commit.id)).toEqual([
+      "d5fd016fac43cef3d270736cb169753495f58282",
+      "b6d5e7979c71e7e7e7b537838c0d249ec5e63375",
+      "04b02e3efb9e432e3ce91f1b36bbdeb284fddcf5",
+    ]);
+  });
+
+  it("should make stem", () => {
+    const stemDict = buildStemDict(commitDict);
+    expect(stemDict.get("main")?.nodes.map((node) => node.commit.id)).toEqual([
+      "d5fd016fac43cef3d270736cb169753495f58282",
+      "421fb1cbabae99dc314f3076ea17c0bfd16457cb",
+      "699116bdd4e2de914e5f5df76cd5aac3e4b5babe",
+      "f72a762bd84cae2da0933e637f800a30d6a1840c",
+      "10d086ff54073d5e9b634ffb378a3da4c15b05a9",
+      "a1a605b38df7462e14503a2a0bb8d7453df7c8ae",
+    ]);
+    expect(
+      stemDict.get("implicit-1")?.nodes.map((node) => node.commit.id)
+    ).toEqual([
+      "704ba519d85c2d78914a1b7e5100bae19d36814b",
+      "e40da20d4c80677f272b6ed104c55b237ecaa601",
+      "718352fcc051c2a8691d3d96e968d76f7bc6d846",
+    ]);
+    expect(stemDict.get("dev")?.nodes.map((node) => node.commit.id)).toEqual([
+      "b6d5e7979c71e7e7e7b537838c0d249ec5e63375",
+      "0beb987c722838f5d4bfadfa631c0792cd83849b",
+      "48f1d4f2a1b7b0ac21095f3aa43f35f2cb733918",
+      "6f77d7232b08e9444791e3931acd3b1aa59abe32",
+    ]);
+    expect(stemDict.get("HEAD")?.nodes.map((node) => node.commit.id)).toEqual([
+      "04b02e3efb9e432e3ce91f1b36bbdeb284fddcf5",
+      "dcb3b0752a99d5c9449710f7f781dc2b5bc22cd9",
+    ]);
   });
 });

packages/analysis-engine/src/stem.ts

@@ -1,3 +1,97 @@
-export const stem = () => "stem";
+import { getLeafNodes } from "./commit.util";
+import Queue from "./queue";
+import { CommitNode } from "./types/CommitNode";
+import { Stem } from "./types/Stem";
 
-export default stem;
+export function getStemNodes(
+  tailId: string,
+  commitDict: Map<string, CommitNode>,
+  q: Queue<CommitNode>,
+  stemId: string
+): CommitNode[] {
+  let now = commitDict.get(tailId);
+  if (!now) return [];
+
+  const nodes: CommitNode[] = [];
+  while (now && !now.stemId) {
+    now.stemId = stemId;
+    if (now.commit.parents.length > 1) {
+      now.commit.parents.forEach((parent, idx) => {
+        if (idx === 0) return;
+        const parentNode = commitDict.get(parent);
+        if (parentNode) {
+          q.push(parentNode);
+        }
+      }, q);
+    }
+    nodes.push(now);
+    now = commitDict.get(now.commit.parents?.[0]);
+  }
+  return nodes;
+}
+
+function compareCommitPriority(a: CommitNode, b: CommitNode): number {
+  // branches 값 존재하는 노드 => leaf / main / HEAD 노드.
+  // 이 노드는 큐에 들어올 때 순서가 정해져 있기 때문에 순서를 바꾸지 않음.
+  if (a.commit.branches.length || b.commit.branches.length) {
+    return 0;
+  }
+  // 나중에 커밋된 것을 먼저 담기
+  return (
+    new Date(b.commit.committerDate).getTime() -
+    new Date(a.commit.committerDate).getTime()
+  );
+}
+
+export function buildStemDict(
+  commitDict: Map<string, CommitNode>
+): Map<string, Stem> {
+  const q = new Queue<CommitNode>(compareCommitPriority);
+
+  /**
+   * 처음 큐에 담기는 순서
+   * 1. main
+   * 2. sub-branches
+   * 3. HEAD
+   */
+  const stemDict = new Map<string, Stem>();
+  const leafNodes = getLeafNodes(commitDict);
+  const mainNode = leafNodes.find(
+    (node) =>
+      node.commit.branches.includes("main") ||
+      node.commit.branches.includes("master")
+  );
+  const headNode = leafNodes.find((node) =>
+    node.commit.branches.includes("HEAD")
+  );
+  leafNodes
+    .filter(
+      (node) =>
+        node.commit.id !== mainNode?.commit.id &&
+        node.commit.id !== headNode?.commit.id
+    )
+    .forEach((node) => q.push(node), q);
+  if (mainNode) q.pushFront(mainNode);
+  if (headNode) q.pushBack(headNode);
+
+  let implicitBranchNumber = 1;
+
+  while (!q.isEmpty()) {
+    const tail = q.pop();
+    if (!tail) continue;
+
+    const stemId =
+      tail.commit.branches[0] ?? `implicit-${implicitBranchNumber}`;
+    if (tail.commit.branches.length === 0) {
+      implicitBranchNumber += 1;
+    }
+
+    const nodes = getStemNodes(tail.commit.id, commitDict, q, stemId);
+    if (nodes.length === 0) continue;
+
+    const stem: Stem = { nodes };
+    stemDict.set(stemId, stem);
+  }
+
+  return stemDict;
+}

packages/analysis-engine/src/types/CommitNode.ts

@@ -0,0 +1,7 @@
+import { CommitRaw } from "./CommitRaw";
+
+export interface CommitNode {
+  // 순회 이전에는 stemId가 존재하지 않음.
+  stemId?: string;
+  commit: CommitRaw;
+}