From df9bbd7ab3be2ae44b598b25bd9d49bdf62cd809 Mon Sep 17 00:00:00 2001
From: Sam Stephenson <sam@37signals.com>
Date: Thu, 27 Dec 2012 17:08:54 -0600
Subject: [PATCH] Speed up rbenv-rehash with a simpler indexing approach

---
 libexec/rbenv-rehash | 58 ++++++++++----------------------------------
 1 file changed, 13 insertions(+), 45 deletions(-)

diff --git a/libexec/rbenv-rehash b/libexec/rbenv-rehash
index eebc4d3c..a1d79864 100755
--- a/libexec/rbenv-rehash
+++ b/libexec/rbenv-rehash
@@ -55,58 +55,27 @@ make_shims() {
   done
 }
 
-# Create an empty array for the list of registered shims.
+# Create an empty array for the list of registered shims and an empty
+# string to use as a search index.
 registered_shims=()
+registered_shims_index=""
 
 # We will keep track of shims registered for installation with the
-# global `reigstered_shims` array and with a global variable for each
-# shim. The array will let us iterate over all registered shims. The
-# global variables will let us quickly check whether a shim with the
-# given name has been registered or not.
+# global `reigstered_shims` array and with a global search index
+# string. The array will let us iterate over all registered shims. The
+# index string will let us quickly check whether a shim with the given
+# name has been registered or not.
 register_shim() {
   local shim="$@"
-  local var="$(shim_variable_name "$shim")"
-
-  if [ -z "${!var}" ]; then
-    registered_shims[${#registered_shims[*]}]="$shim"
-    eval "${var}=1"
-  fi
-}
-
-# To compute the global variable name for a given shim we must first
-# escape any non-alphanumeric characters. If the shim name is
-# alphanumeric (including a hyphen or underscore) we can take a
-# shorter path. Otherwise, we must iterate over each character and
-# escape the non-alphanumeric ones using `printf`.
-shim_variable_name() {
-  local shim="$1"
-  local result="_shim_"
-
-  if [[ ! "$shim" =~ [^[:alnum:]_-] ]]; then
-    shim="${shim//_/_5f}"
-    shim="${shim//-/_2d}"
-    result="$result$shim"
-  else
-    local length="${#shim}"
-    local char i
-
-    for ((i=0; i<length; i++)); do
-      char="${shim:$i:1}"
-      if [[ "$char" =~ [[:alnum:]] ]]; then
-        result="$result$char"
-      else
-        result="$result$(printf "_%02x" \'"$char")"
-      fi
-    done
-  fi
-
-  echo "$result"
+  registered_shims["${#registered_shims[@]}"]="$shim"
+  registered_shims_index="$registered_shims_index/$shim/"
 }
 
 # To install all the registered shims, we iterate over the
 # `registered_shims` array and create a link if one does not already
 # exist.
 install_registered_shims() {
+  local shim
   for shim in "${registered_shims[@]}"; do
     [ -e "$shim" ] || ln -f "$PROTOTYPE_SHIM_PATH" "$shim"
   done
@@ -117,11 +86,10 @@ install_registered_shims() {
 # in the directory but has not been registered as a shim should be
 # removed.
 remove_stale_shims() {
-  local var
+  local shim
   for shim in *; do
-    var="$(shim_variable_name "$shim")"
-    if [ -z "${!var}" ]; then
-      rm -f "$shim" 
+    if [[ "$registered_shims_index" != *"/$shim/"* ]]; then
+      rm -f "$shim"
     fi
   done
 }