mirror of
https://github.com/pyenv/pyenv.git
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150 lines
4.1 KiB
Bash
Executable file
150 lines
4.1 KiB
Bash
Executable file
#!/usr/bin/env bash
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set -e
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[ -n "$PYENV_DEBUG" ] && set -x
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SHIM_PATH="${PYENV_ROOT}/shims"
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PROTOTYPE_SHIM_PATH="${SHIM_PATH}/.pyenv-shim"
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# Create the shims directory if it doesn't already exist.
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mkdir -p "$SHIM_PATH"
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# Ensure only one instance of pyenv-rehash is running at a time by
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# setting the shell's `noclobber` option and attempting to write to
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# the prototype shim file. If the file already exists, print a warning
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# to stderr and exit with a non-zero status.
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set -o noclobber
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{ echo > "$PROTOTYPE_SHIM_PATH"
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} 2>/dev/null ||
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{ echo "pyenv: cannot rehash: $PROTOTYPE_SHIM_PATH exists"
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exit 1
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} >&2
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set +o noclobber
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# If we were able to obtain a lock, register a trap to clean up the
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# prototype shim when the process exits.
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trap remove_prototype_shim EXIT
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remove_prototype_shim() {
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rm -f "$PROTOTYPE_SHIM_PATH"
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}
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# The prototype shim file is a script that re-execs itself, passing
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# its filename and any arguments to `pyenv exec`. This file is
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# hard-linked for every binary and then removed. The linking technique
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# is fast, uses less disk space than unique files, and also serves as
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# a locking mechanism.
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create_prototype_shim() {
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cat > "$PROTOTYPE_SHIM_PATH" <<SH
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#!/usr/bin/env bash
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set -e
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export PYENV_ROOT="$PYENV_ROOT"
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exec pyenv exec "\${0##*/}" "\$@"
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SH
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chmod +x "$PROTOTYPE_SHIM_PATH"
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}
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# The basename of each argument passed to `make_shims` will be
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# registered for installation as a shim. In this way, plugins may call
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# `make_shims` with a glob to register many shims at once.
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make_shims() {
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local shims="$@"
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for file in $shims; do
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local shim="${file##*/}"
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register_shim "$shim"
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done
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}
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# Create an empty array for the list of registered shims.
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registered_shims=()
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# We will keep track of shims registered for installation with the
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# global `reigstered_shims` array and with a global variable for each
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# shim. The array will let us iterate over all registered shims. The
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# global variables will let us quickly check whether a shim with the
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# given name has been registered or not.
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register_shim() {
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local shim="$@"
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local var="$(shim_variable_name "$shim")"
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if [ -z "${!var}" ]; then
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registered_shims[${#registered_shims[*]}]="$shim"
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eval "${var}=1"
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fi
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}
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# To compute the global variable name for a given shim we must first
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# escape any non-alphanumeric characters. If the shim name is
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# alphanumeric (including a hyphen or underscore) we can take a
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# shorter path. Otherwise, we must iterate over each character and
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# escape the non-alphanumeric ones using `printf`.
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shim_variable_name() {
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local shim="$1"
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local result="_shim_"
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if [[ ! "$shim" =~ [^[:alnum:]_-] ]]; then
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shim="${shim//_/_5f}"
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shim="${shim//-/_2d}"
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result="$result$shim"
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else
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local length="${#shim}"
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local char i
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for ((i=0; i<length; i++)); do
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char="${shim:$i:1}"
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if [[ "$char" =~ [[:alnum:]] ]]; then
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result="$result$char"
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else
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result="$result$(printf "_%02x" \'"$char")"
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fi
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done
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fi
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echo "$result"
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}
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# To install all the registered shims, we iterate over the
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# `registered_shims` array and create a link if one does not already
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# exist.
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install_registered_shims() {
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for shim in "${registered_shims[@]}"; do
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[ -e "$shim" ] || ln -f "$PROTOTYPE_SHIM_PATH" "$shim"
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done
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}
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# Once the registered shims have been installed, we make a second pass
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# over the contents of the shims directory. Any file that is present
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# in the directory but has not been registered as a shim should be
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# removed.
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remove_stale_shims() {
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local var
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for shim in *; do
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var="$(shim_variable_name "$shim")"
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if [ -z "${!var}" ]; then
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rm -f "$shim"
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fi
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done
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}
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# Change to the shims directory.
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cd "$SHIM_PATH"
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# Create the prototype shim, then register shims for all known binaries.
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create_prototype_shim
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shopt -s nullglob
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make_shims ../versions/*/bin/*
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# Restore the previous working directory.
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cd "$OLDPWD"
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# Allow plugins to register shims.
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for script in $(pyenv-hooks rehash); do
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source "$script"
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done
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# Change back to the shims directory to install the registered shims
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# and remove stale shims.
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cd "$SHIM_PATH"
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install_registered_shims
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remove_stale_shims
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