#!/usr/bin/env python
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"""This module is used to find all of the layout test files used by
run-webkit-tests. It exposes one public function - find() -
which takes an optional list of paths. If a list is passed in, the returned
list of test files is constrained to those found under the paths passed in,
i.e. calling find(["LayoutTests/fast"]) will only return files
under that directory."""

import time

from webkitpy.common.system import logutils


_log = logutils.get_logger(__file__)


# When collecting test cases, we include any file with these extensions.
_supported_file_extensions = set(['.html', '.shtml', '.xml', '.xhtml', '.xhtmlmp', '.pl',
                                  '.php', '.svg'])
# When collecting test cases, skip these directories
_skipped_directories = set(['.svn', '_svn', 'resources', 'script-tests'])


def find(port, paths=None):
    """Finds the set of tests under a given list of sub-paths.

    Args:
      paths: a list of path expressions relative to port.layout_tests_dir()
          to search. Glob patterns are ok, as are path expressions with
          forward slashes on Windows. If paths is empty, we look at
          everything under the layout_tests_dir().
    """
    paths = paths or ['*']
    filesystem = port._filesystem
    return normalized_find(filesystem, normalize(filesystem, port.layout_tests_dir(), paths))


def normalize(filesystem, base_dir, paths):
    return [filesystem.normpath(filesystem.join(base_dir, path)) for path in paths]


def normalized_find(filesystem, paths):
    """Finds the set of tests under the list of paths.

    Args:
      paths: a list of absolute path expressions to search.
          Glob patterns are ok.
    """
    gather_start_time = time.time()
    paths_to_walk = set()

    for path in paths:
        # If there's an * in the name, assume it's a glob pattern.
        if path.find('*') > -1:
            filenames = filesystem.glob(path)
            paths_to_walk.update(filenames)
        else:
            paths_to_walk.add(path)

    # FIXME: I'm not sure there's much point in this being a set. A list would
    # probably be faster.
    test_files = set()
    for path in paths_to_walk:
        files = filesystem.files_under(path, _skipped_directories, _is_test_file)
        test_files.update(set(files))

    gather_time = time.time() - gather_start_time
    _log.debug("Test gathering took %f seconds" % gather_time)

    return test_files


def _has_supported_extension(filesystem, filename):
    """Return true if filename is one of the file extensions we want to run a
    test on."""
    extension = filesystem.splitext(filename)[1]
    return extension in _supported_file_extensions


def _is_reference_html_file(filename):
    """Return true if the filename points to a reference HTML file."""
    if (filename.endswith('-expected.html') or
        filename.endswith('-expected-mismatch.html')):
        _log.warn("Reftests are not supported - ignoring %s" % filename)
        return True
    return False


def _is_test_file(filesystem, dirname, filename):
    """Return true if the filename points to a test file."""
    return (_has_supported_extension(filesystem, filename) and
            not _is_reference_html_file(filename))