update

.iterm2/it2getvar

@@ -1,99 +1,133 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
-function ctrl_c() {
-  stty "$saved_stty"
-  exit 1
-}
+set -o pipefail
 
 # tmux requires unrecognized OSC sequences to be wrapped with DCS tmux;
 # <sequence> ST, and for all ESCs in <sequence> to be replaced with ESC ESC. It
 # only accepts ESC backslash for ST.
 function print_osc() {
-    if [[ $TERM == screen* ]] ; then printf "\033Ptmux;\033\033]"
+    if [[ $TERM == screen* || $TERM == tmux* ]] ; then
+        printf "\033Ptmux;\033\033]"
     else
-        printf "\033]" >& 2
+        printf "\033]"
     fi
 }
 
 # More of the tmux workaround described above.
 function print_st() {
-    if [[ $TERM == screen* ]] ; then
-        printf "\a\033\\" >& 2
+    if [[ $TERM == screen* || $TERM == tmux* ]] ; then
+        printf "\a\033\\"
     else
-        printf "\a" >& 2
+        printf "\a"
     fi
 }
 
+function get_b64_version() {
+    if [[ -z "${BASE64_VERSION+x}" ]]; then
+        BASE64_VERSION=$(base64 --version 2>&1)
+        export BASE64_VERSION
+    fi
+}
+
+function b64_encode() {
+    get_b64_version
+    if [[ $BASE64_VERSION =~ GNU ]]; then
+        # Disable line wrap
+        base64 -w0
+    else
+        base64
+    fi
+}
+
+function b64_decode() {
+    get_b64_version
+    if [[ $BASE64_VERSION =~ fourmilab ]]; then
+        BASE64_ARG=-d
+    elif [[ $BASE64_VERSION =~ GNU ]]; then
+        BASE64_ARG=-di
+    else
+        BASE64_ARG=-D
+    fi
+    base64 $BASE64_ARG
+}
+
+function error() {
+    errcho "ERROR: $*"
+}
+
+function errcho() {
+    echo "$@" >&2
+}
+
 function show_help() {
-    echo "Usage:" 1>& 2
-    echo "   $(basename $0) name" 1>& 2
+    errcho
+    errcho "Usage: it2getvar variable_name"
+    errcho
+    errcho "Output value of the iTerm2 variable"
+    errcho
+    errcho "See the Variables Reference for information about built-in iTerm2 variables:"
+    errcho "  -> https://iterm2.com/documentation-variables.html"
+    errcho
 }
 
-# Read some bytes from stdin. Pass the number of bytes to read as the first argument.
-function read_bytes() {
-  numbytes=$1
-  dd bs=1 count=$numbytes 2>/dev/null
-}
-
-# read_until c
-# Returns bytes read from stdin up to but not including the fist one equal to c
-function read_until() {
-  result=""
-  while :
-  do
-    b=$(read_bytes 1)
-    if [[ $b == $1 ]]
-    then
-      echo "$result"
-      return
+function check_dependency() {
+    if ! (builtin command -V "$1" >/dev/null 2>&1); then
+        error "missing dependency: can't find $1"
+        exit 1
     fi
-    result="$result$b"
-  done
 }
 
-## Main
-if [[ $# != 1 ]]
-then
-  show_help
-  exit 1
+# get_variable variable_name
+#
+# This function uses POSIX standard synonym for the controlling terminal
+# associated with the current process group - /dev/tty. It is useful for programs
+# that wish to be sure of writing or reading data from the terminal
+# no matter how STDIN/STDOUT/STDERR has been redirected.
+function get_variable() {
+    trap 'cleanup' EXIT
+    stty -echo < /dev/tty
+    exec 9<> /dev/tty
+    print_osc >&9
+    printf "1337;ReportVariable=%s" "$(echo -n "$1" | b64_encode)" >&9
+    print_st >&9
+    read -r -t 5 -d $'\a' iterm_response <&9
+    exec 9>&-
+    stty echo < /dev/tty
+    [[ "$iterm_response" =~ ReportVariable= ]] || {
+        error "Failed to read response from iTerm2"
+        exit 2
+    }
+    echo "$(b64_decode <<< ${iterm_response#*=})"
+}
+
+function cleanup() {
+    stty echo < /dev/tty
+}
+
+# Show help if no arguments
+if [ $# -eq 0 ]; then
+    show_help
+    exit
 fi
 
-if ! test -t 1
-then
-  echo "Standard error not a terminal"
-  exit 1
-fi
+check_dependency stty
+check_dependency base64
 
-# Save the tty's state.
-saved_stty=$(stty -g)
-
-# Trap ^C to fix the tty.
-trap ctrl_c INT
-
-# Enter raw mode and turn off echo so the terminal and I can chat quietly.
-stty -echo -icanon raw
-
-print_osc
-printf "1337;ReportVariable=%s" "$(printf "%s" "$1" | base64)" >& 2
-print_st
-
-VERSION=$(base64 --version 2>&1)
-if [[ "$VERSION" =~ fourmilab ]]; then
-  BASE64ARG=-d
-elif [[ "$VERSION" =~ GNU ]]; then
-  BASE64ARG=-di
-else
-  BASE64ARG=-D
-fi
-
-ignore=$(read_bytes 1)
-name=$(read_until )
-re='^]1337;ReportVariable=(.*)'
-if [[ $name =~ $re ]]
-then
-  printf "%s" $(base64 $BASE64ARG <<< ${BASH_REMATCH[1]})
-  exit 0
-else
-  exit 1
-fi
+# Process command line arguments
+case "$1" in
+    -h|--h|--help)
+        show_help
+        exit
+        ;;
+    -*)
+        error "Unknown option: $1"
+        show_help
+        exit 1
+        ;;
+    *)
+        [[ -z "$1" ]] && error "Variable name can't be empty" && exit 1
+        get_variable "$1"
+        ;;
+esac
 
+exit 0