feat: add git sync info

prompt.zsh

@@ -12,7 +12,7 @@ function git_prompt_info() {
   if ! __git_prompt_git rev-parse --git-dir &> /dev/null ; then
     return 0
   fi
-  echo "%{$reset_color%}\ue725 on %{$fg[green]%}$(git_current_branch)$(parse_git_dirty)%{$reset_color%} "
+  echo "%{$reset_color%}\ue725 on %{$fg[green]%}$(git_current_branch)$(git_sync_info)%{$reset_color%} "
 }
 
 function git_current_branch() {
@@ -26,29 +26,16 @@ function git_current_branch() {
   echo ${ref#refs/heads/}
 }
 
-function parse_git_dirty() {
-  local STATUS
-  local -a FLAGS
-  FLAGS=('--porcelain')
-  if [[ "$(__git_prompt_git config --get oh-my-zsh.hide-dirty)" != "1" ]]; then
-    if [[ "${DISABLE_UNTRACKED_FILES_DIRTY:-}" == "true" ]]; then
-      FLAGS+='--untracked-files=no'
-    fi
-    case "${GIT_STATUS_IGNORE_SUBMODULES:-}" in
-      git)
-        # let git decide (this respects per-repo config in .gitmodules)
-        ;;
-      *)
-        # if unset: ignore dirty submodules
-        # other values are passed to --ignore-submodules
-        FLAGS+="--ignore-submodules=${GIT_STATUS_IGNORE_SUBMODULES:-dirty}"
-        ;;
-    esac
-    STATUS=$(__git_prompt_git status ${FLAGS} 2> /dev/null | tail -n 1)
-  fi
-  if [[ -n $STATUS ]]; then
+function git_sync_info() {
+  local behind
+  local ahead
+  if git rev-parse --is-inside-work-tree &>/dev/null; then
+    local branch=$(git_current_branch)
+    IFS=: read behind ahead <<<"$(git rev-list --left-right --count ${branch}...origin/${branch} 2>/dev/null | sed 's|^\([0-9]\+\)\s\+\([0-9]\+\)|\1:\2|')"
+    if [[ "${ahead}" != "0" ]] || [[ "${behind}" != "0" ]]; then
       echo "%{$fg[yellow]%}%1{±%}"
     fi
+  fi
 }
 
 function prompt_python_venv() {