From a716badfd4777ecb1589cc636126a874ee8e8082 Mon Sep 17 00:00:00 2001
From: Derek Stavis <dekestavis@gmail.com>
Date: Tue, 23 Feb 2016 22:59:10 -0300
Subject: [PATCH] Implement safe shell reloading inside omf plugin

This commit adds an improved reload code for Oh My Fish, besides
saving the history now the reloading technique keeps directory
history and stack and clears fish_greeting, for a transparent
transition.

The reloading code is now safe regarding to background jobs. exec
wipes fish job control, so the user-facing code under the (just-
introduced by this commit) `omf reload` command is kept safe by a
warning. For testing purposes, `omf update` and `omf remove` rolls
automatic refresh only when `OMF_AUTO_RELOAD` variable is set.

Recap of the commit:
- Add improved reload code (omf.reload)
- Add a safe reload code (omf.cli.reload)
- Add `omf reload` command
- Add opt-in reload to `omf update` and `omf remove` commands
---
 README.md                                 |  6 ++++++
 pkg/omf/functions/cli/omf.cli.reload.fish | 18 ++++++++++++++++++
 pkg/omf/functions/cli/omf.cli.remove.fish |  3 +++
 pkg/omf/functions/cli/omf.cli.update.fish |  4 ++++
 pkg/omf/functions/core/omf.reload.fish    | 11 +++++++++++
 pkg/omf/functions/omf.fish                |  3 +++
 6 files changed, 45 insertions(+)
 create mode 100644 pkg/omf/functions/cli/omf.cli.reload.fish
 create mode 100644 pkg/omf/functions/core/omf.reload.fish

diff --git a/README.md b/README.md
index 89516af..51b295e 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,12 @@ Remove a theme or package.
 
 > Packages subscribed to `uninstall_<pkg>` events are notified before the package is removed, so custom cleanup of resources can be done. See [Uninstall](/docs/en-US/Packages.md#uninstall) for more information.
 
+#### `omf reload`
+
+Reload Oh My Fish and all plugins by using `exec` to replace current shell process with a brand new.
+
+> This command try to be as safe as possible, mitigating side-effects caused by `exec` and preventing the reload in case of background processes.
+
 #### `omf new pkg | theme` _`<name>`_
 
 Scaffold out a new package or theme.
diff --git a/pkg/omf/functions/cli/omf.cli.reload.fish b/pkg/omf/functions/cli/omf.cli.reload.fish
new file mode 100644
index 0000000..4746220
--- /dev/null
+++ b/pkg/omf/functions/cli/omf.cli.reload.fish
@@ -0,0 +1,18 @@
+function omf.cli.reload
+  if not contains -- --force $argv
+    if count (jobs) >/dev/null ^&1
+      __omf.cli.reload.job_warning
+      return 1
+    end
+  end
+  omf.reload
+end
+
+function __omf.cli.reload.job_warning
+  echo (set_color -u)"Reload aborted. There are background jobs:"(set_color normal)
+  echo
+  jobs
+  echo
+  echo "For your safety, finish all background jobs before reloading Oh My Fish."
+  echo "If you are absolutely sure of what you are doing, you can bypass this check using --force."
+end
diff --git a/pkg/omf/functions/cli/omf.cli.remove.fish b/pkg/omf/functions/cli/omf.cli.remove.fish
index 56c12d7..2348d15 100644
--- a/pkg/omf/functions/cli/omf.cli.remove.fish
+++ b/pkg/omf/functions/cli/omf.cli.remove.fish
@@ -7,6 +7,9 @@ function omf.cli.remove -a name
     switch $code
     case 0
       echo (omf::em)"$name successfully removed."(omf::off)
+      # Opt-in flag for testing
+      set -q OMF_AUTO_RELOAD
+        and omf.cli.reload
     case 1
       echo (omf::err)"$name could not be removed."(omf::off) 1^&2
     case 2
diff --git a/pkg/omf/functions/cli/omf.cli.update.fish b/pkg/omf/functions/cli/omf.cli.update.fish
index 0d11643..b280be9 100644
--- a/pkg/omf/functions/cli/omf.cli.update.fish
+++ b/pkg/omf/functions/cli/omf.cli.update.fish
@@ -23,4 +23,8 @@ function omf.cli.update
   for package in $packages
     omf.packages.update $package
   end
+
+  # Opt-in flag for testing
+  set -q OMF_AUTO_RELOAD
+    and omf.cli.reload
 end
diff --git a/pkg/omf/functions/core/omf.reload.fish b/pkg/omf/functions/core/omf.reload.fish
new file mode 100644
index 0000000..41e3920
--- /dev/null
+++ b/pkg/omf/functions/core/omf.reload.fish
@@ -0,0 +1,11 @@
+function omf.reload -d "Reload fish process via exec, keeping some context"
+  set -q CI; and return 0
+
+  history --save
+  set -gx dirprev $dirprev
+  set -gx dirnext $dirnext
+  set -gx dirstack $dirstack
+  set -gx fish_greeting ''
+
+  exec fish
+end
diff --git a/pkg/omf/functions/omf.fish b/pkg/omf/functions/omf.fish
index 7b8c4c3..5ee4a52 100644
--- a/pkg/omf/functions/omf.fish
+++ b/pkg/omf/functions/omf.fish
@@ -40,6 +40,9 @@ function omf -d "Oh My Fish"
     case "doctor"
       omf.cli.doctor
 
+    case "reload"
+      omf.cli.reload $arguments
+
     case "i" "install" "get"
       omf.cli.install $arguments