emacs-合并dired中pdf文件

(defun pdftk-merge (filenames output-file)
  "Merge PDF files listed in FILENAMES and save them to OUTPUT-FILE.

FILENAMES is a list of filenames to be merged, while OUTPUT-FILE
is the path where the new PDF should be saved.

This function requires 'pdftk' command-line tool to be installed
and available in the system's PATH.

Example: (pdftk-merge
             '(\"/path/to/input_1.pdf\" \"/path/to/input_2.pdf\")
             \"/path/to/output.pdf\")"
  ;; 1. 检查是否安装了 pdftk
  (unless (executable-find "pdftk")
    (error "Command 'pdftk' not found. Please install it first"))
  
  ;; 2. 将所有文件路径转换为绝对路径，避免因为 default-directory 改变导致找不到文件
  (let* ((abs-filenames (mapcar #'expand-file-name filenames))
         (abs-output (expand-file-name output-file))
         ;; 3. 构建参数列表 (不需要手动处理引号了)
         (args (append abs-filenames (list "cat" "output" abs-output)))
         ;; 4. 使用 call-process 直接调用程序，规避 shell 注入和转义问题
         (exit-code (apply #'call-process "pdftk" nil nil nil args)))
    
    ;; 5. 检查退出状态码
    (if (zerop exit-code)
        (message "Successfully merged PDFs into %s" output-file)
      (error "pdftk failed to merge files (exit code %d)" exit-code))
    abs-output))

(defun my/dired-merge-pdfs ()
  "Merge selected PDF files in Dired.
Note: Files are merged in the order they appear in the Dired buffer.

This function prompts the user for an output file name and then 
merges the marked PDF files into this new file."
  (interactive)
  ;; 1. 确保在 Dired 模式下运行
  (unless (derived-mode-p 'dired-mode)
    (error "This command must be run in a Dired buffer"))
  
  (let* ((all-marked (dired-get-marked-files))
         ;; 2. 过滤掉非 PDF 文件和目录，确保安全
         (pdf-files (seq-filter (lambda (f)
                                  (and (not (file-directory-p f))
                                       (string-match-p "\\.[pP][dD][fF]\\'" f)))
                                all-marked)))
    
    ;; 3. 检查是否有足够的文件进行合并
    (when (< (length pdf-files) 2)
      (error "Please mark at least 2 PDF files to merge"))
    
    (let* ((default-output-file "merged.pdf")
           ;; 4. 优化交互提示，使用当前目录作为默认路径
           (output-file (read-file-name "Output file: "
                                        default-directory
                                        default-output-file
                                        nil
                                        default-output-file)))
      
      ;; 5. 执行合并
      (pdftk-merge pdf-files output-file)
      ;; 6. 刷新 Dired buffer，让新生成的文件显示出来
      (revert-buffer))))

(use-package dired
  ;;  内置包
  :ensure nil
  :config
  (defun my/dired-narrow ()
    (interactive)
    (call-interactively #'dired-mark-files-regexp)
    (command-execute "tk"))
  :bind
  (:map dired-mode-map
        ("M-m" . my/dired-merge-pdfs)
        ("/" . my/dired-narrow)))