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Diffstat (limited to 'lib/jinja2/compiler.py')
| -rw-r--r-- | lib/jinja2/compiler.py | 1640 |
1 files changed, 1640 insertions, 0 deletions
diff --git a/lib/jinja2/compiler.py b/lib/jinja2/compiler.py new file mode 100644 index 000000000..57641596a --- /dev/null +++ b/lib/jinja2/compiler.py @@ -0,0 +1,1640 @@ +# -*- coding: utf-8 -*- +""" + jinja2.compiler + ~~~~~~~~~~~~~~~ + + Compiles nodes into python code. + + :copyright: (c) 2010 by the Jinja Team. + :license: BSD, see LICENSE for more details. +""" +from cStringIO import StringIO +from itertools import chain +from copy import deepcopy +from jinja2 import nodes +from jinja2.nodes import EvalContext +from jinja2.visitor import NodeVisitor, NodeTransformer +from jinja2.exceptions import TemplateAssertionError +from jinja2.utils import Markup, concat, escape, is_python_keyword, next + + +operators = { + 'eq': '==', + 'ne': '!=', + 'gt': '>', + 'gteq': '>=', + 'lt': '<', + 'lteq': '<=', + 'in': 'in', + 'notin': 'not in' +} + +try: + exec '(0 if 0 else 0)' +except SyntaxError: + have_condexpr = False +else: + have_condexpr = True + + +# 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' + + +# does if 0: dummy(x) get us x into the scope? +def unoptimize_before_dead_code(): + x = 42 + def f(): + if 0: dummy(x) + return f +unoptimize_before_dead_code = bool(unoptimize_before_dead_code().func_closure) + + +def generate(node, environment, name, filename, stream=None, + defer_init=False): + """Generate the python source for a node tree.""" + if not isinstance(node, nodes.Template): + raise TypeError('Can\'t compile non template nodes') + generator = CodeGenerator(environment, name, filename, stream, defer_init) + 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 isinstance(value, (bool, int, long, float, complex, basestring, + xrange, Markup)): + return True + if isinstance(value, (tuple, list, set, frozenset)): + for item in value: + if not has_safe_repr(item): + return False + return True + elif isinstance(value, dict): + for key, value in value.iteritems(): + 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 Identifiers(object): + """Tracks the status of identifiers in frames.""" + + def __init__(self): + # variables that are known to be declared (probably from outer + # frames or because they are special for the frame) + self.declared = set() + + # undeclared variables from outer scopes + self.outer_undeclared = set() + + # names that are accessed without being explicitly declared by + # this one or any of the outer scopes. Names can appear both in + # declared and undeclared. + self.undeclared = set() + + # names that are declared locally + self.declared_locally = set() + + # names that are declared by parameters + self.declared_parameter = set() + + def add_special(self, name): + """Register a special name like `loop`.""" + self.undeclared.discard(name) + self.declared.add(name) + + def is_declared(self, name, local_only=False): + """Check if a name is declared in this or an outer scope.""" + if name in self.declared_locally or name in self.declared_parameter: + return True + if local_only: + return False + return name in self.declared + + def copy(self): + return deepcopy(self) + + +class Frame(object): + """Holds compile time information for us.""" + + def __init__(self, eval_ctx, parent=None): + self.eval_ctx = eval_ctx + self.identifiers = Identifiers() + + # 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 + + # a set of actually assigned names + self.assigned_names = set() + + # the parent of this frame + self.parent = parent + + if parent is not None: + self.identifiers.declared.update( + parent.identifiers.declared | + parent.identifiers.declared_parameter | + parent.assigned_names + ) + self.identifiers.outer_undeclared.update( + parent.identifiers.undeclared - + self.identifiers.declared + ) + 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.identifiers = object.__new__(self.identifiers.__class__) + rv.identifiers.__dict__.update(self.identifiers.__dict__) + return rv + + def inspect(self, nodes, hard_scope=False): + """Walk the node and check for identifiers. If the scope is hard (eg: + enforce on a python level) overrides from outer scopes are tracked + differently. + """ + visitor = FrameIdentifierVisitor(self.identifiers, hard_scope) + for node in nodes: + visitor.visit(node) + + def find_shadowed(self, extra=()): + """Find all the shadowed names. extra is an iterable of variables + that may be defined with `add_special` which may occour scoped. + """ + i = self.identifiers + return (i.declared | i.outer_undeclared) & \ + (i.declared_locally | i.declared_parameter) | \ + set(x for x in extra if i.is_declared(x)) + + def inner(self): + """Return an inner frame.""" + 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. + """ + 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 FrameIdentifierVisitor(NodeVisitor): + """A visitor for `Frame.inspect`.""" + + def __init__(self, identifiers, hard_scope): + self.identifiers = identifiers + self.hard_scope = hard_scope + + def visit_Name(self, node): + """All assignments to names go through this function.""" + if node.ctx == 'store': + self.identifiers.declared_locally.add(node.name) + elif node.ctx == 'param': + self.identifiers.declared_parameter.add(node.name) + elif node.ctx == 'load' and not \ + self.identifiers.is_declared(node.name, self.hard_scope): + self.identifiers.undeclared.add(node.name) + + def visit_If(self, node): + self.visit(node.test) + real_identifiers = self.identifiers + + old_names = real_identifiers.declared_locally | \ + real_identifiers.declared_parameter + + def inner_visit(nodes): + if not nodes: + return set() + self.identifiers = real_identifiers.copy() + for subnode in nodes: + self.visit(subnode) + rv = self.identifiers.declared_locally - old_names + # we have to remember the undeclared variables of this branch + # because we will have to pull them. + real_identifiers.undeclared.update(self.identifiers.undeclared) + self.identifiers = real_identifiers + return rv + + body = inner_visit(node.body) + else_ = inner_visit(node.else_ or ()) + + # the differences between the two branches are also pulled as + # undeclared variables + real_identifiers.undeclared.update(body.symmetric_difference(else_) - + real_identifiers.declared) + + # remember those that are declared. + real_identifiers.declared_locally.update(body | else_) + + def visit_Macro(self, node): + self.identifiers.declared_locally.add(node.name) + + def visit_Import(self, node): + self.generic_visit(node) + self.identifiers.declared_locally.add(node.target) + + def visit_FromImport(self, node): + self.generic_visit(node) + for name in node.names: + if isinstance(name, tuple): + self.identifiers.declared_locally.add(name[1]) + else: + self.identifiers.declared_locally.add(name) + + def visit_Assign(self, node): + """Visit assignments in the correct order.""" + self.visit(node.node) + self.visit(node.target) + + def visit_For(self, node): + """Visiting stops at for blocks. However the block sequence + is visited as part of the outer scope. + """ + self.visit(node.iter) + + def visit_CallBlock(self, node): + self.visit(node.call) + + def visit_FilterBlock(self, node): + self.visit(node.filter) + + def visit_Scope(self, node): + """Stop visiting at scopes.""" + + def visit_Block(self, node): + """Stop visiting at 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): + if stream is None: + stream = StringIO() + self.environment = environment + self.name = name + self.filename = filename + self.stream = stream + self.created_block_context = False + self.defer_init = defer_init + + # 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 + + # -- 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): + """Return the buffer contents of the frame.""" + 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() + elif frame.eval_ctx.autoescape: + self.writeline('return Markup(concat(%s))' % frame.buffer) + else: + 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 + unless the force_generator parameter is set to False. + """ + if frame.buffer is None: + self.writeline('if 0: yield None') + else: + self.writeline('pass') + try: + 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 extra_kwargs.iteritems(): + 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 extra_kwargs.iteritems(): + 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_locals(self, frame): + """Pull all the references identifiers into the local scope.""" + for name in frame.identifiers.undeclared: + self.writeline('l_%s = context.resolve(%r)' % (name, name)) + + 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 unoptimize_scope(self, frame): + """Disable Python optimizations for the frame.""" + # XXX: this is not that nice but it has no real overhead. It + # mainly works because python finds the locals before dead code + # is removed. If that breaks we have to add a dummy function + # that just accepts the arguments and does nothing. + if frame.identifiers.declared: + self.writeline('%sdummy(%s)' % ( + unoptimize_before_dead_code and 'if 0: ' or '', + ', '.join('l_' + name for name in frame.identifiers.declared) + )) + + def push_scope(self, frame, extra_vars=()): + """This function returns all the shadowed variables in a dict + in the form name: alias and will write the required assignments + into the current scope. No indentation takes place. + + This also predefines locally declared variables from the loop + body because under some circumstances it may be the case that + + `extra_vars` is passed to `Frame.find_shadowed`. + """ + aliases = {} + for name in frame.find_shadowed(extra_vars): + aliases[name] = ident = self.temporary_identifier() + self.writeline('%s = l_%s' % (ident, name)) + to_declare = set() + for name in frame.identifiers.declared_locally: + if name not in aliases: + to_declare.add('l_' + name) + if to_declare: + self.writeline(' = '.join(to_declare) + ' = missing') + return aliases + + def pop_scope(self, aliases, frame): + """Restore all aliases and delete unused variables.""" + for name, alias in aliases.iteritems(): + self.writeline('l_%s = %s' % (name, alias)) + to_delete = set() + for name in frame.identifiers.declared_locally: + if name not in aliases: + to_delete.add('l_' + name) + if to_delete: + # we cannot use the del statement here because enclosed + # scopes can trigger a SyntaxError: + # a = 42; b = lambda: a; del a + self.writeline(' = '.join(to_delete) + ' = missing') + + def function_scoping(self, node, frame, children=None, + find_special=True): + """In Jinja a few statements require the help of anonymous + functions. Those are currently macros and call blocks and in + the future also recursive loops. As there is currently + technical limitation that doesn't allow reading and writing a + variable in a scope where the initial value is coming from an + outer scope, this function tries to fall back with a common + error message. Additionally the frame passed is modified so + that the argumetns are collected and callers are looked up. + + This will return the modified frame. + """ + # we have to iterate twice over it, make sure that works + if children is None: + children = node.iter_child_nodes() + children = list(children) + func_frame = frame.inner() + func_frame.inspect(children, hard_scope=True) + + # variables that are undeclared (accessed before declaration) and + # declared locally *and* part of an outside scope raise a template + # assertion error. Reason: we can't generate reasonable code from + # it without aliasing all the variables. + # this could be fixed in Python 3 where we have the nonlocal + # keyword or if we switch to bytecode generation + overriden_closure_vars = ( + func_frame.identifiers.undeclared & + func_frame.identifiers.declared & + (func_frame.identifiers.declared_locally | + func_frame.identifiers.declared_parameter) + ) + if overriden_closure_vars: + self.fail('It\'s not possible to set and access variables ' + 'derived from an outer scope! (affects: %s)' % + ', '.join(sorted(overriden_closure_vars)), node.lineno) + + # remove variables from a closure from the frame's undeclared + # identifiers. + func_frame.identifiers.undeclared -= ( + func_frame.identifiers.undeclared & + func_frame.identifiers.declared + ) + + # no special variables for this scope, abort early + if not find_special: + return func_frame + + func_frame.accesses_kwargs = False + func_frame.accesses_varargs = False + func_frame.accesses_caller = False + func_frame.arguments = args = ['l_' + x.name for x in node.args] + + undeclared = find_undeclared(children, ('caller', 'kwargs', 'varargs')) + + if 'caller' in undeclared: + func_frame.accesses_caller = True + func_frame.identifiers.add_special('caller') + args.append('l_caller') + if 'kwargs' in undeclared: + func_frame.accesses_kwargs = True + func_frame.identifiers.add_special('kwargs') + args.append('l_kwargs') + if 'varargs' in undeclared: + func_frame.accesses_varargs = True + func_frame.identifiers.add_special('varargs') + args.append('l_varargs') + return func_frame + + def macro_body(self, node, frame, children=None): + """Dump the function def of a macro or call block.""" + frame = self.function_scoping(node, frame, children) + # macros are delayed, they never require output checks + frame.require_output_check = False + args = frame.arguments + # XXX: this is an ugly fix for the loop nesting bug + # (tests.test_old_bugs.test_loop_call_bug). This works around + # a identifier nesting problem we have in general. It's just more + # likely to happen in loops which is why we work around it. The + # real solution would be "nonlocal" all the identifiers that are + # leaking into a new python frame and might be used both unassigned + # and assigned. + if 'loop' in frame.identifiers.declared: + args = args + ['l_loop=l_loop'] + self.writeline('def macro(%s):' % ', '.join(args), node) + self.indent() + self.buffer(frame) + self.pull_locals(frame) + self.blockvisit(node.body, frame) + self.return_buffer_contents(frame) + self.outdent() + return frame + + def macro_def(self, node, frame): + """Dump the macro definition for the def created by macro_body.""" + arg_tuple = ', '.join(repr(x.name) for x in node.args) + name = getattr(node, 'name', None) + if len(node.args) == 1: + arg_tuple += ',' + self.write('Macro(environment, macro, %r, (%s), (' % + (name, arg_tuple)) + for arg in node.defaults: + self.visit(arg, frame) + self.write(', ') + self.write('), %r, %r, %r)' % ( + bool(frame.accesses_kwargs), + bool(frame.accesses_varargs), + bool(frame.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 + + # -- 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 division') + self.writeline('from jinja2.runtime import ' + ', '.join(exported)) + if not unoptimize_before_dead_code: + self.writeline('dummy = lambda *x: None') + + # 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('def root(context%s):' % envenv, extra=1) + + # process the root + frame = Frame(eval_ctx) + frame.inspect(node.body) + frame.toplevel = frame.rootlevel = True + frame.require_output_check = have_extends and not self.has_known_extends + self.indent() + if have_extends: + self.writeline('parent_template = None') + if 'self' in find_undeclared(node.body, ('self',)): + frame.identifiers.add_special('self') + self.writeline('l_self = TemplateReference(context)') + self.pull_locals(frame) + self.pull_dependencies(node.body) + self.blockvisit(node.body, frame) + 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() + self.writeline('for event in parent_template.' + 'root_render_func(context):') + self.indent() + self.writeline('yield event') + self.outdent(2 + (not self.has_known_extends)) + + # at this point we now have the blocks collected and can visit them too. + for name, block in self.blocks.iteritems(): + block_frame = Frame(eval_ctx) + block_frame.inspect(block.body) + block_frame.block = name + self.writeline('def block_%s(context%s):' % (name, envenv), + block, 1) + self.indent() + undeclared = find_undeclared(block.body, ('self', 'super')) + if 'self' in undeclared: + block_frame.identifiers.add_special('self') + self.writeline('l_self = TemplateReference(context)') + if 'super' in undeclared: + block_frame.identifiers.add_special('super') + self.writeline('l_super = context.super(%r, ' + 'block_%s)' % (name, name)) + self.pull_locals(block_frame) + self.pull_dependencies(block.body) + self.blockvisit(block.body, block_frame) + 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 = 1 + 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 + context = node.scoped and 'context.derived(locals())' or 'context' + self.writeline('for event in context.blocks[%r][0](%s):' % ( + node.name, context), node) + self.indent() + self.simple_write('event', frame) + 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') + self.outdent() + + # 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() + + 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.with_context: + self.unoptimize_scope(frame) + 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, basestring): + 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() + + if node.with_context: + self.writeline('for event in template.root_render_func(' + 'template.new_context(context.parent, True, ' + 'locals())):') + else: + self.writeline('for event in template.module._body_stream:') + + self.indent() + self.simple_write('event', frame) + self.outdent() + + if node.ignore_missing: + self.outdent() + + def visit_Import(self, node, frame): + """Visit regular imports.""" + if node.with_context: + self.unoptimize_scope(frame) + self.writeline('l_%s = ' % node.target, node) + if frame.toplevel: + self.write('context.vars[%r] = ' % node.target) + self.write('environment.get_template(') + self.visit(node.template, frame) + self.write(', %r).' % self.name) + if node.with_context: + self.write('make_module(context.parent, True, locals())') + else: + self.write('module') + if frame.toplevel and not node.target.startswith('_'): + self.writeline('context.exported_vars.discard(%r)' % node.target) + frame.assigned_names.add(node.target) + + def visit_FromImport(self, node, frame): + """Visit named imports.""" + self.newline(node) + self.write('included_template = environment.get_template(') + self.visit(node.template, frame) + self.write(', %r).' % self.name) + if node.with_context: + self.write('make_module(context.parent, True)') + else: + self.write('module') + + var_names = [] + discarded_names = [] + for name in node.names: + if isinstance(name, tuple): + name, alias = name + else: + alias = name + self.writeline('l_%s = getattr(included_template, ' + '%r, missing)' % (alias, name)) + self.writeline('if l_%s is missing:' % alias) + self.indent() + self.writeline('l_%s = environment.undefined(%r %% ' + 'included_template.__name__, ' + 'name=%r)' % + (alias, 'the template %%r (imported on %s) does ' + 'not export the requested name %s' % ( + self.position(node), + repr(name) + ), name)) + self.outdent() + if frame.toplevel: + var_names.append(alias) + if not alias.startswith('_'): + discarded_names.append(alias) + frame.assigned_names.add(alias) + + if var_names: + if len(var_names) == 1: + name = var_names[0] + self.writeline('context.vars[%r] = l_%s' % (name, name)) + else: + self.writeline('context.vars.update({%s})' % ', '.join( + '%r: l_%s' % (name, 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(map(repr, discarded_names))) + + def visit_For(self, node, frame): + # when calculating the nodes for the inner frame we have to exclude + # the iterator contents from it + children = node.iter_child_nodes(exclude=('iter',)) + if node.recursive: + loop_frame = self.function_scoping(node, frame, children, + find_special=False) + else: + loop_frame = frame.inner() + loop_frame.inspect(children) + + # 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',)) + + # 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 not node.recursive: + aliases = self.push_scope(loop_frame, ('loop',)) + + # otherwise we set up a buffer and add a function def + else: + self.writeline('def loop(reciter, loop_render_func):', node) + self.indent() + self.buffer(loop_frame) + aliases = {} + + # 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: + loop_frame.identifiers.add_special('loop') + 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) + + self.pull_locals(loop_frame) + if node.else_: + iteration_indicator = self.temporary_identifier() + self.writeline('%s = 1' % iteration_indicator) + + # Create a fake parent loop if the else or test section of a + # loop is accessing the special loop variable and no parent loop + # exists. + if 'loop' not in aliases and 'loop' in find_undeclared( + node.iter_child_nodes(only=('else_', 'test')), ('loop',)): + self.writeline("l_loop = environment.undefined(%r, name='loop')" % + ("'loop' is undefined. the filter section of a loop as well " + "as the else block doesn't have access to the special 'loop'" + " variable of the current loop. Because there is no parent " + "loop it's undefined. Happened in loop on %s" % + self.position(node))) + + self.writeline('for ', node) + self.visit(node.target, loop_frame) + self.write(extended_loop and ', l_loop in LoopContext(' or ' in ') + + # if we have an extened loop and a node test, we filter in the + # "outer frame". + if extended_loop and node.test is not None: + self.write('(') + self.visit(node.target, loop_frame) + self.write(' for ') + self.visit(node.target, loop_frame) + self.write(' in ') + if node.recursive: + self.write('reciter') + else: + self.visit(node.iter, loop_frame) + self.write(' if (') + test_frame = loop_frame.copy() + self.visit(node.test, test_frame) + self.write('))') + + elif node.recursive: + self.write('reciter') + else: + self.visit(node.iter, loop_frame) + + if node.recursive: + self.write(', recurse=loop_render_func):') + else: + self.write(extended_loop and '):' or ':') + + # tests in not extended loops become a continue + if not extended_loop and node.test is not None: + self.indent() + self.writeline('if not ') + self.visit(node.test, loop_frame) + self.write(':') + self.indent() + self.writeline('continue') + self.outdent(2) + + self.indent() + self.blockvisit(node.body, loop_frame) + if node.else_: + self.writeline('%s = 0' % iteration_indicator) + self.outdent() + + if node.else_: + self.writeline('if %s:' % iteration_indicator) + self.indent() + self.blockvisit(node.else_, loop_frame) + self.outdent() + + # reset the aliases if there are any. + if not node.recursive: + self.pop_scope(aliases, loop_frame) + + # 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) + self.write('loop(') + self.visit(node.iter, frame) + 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() + if node.else_: + self.writeline('else:') + self.indent() + self.blockvisit(node.else_, if_frame) + self.outdent() + + def visit_Macro(self, node, frame): + macro_frame = self.macro_body(node, frame) + self.newline() + if frame.toplevel: + if not node.name.startswith('_'): + self.write('context.exported_vars.add(%r)' % node.name) + self.writeline('context.vars[%r] = ' % node.name) + self.write('l_%s = ' % node.name) + self.macro_def(node, macro_frame) + frame.assigned_names.add(node.name) + + def visit_CallBlock(self, node, frame): + children = node.iter_child_nodes(exclude=('call',)) + call_frame = self.macro_body(node, frame, children) + self.writeline('caller = ') + self.macro_def(node, call_frame) + self.start_write(frame, node) + self.visit_Call(node.call, call_frame, forward_caller=True) + self.end_write(frame) + + def visit_FilterBlock(self, node, frame): + filter_frame = frame.inner() + filter_frame.inspect(node.iter_child_nodes()) + aliases = self.push_scope(filter_frame) + self.pull_locals(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.pop_scope(aliases, filter_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 + + if self.environment.finalize: + finalize = lambda x: unicode(self.environment.finalize(x)) + else: + finalize = unicode + + # 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: + 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: + # 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('(context.eval_ctx.autoescape and' + ' escape or 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(') + 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)) + ' % (') + idx = -1 + self.indent() + for argument in arguments: + self.newline(argument) + close = 0 + if frame.eval_ctx.volatile: + self.write('(context.eval_ctx.autoescape and' + ' escape or 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(') + 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.newline(node) + # toplevel assignments however go into the local namespace and + # the current template's context. We create a copy of the frame + # here and add a set so that the Name visitor can add the assigned + # names here. + if frame.toplevel: + assignment_frame = frame.copy() + assignment_frame.toplevel_assignments = set() + else: + assignment_frame = frame + self.visit(node.target, assignment_frame) + self.write(' = ') + self.visit(node.node, frame) + + # make sure toplevel assignments are added to the context. + if frame.toplevel: + public_names = [x for x in assignment_frame.toplevel_assignments + if not x.startswith('_')] + if len(assignment_frame.toplevel_assignments) == 1: + name = next(iter(assignment_frame.toplevel_assignments)) + self.writeline('context.vars[%r] = l_%s' % (name, name)) + else: + self.writeline('context.vars.update({') + for idx, name in enumerate(assignment_frame.toplevel_assignments): + if idx: + self.write(', ') + self.write('%r: l_%s' % (name, name)) + 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(map(repr, public_names))) + + # -- Expression Visitors + + def visit_Name(self, node, frame): + if node.ctx == 'store' and frame.toplevel: + frame.toplevel_assignments.add(node.name) + self.write('l_' + node.name) + frame.assigned_names.add(node.name) + + def visit_Const(self, node, frame): + val = node.value + 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('(context.eval_ctx.autoescape and Markup or 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): + def visitor(self, node, frame): + self.write('(') + self.visit(node.left, frame) + self.write(' %s ' % operator) + self.visit(node.right, frame) + self.write(')') + return visitor + + def uaop(operator): + def visitor(self, node, frame): + 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') + visit_Or = binop('or') + visit_Pos = uaop('+') + visit_Neg = uaop('-') + visit_Not = uaop('not ') + del binop, uaop + + 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('))') + + 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) + + def visit_Getattr(self, node, frame): + self.write('environment.getattr(') + self.visit(node.node, frame) + self.write(', %r)' % node.attr) + + 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) + + def visit_Filter(self, node, frame): + 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(')') + + 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(')') + + def visit_CondExpr(self, node, frame): + def write_expr2(): + if node.expr2 is not None: + return self.visit(node.expr2, frame) + self.write('environment.undefined(%r)' % ('the inline if-' + 'expression on %s evaluated to false and ' + 'no else section was defined.' % self.position(node))) + + if not have_condexpr: + self.write('((') + self.visit(node.test, frame) + self.write(') and (') + self.visit(node.expr1, frame) + self.write(',) or (') + write_expr2() + self.write(',))[0]') + else: + self.write('(') + self.visit(node.expr1, frame) + self.write(' if ') + self.visit(node.test, frame) + self.write(' else ') + write_expr2() + self.write(')') + + def visit_Call(self, node, frame, forward_caller=False): + 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(')') + + 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.inspect(node.iter_child_nodes()) + aliases = self.push_scope(scope_frame) + self.pull_locals(scope_frame) + self.blockvisit(node.body, scope_frame) + self.pop_scope(aliases, scope_frame) + + 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() + safed_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(safed_ctx) + self.writeline('context.eval_ctx.revert(%s)' % old_ctx_name) |