From e531d6fcc133cfa82c0849a1845e7cbeaeff5600 Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Mon, 17 May 2010 11:57:31 +0200
Subject: [PATCH] zsh/rc: Use caching with vcs_info to speed up the prompt.

---
 zsh/rc | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/zsh/rc b/zsh/rc
index cfd3f43..643d7ae 100644
--- a/zsh/rc
+++ b/zsh/rc
@@ -212,6 +212,45 @@ if [[ $ZSH_VERSION == (4.3.<9->|4.<4->*|<5->*) ||
     zstyle ':vcs_info:*' unstagedstr '¹'
     zstyle ':vcs_info:*' stagedstr   '²'
 
+    # Default to running vcs_info. If possible we prevent running it later for
+    # speed reasons. If set to a non empty value vcs_info is run.
+    FORCE_RUN_VCS_INFO=1
+
+    # Cache system inspired by Bart Trojanowski
+    # (http://jukie.net/~bart/blog/pimping-out-zsh-prompt).
+    #zstyle ':vcs_info:*+pre-get-data:*' hooks pre-get-data
+    +vi-pre-get-data() {
+        # Only Git and Mercurial support and need caching. Abort if any other
+        # VCS is used.
+        [[ "$vcs" != git && "$vcs" != hg ]] && return
+
+        # If the shell just started up or we changed directories (or for other
+        # custom reasons) we must run vcs_info.
+        if [[ -n $FORCE_RUN_VCS_INFO ]]; then
+            FORCE_RUN_VCS_INFO=
+            return
+        fi
+
+        # Don't run vcs_info by default to speed up the shell.
+        ret=1
+        # If a git/hg command was run then run vcs_info as the status might
+        # need to be updated.
+        case "$(fc -ln $(($HISTCMD-1)))" in
+            git* | g\ *)
+                ret=0
+                ;;
+            hg*)
+                ret=0
+                ;;
+        esac
+    }
+
+    # Must run vcs_info when changing directories.
+    prompt_chpwd() {
+        FORCE_RUN_VCS_INFO=1
+    }
+    add-zsh-hook chpwd prompt_chpwd
+
     # Call vcs_info as precmd before every prompt.
     prompt_precmd() {
         vcs_info
-- 
2.45.2