perf: optimize git log explore by paginating to minimize traversal

packages/reg-keygen-git-hash-plugin/src/commit-explorer.test.ts

@@ -4,6 +4,8 @@ import { CommitExplorer } from "./commit-explorer";
 import process from "process";
 import path from "path";
 
+const GIT_LOG_COUNT_PER_PAGE_FOR_TEST = 2;
+
 const rimraf = require("rimraf");
 
 process.chdir("./test");
@@ -21,20 +23,20 @@ const copyGitFiles = (name: string) => {
 //        assert.equal issue will be fixed in version using git-tiny-walker
 // test.serial("no commit", () => {
 //   copyGitFiles("no-commit");
-//   t.throws(() => new CommitExplorer().getCurrentCommitHash());
+//   t.throws(() => new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getCurrentCommitHash());
 // });
 
 test("detached head", () => {
   copyGitFiles("detached-head");
-  expect(() => new CommitExplorer().getCurrentBranchName()).toThrowError();
+  expect(() => new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getCurrentBranchName()).toThrowError();
 });
 
 /*
  * first commit
  */
 test("initial commit", () => {
   copyGitFiles("initial-commit");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   assert.equal(null, baseHash);
 });
 
@@ -44,7 +46,7 @@ test("initial commit", () => {
  */
 test("master two commits", () => {
   copyGitFiles("master-two-commits");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   assert.equal(null, baseHash);
 });
 
@@ -54,7 +56,7 @@ test("master two commits", () => {
  */
 test("after create new branch", () => {
   copyGitFiles("after-create-new-branch");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   assert.equal(null, baseHash);
 });
 
@@ -65,7 +67,7 @@ test("after create new branch", () => {
  */
 test("commit after create new branch", () => {
   copyGitFiles("commit-new-branch");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -78,7 +80,7 @@ test("commit after create new branch", () => {
  */
 test("two commits after create new branch", () => {
   copyGitFiles("two-commit-new-branch");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -95,7 +97,7 @@ test("two commits after create new branch", () => {
 */
 test("after catch up master merge", () => {
   copyGitFiles("after-catch-up-master");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -113,7 +115,7 @@ test("after catch up master merge", () => {
 */
 test("commit after merge", () => {
   copyGitFiles("commit-after-merge");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -131,7 +133,7 @@ test("commit after merge", () => {
 
 test("master to catch up branch", () => {
   copyGitFiles("master-to-catch-up-branch");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -157,7 +159,7 @@ test("master to catch up branch", () => {
 
 test("commit after catch up and merge", () => {
   copyGitFiles("commit-after-catch-up-and-merge");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -175,7 +177,7 @@ test("commit after catch up and merge", () => {
 // * first commit
 test("after merge catch up", () => {
   copyGitFiles("after-merge-catch-up");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -195,7 +197,7 @@ test("after merge catch up", () => {
 // * first commit
 test("merge catch up and commit", () => {
   copyGitFiles("merge-catch-up-then-commit");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
@@ -213,14 +215,14 @@ test("merge catch up and commit", () => {
 // * (tag: expected) init import
 test("merge multipe commit three", () => {
   copyGitFiles("merge-multipe-commit-three");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = execSync("git rev-parse expected", { encoding: "utf8" }).trim();
   assert.equal(expected, baseHash);
 });
 
 test("error patter found in reg-suit repository", () => {
   copyGitFiles("reg-suit-error-pattern");
-  const baseHash = new CommitExplorer().getBaseCommitHash();
+  const baseHash = new CommitExplorer(GIT_LOG_COUNT_PER_PAGE_FOR_TEST).getBaseCommitHash();
   const expected = "49d38a929ae3675a1c79216709c35884f0b78900";
   assert.equal(expected, baseHash);
 });

packages/reg-keygen-git-hash-plugin/src/commit-explorer.ts

@@ -4,17 +4,23 @@ export type CommitNode = string[];
 
 export class CommitExplorer {
   private _gitCmdClient = new GitCmdClient();
-  private _commitNodes!: CommitNode[];
   private _branchName!: string;
+  private _commitHash!: string;
+  private _branchHash!: string;
   private _branchNameCache: { [hash: string]: string[] } = {};
 
+  constructor(private _gitLogCountPerPage = 10) {}
+
   /*
    * e.g. return `[["a38df15", "8e1ac3a"], ["8e1ac3a", "7ba8507"]]`.
    *      The first element of node means commit hash, rest elements means parent commit hashes.
    */
-  getCommitNodes(): CommitNode[] {
+  getCommitNodes(skip: number): CommitNode[] {
     return this._gitCmdClient
-      .logGraph()
+      .logGraph({
+        number: this._gitLogCountPerPage,
+        skip,
+      })
       .split("\n")
       .map((hashes: string) =>
         hashes
@@ -95,11 +101,11 @@ export class CommitExplorer {
       .map(b => b.hash)[0];
   }
 
-  getCandidateHashes(): string[] {
-    const mergedBranches = this.getBranchNames(this._commitNodes[0][0]).filter(
+  getCandidateHashes(commitNotes: ReadonlyArray<CommitNode>): string[] {
+    const mergedBranches = this.getBranchNames(this._commitHash).filter(
       b => !b.endsWith("/" + this._branchName) && b !== this._branchName,
     );
-    return this._commitNodes
+    return commitNotes
       .map(c => c[0])
       .filter(c => {
         const branches = this.getBranchNames(c);
@@ -125,15 +131,31 @@ export class CommitExplorer {
     return target;
   }
 
+  getBaseCommitHashRec(cursor: number = 0): string | null {
+    const commitNotes = this.getCommitNodes(cursor);
+    if (commitNotes.length === 0) return null;
+
+    const candidateHashes = this.getCandidateHashes(commitNotes);
+    const baseHash = this.findBaseCommitHash(candidateHashes, this._branchHash);
+    if (!baseHash) {
+      const lastCommitNode = commitNotes.at(-1)!;
+      if (lastCommitNode.length === 1) return null;
+      const nextCursor = cursor + this._gitLogCountPerPage;
+      if (nextCursor === 300) return null;
+      return this.getBaseCommitHashRec(nextCursor);
+    }
+
+    const result = this._gitCmdClient.revParse(baseHash).replace("\n", "");
+    return result ? result : null;
+  }
+
   getBaseCommitHash(): string | null {
     this._branchName = this.getCurrentBranchName();
-    this._commitNodes = this.getCommitNodes();
-    const candidateHashes = this.getCandidateHashes();
+    this._commitHash = this.getCurrentCommitHash();
     const branchHash = this.getBranchHash();
-    if (!branchHash) return null;
-    const baseHash = this.findBaseCommitHash(candidateHashes, branchHash);
-    if (!baseHash) return null;
-    const result = this._gitCmdClient.revParse(baseHash).replace("\n", "");
-    return result ? result : null;
+    if (branchHash === undefined) return null;
+    this._branchHash = branchHash;
+
+    return this.getBaseCommitHashRec();
   }
 }

packages/reg-keygen-git-hash-plugin/src/git-cmd-client.ts

@@ -31,8 +31,26 @@ export class GitCmdClient {
     return execSync(shellEscape(["git", "log", "--oneline", `${a}..${b}`]), { encoding: "utf8" });
   }
 
-  logGraph() {
-    return execSync('git log -n 300 --graph --pretty=format:"%h %p"', { encoding: "utf8" });
+  logGraph(
+    options?: Partial<{
+      number: number;
+      skip: number;
+    }>,
+  ) {
+    const { number = 300, skip = 0 } = options ?? {};
+    return execSync(
+      shellEscape([
+        "git",
+        "log",
+        "-n",
+        number.toString(),
+        "--skip",
+        skip.toString(),
+        "--graph",
+        "--pretty=format:%h %p",
+      ]),
+      { encoding: "utf8" },
+    );
   }
 
   mergeBase(a: string, b: string) {