Get rid of forking to basename and dirname on the hot path

Author: reegnz

bin/terraform

@@ -17,16 +17,16 @@ if [ -z "${TFENV_ROOT:-""}" ]; then
     local file_name;
 
     while [ "${target_file}" != "" ]; do
-      cd "$(dirname ${target_file})" || early_death "Failed to 'cd \$(dirname ${target_file})' while trying to determine TFENV_ROOT";
-      file_name="$(basename "${target_file}")" || early_death "Failed to 'basename \"${target_file}\"' while trying to determine TFENV_ROOT";
+      cd "${target_file%/*}" || early_death "Failed to 'cd \$(${target_file%/*})' while trying to determine TFENV_ROOT";
+      file_name="${target_file##*/}" || early_death "Failed to '\"${target_file##*/}\"' while trying to determine TFENV_ROOT";
       target_file="$(readlink "${file_name}")";
     done;
 
     echo "$(pwd -P)/${file_name}";
   };
-
-  TFENV_ROOT="$(cd "$(dirname "$(readlink_f "${0}")")/.." && pwd)";
-  [ -n ${TFENV_ROOT} ] || early_death "Failed to 'cd \"\$(dirname \"\$(readlink_f \"${0}\")\")/..\" && pwd' while trying to determine TFENV_ROOT";
+  TFENV_SHIM=$(readlink_f "${0}")
+  TFENV_ROOT="${TFENV_SHIM%/*/*}";
+  [ -n "${TFENV_ROOT}" ] || early_death "Failed to determine TFENV_ROOT"
 else
   TFENV_ROOT="${TFENV_ROOT%/}";
 fi;

bin/tfenv

@@ -17,16 +17,17 @@ if [ -z "${TFENV_ROOT:-""}" ]; then
     local file_name;
 
     while [ "${target_file}" != "" ]; do
-      cd "$(dirname ${target_file})" || early_death "Failed to 'cd \$(dirname ${target_file})' while trying to determine TFENV_ROOT";
-      file_name="$(basename "${target_file}")" || early_death "Failed to 'basename \"${target_file}\"' while trying to determine TFENV_ROOT";
+      cd "${target_file%/*}" || early_death "Failed to 'cd \$(${target_file%/*})' while trying to determine TFENV_ROOT";
+      file_name="${target_file##*/}" || early_death "Failed to '\"${target_file##*/}\"' while trying to determine TFENV_ROOT";
       target_file="$(readlink "${file_name}")";
     done;
 
     echo "$(pwd -P)/${file_name}";
   };
+  TFENV_SHIM=$(readlink_f "${0}")
+  TFENV_ROOT="${TFENV_SHIM%/*/*}";
+  [ -n "${TFENV_ROOT}" ] || early_death "Failed to determine TFENV_ROOT"
 
-  TFENV_ROOT="$(cd "$(dirname "$(readlink_f "${0}")")/.." && pwd)";
-  [ -n ${TFENV_ROOT} ] || early_death "Failed to 'cd \"\$(dirname \"\$(readlink_f \"${0}\")\")/..\" && pwd' while trying to determine TFENV_ROOT";
 else
   TFENV_ROOT="${TFENV_ROOT%/}";
 fi;

lib/helpers.sh

@@ -9,16 +9,16 @@ if [ -z "${TFENV_ROOT:-""}" ]; then
     local file_name;
 
     while [ "${target_file}" != "" ]; do
-      cd "$(dirname ${target_file})" || early_death "Failed to 'cd \$(dirname ${target_file})' while trying to determine TFENV_ROOT";
-      file_name="$(basename "${target_file}")" || early_death "Failed to 'basename \"${target_file}\"' while trying to determine TFENV_ROOT";
+      cd "${target_file%/*}" || early_death "Failed to 'cd \$(${target_file%/*})' while trying to determine TFENV_ROOT";
+      file_name="${target_file##*/}" || early_death "Failed to '\"${target_file##*/}\"' while trying to determine TFENV_ROOT";
       target_file="$(readlink "${file_name}")";
     done;
 
     echo "$(pwd -P)/${file_name}";
   };
-
-  TFENV_ROOT="$(cd "$(dirname "$(readlink_f "${0}")")/.." && pwd)";
-  [ -n ${TFENV_ROOT} ] || early_death "Failed to 'cd \"\$(dirname \"\$(readlink_f \"${0}\")\")/..\" && pwd' while trying to determine TFENV_ROOT";
+  TFENV_SHIM=$(readlink_f "${0}")
+  TFENV_ROOT="${TFENV_SHIM%/*/*}";
+  [ -n "${TFENV_ROOT}" ] || early_death "Failed to determine TFENV_ROOT"
 else
   TFENV_ROOT="${TFENV_ROOT%/}";
 fi;