Improve Helm integration.

2 files changed, 58 insertions, 3 deletions

diff --git a/README.md b/README.md
index 94daa76..1027803 100644
--- a/README.md
+++ b/README.md
@@ -235,7 +235,11 @@ listing buffers, so they did not require this advice; see [`this Helm
 commit`](https://github.com/emacs-helm/helm/commit/f7fa3a9e0ef1f69c42e0c513d02c9f76ea9a4344)
 and [`this Perspective
 commit`](https://github.com/nex3/perspective-el/commit/c2d3542418967b55f05d5b5ba71c9fbfe4cd3d4f)
-for details.)
+for details.) If `helm-buffers-list` is called with a prefix argument, it will
+show buffers in all perspectives. In addition, Perspective adds actions to
+`helm-buffers-list` to add buffers to the current perspective (mainly relevant
+to the prefix-argument version) and to remove buffers from the current
+perspective.
 
 **Ivy / Counsel**: Perspective provides two commands for listing buffers using
 Ivy and Counsel: `persp-ivy-switch-buffer` and `persp-counsel-switch-buffer`.
diff --git a/perspective.el b/perspective.el
index 038176d..113a6b9 100644
--- a/perspective.el
+++ b/perspective.el
@@ -1085,7 +1085,7 @@ named collections of buffers and window configurations."
         (ad-activate 'switch-to-prev-buffer)
         (ad-activate 'recursive-edit)
         (ad-activate 'exit-recursive-edit)
-        (advice-add 'helm-buffer-list-1 :filter-return #'persp-buffer-list-filter)
+        (persp--helm-enable)
         (add-hook 'after-make-frame-functions 'persp-init-frame)
         (add-hook 'delete-frame-functions 'persp-delete-frame)
         (add-hook 'ido-make-buffer-list-hook 'persp-set-ido-buffers)
@@ -1093,7 +1093,7 @@ named collections of buffers and window configurations."
         (mapc 'persp-init-frame (frame-list))
         (setf (persp-current-buffers) (buffer-list))
         (run-hooks 'persp-mode-hook))
-    (advice-remove 'helm-buffer-list-1 #'persp-buffer-list-filter)
+    (persp--helm-disable)
     (ad-deactivate-regexp "^persp-.*")
     (remove-hook 'delete-frame-functions 'persp-delete-frame)
     (remove-hook 'after-make-frame-functions 'persp-init-frame)
@@ -1384,6 +1384,57 @@ PERSP-SET-IDO-BUFFERS)."
   (persp--switch-buffer-ivy-counsel-helper arg #'counsel-switch-buffer))
 
 
+;;; --- Helm integration
+
+(defun persp--helm-buffer-list-filter (bufs)
+  (if current-prefix-arg
+      bufs
+    (persp-buffer-list-filter bufs)))
+
+(defun persp--helm-remove-buffers-from-perspective (_arg)
+  (interactive)
+  (declare-function helm-marked-candidates "helm.el")
+  (cl-loop for candidate in (helm-marked-candidates) do
+           (persp-remove-buffer candidate)))
+
+(defun persp--helm-add-buffers-to-perspective (_arg)
+  (declare-function helm-marked-candidates "helm.el")
+  (cl-loop for candidate in (helm-marked-candidates) do
+           (persp-add-buffer candidate)))
+
+(defun persp--helm-activate (&rest _args)
+  (defvar helm-source-buffers-list)
+  (declare-function helm-add-action-to-source "helm.el")
+  (advice-add 'helm-buffer-list-1 :filter-return #'persp--helm-buffer-list-filter)
+  (helm-add-action-to-source
+   "Perspective: Add buffer to current perspective"
+   #'persp--helm-add-buffers-to-perspective helm-source-buffers-list)
+  (helm-add-action-to-source
+   "Perspective: Remove buffer from current perspective"
+   #'persp--helm-remove-buffers-from-perspective helm-source-buffers-list)
+  ;; remove persp--helm-activate advice once it has run
+  (advice-remove 'helm-initial-setup #'persp--helm-activate))
+
+(defun persp--helm-enable ()
+  ;; We do not know if Helm has been loaded before Perspective is activated, so
+  ;; we need a way to activate Perspective-Helm integration once we know for
+  ;; certain that Helm is ready. An advice functino should do the trick, which
+  ;; will remove itself once it does its job.
+  (advice-add 'helm-initial-setup :before #'persp--helm-activate))
+
+(defun persp--helm-disable ()
+  (defvar helm-source-buffers-list)
+  (declare-function helm-delete-action-from-source "helm.el")
+  (if (not (featurep 'helm))
+      (advice-remove 'helm-initial-setup #'persp--helm-activate)
+    ;; actual cleanup if Helm-perspective integration has loaded:
+    (helm-delete-action-from-source
+     #'persp--helm-remove-buffers-from-perspective helm-source-buffers-list)
+    (helm-delete-action-from-source
+     #'persp--helm-add-buffers-to-perspective helm-source-buffers-list)
+    (advice-remove 'helm-buffer-list-1 #'persp--helm-buffer-list-filter)))
+
+
 ;;; --- durability implementation (persp-state-save and persp-state-load)
 
 ;; Symbols namespaced by persp--state (internal) and persp-state (user