Introduce WPTServe for running W3C Blink Layout tests

Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/pipes.py

Index: Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/pipes.py
diff --git a/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/pipes.py b/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/pipes.py
new file mode 100644
index 0000000000000000000000000000000000000000..3f1f1e4554c86542effb1d9e16949407881d252c
--- /dev/null
+++ b/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/pipes.py
@@ -0,0 +1,447 @@
+from cgi import escape
+import gzip as gzip_module
+import re
+import time
+import types
+import uuid
+from cStringIO import StringIO
+
+
+def resolve_content(response):
+    rv = "".join(item for item in response.iter_content())
+    if type(rv) == unicode:
+        rv = rv.encode(response.encoding)
+    return rv
+
+
+class Pipeline(object):
+    pipes = {}
+
+    def __init__(self, pipe_string):
+        self.pipe_functions = self.parse(pipe_string)
+
+    def parse(self, pipe_string):
+        functions = []
+        for item in PipeTokenizer().tokenize(pipe_string):
+            if not item:
+                break
+            if item[0] == "function":
+                functions.append((self.pipes[item[1]], []))
+            elif item[0] == "argument":
+                functions[-1][1].append(item[1])
+        return functions
+
+    def __call__(self, request, response):
+        for func, args in self.pipe_functions:
+            response = func(request, response, *args)
+        return response
+
+
+class PipeTokenizer(object):
+    def __init__(self):
+        #This whole class can likely be replaced by some regexps
+        self.state = None
+
+    def tokenize(self, string):
+        self.string = string
+        self.state = self.func_name_state
+        self._index = 0
+        while self.state:
+            yield self.state()
+        yield None
+
+    def get_char(self):
+        if self._index >= len(self.string):
+            return None
+        rv = self.string[self._index]
+        self._index += 1
+        return rv
+
+    def func_name_state(self):
+        rv = ""
+        while True:
+            char = self.get_char()
+            if char is None:
+                self.state = None
+                if rv:
+                    return ("function", rv)
+                else:
+                    return None
+            elif char == "(":
+                self.state = self.argument_state
+                return ("function", rv)
+            elif char == "|":
+                if rv:
+                    return ("function", rv)
+            else:
+                rv += char
+
+    def argument_state(self):
+        rv = ""
+        while True:
+            char = self.get_char()
+            if char is None:
+                self.state = None
+                return ("argument", rv)
+            elif char == "\\":
+                rv += self.get_escape()
+                if rv is None:
+                    #This should perhaps be an error instead
+                    return ("argument", rv)
+            elif char == ",":
+                return ("argument", rv)
+            elif char == ")":
+                self.state = self.func_name_state
+                return ("argument", rv)
+            else:
+                rv += char
+
+    def get_escape(self):
+        char = self.get_char()
+        escapes = {"n": "\n",
+                   "r": "\r",
+                   "t": "\t"}
+        return escapes.get(char, char)
+
+
+class pipe(object):
+    def __init__(self, *arg_converters):
+        self.arg_converters = arg_converters
+        self.max_args = len(self.arg_converters)
+        self.min_args = 0
+        opt_seen = False
+        for item in self.arg_converters:
+            if not opt_seen:
+                if isinstance(item, opt):
+                    opt_seen = True
+                else:
+                    self.min_args += 1
+            else:
+                if not isinstance(item, opt):
+                    raise ValueError("Non-optional argument cannot follow optional argument")
+
+    def __call__(self, f):
+        def inner(request, response, *args):
+            if not (self.min_args <= len(args) <= self.max_args):
+                raise ValueError("Expected between %d and %d args, got %d" %
+                                 (self.min_args, self.max_args, len(args)))
+            arg_values = tuple(f(x) for f, x in zip(self.arg_converters, args))
+            return f(request, response, *arg_values)
+        Pipeline.pipes[f.__name__] = inner
+        #We actually want the undecorated function in the main namespace
+        return f
+
+
+class opt(object):
+    def __init__(self, f):
+        self.f = f
+
+    def __call__(self, arg):
+        return self.f(arg)
+
+
+def nullable(func):
+    def inner(arg):
+        if arg.lower() == "null":
+            return None
+        else:
+            return func(arg)
+    return inner
+
+
+def boolean(arg):
+    if arg.lower() in ("true", "1"):
+        return True
+    elif arg.lower() in ("false", "0"):
+        return False
+    raise ValueError
+
+
+@pipe(int)
+def status(request, response, code):
+    """Alter the status code.
+
+    :param code: Status code to use for the response."""
+    response.status = code
+    return response
+
+
+@pipe(str, str, opt(boolean))
+def header(request, response, name, value, append=False):
+    """Set a HTTP header.
+
+    Replaces any existing HTTP header of the same name unless
+    append is set, in which case the header is appended without
+    replacement.
+
+    :param name: Name of the header to set.
+    :param value: Value to use for the header.
+    :param append: True if existing headers should not be replaced
+    """
+    if not append:
+        response.headers.set(name, value)
+    else:
+        response.headers.append(name, value)
+    return response
+
+
+@pipe(str)
+def trickle(request, response, delays):
+    """Send the response in parts, with time delays.
+
+    :param delays: A string of delays and amounts, in bytes, of the
+                   response to send. Each component is separated by
+                   a colon. Amounts in bytes are plain integers, whilst
+                   delays are floats prefixed with a single d e.g.
+                   d1:100:d2
+                   Would cause a 1 second delay, would then send 100 bytes
+                   of the file, and then cause a 2 second delay, before sending
+                   the remainder of the file.
+
+                   If the last token is of the form rN, instead of sending the
+                   remainder of the file, the previous N instructions will be
+                   repeated until the whole file has been sent e.g.
+                   d1:100:d2:r2
+                   Causes a delay of 1s, then 100 bytes to be sent, then a 2s delay
+                   and then a further 100 bytes followed by a two second delay
+                   until the response has been fully sent.
+                   """
+    def parse_delays():
+        parts = delays.split(":")
+        rv = []
+        for item in parts:
+            if item.startswith("d"):
+                item_type = "delay"
+                item = item[1:]
+                value = float(item)
+            elif item.startswith("r"):
+                item_type = "repeat"
+                value = int(item[1:])
+                if not value % 2 == 0:
+                    raise ValueError
+            else:
+                item_type = "bytes"
+                value = int(item)
+            if len(rv) and rv[-1][0] == item_type:
+                rv[-1][1] += value
+            else:
+                rv.append((item_type, value))
+        return rv
+
+    delays = parse_delays()
+    if not delays:
+        return response
+    content = resolve_content(response)
+    modified_content = []
+    offset = [0]
+
+    def sleep(seconds):
+        def inner():
+            time.sleep(seconds)
+            return ""
+        return inner
+
+    def add_content(delays, repeat=False):
+        for i, (item_type, value) in enumerate(delays):
+            if item_type == "bytes":
+                modified_content.append(content[offset[0]:offset[0] + value])
+                offset[0] += value
+            elif item_type == "delay":
+                modified_content.append(sleep(value))
+            elif item_type == "repeat":
+                assert i == len(delays) - 1
+                while offset[0] < len(content):
+                    add_content(delays[-(value + 1):-1], True)
+
+        if not repeat and offset[0] < len(content):
+            modified_content.append(content[offset[0]:])
+
+    add_content(delays)
+
+    response.content = modified_content
+    return response
+
+
+@pipe(nullable(int), opt(nullable(int)))
+def slice(request, response, start, end=None):
+    """Send a byte range of the response body
+
+    :param start: The starting offset. Follows python semantics including
+                  negative numbers.
+
+    :param end: The ending offset, again with python semantics and None
+                (spelled "null" in a query string) to indicate the end of
+                the file.
+    """
+    content = resolve_content(response)
+    response.content = content[start:end]
+    return response
+
+
+class ReplacementTokenizer(object):
+    def ident(scanner, token):
+        return ("ident", token)
+
+    def index(scanner, token):
+        token = token[1:-1]
+        try:
+            token = int(token)
+        except ValueError:
+            token = unicode(token, "utf8")
+        return ("index", token)
+
+    def var(scanner, token):
+        token = token[:-1]
+        return ("var", token)
+
+    def tokenize(self, string):
+        return self.scanner.scan(string)[0]
+
+    scanner = re.Scanner([(r"\$\w+:", var),
+                          (r"\$?\w+(?:\(\))?", ident),
+                          (r"\[[^\]]*\]", index)])
+
+
+class FirstWrapper(object):
+    def __init__(self, params):
+        self.params = params
+
+    def __getitem__(self, key):
+        try:
+            return self.params.first(key)
+        except KeyError:
+            return ""
+
+
+@pipe()
+def sub(request, response):
+    """Substitute environment information about the server and request into the script.
+
+    The format is a very limited template language. Substitutions are
+    enclosed by {{ and }}. There are several avaliable substitutions:
+
+    host
+      A simple string value and represents the primary host from which the
+      tests are being run.
+    domains
+      A dictionary of available domains indexed by subdomain name.
+    ports
+      A dictionary of lists of ports indexed by protocol.
+    location
+      A dictionary of parts of the request URL. Valid keys are
+      'server, 'scheme', 'host', 'hostname', 'port', 'path' and 'query'.
+      'server' is scheme://host:port, 'host' is hostname:port, and query
+       includes the leading '?', but other delimiters are omitted.
+    headers
+      A dictionary of HTTP headers in the request.
+    GET
+      A dictionary of query parameters supplied with the request.
+    uuid()
+      A pesudo-random UUID suitable for usage with stash
+
+    So for example in a setup running on localhost with a www
+    subdomain and a http server on ports 80 and 81::
+
+      {{host}} => localhost
+      {{domains[www]}} => www.localhost
+      {{ports[http][1]}} => 81
+
+
+    It is also possible to assign a value to a variable name, which must start with
+    the $ character, using the ":" syntax e.g.
+
+    {{$id:uuid()}
+
+    Later substitutions in the same file may then refer to the variable
+    by name e.g.
+
+    {{$id}}
+    """
+    content = resolve_content(response)
+
+    new_content = template(request, content)
+
+    response.content = new_content
+    return response
+
+def template(request, content):
+    #TODO: There basically isn't any error handling here
+    tokenizer = ReplacementTokenizer()
+
+    variables = {}
+
+    def config_replacement(match):
+        content, = match.groups()
+
+        tokens = tokenizer.tokenize(content)
+
+        if tokens[0][0] == "var":
+            variable = tokens[0][1]
+            tokens = tokens[1:]
+        else:
+            variable = None
+
+        assert tokens[0][0] == "ident" and all(item[0] == "index" for item in tokens[1:]), tokens
+
+        field = tokens[0][1]
+
+        if field in variables:
+            value = variables[field]
+        elif field == "headers":
+            value = request.headers
+        elif field == "GET":
+            value = FirstWrapper(request.GET)
+        elif field in request.server.config:
+            value = request.server.config[tokens[0][1]]
+        elif field == "location":
+            value = {"server": "%s://%s:%s" % (request.url_parts.scheme,
+                                               request.url_parts.hostname,
+                                               request.url_parts.port),
+                     "scheme": request.url_parts.scheme,
+                     "host": "%s:%s" % (request.url_parts.hostname,
+                                        request.url_parts.port),
+                     "hostname": request.url_parts.hostname,
+                     "port": request.url_parts.port,
+                     "path": request.url_parts.path,
+                     "query": "?%s" % request.url_parts.query}
+        elif field == "uuid()":
+            value = str(uuid.uuid4())
+        else:
+            raise Exception("Undefined template variable %s" % field)
+
+        for item in tokens[1:]:
+            value = value[item[1]]
+
+        assert isinstance(value, (int,) + types.StringTypes), tokens
+
+        if variable is not None:
+            variables[variable] = value
+
+        #Should possibly support escaping for other contexts e.g. script
+        #TODO: read the encoding of the response
+        return escape(unicode(value)).encode("utf-8")
+
+    template_regexp = re.compile(r"{{([^}]*)}}")
+    new_content, count = template_regexp.subn(config_replacement, content)
+
+    return new_content
+
+@pipe()
+def gzip(request, response):
+    """This pipe gzip-encodes response data.
+
+    It sets (or overwrites) these HTTP headers:
+    Content-Encoding is set to gzip
+    Content-Length is set to the length of the compressed content
+    """
+    content = resolve_content(response)
+    response.headers.set("Content-Encoding", "gzip")
+
+    out = StringIO()
+    with gzip_module.GzipFile(fileobj=out, mode="w") as f:
+        f.write(content)
+    response.content = out.getvalue()
+
+    response.headers.set("Content-Length", len(response.content))
+
+    return response