[Fix #896] Add previous/next project buffer commands (#1312)

3 files changed, 41 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a7e6d58..25f7cdc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,8 @@
 * Add [crystal](https://crystal-lang.org) project type.
 * [#850](https://github.com/bbatsov/projectile/issues/850): Make it possible to prompt for a project, when you're not in a project, instead of raising an error. (see `projectile-require-project-root`).
 * **(Breaking)** [#1147](https://github.com/bbatsov/projectile/issues/1147): Introduce a faster indexing method - `turbo-alien` (it's the default now).
+* [#896](https://github.com/bbatsov/projectile/issues/896) Add commands `projectile-previous-project-buffer ` and
+`projectile-next-project-buffer ` to switch to other buffer in the project.
 
 ### Changes
 
diff --git a/doc/usage.md b/doc/usage.md
index 8643a4b..54af789 100644
--- a/doc/usage.md
+++ b/doc/usage.md
@@ -94,6 +94,8 @@ Keybinding         | Description
 <kbd>s-p 4 D</kbd> | Opens the root of the project in `dired` in another window.
 <kbd>s-p 5 D</kbd> | Opens the root of the project in `dired` in another frame.
 <kbd>s-p e</kbd> | Shows a list of recently visited project files.
+<kbd>s-p left</kbd> | Switch to the previous project buffer.
+<kbd>s-p right</kbd> | Switch to the next project buffer.
 <kbd>s-p E</kbd> | Opens the root `dir-locals-file` of the project.
 <kbd>s-p s s</kbd> | Runs `ag` on the project. Requires the presence of `ag.el`.
 <kbd>s-p !</kbd> | Runs `shell-command` in the root directory of the project.
diff --git a/projectile.el b/projectile.el
index 046d218..d9d1ba1 100644
--- a/projectile.el
+++ b/projectile.el
@@ -1361,6 +1361,7 @@ If PROJECT is not specified the command acts on the current project."
   (with-current-buffer buffer
     (and (not (string-prefix-p " " (buffer-name buffer)))
          (not (projectile-ignored-buffer-p buffer))
+         default-directory
          (string-equal (file-remote-p default-directory)
                        (file-remote-p project-root))
          (not (string-match-p "^http\\(s\\)?://" default-directory))
@@ -4025,6 +4026,8 @@ thing shown in the mode line otherwise."
     (define-key map (kbd "x t") #'projectile-run-term)
     (define-key map (kbd "x s") #'projectile-run-shell)
     (define-key map (kbd "z") #'projectile-cache-current-file)
+    (define-key map (kbd "<left>") #'projectile-previous-project-buffer)
+    (define-key map (kbd "<right>") #'projectile-next-project-buffer)
     (define-key map (kbd "ESC") #'projectile-project-buffers-other-buffer)
     map)
   "Keymap for Projectile commands after `projectile-keymap-prefix'.")
@@ -4048,6 +4051,8 @@ thing shown in the mode line otherwise."
         ["Kill project buffers" projectile-kill-buffers]
         ["Save project buffers" projectile-save-buffers]
         ["Recent files" projectile-recentf]
+        ["Previous buffer" projectile-previous-project-buffer]
+        ["Next buffer" projectile-next-project-buffer]
         "--"
         ["Toggle project wide read-only" projectile-toggle-project-read-only]
         ["Edit .dir-locals.el" projectile-edit-dir-locals]
@@ -4144,6 +4149,38 @@ Otherwise behave as if called interactively.
 ;;;###autoload
 (define-obsolete-function-alias 'projectile-global-mode 'projectile-mode "1.0")
 
+(defun projectile--repeat-until-project-buffer (orig-fun &rest args)
+  "Repeat ORIG-FUN with ARGS until the current buffer is a project buffer."
+  (if (projectile-project-root)
+      (let* ((other-project-buffers (make-hash-table :test 'eq))
+             (projectile-project-buffers (projectile-project-buffers))
+             (max-iterations (length (buffer-list)))
+             (counter 0))
+        (dolist (buffer projectile-project-buffers)
+          (unless (eq buffer (current-buffer))
+            (puthash buffer t other-project-buffers)))
+        (when (cdr-safe projectile-project-buffers)
+          (while (and (< counter max-iterations)
+                      (not (gethash (current-buffer) other-project-buffers)))
+            (apply orig-fun args)
+            (incf counter))))
+    (apply orig-fun args)))
+
+(defun projectile-next-project-buffer ()
+  "In selected window switch to the next project buffer.
+
+If the current buffer does not belong to a project, call `next-buffer'."
+  (interactive)
+  (projectile--repeat-until-project-buffer #'next-buffer))
+
+(defun projectile-previous-project-buffer ()
+  "In selected window switch to the previous project buffer.
+
+If the current buffer does not belong to a project, call `previous-buffer'."
+  (interactive)
+  (projectile--repeat-until-project-buffer #'previous-buffer))
+
+
 (provide 'projectile)
 
 ;;; projectile.el ends here