Function getGitFileDiff

lib/git-changes.ts:124–164

(cwd: string, filePath: string)

}

export async function getGitFileDiff(cwd: string, filePath: string): Promise<GitFileDiffResponse> {
  const repositoryRoot = await findRepositoryRoot(cwd);
  if (!repositoryRoot || !isWithinPath(repositoryRoot, filePath)) return { supported: false };

  const resolvedFilePath = path.resolve(filePath);
  let stat: fs.Stats;
  try {
    stat = fs.lstatSync(resolvedFilePath);
  } catch {
    return { supported: false };
  }
  if (!stat.isFile() || stat.size > TEXT_PREVIEW_MAX_BYTES) return { supported: false };

  const relativePath = toGitPath(path.relative(repositoryRoot, resolvedFilePath));
  const entries = await readStatusEntries(repositoryRoot);
  const entry = entries.find((candidate) => candidate.path === relativePath);
  if (!entry) return { supported: false };

  const { status } = classifyGitStatus(entry);
  if (status === "deleted") return { supported: false };

  const currentBuffer = fs.readFileSync(resolvedFilePath);
  if (hasNullByte(currentBuffer)) return { supported: false };
  const newContent = currentBuffer.toString("utf8");

  let patch: string;
  if (status === "untracked") {
    patch = createAddedFilePatch(relativePath, newContent);
  } else {
    const trackedPatch = await createTrackedFilePatch(repositoryRoot, relativePath, entry.originalPath);
    if (trackedPatch === null) {
      if (status !== "added") return { supported: false };
      patch = createAddedFilePatch(relativePath, newContent);
    } else {
      patch = trackedPatch;
    }
  }

  if (!patch.includes("\n@@ ")) return { supported: false };
  return { supported: true, status, patch };
}