#!/bin/bash
#---------------------------------*- sh -*-------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | Copyright (C) 2010-2010 OpenCFD Ltd.
#    \\/     M anipulation  |
#------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM.
#
#     OpenFOAM is free software: you can redistribute it and/or modify it
#     under the terms of the GNU General Public License as published by
#     the Free Software Foundation, either version 3 of the License, or
#     (at your option) any later version.
#
#     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
#     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
#     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
#     for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
#
# Script
#     pre-commit-hook
#
# Description
#     pre-commit hook for git.
#     Copy or link this file as ".git/hooks/pre-commit"
#
#     Eg,
#     (
#         cd $WM_PROJECT_DIR/.git/hooks &&
#         ln -sf ../../bin/tools/pre-commit-hook pre-commit
#     )
#
#     Hook receives: empty
#
#     Checks for
#     - illegal code, e.g. <TAB>
#     - copyright is current, e.g. if present, contains XXX-<current-year>
#     - columns greater than 80 for *.[CH] files
#
# Note
#     Using "git commit --no-verify" it is possible to override the hook.
#
#     By supplying arguments to the hook, it can also be used to manually
#     test the specified files/directories for standards conformance.
#
#------------------------------------------------------------------------------
hookName="pre-commit"
die()
{
    echo '$hookName hook failure' 1>&2
    echo '-----------------------' 1>&2
    echo '' 1>&2
    echo "$@" 1>&2
    echo '' 1>&2
    exit 1
}

#-----------------------------------------------------------------------------
# Check content that will be added by this commit.

if git rev-parse --verify HEAD > /dev/null 2>&1
then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

# called manually with arguments for the files/directories to be tested?
if [ "$#" -gt 0 ]
then
    case "$1" in
    -h | -help)
        die "interactive usage: supply list of files/directories to check"
        ;;
    esac

    # obtain list of all specified files/directories
    fileList=$(git ls-files -- $@ 2>/dev/null)
else
    # list of all files to be committed
    fileList=$(git diff-index --cached --name-only $against --)
fi

#
# no files changed: can skip all the checks
# this usage can correspond to a 'git commit --amend'
#
[ -n "$fileList" ] || exit 0


unset badFiles
# join list of files with this amount of space
Indent="    "

#
# report bad files and die if there are any
#
dieOnBadFiles()
{
    if [ -n "$badFiles" ]
    then
        echo '$hookName hook failure' 1>&2
        echo '-----------------------' 1>&2
        echo "$@" 1>&2
        echo '' 1>&2
        echo "File(s):" 1>&2
        echo "$badFiles" 1>&2
        echo ''  1>&2
        exit 1
    fi
}


#
# qualify 'git grep' to check cached value or from a specific commit
#
gitScope()
{
    if [ "$#" -gt 0 ]
    then
        echo "$1:"
    else
        echo "--cached -- "
    fi
}


#
# check for bad strings, characters, etc
#
checkIllegalCode()
{
    echo "$hookName: check bad strings/characters etc ..." 1>&2

    reBad="(N""abla|"$'\t'")"
    msgBad="N""abla or <TAB>"

    scope=$(gitScope $@)

    badFiles=$(
    for f in $fileList
    do
        case "$f" in
        # exclude potential makefiles
        (wmake/[Mm]akefile* | wmake/rules/*)
        ;;
        (*)
            # parse line numbers from grep output:
            #        <lineNr>:   contents
            lines=$(git grep -E -hn -e "$reBad" $scope"$f" |
                sed -e 's@:.*@@' |
                tr '\n' ' '
            )
            [ -n "$lines" ] && echo "$Indent$f -- lines: $lines"
        ;;
        esac
    done
    )

    dieOnBadFiles "Remove/correct bad '$msgBad' references"
}


#
# check that OpenCFD copyright is current
#
checkCopyright()
{
    year=$(date +%Y)
    echo "$hookName: check copyright ..." 1>&2

    scope=$(gitScope $@)

    badFiles=$(
    for f in $fileList
    do
        # NB: need to have OpenCFD on a separate line to prevent
        #     this check being caught by itself!
        #
        # parse line numbers from grep output:
        #        <lineNr>:   contents
        #
        lines=$(git grep -F -hn -e Copyright \
            --and -e OpenCFD \
            --and --not -e "$year" \
            $scope"$f" |
            sed -e 's@:.*@@' |
            tr '\n' ' '
        )
        [ -n "$lines" ] && echo "$Indent$f -- lines: $lines"
    done
    )

    dieOnBadFiles "Update copyright year, e.g. XXXX-$year"
}


#
# limit line length to 80-columns
#
checkLineLength()
{
    echo "$hookName: check line lengths ..." 1>&2

    scope=$(gitScope $@)

    badFiles=$(
    for f in $fileList
    do
        # limit to *.[CH] files
        case "$f" in
        (*.[CH])
            # parse line numbers from grep output:
            #        <lineNr>:   contents
            lines=$(git grep -hn -e '^.\{81,\}' $scope"$f" |
                sed -e 's@:.*@@' |
                tr '\n' ' '
            )
            [ -n "$lines" ] && echo "$Indent$f -- lines: $lines"
        ;;
        esac
    done
    )

    dieOnBadFiles "Limit code to 80 columns before pushing"
}


#
# limit line length to 80-columns, except C++ comment lines
#
checkLineLengthNonComments()
{
    echo "$hookName: check line lengths ..." 1>&2

    scope=$(gitScope $@)

    badFiles=$(
    for f in $fileList
    do
        # limit to *.[CH] files
        case "$f" in
        (*.[CH])
            # parse line numbers from grep output:
            #        <lineNr>:   contents
            lines=$(git grep -hn -e '^.\{81,\}' \
                --and --not -e '^ *//' \
                $scope"$f" |
                sed -e 's@:.*@@' |
                tr '\n' ' '
            )
            [ -n "$lines" ] && echo "$Indent$f -- lines: $lines"
        ;;
        esac
    done
    )

    dieOnBadFiles "Limit code to 80 columns before pushing"
}


#
# limit line length to 80-columns, except #directive lines
#
checkLineLengthNonDirective()
{
    echo "$hookName: check line lengths ..." 1>&2

    scope=$(gitScope $@)

    badFiles=$(
    for f in $fileList
    do
        # limit to *.[CH] files
        case "$f" in
        (*.[CH])
            # parse line numbers from grep output:
            #        <lineNr>:   contents
            lines=$(git grep -hn -e '^.\{81,\}' \
                --and --not -e '^ *#' \
                $scope"$f" |
                sed -e 's@:.*@@' |
                tr '\n' ' '
            )
            [ -n "$lines" ] && echo "$Indent$f -- lines: $lines"
        ;;
        esac
    done
    )

    dieOnBadFiles "Limit code to 80 columns before pushing"
}


#------------------------------------------------------------------------------
# Main code : do all checks
#

# builtin whitespace check to avoid trailing space, including CR-LF endings
bad=$(git diff-index --cached --check $against --) || die "$bad"

# check for illegal code, e.g. <TAB>, etc
checkIllegalCode

# ensure OpenCFD copyright contains correct year
checkCopyright

# ensure code conforms to 80 columns max
checkLineLengthNonDirective


exit 0
#------------------------------------------------------------------------------