# Nick's web site: Workarounds for Nanoc's busted handling of broken symlinks.
#
# Copyright © 2020 Nick Bowler
#
# This program 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.
#
# This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.

# Monkey patch the filesystem data source to adjust some strange behavoiur.
class Nanoc::DataSources::Filesystem < Nanoc::DataSource
    # The filesystem mtime_of crashes on broken symlinks.  Let's not do that,
    # instead we'll fall back to the link mtime for broken links.
    def mtime_of(*args)
        mtimes = args.compact.map do |f|
            File.stat(f).mtime
        rescue Errno::ENOENT
            File.lstat(f).mtime
        end
        mtimes.max
    end

    module Tools
        @dummy_file = Tempfile.new('dummy')

        # The original resolve_symlink helper uses a readlink loop which
        # crashes on broken links.  I'm also fairly sure symlinks in path
        # components are not correctly resolved.  Let's just use realpath
        # instead and hope ruby itself doesn't have these bugs.
        def resolve_symlink(filename, recursion_limit = nil)
            File.realpath(filename)
        rescue Errno::ENOENT
            # Dead link.  Return a valid filename otherwise the filesystem
            # source does bizarre things.  The actual items are created with
            # the original filename so this dummy file does not appear to
            # leak outside of the filesystem data source implementation.
            @dummy_file.path
        end
        module_function :resolve_symlink
    end
end