#!/usr/bin/env python
# Copyright (C) 2010 Google Inc. All rights reserved.
#
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# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
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# in the documentation and/or other materials provided with the
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

"""This is the Linux implementation of the port
   package. This file should only be imported by that package."""

import os
import signal
import subprocess
import sys
import logging

import chromium_win
import path_utils


def platform_name():
    """Returns the name of the platform we're currently running on."""
    return 'chromium-linux' + platform_version()


def platform_version():
    """Returns the version string for the platform, e.g. '-vista' or
    '-snowleopard'. If the platform does not distinguish between
    minor versions, it returns ''."""
    return ''


def get_num_cores():
    """Returns the number of cores on the machine. For hyperthreaded machines,
    this will be double the number of actual processors."""
    num_cores = os.sysconf("SC_NPROCESSORS_ONLN")
    if isinstance(num_cores, int) and num_cores > 0:
        return num_cores
    return 1


def baseline_path(platform=None):
    """Returns the path relative to the top of the source tree for the
    baselines for the specified platform version. If |platform| is None,
    then the version currently in use is used."""
    if platform is None:
        platform = platform_name()
    return path_utils.path_from_base('webkit', 'data', 'layout_tests',
                                     'platform', platform, 'LayoutTests')


def baseline_search_path(platform=None):
    """Returns the list of directories to search for baselines/results, in
    order of preference. Paths are relative to the top of the source tree."""
    return [baseline_path(platform),
            chromium_win.baseline_path('chromium-win'),
            path_utils.webkit_baseline_path('win'),
            path_utils.webkit_baseline_path('mac')]


def apache_executable_path():
    """Returns the executable path to start Apache"""
    path = os.path.join("/usr", "sbin", "apache2")
    if os.path.exists(path):
        return path
    print "Unable to fine Apache executable %s" % path
    _missing_apache()


def apache_config_file_path():
    """Returns the path to Apache config file"""
    return path_utils.path_from_base("third_party", "WebKit", "LayoutTests",
        "http", "conf", "apache2-debian-httpd.conf")


def lighttpd_executable_path():
    """Returns the executable path to start LigHTTPd"""
    binpath = "/usr/sbin/lighttpd"
    if os.path.exists(binpath):
        return binpath
    print "Unable to find LigHTTPd executable %s" % binpath
    _missing_lighttpd()


def lighttpd_module_path():
    """Returns the library module path for LigHTTPd"""
    modpath = "/usr/lib/lighttpd"
    if os.path.exists(modpath):
        return modpath
    print "Unable to find LigHTTPd modules %s" % modpath
    _missing_lighttpd()


def lighttpd_php_path():
    """Returns the PHP executable path for LigHTTPd"""
    binpath = "/usr/bin/php-cgi"
    if os.path.exists(binpath):
        return binpath
    print "Unable to find PHP CGI executable %s" % binpath
    _missing_lighttpd()


def wdiff_path():
    """Path to the WDiff executable, which we assume is already installed and
    in the user's $PATH."""
    return 'wdiff'


def image_diff_path(target):
    """Path to the image_diff binary.

    Args:
      target: Build target mode (debug or release)"""
    return _path_from_build_results(target, 'image_diff')


def layout_test_helper_path(target):
    """Path to the layout_test helper binary, if needed, empty otherwise"""
    return ''


def test_shell_path(target):
    """Return the platform-specific binary path for our TestShell.

    Args:
      target: Build target mode (debug or release) """
    if target in ('Debug', 'Release'):
        try:
            debug_path = _path_from_build_results('Debug', 'test_shell')
            release_path = _path_from_build_results('Release', 'test_shell')

            debug_mtime = os.stat(debug_path).st_mtime
            release_mtime = os.stat(release_path).st_mtime

            if debug_mtime > release_mtime and target == 'Release' or \
               release_mtime > debug_mtime and target == 'Debug':
                logging.info('\x1b[31mWarning: you are not running the most '
                             'recent test_shell binary. You need to pass '
                             '--debug or not to select between Debug and '
                             'Release.\x1b[0m')
        # This will fail if we don't have both a debug and release binary.
        # That's fine because, in this case, we must already be running the
        # most up-to-date one.
        except path_utils.PathNotFound:
            pass

    return _path_from_build_results(target, 'test_shell')


def fuzzy_match_path():
    """Return the path to the fuzzy matcher binary."""
    return path_utils.path_from_base('third_party', 'fuzzymatch', 'fuzzymatch')


def shut_down_http_server(server_pid):
    """Shut down the lighttpd web server. Blocks until it's fully shut down.

    Args:
      server_pid: The process ID of the running server.
    """
    # server_pid is not set when "http_server.py stop" is run manually.
    if server_pid is None:
        # This isn't ideal, since it could conflict with web server processes
        # not started by http_server.py, but good enough for now.
        kill_all_process('lighttpd')
        kill_all_process('apache2')
    else:
        try:
            os.kill(server_pid, signal.SIGTERM)
            #TODO(mmoss) Maybe throw in a SIGKILL just to be sure?
        except OSError:
            # Sometimes we get a bad PID (e.g. from a stale httpd.pid file),
            # so if kill fails on the given PID, just try to 'killall' web
            # servers.
            shut_down_http_server(None)


def kill_process(pid):
    """Forcefully kill the process.

    Args:
      pid: The id of the process to be killed.
    """
    os.kill(pid, signal.SIGKILL)


def kill_all_process(process_name):
    null = open(os.devnull)
    subprocess.call(['killall', '-TERM', '-u', os.getenv('USER'),
                    process_name], stderr=null)
    null.close()


def kill_all_test_shells():
    """Kills all instances of the test_shell binary currently running."""
    kill_all_process('test_shell')

#
# Private helper functions
#


def _missing_lighttpd():
    print 'Please install using: "sudo apt-get install lighttpd php5-cgi"'
    print 'For complete Linux build requirements, please see:'
    print 'http://code.google.com/p/chromium/wiki/LinuxBuildInstructions'
    sys.exit(1)


def _missing_apache():
    print ('Please install using: "sudo apt-get install apache2 '
        'libapache2-mod-php5"')
    print 'For complete Linux build requirements, please see:'
    print 'http://code.google.com/p/chromium/wiki/LinuxBuildInstructions'
    sys.exit(1)


def _path_from_build_results(*pathies):
    # FIXME(dkegel): use latest or warn if more than one found?
    for dir in ["sconsbuild", "out", "xcodebuild"]:
        try:
            return path_utils.path_from_base(dir, *pathies)
        except:
            pass
    raise path_utils.PathNotFound("Unable to find %s in build tree" %
        (os.path.join(*pathies)))