From caba65771b7c9902dda609c79369424b67335e93 Mon Sep 17 00:00:00 2001
From: Alexander Thaller <alexander.thaller@atraveo.de>
Date: Tue, 17 Feb 2015 22:09:49 +0100
Subject: [PATCH] added persistent pre/post commands.

---
 command.go | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/command.go b/command.go
index b4f62632..d15e1303 100644
--- a/command.go
+++ b/command.go
@@ -53,6 +53,10 @@ type Command struct {
 	// PostRun runs the command after run.
 	// The args are the arguments after the command name.
 	PostRun func(cmd *Command, args []string)
+	// PreRun which children of this command will inherit.
+	PersistentPreRun func(cmd *Command, args []string)
+	// PostRun which children of this command will inherit.
+	PersistentPostRun func(cmd *Command, args []string)
 	// Commands is the list of commands supported by this program.
 	commands []*Command
 	// Parent Command for this command
@@ -387,6 +391,9 @@ func (c *Command) execute(a []string) (err error) {
 		c.preRun()
 		argWoFlags := c.Flags().Args()
 
+		if c.PersistentPreRun != nil {
+			c.PersistentPreRun(c, argWoFlags)
+		}
 		if c.PreRun != nil {
 			c.PreRun(c, argWoFlags)
 		}
@@ -396,6 +403,9 @@ func (c *Command) execute(a []string) (err error) {
 		if c.PostRun != nil {
 			c.PostRun(c, argWoFlags)
 		}
+		if c.PersistentPostRun != nil {
+			c.PersistentPostRun(c, argWoFlags)
+		}
 
 		return nil
 	}
@@ -482,19 +492,25 @@ func (c *Command) Execute() (err error) {
 				// print the usage
 				c.Usage()
 			} else {
-				// Only flags left... Call root.Run
 				c.preRun()
 
+				if c.PersistentPreRun != nil {
+					c.PersistentPreRun(c, argWoFlags)
+				}
 				if c.PreRun != nil {
 					c.PreRun(c, argWoFlags)
 				}
 
+				// Only flags left... Call root.Run
 				c.Run(c, argWoFlags)
 				err = nil
 
 				if c.PostRun != nil {
 					c.PostRun(c, argWoFlags)
 				}
+				if c.PersistentPostRun != nil {
+					c.PersistentPostRun(c, argWoFlags)
+				}
 			}
 		}
 	}
@@ -519,7 +535,9 @@ func (c *Command) initHelp() {
 			Short: "Help about any command",
 			Long: `Help provides help for any command in the application.
     Simply type ` + c.Name() + ` help [path to command] for full details.`,
-			Run: c.HelpFunc(),
+			Run:               c.HelpFunc(),
+			PersistentPreRun:  func(cmd *Command, args []string) {},
+			PersistentPostRun: func(cmd *Command, args []string) {},
 		}
 	}
 	c.AddCommand(c.helpCommand)
@@ -555,6 +573,14 @@ func (c *Command) AddCommand(cmds ...*Command) {
 			c.commandsMaxCommandPathLen = commandPathLen
 		}
 		c.commands = append(c.commands, x)
+
+		// Pass on peristent pre/post functions to children
+		if x.PersistentPreRun == nil {
+			x.PersistentPreRun = c.PersistentPreRun
+		}
+		if x.PersistentPostRun == nil {
+			x.PersistentPostRun = c.PersistentPostRun
+		}
 	}
 }