refactor: use command realpath instead of function `portableReadLin…

…k` without losing portability 🔗

bin/ap

@@ -35,32 +35,13 @@ die() {
   exit 1
 }
 
-# How can I get the behavior of GNU's readlink -f on a Mac?
-# https://stackoverflow.com/questions/1055671
-portableReadLink() {
-  local file=$1 uname
-
-  uname=$(uname)
-  case "$uname" in
-  Linux* | CYGWIN* | MINGW*)
-    readlink -f -- "$file"
-    ;;
-  Darwin*)
-    local py_args=(-c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file")
-    if command -v greadlink >/dev/null; then
-      greadlink -f -- "$file"
-    elif command -v python3 >/dev/null; then
-      python3 "${py_args[@]}"
-    elif command -v python >/dev/null; then
-      python "${py_args[@]}"
-    else
-      die "fail to find command(greadlink/python3/python) to get absolute path!"
-    fi
-    ;;
-  *)
-    die "NOT support uname($uname)!"
-    ;;
-  esac
+# `realpath` command existed on Linux and macOS, return resolved physical path
+#   - realpath command on macOS do NOT support option `-e`;
+#     combined `[ -e $file ]` to check file existence first.
+#   - How can I get the behavior of GNU's readlink -f on a Mac?
+#     https://stackoverflow.com/questions/1055671
+realpath() {
+  [ -e "$1" ] && command realpath -- "$1"
 }
 
 usage() {
@@ -131,12 +112,10 @@ readonly files=("${files[@]:-.}")
 has_error=false
 
 for f in "${files[@]}"; do
-  if [ -e "$f" ]; then
-    portableReadLink "$f"
-  else
+  realpath "$f" || {
     redPrint "error: $f does not exists!" >&2
     has_error=true
-  fi
+  }
 done
 
 # set exit status

bin/cp-into-docker-run

@@ -36,32 +36,13 @@ isAbsolutePath() {
   [[ "$1" =~ ^/ ]]
 }
 
-# How can I get the behavior of GNU's readlink -f on a Mac?
-# https://stackoverflow.com/questions/1055671
-portableReadLink() {
-  local file=$1 uname
-
-  uname=$(uname)
-  case "$uname" in
-  Linux* | CYGWIN* | MINGW*)
-    readlink -f -- "$file"
-    ;;
-  Darwin*)
-    local py_args=(-c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file")
-    if command -v greadlink >/dev/null; then
-      greadlink -f -- "$file"
-    elif command -v python3 >/dev/null; then
-      python3 "${py_args[@]}"
-    elif command -v python >/dev/null; then
-      python "${py_args[@]}"
-    else
-      die "fail to find command(greadlink/python3/python) for readlink!"
-    fi
-    ;;
-  *)
-    die "NOT support uname($uname)!"
-    ;;
-  esac
+# `realpath` command existed on Linux and macOS, return resolved physical path
+#   - realpath command on macOS do NOT support option `-e`;
+#     combined `[ -e $file ]` to check file existence first.
+#   - How can I get the behavior of GNU's readlink -f on a Mac?
+#     https://stackoverflow.com/questions/1055671
+realpath() {
+  [ -e "$1" ] && command realpath -- "$1"
 }
 
 usage() {
@@ -204,7 +185,8 @@ if [ ! -f "$specified_run_command" ]; then
 
   run_command=$(which "$specified_run_command")
 fi
-run_command=$(portableReadLink "$run_command")
+
+run_command=$(realpath "$run_command")
 readonly run_command run_command_base_name=${run_command##*/}
 
 run_timestamp=$(date "+%Y%m%d_%H%M%S")

bin/xpf

@@ -14,43 +14,22 @@ set -eEuo pipefail
 # util functions
 ################################################################################
 
-# How can I get the behavior of GNU's readlink -f on a Mac?
-# https://stackoverflow.com/questions/1055671
-portableReadLink() {
-  local file=$1 uname
-
-  uname=$(uname)
-  case "$uname" in
-  Linux* | CYGWIN* | MINGW*)
-    readlink -f -- "$file"
-    ;;
-  Darwin*)
-    local py_args=(-c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$file")
-    if command -v greadlink >/dev/null; then
-      greadlink -f -- "$file"
-    elif command -v python3 >/dev/null; then
-      python3 "${py_args[@]}"
-    elif command -v python >/dev/null; then
-      python "${py_args[@]}"
-    else
-      echo "fail to find command(greadlink/python3/python) for readlink!" >&2
-      exit 1
-    fi
-    ;;
-  *)
-    echo "not support uname($uname)!" >&2
-    exit 1
-    ;;
-  esac
+# `realpath` command existed on Linux and macOS, return resolved physical path
+#   - realpath command on macOS do NOT support option `-e`;
+#     combined `[ -e $file ]` to check file existence first.
+#   - How can I get the behavior of GNU's readlink -f on a Mac?
+#     https://stackoverflow.com/questions/1055671
+realpath() {
+  [ -e "$1" ] && command realpath -- "$1"
 }
 
 ################################################################################
 # biz logic
 ################################################################################
 
 # DO NOT inline THIS_SCRIPT into BASE_DIR, because sub-shell:
-#   BASE_DIR=$(dirname -- "$(portableReadLink "${BASH_SOURCE[0]}")")
-THIS_SCRIPT=$(portableReadLink "${BASH_SOURCE[0]}")
+#   BASE_DIR=$(dirname -- "$(realpath "${BASH_SOURCE[0]}")")
+THIS_SCRIPT=$(realpath "${BASH_SOURCE[0]}")
 BASE_DIR=$(dirname -- "$THIS_SCRIPT")
 
 # shellcheck disable=SC1091

test-cases/integration-test.sh

@@ -1,12 +1,11 @@
 #!/usr/bin/env bash
 set -eEuo pipefail
 
-READLINK_CMD=readlink
-if command -v greadlink &>/dev/null; then
-  READLINK_CMD=greadlink
-fi
+realpath() {
+  [ -e "$1" ] && command realpath -- "$1"
+}
 
-cd "$(dirname -- "$($READLINK_CMD -f -- "${BASH_SOURCE[0]}")")"
+cd "$(dirname -- "$(realpath "${BASH_SOURCE[0]}")")"
 
 ################################################################################
 # common util functions

test-cases/lint.sh

@@ -1,8 +1,12 @@
 #!/usr/bin/env bash
 set -eEuo pipefail
 
+realpath() {
+  [ -e "$1" ] && command realpath -- "$1"
+}
+
 # cd to the root of the project
-cd "$(dirname -- "$(readlink -f -- "${BASH_SOURCE[0]}")")"/..
+cd "$(dirname -- "$(realpath "${BASH_SOURCE[0]}")")"/..
 
 find bin lib legacy-bin -type f |
   grep -Pv '/show-duplicate-java-classes$' |

test-cases/uq_test.sh

@@ -1,12 +1,11 @@
 #!/usr/bin/env bash
 set -eEuo pipefail
 
-READLINK_CMD=readlink
-if command -v greadlink &>/dev/null; then
-  READLINK_CMD=greadlink
-fi
+realpath() {
+  [ -e "$1" ] && command realpath -- "$1"
+}
 
-BASE=$(dirname -- "$($READLINK_CMD -f -- "${BASH_SOURCE[0]}")")
+BASE=$(dirname -- "$(realpath "${BASH_SOURCE[0]}")")
 cd "$BASE"
 
 #################################################