Restore Checkpoint Feature (#934)

1 files changed, 132 insertions, 0 deletions

diff --git a/packages/core/src/services/gitService.ts b/packages/core/src/services/gitService.ts
new file mode 100644
index 00000000..8cd6b887
--- /dev/null
+++ b/packages/core/src/services/gitService.ts
@@ -0,0 +1,132 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as fs from 'fs/promises';
+import * as path from 'path';
+import { isNodeError } from '../utils/errors.js';
+import { isGitRepository } from '../utils/gitUtils.js';
+import { exec } from 'node:child_process';
+import { simpleGit, SimpleGit, CheckRepoActions } from 'simple-git';
+
+export const historyDirName = '.gemini_cli_history';
+
+export class GitService {
+  private projectRoot: string;
+
+  constructor(projectRoot: string) {
+    this.projectRoot = path.resolve(projectRoot);
+  }
+
+  async initialize(): Promise<void> {
+    if (!isGitRepository(this.projectRoot)) {
+      throw new Error('GitService requires a Git repository');
+    }
+    const gitAvailable = await this.verifyGitAvailability();
+    if (!gitAvailable) {
+      throw new Error('GitService requires Git to be installed');
+    }
+    this.setupHiddenGitRepository();
+  }
+
+  verifyGitAvailability(): Promise<boolean> {
+    return new Promise((resolve) => {
+      exec('git --version', (error) => {
+        if (error) {
+          resolve(false);
+        } else {
+          resolve(true);
+        }
+      });
+    });
+  }
+
+  /**
+   * Creates a hidden git repository in the project root.
+   * The Git repository is used to support checkpointing.
+   */
+  async setupHiddenGitRepository() {
+    const historyDir = path.join(this.projectRoot, historyDirName);
+    const repoDir = path.join(historyDir, 'repository');
+
+    await fs.mkdir(repoDir, { recursive: true });
+    const repoInstance: SimpleGit = simpleGit(repoDir);
+    const isRepoDefined = await repoInstance.checkIsRepo(
+      CheckRepoActions.IS_REPO_ROOT,
+    );
+    if (!isRepoDefined) {
+      await repoInstance.init();
+      try {
+        await repoInstance.raw([
+          'worktree',
+          'add',
+          this.projectRoot,
+          '--force',
+        ]);
+      } catch (error) {
+        console.log('Failed to add worktree:', error);
+      }
+    }
+
+    const visibileGitIgnorePath = path.join(this.projectRoot, '.gitignore');
+    const hiddenGitIgnorePath = path.join(repoDir, '.gitignore');
+
+    let visibileGitIgnoreContent = ``;
+    try {
+      visibileGitIgnoreContent = await fs.readFile(
+        visibileGitIgnorePath,
+        'utf-8',
+      );
+    } catch (error) {
+      if (isNodeError(error) && error.code !== 'ENOENT') {
+        throw error;
+      }
+    }
+
+    await fs.writeFile(hiddenGitIgnorePath, visibileGitIgnoreContent);
+
+    if (!visibileGitIgnoreContent.includes(historyDirName)) {
+      const updatedContent = `${visibileGitIgnoreContent}\n# Gemini CLI history directory\n${historyDirName}\n`;
+      await fs.writeFile(visibileGitIgnorePath, updatedContent);
+    }
+
+    const commit = await repoInstance.raw([
+      'rev-list',
+      '--all',
+      '--max-count=1',
+    ]);
+    if (!commit) {
+      await repoInstance.add(hiddenGitIgnorePath);
+
+      await repoInstance.commit('Initial commit');
+    }
+  }
+
+  private get hiddenGitRepository(): SimpleGit {
+    const historyDir = path.join(this.projectRoot, historyDirName);
+    const repoDir = path.join(historyDir, 'repository');
+    return simpleGit(this.projectRoot).env({
+      GIT_DIR: path.join(repoDir, '.git'),
+      GIT_WORK_TREE: this.projectRoot,
+    });
+  }
+
+  async getCurrentCommitHash(): Promise<string> {
+    const hash = await this.hiddenGitRepository.raw('rev-parse', 'HEAD');
+    return hash.trim();
+  }
+
+  async createFileSnapshot(message: string): Promise<string> {
+    const repo = this.hiddenGitRepository;
+    await repo.add('.');
+    const commitResult = await repo.commit(message);
+    return commitResult.commit;
+  }
+
+  async restoreProjectFromSnapshot(commitHash: string): Promise<void> {
+    const repo = this.hiddenGitRepository;
+    await repo.raw(['restore', '--source', commitHash, '.']);
+  }
+}