vgmstream/version-make.sh

#!/bin/sh

# make current git version (overwrites version_auto.h)
VERSION_EMPTY=$1
VERSION_FILE=$2
VERSION_NAME=$3
if [ -z "$VERSION_EMPTY" ]; then VERSION_EMPTY=false; fi
if [ -z "$VERSION_FILE" ]; then VERSION_FILE=version_auto.h; fi
if [ -z "$VERSION_NAME" ]; then VERSION_NAME=VGMSTREAM_VERSION; fi
VERSION_DEFAULT=unknown

# try get version from Git (dynamic), including lightweight tags
if ! command -v git > /dev/null ; then
    VERSION=""
else
    VERSION=$(git describe --tags --always 2>&1 | tr : _ )
    if case "$VERSION" in fatal*) true;; *) false;; esac; then
        VERSION=""
    fi
fi


if [ ! -z "$VERSION" ]; then
    LINE="#define $VERSION_NAME \"$VERSION\" /* autogenerated */"
else
    # try to get version from version.h (static)
    echo "Git version not found, can't autogenerate version (using default)"

    # option to output empty line instead of default version, so plugins can detect git-less builds
    if [ "$VERSION_EMPTY" = "true" ]; then 
        LINE="/* ignored */"
    else
        LINE="#define $VERSION_NAME \"$VERSION_DEFAULT\" /* autogenerated */"
        while IFS= read -r <&3 ITEM; do
            COMP="#define $VERSION_NAME"
            if case "$ITEM" in *"$COMP"*) true;; *) false;; esac; then
                LINE="$ITEM /* default */"
            fi
        done 3< "version.h"
    fi
fi


# avoid overwritting if contents are the same, as some systems rebuild on timestamp
LINE_ORIGINAL="none"
if test -f "version_auto.h"; then
    LINE_ORIGINAL=$(<version_auto.h)
fi
if [ ! "$LINE" = "$LINE_ORIGINAL" ]; then
    echo "$LINE" > "$VERSION_FILE"
fi