From d5f3c198c9080fc463d3b7cfa7bb99beb7c4cd09 Mon Sep 17 00:00:00 2001
From: Romain Failliot <romain.failliot@foolstep.com>
Date: Sun, 18 Feb 2018 18:54:32 -0500
Subject: [PATCH] Increase prompt speed

On huge repositories, like the one we use at work, calling `hg branch`
can be very long. To get a sensible boost, directly get the branch name
from .hg/branch. It is tremendously faster.

Average time on 10 calls of `hg_get_branch_name`:

    Before: `/tmp/test.zsh 0.08s user 0.04s system 96% cpu 0.133 total`
    After:  `/tmp/test.zsh 0.00s user 0.00s system 71% cpu 0.008 total`

It's faster and it uses less CPU.
---
 plugins/mercurial/mercurial.plugin.zsh | 36 +++++++++++++++++++-------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/plugins/mercurial/mercurial.plugin.zsh b/plugins/mercurial/mercurial.plugin.zsh
index 3ae59496..592a7f02 100644
--- a/plugins/mercurial/mercurial.plugin.zsh
+++ b/plugins/mercurial/mercurial.plugin.zsh
@@ -18,24 +18,42 @@ alias hgca='hg commit --amend'
 # list unresolved files (since hg does not list unmerged files in the status command)
 alias hgun='hg resolve --list'
 
+function hg_get_dir() {
+  # Defines path as current directory
+  local current_dir=$PWD
+  # While current path is not root path
+  while [[ $current_dir != '/' ]]; do
+    if [[ -d "${current_dir}/.hg" ]]; then
+      echo "${current_dir}/.hg"
+      return
+    fi
+    # Defines path as parent directory and keeps looking for
+    current_dir="${current_dir:h}"
+  done
+}
+
 function in_hg() {
-  if [[ -d .hg ]] || $(hg summary > /dev/null 2>&1); then
+  if [[ $(hg_get_dir) != "" ]]; then
     echo 1
   fi
 }
 
 function hg_get_branch_name() {
-  if [ $(in_hg) ]; then
-    echo $(hg branch)
+  local hg_dir=$(hg_get_dir)
+  if [[ $hg_dir != "" ]]; then
+    if [[ -f "${hg_dir}/branch" ]]; then
+      echo $(<"${hg_dir}/branch")
+    else
+      echo "default"
+    fi
   fi
 }
 
 function hg_prompt_info {
-  if [ $(in_hg) ]; then
-    _DISPLAY=$(hg_get_branch_name)
+  local branch=$(hg_get_branch_name)
+  if [[ $branch != "" ]]; then
     echo "$ZSH_PROMPT_BASE_COLOR$ZSH_THEME_HG_PROMPT_PREFIX\
-$ZSH_THEME_REPO_NAME_COLOR$_DISPLAY$ZSH_PROMPT_BASE_COLOR$ZSH_PROMPT_BASE_COLOR$(hg_dirty)$ZSH_THEME_HG_PROMPT_SUFFIX$ZSH_PROMPT_BASE_COLOR"
-    unset _DISPLAY
+$ZSH_THEME_REPO_NAME_COLOR${branch}$ZSH_PROMPT_BASE_COLOR$ZSH_PROMPT_BASE_COLOR$(hg_dirty)$ZSH_THEME_HG_PROMPT_SUFFIX$ZSH_PROMPT_BASE_COLOR"
   fi
 }
 
@@ -57,9 +75,9 @@ function hg_dirty {
 }
 
 function hgic() {
-    hg incoming "$@" | grep "changeset" | wc -l
+  hg incoming "$@" | grep "changeset" | wc -l
 }
 
 function hgoc() {
-    hg outgoing "$@" | grep "changeset" | wc -l
+  hg outgoing "$@" | grep "changeset" | wc -l
 }