pyenv/libexec/rbenv-rehash
2011-12-24 15:16:37 -05:00

149 lines
4.1 KiB
Bash
Executable file

#!/usr/bin/env bash
set -e
[ -n "$RBENV_DEBUG" ] && set -x
SHIM_PATH="${RBENV_ROOT}/shims"
PROTOTYPE_SHIM_PATH="${SHIM_PATH}/.rbenv-shim"
# Create the shims directory if it doesn't already exist.
mkdir -p "$SHIM_PATH"
# Ensure only one instance of rbenv-rehash is running at a time by
# setting the shell's `noclobber` option and attempting to write to
# the prototype shim file. If the file already exists, print a warning
# to stderr and exit with a non-zero status.
set -o noclobber
{ echo > "$PROTOTYPE_SHIM_PATH"
} 2>/dev/null ||
{ echo "rbenv: cannot rehash: $PROTOTYPE_SHIM_PATH exists"
exit 1
} >&2
set +o noclobber
# If we were able to obtain a lock, register a trap to clean up the
# prototype shim when the process exits.
trap remove_prototype_shim SIGINT SIGTERM EXIT
remove_prototype_shim() {
rm -f "$PROTOTYPE_SHIM_PATH"
}
# The prototype shim file is a script that re-execs itself, passing
# its filename and any arguments to `rbenv exec`. This file is
# hard-linked for every binary and then removed. The linking technique
# is fast, uses less disk space than unique files, and also serves as
# a locking mechanism.
create_prototype_shim() {
cat > "$PROTOTYPE_SHIM_PATH" <<SH
#!/usr/bin/env bash
set -e
export RBENV_ROOT="$RBENV_ROOT"
exec rbenv exec "\${0##*/}" "\$@"
SH
chmod +x "$PROTOTYPE_SHIM_PATH"
}
# The basename of each argument passed to `make_shims` will be
# registered for installation as a shim. In this way, plugins may call
# `make_shims` with a glob to register many shims at once.
make_shims() {
local shims="$@"
for file in $shims; do
local shim="${file##*/}"
register_shim "$shim"
done
}
# Create an empty array for the list of registered shims.
registered_shims=()
# We will keep track of shims registered for installation with the
# global `reigstered_shims` array and with a global variable for each
# shim. The array will let us iterate over all registered shims. The
# global variables will let us quickly check whether a shim with the
# given name has been registered or not.
register_shim() {
local shim="$@"
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+="$shim"
else
local length="${#shim}"
local char i
for ((i=0; i<length; i++)); do
char="${shim:$i:1}"
if [[ "$char" =~ [[:alnum:]] ]]; then
result+="$char"
else
result+="$(printf "_%02x" \'"$char")"
fi
done
fi
echo "$result"
}
# To install all the registered shims, we iterate over the
# `registered_shims` array and create a link if one does not already
# exist.
install_registered_shims() {
for shim in "${registered_shims[@]}"; do
[ -e "$shim" ] || ln -f "$PROTOTYPE_SHIM_PATH" "$shim"
done
}
# Once the registered shims have been installed, we make a second pass
# over the contents of the shims directory. Any file that is present
# in the directory but has not been registered as a shim should be
# removed.
remove_stale_shims() {
local var
for shim in *; do
var="$(shim_variable_name "$shim")"
[ -z "${!var}" ] && rm -f "$shim"
done
}
# Save the working directory and change to the shims directory.
CUR_PATH=$PWD
cd "$SHIM_PATH"
# Create the prototype shim, then register shims for all known binaries.
create_prototype_shim
shopt -s nullglob
make_shims ../versions/*/bin/*
# Restore the previous working directory.
cd "$CUR_PATH"
# Allow plugins to register shims.
for script in $(rbenv-hooks rehash); do
source "$script"
done
# Change back to the shims directory to install the registered shims
# and remove stale shims.
cd "$SHIM_PATH"
install_registered_shims
remove_stale_shims