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# -*- coding: utf-8 -*-
"""
jinja2.compiler
~~~~~~~~~~~~~~~
Compiles nodes into python code.
:copyright: (c) 2017 by the Jinja Team.
:license: BSD, see LICENSE for more details.
"""
from itertools import chain
from copy import deepcopy
from keyword import iskeyword as is_python_keyword
from functools import update_wrapper
from jinja2 import nodes
from jinja2.nodes import EvalContext
from jinja2.visitor import NodeVisitor
from jinja2.optimizer import Optimizer
from jinja2.exceptions import TemplateAssertionError
from jinja2.utils import Markup, concat, escape
from jinja2._compat import range_type, text_type, string_types, \
iteritems, NativeStringIO, imap, izip
from jinja2.idtracking import Symbols, VAR_LOAD_PARAMETER, \
VAR_LOAD_RESOLVE, VAR_LOAD_ALIAS, VAR_LOAD_UNDEFINED
operators = {
'eq': '==',
'ne': '!=',
'gt': '>',
'gteq': '>=',
'lt': '<',
'lteq': '<=',
'in': 'in',
'notin': 'not in'
}
# what method to iterate over items do we want to use for dict iteration
# in generated code? on 2.x let's go with iteritems, on 3.x with items
if hasattr(dict, 'iteritems'):
dict_item_iter = 'iteritems'
else:
dict_item_iter = 'items'
code_features = ['division']
# does this python version support generator stops? (PEP 0479)
try:
exec('from __future__ import generator_stop')
code_features.append('generator_stop')
except SyntaxError:
pass
# does this python version support yield from?
try:
exec('def f(): yield from x()')
except SyntaxError:
supports_yield_from = False
else:
supports_yield_from = True
def optimizeconst(f):
def new_func(self, node, frame, **kwargs):
# Only optimize if the frame is not volatile
if self.optimized and not frame.eval_ctx.volatile:
new_node = self.optimizer.visit(node, frame.eval_ctx)
if new_node != node:
return self.visit(new_node, frame)
return f(self, node, frame, **kwargs)
return update_wrapper(new_func, f)
def generate(node, environment, name, filename, stream=None,
defer_init=False, optimized=True):
"""Generate the python source for a node tree."""
if not isinstance(node, nodes.Template):
raise TypeError('Can\'t compile non template nodes')
generator = environment.code_generator_class(environment, name, filename,
stream, defer_init,
optimized)
generator.visit(node)
if stream is None:
return generator.stream.getvalue()
def has_safe_repr(value):
"""Does the node have a safe representation?"""
if value is None or value is NotImplemented or value is Ellipsis:
return True
if type(value) in (bool, int, float, complex, range_type, Markup) + string_types:
return True
if type(value) in (tuple, list, set, frozenset):
for item in value:
if not has_safe_repr(item):
return False
return True
elif type(value) is dict:
for key, value in iteritems(value):
if not has_safe_repr(key):
return False
if not has_safe_repr(value):
return False
return True
return False
def find_undeclared(nodes, names):
"""Check if the names passed are accessed undeclared. The return value
is a set of all the undeclared names from the sequence of names found.
"""
visitor = UndeclaredNameVisitor(names)
try:
for node in nodes:
visitor.visit(node)
except VisitorExit:
pass
return visitor.undeclared
class MacroRef(object):
def __init__(self, node):
self.node = node
self.accesses_caller = False
self.accesses_kwargs = False
self.accesses_varargs = False
class Frame(object):
"""Holds compile time information for us."""
def __init__(self, eval_ctx, parent=None, level=None):
self.eval_ctx = eval_ctx
self.symbols = Symbols(parent and parent.symbols or None,
level=level)
# a toplevel frame is the root + soft frames such as if conditions.
self.toplevel = False
# the root frame is basically just the outermost frame, so no if
# conditions. This information is used to optimize inheritance
# situations.
self.rootlevel = False
# in some dynamic inheritance situations the compiler needs to add
# write tests around output statements.
self.require_output_check = parent and parent.require_output_check
# inside some tags we are using a buffer rather than yield statements.
# this for example affects {% filter %} or {% macro %}. If a frame
# is buffered this variable points to the name of the list used as
# buffer.
self.buffer = None
# the name of the block we're in, otherwise None.
self.block = parent and parent.block or None
# the parent of this frame
self.parent = parent
if parent is not None:
self.buffer = parent.buffer
def copy(self):
"""Create a copy of the current one."""
rv = object.__new__(self.__class__)
rv.__dict__.update(self.__dict__)
rv.symbols = self.symbols.copy()
return rv
def inner(self, isolated=False):
"""Return an inner frame."""
if isolated:
return Frame(self.eval_ctx, level=self.symbols.level + 1)
return Frame(self.eval_ctx, self)
def soft(self):
"""Return a soft frame. A soft frame may not be modified as
standalone thing as it shares the resources with the frame it
was created of, but it's not a rootlevel frame any longer.
This is only used to implement if-statements.
"""
rv = self.copy()
rv.rootlevel = False
return rv
__copy__ = copy
class VisitorExit(RuntimeError):
"""Exception used by the `UndeclaredNameVisitor` to signal a stop."""
class DependencyFinderVisitor(NodeVisitor):
"""A visitor that collects filter and test calls."""
def __init__(self):
self.filters = set()
self.tests = set()
def visit_Filter(self, node):
self.generic_visit(node)
self.filters.add(node.name)
def visit_Test(self, node):
self.generic_visit(node)
self.tests.add(node.name)
def visit_Block(self, node):
"""Stop visiting at blocks."""
class UndeclaredNameVisitor(NodeVisitor):
"""A visitor that checks if a name is accessed without being
declared. This is different from the frame visitor as it will
not stop at closure frames.
"""
def __init__(self, names):
self.names = set(names)
self.undeclared = set()
def visit_Name(self, node):
if node.ctx == 'load' and node.name in self.names:
self.undeclared.add(node.name)
if self.undeclared == self.names:
raise VisitorExit()
else:
self.names.discard(node.name)
def visit_Block(self, node):
"""Stop visiting a blocks."""
class CompilerExit(Exception):
"""Raised if the compiler encountered a situation where it just
doesn't make sense to further process the code. Any block that
raises such an exception is not further processed.
"""
class CodeGenerator(NodeVisitor):
def __init__(self, environment, name, filename, stream=None,
defer_init=False, optimized=True):
if stream is None:
stream = NativeStringIO()
self.environment = environment
self.name = name
self.filename = filename
self.stream = stream
self.created_block_context = False
self.defer_init = defer_init
self.optimized = optimized
if optimized:
self.optimizer = Optimizer(environment)
# aliases for imports
self.import_aliases = {}
# a registry for all blocks. Because blocks are moved out
# into the global python scope they are registered here
self.blocks = {}
# the number of extends statements so far
self.extends_so_far = 0
# some templates have a rootlevel extends. In this case we
# can safely assume that we're a child template and do some
# more optimizations.
self.has_known_extends = False
# the current line number
self.code_lineno = 1
# registry of all filters and tests (global, not block local)
self.tests = {}
self.filters = {}
# the debug information
self.debug_info = []
self._write_debug_info = None
# the number of new lines before the next write()
self._new_lines = 0
# the line number of the last written statement
self._last_line = 0
# true if nothing was written so far.
self._first_write = True
# used by the `temporary_identifier` method to get new
# unique, temporary identifier
self._last_identifier = 0
# the current indentation
self._indentation = 0
# Tracks toplevel assignments
self._assign_stack = []
# Tracks parameter definition blocks
self._param_def_block = []
# Tracks the current context.
self._context_reference_stack = ['context']
# -- Various compilation helpers
def fail(self, msg, lineno):
"""Fail with a :exc:`TemplateAssertionError`."""
raise TemplateAssertionError(msg, lineno, self.name, self.filename)
def temporary_identifier(self):
"""Get a new unique identifier."""
self._last_identifier += 1
return 't_%d' % self._last_identifier
def buffer(self, frame):
"""Enable buffering for the frame from that point onwards."""
frame.buffer = self.temporary_identifier()
self.writeline('%s = []' % frame.buffer)
def return_buffer_contents(self, frame, force_unescaped=False):
"""Return the buffer contents of the frame."""
if not force_unescaped:
if frame.eval_ctx.volatile:
self.writeline('if context.eval_ctx.autoescape:')
self.indent()
self.writeline('return Markup(concat(%s))' % frame.buffer)
self.outdent()
self.writeline('else:')
self.indent()
self.writeline('return concat(%s)' % frame.buffer)
self.outdent()
return
elif frame.eval_ctx.autoescape:
self.writeline('return Markup(concat(%s))' % frame.buffer)
return
self.writeline('return concat(%s)' % frame.buffer)
def indent(self):
"""Indent by one."""
self._indentation += 1
def outdent(self, step=1):
"""Outdent by step."""
self._indentation -= step
def start_write(self, frame, node=None):
"""Yield or write into the frame buffer."""
if frame.buffer is None:
self.writeline('yield ', node)
else:
self.writeline('%s.append(' % frame.buffer, node)
def end_write(self, frame):
"""End the writing process started by `start_write`."""
if frame.buffer is not None:
self.write(')')
def simple_write(self, s, frame, node=None):
"""Simple shortcut for start_write + write + end_write."""
self.start_write(frame, node)
self.write(s)
self.end_write(frame)
def blockvisit(self, nodes, frame):
"""Visit a list of nodes as block in a frame. If the current frame
is no buffer a dummy ``if 0: yield None`` is written automatically.
"""
try:
self.writeline('pass')
for node in nodes:
self.visit(node, frame)
except CompilerExit:
pass
def write(self, x):
"""Write a string into the output stream."""
if self._new_lines:
if not self._first_write:
self.stream.write('\n' * self._new_lines)
self.code_lineno += self._new_lines
if self._write_debug_info is not None:
self.debug_info.append((self._write_debug_info,
self.code_lineno))
self._write_debug_info = None
self._first_write = False
self.stream.write(' ' * self._indentation)
self._new_lines = 0
self.stream.write(x)
def writeline(self, x, node=None, extra=0):
"""Combination of newline and write."""
self.newline(node, extra)
self.write(x)
def newline(self, node=None, extra=0):
"""Add one or more newlines before the next write."""
self._new_lines = max(self._new_lines, 1 + extra)
if node is not None and node.lineno != self._last_line:
self._write_debug_info = node.lineno
self._last_line = node.lineno
def signature(self, node, frame, extra_kwargs=None):
"""Writes a function call to the stream for the current node.
A leading comma is added automatically. The extra keyword
arguments may not include python keywords otherwise a syntax
error could occour. The extra keyword arguments should be given
as python dict.
"""
# if any of the given keyword arguments is a python keyword
# we have to make sure that no invalid call is created.
kwarg_workaround = False
for kwarg in chain((x.key for x in node.kwargs), extra_kwargs or ()):
if is_python_keyword(kwarg):
kwarg_workaround = True
break
for arg in node.args:
self.write(', ')
self.visit(arg, frame)
if not kwarg_workaround:
for kwarg in node.kwargs:
self.write(', ')
self.visit(kwarg, frame)
if extra_kwargs is not None:
for key, value in iteritems(extra_kwargs):
self.write(', %s=%s' % (key, value))
if node.dyn_args:
self.write(', *')
self.visit(node.dyn_args, frame)
if kwarg_workaround:
if node.dyn_kwargs is not None:
self.write(', **dict({')
else:
self.write(', **{')
for kwarg in node.kwargs:
self.write('%r: ' % kwarg.key)
self.visit(kwarg.value, frame)
self.write(', ')
if extra_kwargs is not None:
for key, value in iteritems(extra_kwargs):
self.write('%r: %s, ' % (key, value))
if node.dyn_kwargs is not None:
self.write('}, **')
self.visit(node.dyn_kwargs, frame)
self.write(')')
else:
self.write('}')
elif node.dyn_kwargs is not None:
self.write(', **')
self.visit(node.dyn_kwargs, frame)
def pull_dependencies(self, nodes):
"""Pull all the dependencies."""
visitor = DependencyFinderVisitor()
for node in nodes:
visitor.visit(node)
for dependency in 'filters', 'tests':
mapping = getattr(self, dependency)
for name in getattr(visitor, dependency):
if name not in mapping:
mapping[name] = self.temporary_identifier()
self.writeline('%s = environment.%s[%r]' %
(mapping[name], dependency, name))
def enter_frame(self, frame):
undefs = []
for target, (action, param) in iteritems(frame.symbols.loads):
if action == VAR_LOAD_PARAMETER:
pass
elif action == VAR_LOAD_RESOLVE:
self.writeline('%s = %s(%r)' %
(target, self.get_resolve_func(), param))
elif action == VAR_LOAD_ALIAS:
self.writeline('%s = %s' % (target, param))
elif action == VAR_LOAD_UNDEFINED:
undefs.append(target)
else:
raise NotImplementedError('unknown load instruction')
if undefs:
self.writeline('%s = missing' % ' = '.join(undefs))
def leave_frame(self, frame, with_python_scope=False):
if not with_python_scope:
undefs = []
for target, _ in iteritems(frame.symbols.loads):
undefs.append(target)
if undefs:
self.writeline('%s = missing' % ' = '.join(undefs))
def func(self, name):
if self.environment.is_async:
return 'async def %s' % name
return 'def %s' % name
def macro_body(self, node, frame):
"""Dump the function def of a macro or call block."""
frame = frame.inner()
frame.symbols.analyze_node(node)
macro_ref = MacroRef(node)
explicit_caller = None
skip_special_params = set()
args = []
for idx, arg in enumerate(node.args):
if arg.name == 'caller':
explicit_caller = idx
if arg.name in ('kwargs', 'varargs'):
skip_special_params.add(arg.name)
args.append(frame.symbols.ref(arg.name))
undeclared = find_undeclared(node.body, ('caller', 'kwargs', 'varargs'))
if 'caller' in undeclared:
# In older Jinja2 versions there was a bug that allowed caller
# to retain the special behavior even if it was mentioned in
# the argument list. However thankfully this was only really
# working if it was the last argument. So we are explicitly
# checking this now and error out if it is anywhere else in
# the argument list.
if explicit_caller is not None:
try:
node.defaults[explicit_caller - len(node.args)]
except IndexError:
self.fail('When defining macros or call blocks the '
'special "caller" argument must be omitted '
'or be given a default.', node.lineno)
else:
args.append(frame.symbols.declare_parameter('caller'))
macro_ref.accesses_caller = True
if 'kwargs' in undeclared and not 'kwargs' in skip_special_params:
args.append(frame.symbols.declare_parameter('kwargs'))
macro_ref.accesses_kwargs = True
if 'varargs' in undeclared and not 'varargs' in skip_special_params:
args.append(frame.symbols.declare_parameter('varargs'))
macro_ref.accesses_varargs = True
# macros are delayed, they never require output checks
frame.require_output_check = False
frame.symbols.analyze_node(node)
self.writeline('%s(%s):' % (self.func('macro'), ', '.join(args)), node)
self.indent()
self.buffer(frame)
self.enter_frame(frame)
self.push_parameter_definitions(frame)
for idx, arg in enumerate(node.args):
ref = frame.symbols.ref(arg.name)
self.writeline('if %s is missing:' % ref)
self.indent()
try:
default = node.defaults[idx - len(node.args)]
except IndexError:
self.writeline('%s = undefined(%r, name=%r)' % (
ref,
'parameter %r was not provided' % arg.name,
arg.name))
else:
self.writeline('%s = ' % ref)
self.visit(default, frame)
self.mark_parameter_stored(ref)
self.outdent()
self.pop_parameter_definitions()
self.blockvisit(node.body, frame)
self.return_buffer_contents(frame, force_unescaped=True)
self.leave_frame(frame, with_python_scope=True)
self.outdent()
return frame, macro_ref
def macro_def(self, macro_ref, frame):
"""Dump the macro definition for the def created by macro_body."""
arg_tuple = ', '.join(repr(x.name) for x in macro_ref.node.args)
name = getattr(macro_ref.node, 'name', None)
if len(macro_ref.node.args) == 1:
arg_tuple += ','
self.write('Macro(environment, macro, %r, (%s), %r, %r, %r, '
'context.eval_ctx.autoescape)' %
(name, arg_tuple, macro_ref.accesses_kwargs,
macro_ref.accesses_varargs, macro_ref.accesses_caller))
def position(self, node):
"""Return a human readable position for the node."""
rv = 'line %d' % node.lineno
if self.name is not None:
rv += ' in ' + repr(self.name)
return rv
def dump_local_context(self, frame):
return '{%s}' % ', '.join(
'%r: %s' % (name, target) for name, target
in iteritems(frame.symbols.dump_stores()))
def write_commons(self):
"""Writes a common preamble that is used by root and block functions.
Primarily this sets up common local helpers and enforces a generator
through a dead branch.
"""
self.writeline('resolve = context.resolve_or_missing')
self.writeline('undefined = environment.undefined')
self.writeline('if 0: yield None')
def push_parameter_definitions(self, frame):
"""Pushes all parameter targets from the given frame into a local
stack that permits tracking of yet to be assigned parameters. In
particular this enables the optimization from `visit_Name` to skip
undefined expressions for parameters in macros as macros can reference
otherwise unbound parameters.
"""
self._param_def_block.append(frame.symbols.dump_param_targets())
def pop_parameter_definitions(self):
"""Pops the current parameter definitions set."""
self._param_def_block.pop()
def mark_parameter_stored(self, target):
"""Marks a parameter in the current parameter definitions as stored.
This will skip the enforced undefined checks.
"""
if self._param_def_block:
self._param_def_block[-1].discard(target)
def push_context_reference(self, target):
self._context_reference_stack.append(target)
def pop_context_reference(self):
self._context_reference_stack.pop()
def get_context_ref(self):
return self._context_reference_stack[-1]
def get_resolve_func(self):
target = self._context_reference_stack[-1]
if target == 'context':
return 'resolve'
return '%s.resolve' % target
def derive_context(self, frame):
return '%s.derived(%s)' % (
self.get_context_ref(),
self.dump_local_context(frame),
)
def parameter_is_undeclared(self, target):
"""Checks if a given target is an undeclared parameter."""
if not self._param_def_block:
return False
return target in self._param_def_block[-1]
def push_assign_tracking(self):
"""Pushes a new layer for assignment tracking."""
self._assign_stack.append(set())
def pop_assign_tracking(self, frame):
"""Pops the topmost level for assignment tracking and updates the
context variables if necessary.
"""
vars = self._assign_stack.pop()
if not frame.toplevel or not vars:
return
public_names = [x for x in vars if x[:1] != '_']
if len(vars) == 1:
name = next(iter(vars))
ref = frame.symbols.ref(name)
self.writeline('context.vars[%r] = %s' % (name, ref))
else:
self.writeline('context.vars.update({')
for idx, name in enumerate(vars):
if idx:
self.write(', ')
ref = frame.symbols.ref(name)
self.write('%r: %s' % (name, ref))
self.write('})')
if public_names:
if len(public_names) == 1:
self.writeline('context.exported_vars.add(%r)' %
public_names[0])
else:
self.writeline('context.exported_vars.update((%s))' %
', '.join(imap(repr, public_names)))
# -- Statement Visitors
def visit_Template(self, node, frame=None):
assert frame is None, 'no root frame allowed'
eval_ctx = EvalContext(self.environment, self.name)
from jinja2.runtime import __all__ as exported
self.writeline('from __future__ import %s' % ', '.join(code_features))
self.writeline('from jinja2.runtime import ' + ', '.join(exported))
if self.environment.is_async:
self.writeline('from jinja2.asyncsupport import auto_await, '
'auto_aiter, make_async_loop_context')
# if we want a deferred initialization we cannot move the
# environment into a local name
envenv = not self.defer_init and ', environment=environment' or ''
# do we have an extends tag at all? If not, we can save some
# overhead by just not processing any inheritance code.
have_extends = node.find(nodes.Extends) is not None
# find all blocks
for block in node.find_all(nodes.Block):
if block.name in self.blocks:
self.fail('block %r defined twice' % block.name, block.lineno)
self.blocks[block.name] = block
# find all imports and import them
for import_ in node.find_all(nodes.ImportedName):
if import_.importname not in self.import_aliases:
imp = import_.importname
self.import_aliases[imp] = alias = self.temporary_identifier()
if '.' in imp:
module, obj = imp.rsplit('.', 1)
self.writeline('from %s import %s as %s' %
(module, obj, alias))
else:
self.writeline('import %s as %s' % (imp, alias))
# add the load name
self.writeline('name = %r' % self.name)
# generate the root render function.
self.writeline('%s(context, missing=missing%s):' %
(self.func('root'), envenv), extra=1)
self.indent()
self.write_commons()
# process the root
frame = Frame(eval_ctx)
if 'self' in find_undeclared(node.body, ('self',)):
ref = frame.symbols.declare_parameter('self')
self.writeline('%s = TemplateReference(context)' % ref)
frame.symbols.analyze_node(node)
frame.toplevel = frame.rootlevel = True
frame.require_output_check = have_extends and not self.has_known_extends
if have_extends:
self.writeline('parent_template = None')
self.enter_frame(frame)
self.pull_dependencies(node.body)
self.blockvisit(node.body, frame)
self.leave_frame(frame, with_python_scope=True)
self.outdent()
# make sure that the parent root is called.
if have_extends:
if not self.has_known_extends:
self.indent()
self.writeline('if parent_template is not None:')
self.indent()
if supports_yield_from and not self.environment.is_async:
self.writeline('yield from parent_template.'
'root_render_func(context)')
else:
self.writeline('%sfor event in parent_template.'
'root_render_func(context):' %
(self.environment.is_async and 'async ' or ''))
self.indent()
self.writeline('yield event')
self.outdent()
self.outdent(1 + (not self.has_known_extends))
# at this point we now have the blocks collected and can visit them too.
for name, block in iteritems(self.blocks):
self.writeline('%s(context, missing=missing%s):' %
(self.func('block_' + name), envenv),
block, 1)
self.indent()
self.write_commons()
# It's important that we do not make this frame a child of the
# toplevel template. This would cause a variety of
# interesting issues with identifier tracking.
block_frame = Frame(eval_ctx)
undeclared = find_undeclared(block.body, ('self', 'super'))
if 'self' in undeclared:
ref = block_frame.symbols.declare_parameter('self')
self.writeline('%s = TemplateReference(context)' % ref)
if 'super' in undeclared:
ref = block_frame.symbols.declare_parameter('super')
self.writeline('%s = context.super(%r, '
'block_%s)' % (ref, name, name))
block_frame.symbols.analyze_node(block)
block_frame.block = name
self.enter_frame(block_frame)
self.pull_dependencies(block.body)
self.blockvisit(block.body, block_frame)
self.leave_frame(block_frame, with_python_scope=True)
self.outdent()
self.writeline('blocks = {%s}' % ', '.join('%r: block_%s' % (x, x)
for x in self.blocks),
extra=1)
# add a function that returns the debug info
self.writeline('debug_info = %r' % '&'.join('%s=%s' % x for x
in self.debug_info))
def visit_Block(self, node, frame):
"""Call a block and register it for the template."""
level = 0
if frame.toplevel:
# if we know that we are a child template, there is no need to
# check if we are one
if self.has_known_extends:
return
if self.extends_so_far > 0:
self.writeline('if parent_template is None:')
self.indent()
level += 1
if node.scoped:
context = self.derive_context(frame)
else:
context = self.get_context_ref()
if supports_yield_from and not self.environment.is_async and \
frame.buffer is None:
self.writeline('yield from context.blocks[%r][0](%s)' % (
node.name, context), node)
else:
loop = self.environment.is_async and 'async for' or 'for'
self.writeline('%s event in context.blocks[%r][0](%s):' % (
loop, node.name, context), node)
self.indent()
self.simple_write('event', frame)
self.outdent()
self.outdent(level)
def visit_Extends(self, node, frame):
"""Calls the extender."""
if not frame.toplevel:
self.fail('cannot use extend from a non top-level scope',
node.lineno)
# if the number of extends statements in general is zero so
# far, we don't have to add a check if something extended
# the template before this one.
if self.extends_so_far > 0:
# if we have a known extends we just add a template runtime
# error into the generated code. We could catch that at compile
# time too, but i welcome it not to confuse users by throwing the
# same error at different times just "because we can".
if not self.has_known_extends:
self.writeline('if parent_template is not None:')
self.indent()
self.writeline('raise TemplateRuntimeError(%r)' %
'extended multiple times')
# if we have a known extends already we don't need that code here
# as we know that the template execution will end here.
if self.has_known_extends:
raise CompilerExit()
else:
self.outdent()
self.writeline('parent_template = environment.get_template(', node)
self.visit(node.template, frame)
self.write(', %r)' % self.name)
self.writeline('for name, parent_block in parent_template.'
'blocks.%s():' % dict_item_iter)
self.indent()
self.writeline('context.blocks.setdefault(name, []).'
'append(parent_block)')
self.outdent()
# if this extends statement was in the root level we can take
# advantage of that information and simplify the generated code
# in the top level from this point onwards
if frame.rootlevel:
self.has_known_extends = True
# and now we have one more
self.extends_so_far += 1
def visit_Include(self, node, frame):
"""Handles includes."""
if node.ignore_missing:
self.writeline('try:')
self.indent()
func_name = 'get_or_select_template'
if isinstance(node.template, nodes.Const):
if isinstance(node.template.value, string_types):
func_name = 'get_template'
elif isinstance(node.template.value, (tuple, list)):
func_name = 'select_template'
elif isinstance(node.template, (nodes.Tuple, nodes.List)):
func_name = 'select_template'
self.writeline('template = environment.%s(' % func_name, node)
self.visit(node.template, frame)
self.write(', %r)' % self.name)
if node.ignore_missing:
self.outdent()
self.writeline('except TemplateNotFound:')
self.indent()
self.writeline('pass')
self.outdent()
self.writeline('else:')
self.indent()
skip_event_yield = False
if node.with_context:
loop = self.environment.is_async and 'async for' or 'for'
self.writeline('%s event in template.root_render_func('
'template.new_context(context.get_all(), True, '
'%s)):' % (loop, self.dump_local_context(frame)))
elif self.environment.is_async:
self.writeline('for event in (await '
'template._get_default_module_async())'
'._body_stream:')
else:
if supports_yield_from:
self.writeline('yield from template._get_default_module()'
'._body_stream')
skip_event_yield = True
else:
self.writeline('for event in template._get_default_module()'
'._body_stream:')
if not skip_event_yield:
self.indent()
self.simple_write('event', frame)
self.outdent()
if node.ignore_missing:
self.outdent()
def visit_Import(self, node, frame):
"""Visit regular imports."""
self.writeline('%s = ' % frame.symbols.ref(node.target), node)
if frame.toplevel:
self.write('context.vars[%r] = ' % node.target)
if self.environment.is_async:
self.write('await ')
self.write('environment.get_template(')
self.visit(node.template, frame)
self.write(', %r).' % self.name)
if node.with_context:
self.write('make_module%s(context.get_all(), True, %s)'
% (self.environment.is_async and '_async' or '',
self.dump_local_context(frame)))
elif self.environment.is_async:
self.write('_get_default_module_async()')
else:
self.write('_get_default_module()')
if frame.toplevel and not node.target.startswith('_'):
self.writeline('context.exported_vars.discard(%r)' % node.target)
def visit_FromImport(self, node, frame):
"""Visit named imports."""
self.newline(node)
self.write('included_template = %senvironment.get_template('
% (self.environment.is_async and 'await ' or ''))
self.visit(node.template, frame)
self.write(', %r).' % self.name)
if node.with_context:
self.write('make_module%s(context.get_all(), True, %s)'
% (self.environment.is_async and '_async' or '',
self.dump_local_context(frame)))
elif self.environment.is_async:
self.write('_get_default_module_async()')
else:
self.write('_get_default_module()')
var_names = []
discarded_names = []
for name in node.names:
if isinstance(name, tuple):
name, alias = name
else:
alias = name
self.writeline('%s = getattr(included_template, '
'%r, missing)' % (frame.symbols.ref(alias), name))
self.writeline('if %s is missing:' % frame.symbols.ref(alias))
self.indent()
# The position will contain the template name, and will be formatted
# into a string that will be compiled into an f-string. Curly braces
# in the name must be replaced with escapes so that they will not be
# executed as part of the f-string.
position = self.position(node).replace("{", "{{").replace("}", "}}")
self.writeline('%s = undefined(%r %% '
'included_template.__name__, '
'name=%r)' %
(frame.symbols.ref(alias),
'the template %%r (imported on %s) does '
'not export the requested name %s' % (
position,
repr(name)
), name))
self.outdent()
if frame.toplevel:
var_names.append(alias)
if not alias.startswith('_'):
discarded_names.append(alias)
if var_names:
if len(var_names) == 1:
name = var_names[0]
self.writeline('context.vars[%r] = %s' %
(name, frame.symbols.ref(name)))
else:
self.writeline('context.vars.update({%s})' % ', '.join(
'%r: %s' % (name, frame.symbols.ref(name)) for name in var_names
))
if discarded_names:
if len(discarded_names) == 1:
self.writeline('context.exported_vars.discard(%r)' %
discarded_names[0])
else:
self.writeline('context.exported_vars.difference_'
'update((%s))' % ', '.join(imap(repr, discarded_names)))
def visit_For(self, node, frame):
loop_frame = frame.inner()
test_frame = frame.inner()
else_frame = frame.inner()
# try to figure out if we have an extended loop. An extended loop
# is necessary if the loop is in recursive mode if the special loop
# variable is accessed in the body.
extended_loop = node.recursive or 'loop' in \
find_undeclared(node.iter_child_nodes(
only=('body',)), ('loop',))
loop_ref = None
if extended_loop:
loop_ref = loop_frame.symbols.declare_parameter('loop')
loop_frame.symbols.analyze_node(node, for_branch='body')
if node.else_:
else_frame.symbols.analyze_node(node, for_branch='else')
if node.test:
loop_filter_func = self.temporary_identifier()
test_frame.symbols.analyze_node(node, for_branch='test')
self.writeline('%s(fiter):' % self.func(loop_filter_func), node.test)
self.indent()
self.enter_frame(test_frame)
self.writeline(self.environment.is_async and 'async for ' or 'for ')
self.visit(node.target, loop_frame)
self.write(' in ')
self.write(self.environment.is_async and 'auto_aiter(fiter)' or 'fiter')
self.write(':')
self.indent()
self.writeline('if ', node.test)
self.visit(node.test, test_frame)
self.write(':')
self.indent()
self.writeline('yield ')
self.visit(node.target, loop_frame)
self.outdent(3)
self.leave_frame(test_frame, with_python_scope=True)
# if we don't have an recursive loop we have to find the shadowed
# variables at that point. Because loops can be nested but the loop
# variable is a special one we have to enforce aliasing for it.
if node.recursive:
self.writeline('%s(reciter, loop_render_func, depth=0):' %
self.func('loop'), node)
self.indent()
self.buffer(loop_frame)
# Use the same buffer for the else frame
else_frame.buffer = loop_frame.buffer
# make sure the loop variable is a special one and raise a template
# assertion error if a loop tries to write to loop
if extended_loop:
self.writeline('%s = missing' % loop_ref)
for name in node.find_all(nodes.Name):
if name.ctx == 'store' and name.name == 'loop':
self.fail('Can\'t assign to special loop variable '
'in for-loop target', name.lineno)
if node.else_:
iteration_indicator = self.temporary_identifier()
self.writeline('%s = 1' % iteration_indicator)
self.writeline(self.environment.is_async and 'async for ' or 'for ', node)
self.visit(node.target, loop_frame)
if extended_loop:
if self.environment.is_async:
self.write(', %s in await make_async_loop_context(' % loop_ref)
else:
self.write(', %s in LoopContext(' % loop_ref)
else:
self.write(' in ')
if node.test:
self.write('%s(' % loop_filter_func)
if node.recursive:
self.write('reciter')
else:
if self.environment.is_async and not extended_loop:
self.write('auto_aiter(')
self.visit(node.iter, frame)
if self.environment.is_async and not extended_loop:
self.write(')')
if node.test:
self.write(')')
if node.recursive:
self.write(', undefined, loop_render_func, depth):')
else:
self.write(extended_loop and ', undefined):' or ':')
self.indent()
self.enter_frame(loop_frame)
self.blockvisit(node.body, loop_frame)
if node.else_:
self.writeline('%s = 0' % iteration_indicator)
self.outdent()
self.leave_frame(loop_frame, with_python_scope=node.recursive
and not node.else_)
if node.else_:
self.writeline('if %s:' % iteration_indicator)
self.indent()
self.enter_frame(else_frame)
self.blockvisit(node.else_, else_frame)
self.leave_frame(else_frame)
self.outdent()
# if the node was recursive we have to return the buffer contents
# and start the iteration code
if node.recursive:
self.return_buffer_contents(loop_frame)
self.outdent()
self.start_write(frame, node)
if self.environment.is_async:
self.write('await ')
self.write('loop(')
if self.environment.is_async:
self.write('auto_aiter(')
self.visit(node.iter, frame)
if self.environment.is_async:
self.write(')')
self.write(', loop)')
self.end_write(frame)
def visit_If(self, node, frame):
if_frame = frame.soft()
self.writeline('if ', node)
self.visit(node.test, if_frame)
self.write(':')
self.indent()
self.blockvisit(node.body, if_frame)
self.outdent()
for elif_ in node.elif_:
self.writeline('elif ', elif_)
self.visit(elif_.test, if_frame)
self.write(':')
self.indent()
self.blockvisit(elif_.body, if_frame)
self.outdent()
if node.else_:
self.writeline('else:')
self.indent()
self.blockvisit(node.else_, if_frame)
self.outdent()
def visit_Macro(self, node, frame):
macro_frame, macro_ref = self.macro_body(node, frame)
self.newline()
if frame.toplevel:
if not node.name.startswith('_'):
self.write('context.exported_vars.add(%r)' % node.name)
ref = frame.symbols.ref(node.name)
self.writeline('context.vars[%r] = ' % node.name)
self.write('%s = ' % frame.symbols.ref(node.name))
self.macro_def(macro_ref, macro_frame)
def visit_CallBlock(self, node, frame):
call_frame, macro_ref = self.macro_body(node, frame)
self.writeline('caller = ')
self.macro_def(macro_ref, call_frame)
self.start_write(frame, node)
self.visit_Call(node.call, frame, forward_caller=True)
self.end_write(frame)
def visit_FilterBlock(self, node, frame):
filter_frame = frame.inner()
filter_frame.symbols.analyze_node(node)
self.enter_frame(filter_frame)
self.buffer(filter_frame)
self.blockvisit(node.body, filter_frame)
self.start_write(frame, node)
self.visit_Filter(node.filter, filter_frame)
self.end_write(frame)
self.leave_frame(filter_frame)
def visit_With(self, node, frame):
with_frame = frame.inner()
with_frame.symbols.analyze_node(node)
self.enter_frame(with_frame)
for idx, (target, expr) in enumerate(izip(node.targets, node.values)):
self.newline()
self.visit(target, with_frame)
self.write(' = ')
self.visit(expr, frame)
self.blockvisit(node.body, with_frame)
self.leave_frame(with_frame)
def visit_ExprStmt(self, node, frame):
self.newline(node)
self.visit(node.node, frame)
def visit_Output(self, node, frame):
# if we have a known extends statement, we don't output anything
# if we are in a require_output_check section
if self.has_known_extends and frame.require_output_check:
return
allow_constant_finalize = True
if self.environment.finalize:
func = self.environment.finalize
if getattr(func, 'contextfunction', False) or \
getattr(func, 'evalcontextfunction', False):
allow_constant_finalize = False
elif getattr(func, 'environmentfunction', False):
finalize = lambda x: text_type(
self.environment.finalize(self.environment, x))
else:
finalize = lambda x: text_type(self.environment.finalize(x))
else:
finalize = text_type
# if we are inside a frame that requires output checking, we do so
outdent_later = False
if frame.require_output_check:
self.writeline('if parent_template is None:')
self.indent()
outdent_later = True
# try to evaluate as many chunks as possible into a static
# string at compile time.
body = []
for child in node.nodes:
try:
if not allow_constant_finalize:
raise nodes.Impossible()
const = child.as_const(frame.eval_ctx)
except nodes.Impossible:
body.append(child)
continue
# the frame can't be volatile here, becaus otherwise the
# as_const() function would raise an Impossible exception
# at that point.
try:
if frame.eval_ctx.autoescape:
if hasattr(const, '__html__'):
const = const.__html__()
else:
const = escape(const)
const = finalize(const)
except Exception:
# if something goes wrong here we evaluate the node
# at runtime for easier debugging
body.append(child)
continue
if body and isinstance(body[-1], list):
body[-1].append(const)
else:
body.append([const])
# if we have less than 3 nodes or a buffer we yield or extend/append
if len(body) < 3 or frame.buffer is not None:
if frame.buffer is not None:
# for one item we append, for more we extend
if len(body) == 1:
self.writeline('%s.append(' % frame.buffer)
else:
self.writeline('%s.extend((' % frame.buffer)
self.indent()
for item in body:
if isinstance(item, list):
val = repr(concat(item))
if frame.buffer is None:
self.writeline('yield ' + val)
else:
self.writeline(val + ',')
else:
if frame.buffer is None:
self.writeline('yield ', item)
else:
self.newline(item)
close = 1
if frame.eval_ctx.volatile:
self.write('(escape if context.eval_ctx.autoescape'
' else to_string)(')
elif frame.eval_ctx.autoescape:
self.write('escape(')
else:
self.write('to_string(')
if self.environment.finalize is not None:
self.write('environment.finalize(')
if getattr(self.environment.finalize,
"contextfunction", False):
self.write('context, ')
close += 1
self.visit(item, frame)
self.write(')' * close)
if frame.buffer is not None:
self.write(',')
if frame.buffer is not None:
# close the open parentheses
self.outdent()
self.writeline(len(body) == 1 and ')' or '))')
# otherwise we create a format string as this is faster in that case
else:
format = []
arguments = []
for item in body:
if isinstance(item, list):
format.append(concat(item).replace('%', '%%'))
else:
format.append('%s')
arguments.append(item)
self.writeline('yield ')
self.write(repr(concat(format)) + ' % (')
self.indent()
for argument in arguments:
self.newline(argument)
close = 0
if frame.eval_ctx.volatile:
self.write('(escape if context.eval_ctx.autoescape else'
' to_string)(')
close += 1
elif frame.eval_ctx.autoescape:
self.write('escape(')
close += 1
if self.environment.finalize is not None:
self.write('environment.finalize(')
if getattr(self.environment.finalize,
'contextfunction', False):
self.write('context, ')
elif getattr(self.environment.finalize,
'evalcontextfunction', False):
self.write('context.eval_ctx, ')
elif getattr(self.environment.finalize,
'environmentfunction', False):
self.write('environment, ')
close += 1
self.visit(argument, frame)
self.write(')' * close + ', ')
self.outdent()
self.writeline(')')
if outdent_later:
self.outdent()
def visit_Assign(self, node, frame):
self.push_assign_tracking()
self.newline(node)
self.visit(node.target, frame)
self.write(' = ')
self.visit(node.node, frame)
self.pop_assign_tracking(frame)
def visit_AssignBlock(self, node, frame):
self.push_assign_tracking()
block_frame = frame.inner()
# This is a special case. Since a set block always captures we
# will disable output checks. This way one can use set blocks
# toplevel even in extended templates.
block_frame.require_output_check = False
block_frame.symbols.analyze_node(node)
self.enter_frame(block_frame)
self.buffer(block_frame)
self.blockvisit(node.body, block_frame)
self.newline(node)
self.visit(node.target, frame)
self.write(' = (Markup if context.eval_ctx.autoescape '
'else identity)(')
if node.filter is not None:
self.visit_Filter(node.filter, block_frame)
else:
self.write('concat(%s)' % block_frame.buffer)
self.write(')')
self.pop_assign_tracking(frame)
self.leave_frame(block_frame)
# -- Expression Visitors
def visit_Name(self, node, frame):
if node.ctx == 'store' and frame.toplevel:
if self._assign_stack:
self._assign_stack[-1].add(node.name)
ref = frame.symbols.ref(node.name)
# If we are looking up a variable we might have to deal with the
# case where it's undefined. We can skip that case if the load
# instruction indicates a parameter which are always defined.
if node.ctx == 'load':
load = frame.symbols.find_load(ref)
if not (load is not None and load[0] == VAR_LOAD_PARAMETER and \
not self.parameter_is_undeclared(ref)):
self.write('(undefined(name=%r) if %s is missing else %s)' %
(node.name, ref, ref))
return
self.write(ref)
def visit_NSRef(self, node, frame):
# NSRefs can only be used to store values; since they use the normal
# `foo.bar` notation they will be parsed as a normal attribute access
# when used anywhere but in a `set` context
ref = frame.symbols.ref(node.name)
self.writeline('if not isinstance(%s, Namespace):' % ref)
self.indent()
self.writeline('raise TemplateRuntimeError(%r)' %
'cannot assign attribute on non-namespace object')
self.outdent()
self.writeline('%s[%r]' % (ref, node.attr))
def visit_Const(self, node, frame):
val = node.as_const(frame.eval_ctx)
if isinstance(val, float):
self.write(str(val))
else:
self.write(repr(val))
def visit_TemplateData(self, node, frame):
try:
self.write(repr(node.as_const(frame.eval_ctx)))
except nodes.Impossible:
self.write('(Markup if context.eval_ctx.autoescape else identity)(%r)'
% node.data)
def visit_Tuple(self, node, frame):
self.write('(')
idx = -1
for idx, item in enumerate(node.items):
if idx:
self.write(', ')
self.visit(item, frame)
self.write(idx == 0 and ',)' or ')')
def visit_List(self, node, frame):
self.write('[')
for idx, item in enumerate(node.items):
if idx:
self.write(', ')
self.visit(item, frame)
self.write(']')
def visit_Dict(self, node, frame):
self.write('{')
for idx, item in enumerate(node.items):
if idx:
self.write(', ')
self.visit(item.key, frame)
self.write(': ')
self.visit(item.value, frame)
self.write('}')
def binop(operator, interceptable=True):
@optimizeconst
def visitor(self, node, frame):
if self.environment.sandboxed and \
operator in self.environment.intercepted_binops:
self.write('environment.call_binop(context, %r, ' % operator)
self.visit(node.left, frame)
self.write(', ')
self.visit(node.right, frame)
else:
self.write('(')
self.visit(node.left, frame)
self.write(' %s ' % operator)
self.visit(node.right, frame)
self.write(')')
return visitor
def uaop(operator, interceptable=True):
@optimizeconst
def visitor(self, node, frame):
if self.environment.sandboxed and \
operator in self.environment.intercepted_unops:
self.write('environment.call_unop(context, %r, ' % operator)
self.visit(node.node, frame)
else:
self.write('(' + operator)
self.visit(node.node, frame)
self.write(')')
return visitor
visit_Add = binop('+')
visit_Sub = binop('-')
visit_Mul = binop('*')
visit_Div = binop('/')
visit_FloorDiv = binop('//')
visit_Pow = binop('**')
visit_Mod = binop('%')
visit_And = binop('and', interceptable=False)
visit_Or = binop('or', interceptable=False)
visit_Pos = uaop('+')
visit_Neg = uaop('-')
visit_Not = uaop('not ', interceptable=False)
del binop, uaop
@optimizeconst
def visit_Concat(self, node, frame):
if frame.eval_ctx.volatile:
func_name = '(context.eval_ctx.volatile and' \
' markup_join or unicode_join)'
elif frame.eval_ctx.autoescape:
func_name = 'markup_join'
else:
func_name = 'unicode_join'
self.write('%s((' % func_name)
for arg in node.nodes:
self.visit(arg, frame)
self.write(', ')
self.write('))')
@optimizeconst
def visit_Compare(self, node, frame):
self.visit(node.expr, frame)
for op in node.ops:
self.visit(op, frame)
def visit_Operand(self, node, frame):
self.write(' %s ' % operators[node.op])
self.visit(node.expr, frame)
@optimizeconst
def visit_Getattr(self, node, frame):
self.write('environment.getattr(')
self.visit(node.node, frame)
self.write(', %r)' % node.attr)
@optimizeconst
def visit_Getitem(self, node, frame):
# slices bypass the environment getitem method.
if isinstance(node.arg, nodes.Slice):
self.visit(node.node, frame)
self.write('[')
self.visit(node.arg, frame)
self.write(']')
else:
self.write('environment.getitem(')
self.visit(node.node, frame)
self.write(', ')
self.visit(node.arg, frame)
self.write(')')
def visit_Slice(self, node, frame):
if node.start is not None:
self.visit(node.start, frame)
self.write(':')
if node.stop is not None:
self.visit(node.stop, frame)
if node.step is not None:
self.write(':')
self.visit(node.step, frame)
@optimizeconst
def visit_Filter(self, node, frame):
if self.environment.is_async:
self.write('await auto_await(')
self.write(self.filters[node.name] + '(')
func = self.environment.filters.get(node.name)
if func is None:
self.fail('no filter named %r' % node.name, node.lineno)
if getattr(func, 'contextfilter', False):
self.write('context, ')
elif getattr(func, 'evalcontextfilter', False):
self.write('context.eval_ctx, ')
elif getattr(func, 'environmentfilter', False):
self.write('environment, ')
# if the filter node is None we are inside a filter block
# and want to write to the current buffer
if node.node is not None:
self.visit(node.node, frame)
elif frame.eval_ctx.volatile:
self.write('(context.eval_ctx.autoescape and'
' Markup(concat(%s)) or concat(%s))' %
(frame.buffer, frame.buffer))
elif frame.eval_ctx.autoescape:
self.write('Markup(concat(%s))' % frame.buffer)
else:
self.write('concat(%s)' % frame.buffer)
self.signature(node, frame)
self.write(')')
if self.environment.is_async:
self.write(')')
@optimizeconst
def visit_Test(self, node, frame):
self.write(self.tests[node.name] + '(')
if node.name not in self.environment.tests:
self.fail('no test named %r' % node.name, node.lineno)
self.visit(node.node, frame)
self.signature(node, frame)
self.write(')')
@optimizeconst
def visit_CondExpr(self, node, frame):
def write_expr2():
if node.expr2 is not None:
return self.visit(node.expr2, frame)
self.write('undefined(%r)' % ('the inline if-'
'expression on %s evaluated to false and '
'no else section was defined.' % self.position(node)))
self.write('(')
self.visit(node.expr1, frame)
self.write(' if ')
self.visit(node.test, frame)
self.write(' else ')
write_expr2()
self.write(')')
@optimizeconst
def visit_Call(self, node, frame, forward_caller=False):
if self.environment.is_async:
self.write('await auto_await(')
if self.environment.sandboxed:
self.write('environment.call(context, ')
else:
self.write('context.call(')
self.visit(node.node, frame)
extra_kwargs = forward_caller and {'caller': 'caller'} or None
self.signature(node, frame, extra_kwargs)
self.write(')')
if self.environment.is_async:
self.write(')')
def visit_Keyword(self, node, frame):
self.write(node.key + '=')
self.visit(node.value, frame)
# -- Unused nodes for extensions
def visit_MarkSafe(self, node, frame):
self.write('Markup(')
self.visit(node.expr, frame)
self.write(')')
def visit_MarkSafeIfAutoescape(self, node, frame):
self.write('(context.eval_ctx.autoescape and Markup or identity)(')
self.visit(node.expr, frame)
self.write(')')
def visit_EnvironmentAttribute(self, node, frame):
self.write('environment.' + node.name)
def visit_ExtensionAttribute(self, node, frame):
self.write('environment.extensions[%r].%s' % (node.identifier, node.name))
def visit_ImportedName(self, node, frame):
self.write(self.import_aliases[node.importname])
def visit_InternalName(self, node, frame):
self.write(node.name)
def visit_ContextReference(self, node, frame):
self.write('context')
def visit_Continue(self, node, frame):
self.writeline('continue', node)
def visit_Break(self, node, frame):
self.writeline('break', node)
def visit_Scope(self, node, frame):
scope_frame = frame.inner()
scope_frame.symbols.analyze_node(node)
self.enter_frame(scope_frame)
self.blockvisit(node.body, scope_frame)
self.leave_frame(scope_frame)
def visit_OverlayScope(self, node, frame):
ctx = self.temporary_identifier()
self.writeline('%s = %s' % (ctx, self.derive_context(frame)))
self.writeline('%s.vars = ' % ctx)
self.visit(node.context, frame)
self.push_context_reference(ctx)
scope_frame = frame.inner(isolated=True)
scope_frame.symbols.analyze_node(node)
self.enter_frame(scope_frame)
self.blockvisit(node.body, scope_frame)
self.leave_frame(scope_frame)
self.pop_context_reference()
def visit_EvalContextModifier(self, node, frame):
for keyword in node.options:
self.writeline('context.eval_ctx.%s = ' % keyword.key)
self.visit(keyword.value, frame)
try:
val = keyword.value.as_const(frame.eval_ctx)
except nodes.Impossible:
frame.eval_ctx.volatile = True
else:
setattr(frame.eval_ctx, keyword.key, val)
def visit_ScopedEvalContextModifier(self, node, frame):
old_ctx_name = self.temporary_identifier()
saved_ctx = frame.eval_ctx.save()
self.writeline('%s = context.eval_ctx.save()' % old_ctx_name)
self.visit_EvalContextModifier(node, frame)
for child in node.body:
self.visit(child, frame)
frame.eval_ctx.revert(saved_ctx)
self.writeline('context.eval_ctx.revert(%s)' % old_ctx_name)
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