rtags-conf.el

(use-package rtags
    ;; Note that if you recompile and create new compile_commands.json
    ;; you will need to run "rc -J ." for rtags to reflect the changes.
    ;; REMEMBER RTAGS DOES NOT WORK FOR PROJECTS INSIDE /tmp
    :init
    (add-hook  'c++-mode-hook  #'rtags-start-process-unless-running)
    (add-hook  'c-mode-hook    #'rtags-start-process-unless-running)
    (add-hook 'rtags-jump-hook 'evil-set-jump)

    (setq rtags-completions-enabled t)

    (setq lsp-enable-file-watchers nil)

    (defun my/c-c++-tags-find-symbol-at-point (&optional prefix)
      (interactive "P")
      (if (and (not (rtags-find-symbol-at-point prefix))
               rtags-last-request-not-indexed)
          (gtags-find-tag)))

    (defun my/c-c++-tags-find-references-at-point (&optional prefix)
      (interactive "P")
      (if (and (not (rtags-find-references-at-point prefix))
               rtags-last-request-not-indexed)
          (gtags-find-rtag)))

    (defun my/c-c++-tags-find-symbol ()
      (interactive)
      (call-interactively  'rtags-find-symbol))

    (defun spacemacs/rtags-define-keys-for-mode (mode)
      (spacemacs/set-leader-keys-for-major-mode mode
        ".."  'my/c-c++-tags-find-symbol-at-point
        ".,"  'my/c-c++-tags-find-references-at-point
        "./"  'rtags-find-all-references-at-point
        ".<"  '(lambda () (interactive) (call-interactively 'rtags-find-references))
        ".>"  '(lambda () (interactive) (call-interactively 'rtags-find-symbol))

        ".f"  'rtags-find-symbol-at-point
        ".r"  'rtags-references-tree
        ".R"  'rtags-rename-symbol
        ".T"  'rtags-taglist
        ".h"  'rtags-print-class-hierarchy
        ".v"  'rtags-find-virtuals-at-point
        ".D"  'rtags-print-dependencies
        ".d"  'rtags-dependency-tree
        ".C"  'rtags-check-includes
        ".c"  'c-toggle-comment-style
        ".H"  'staur|toggle-headerline
        ".p"  'rtags-peek-definition
        ".s"  'rtags-show-target-in-other-window
        )
      )

    (spacemacs/rtags-define-keys-for-mode 'c-mode)
    (spacemacs/rtags-define-keys-for-mode 'c++-mode)

    (spacemacs/declare-prefix-for-mode  'c++-mode  "m."   "my cmds")
    (spacemacs/declare-prefix-for-mode  'c++-mode  "m.,"  "rtags-find-references-at-point")
    (spacemacs/declare-prefix-for-mode  'c++-mode  "m.."  "rtags-find-symbol-at-point")
    (spacemacs/declare-prefix-for-mode  'c++-mode  "m.<"  "rtags-find-references")
    (spacemacs/declare-prefix-for-mode  'c++-mode  "m.>"  "rtags-find-symbol")


    (spacemacs/declare-prefix-for-mode  'c-mode    "m."   "my cmds")
    (spacemacs/declare-prefix-for-mode  'c-mode    "m.,"  "rtags-find-references-at-point")
    (spacemacs/declare-prefix-for-mode  'c-mode    "m.."  "rtags-find-symbol-at-point")
    (spacemacs/declare-prefix-for-mode  'c-mode    "m.<"  "rtags-find-references")
    (spacemacs/declare-prefix-for-mode  'c++-mode  "m.>"  "rtags-find-symbol")

    :config
    (rtags-enable-standard-keybindings)   ; enable C-c r bindings

    (advice-add 'rtags-show-in-other-window
                :around
                (lambda (oldfn &rest args)
                  (let ((window (selected-window)))
                    (apply oldfn args)
                    (run-at-time ".1 sec" nil `(lambda ()
                                                 (select-window (get-mru-window 'visible nil t))
                                                 (recenter)
                                                 (select-window ,window))))))

    (advice-add 'rtags-references-tree :after (lambda () (pop-to-buffer rtags-buffer-name)))

    (setq rtags-completions-enabled t)


    (defun rtags-peek-definition ()
      "Peek at definition at point using rtags."
      ;; toggle persp-mode, as this seems to break peek-func.
      (if (bound-and-true-p persp-mode)
          (persp-mode -1))
      ;; begin main section of rtags-peek-definition.
      (interactive)
      (let ((func (lambda ()
                    (rtags-find-symbol-at-point)
                    (rtags-location-stack-forward))))
        (rtags-start-process-unless-running)
        (make-peek-frame func))
      ;; restore previous state whether persp-mode was active or not.
      (if (not (bound-and-true-p persp-mode))
          (persp-mode 1))
      )

    (defun make-peek-frame (find-definition-function &rest args)
      "Make a new frame for peeking definition"
      (when (or (not (rtags-called-interactively-p)) (rtags-sandbox-id-matches))
        (let (doc-frame x y (abs-pixel-pos (save-excursion (beginning-of-thing 'symbol)
                                                           (window-absolute-pixel-position))))
          (setq x (car abs-pixel-pos))
          (setq y (+ (cdr abs-pixel-pos) (frame-char-height)))
          (setq doc-frame (make-frame '((minibuffer . nil) (name . "*RTags Peek*")
                                        (width . 80)       (visibility . nil)
                                        (height . 15))))
          (set-frame-position doc-frame x y)
          (with-selected-frame doc-frame
            (apply find-definition-function args)
            (read-only-mode)
            (recenter-top-bottom 0))
          (make-frame-visible doc-frame))))
    )