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Previously, if the common ancestor of the two paths is / we would print the absolute second argument, but this PR asks for a relative path in that case as well, which makes sense for the libstdc++.modules.json use case. PR libstdc++/119081 contrib/ChangeLog: * relpath.sh: Give relative path even at /.
82 lines
1.5 KiB
Bash
Executable File
82 lines
1.5 KiB
Bash
Executable File
#!/bin/sh
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if [ "$1" = "--help" -o $# -ne 2 -o -f "$1" ]; then
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echo Usage: relpath.sh FROM TO
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echo Print the relative path from FROM to TO
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echo FROM must be a directory, but need not exist
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exit 0
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fi
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from="${1%%/}"
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to="${2%%/}"
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# The parent directory of a pathname, handling ..
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parent() {
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name=$(basename "$1")
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path=$(dirname "$1")
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top=$(basename "$path")
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if [ "$top" = ".." ]; then
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path=$(parent "$path")
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fi
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if [ "$name" = ".." ]; then
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path=$(parent "$path")
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fi
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echo $path
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}
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# Canonicalize a directory that contains '..'.
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canonicalize() {
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path=$1
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suffix=
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while ! [ -d "$path" ]; do
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name=$(basename "$path")
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path=$(parent "$path")
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suffix="/$name$suffix"
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done
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if [ -d "$path" ]; then
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echo $(cd "$path"; pwd)$suffix
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else
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echo $1
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fi
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}
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case "$to$from" in
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*..* )
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from=$(canonicalize "$from")
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to=$(canonicalize "$to")
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;;
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esac
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case "$to$from" in
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*..* )
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echo unable to canonicalize .. >&2
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exit 1
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;;
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esac
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back=
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while [ "${to#$from}" = "$to" ]; do
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#echo $from too long
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from=$(dirname $from);
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back=../$back
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if [ "$from" = / ] && [ "${to#/}" = "$to" ]; then
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echo no common ancestor between $1 and $2 >&2
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exit 1
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elif [ "$from" = . ]; then
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echo no common ancestor between $1 and $2 >&2
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exit 1
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fi
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done
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to=${to#$from}
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to=${to##/}
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back=${back%%/}
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if [ -n "$to" ] && [ -n "$back" ]; then
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echo $back/$to
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elif [ -n "$back$to" ]; then
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echo $back$to
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else
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echo .
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fi
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