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"""Starts a local HTTP server which displays layout test failures (given a test
results directory), provides comparisons of expected and actual results (both
images and text) and allows one-click rebaselining of tests."""
from __future__ import with_statement

import codecs
import datetime
import mimetypes
import os
import os.path
import shutil
import threading
import time
import urlparse
import BaseHTTPServer

from optparse import make_option
from wsgiref.handlers import format_date_time

from webkitpy.tool.multicommandtool import AbstractDeclarativeCommand


class RebaselineHTTPServer(BaseHTTPServer.HTTPServer):
    def __init__(self, httpd_port, results_directory):
        BaseHTTPServer.HTTPServer.__init__(self, ("", httpd_port), RebaselineHTTPRequestHandler)
        self.results_directory = results_directory


class RebaselineHTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
    STATIC_FILE_NAMES = frozenset([
        "index.html",
        "main.js",
        "main.css",
    ])

    STATIC_FILE_DIRECTORY = os.path.join(
        os.path.dirname(__file__), "data", "rebaselineserver")

    def do_GET(self):
        self._handle_request()

    def do_POST(self):
        self._handle_request()

    def _handle_request(self):
        # Parse input.
        if "?" in self.path:
            path, query_string = self.path.split("?", 1)
            self.query = urlparse.parse_qs(query_string)
        else:
            path = self.path
            self.query = {}
        function_or_file_name = path[1:] or "index.html"

        # See if a static file matches.
        if function_or_file_name in RebaselineHTTPRequestHandler.STATIC_FILE_NAMES:
            self._serve_static_file(function_or_file_name)
            return

        # See if a class method matches.
        function_name = function_or_file_name.replace(".", "_")
        if not hasattr(self, function_name):
            self.send_error(404, "Unknown function %s" % function_name)
            return
        if function_name[0] == "_":
            self.send_error(
                401, "Not allowed to invoke private or protected methods")
            return
        function = getattr(self, function_name)
        function()

    def _serve_static_file(self, static_path):
        self._serve_file(os.path.join(
            RebaselineHTTPRequestHandler.STATIC_FILE_DIRECTORY, static_path))

    def quitquitquit(self):
        self.send_response(200)
        self.send_header("Content-type", "text/plain")
        self.end_headers()
        self.wfile.write("Quit.\n")

        # Shutdown has to happen on another thread from the server's thread,
        # otherwise there's a deadlock
        threading.Thread(target=lambda: self.server.shutdown()).start()

    def _serve_file(self, file_path, cacheable_seconds=0):
        if not os.path.exists(file_path):
            self.send_error(404, "File not found")
            return
        with codecs.open(file_path, "rb") as static_file:
            self.send_response(200)
            self.send_header("Content-Length", os.path.getsize(file_path))
            mime_type, encoding = mimetypes.guess_type(file_path)
            if mime_type:
                self.send_header("Content-type", mime_type)

            if cacheable_seconds:
                expires_time = (datetime.datetime.now() +
                    datetime.timedelta(0, cacheable_seconds))
                expires_formatted = format_date_time(
                    time.mktime(expires_time.timetuple()))
                self.send_header("Expires", expires_formatted)
            self.end_headers()

            shutil.copyfileobj(static_file, self.wfile)


class RebaselineServer(AbstractDeclarativeCommand):
    name = "rebaseline-server"
    help_text = __doc__
    argument_names = "/path/to/results/directory"

    def __init__(self):
        options = [
            make_option("--httpd-port", action="store", type="int", default=8127, help="Port to use for the the rebaseline HTTP server"),
        ]
        AbstractDeclarativeCommand.__init__(self, options=options)

    def execute(self, options, args, tool):
        results_directory = args[0]

        print "Starting server at http://localhost:%d/" % options.httpd_port
        print ("Use the 'Exit' link in the UI, http://localhost:%d/"
            "quitquitquit or Ctrl-C to stop") % options.httpd_port

        httpd = RebaselineHTTPServer(
            httpd_port=options.httpd_port,
            results_directory=results_directory)
        httpd.serve_forever()