| # -*- coding: utf-8 -*- |
| """ |
| jinja2.compiler |
| ~~~~~~~~~~~~~~~ |
| |
| Compiles nodes into python code. |
| |
| :copyright: Copyright 2008 by Armin Ronacher. |
| :license: GNU GPL. |
| """ |
| from random import randrange |
| from operator import xor |
| from cStringIO import StringIO |
| from jinja2 import nodes |
| from jinja2.visitor import NodeVisitor, NodeTransformer |
| from jinja2.exceptions import TemplateAssertionError |
| |
| |
| operators = { |
| 'eq': '==', |
| 'ne': '!=', |
| 'gt': '>', |
| 'gteq': '>=', |
| 'lt': '<', |
| 'lteq': '<=', |
| 'in': 'in', |
| 'notin': 'not in' |
| } |
| |
| |
| def generate(node, filename, stream=None): |
| is_child = node.find(nodes.Extends) is not None |
| generator = CodeGenerator(is_child, filename, stream) |
| generator.visit(node) |
| if stream is None: |
| return generator.stream.getvalue() |
| |
| |
| 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() |
| |
| # 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): |
| """Check if a name is declared in this or an outer scope.""" |
| return name in self.declared or name in self.declared_locally or \ |
| name in self.declared_parameter |
| |
| def find_shadowed(self): |
| """Find all the shadowed names.""" |
| return self.declared & (self.declared_locally | self.declared_parameter) |
| |
| |
| class Frame(object): |
| |
| def __init__(self, parent=None): |
| self.identifiers = Identifiers() |
| self.parent = parent |
| if parent is not None: |
| self.identifiers.declared.update( |
| parent.identifiers.declared | |
| parent.identifiers.undeclared | |
| parent.identifiers.declared_locally | |
| parent.identifiers.declared_parameter |
| ) |
| |
| def inspect(self, nodes): |
| """Walk the node and check for identifiers.""" |
| visitor = FrameIdentifierVisitor(self.identifiers) |
| for node in nodes: |
| visitor.visit(node) |
| |
| def inner(self): |
| """Return an inner frame.""" |
| return Frame(self) |
| |
| |
| class FrameIdentifierVisitor(NodeVisitor): |
| """A visitor for `Frame.inspect`.""" |
| |
| def __init__(self, identifiers): |
| self.identifiers = identifiers |
| |
| def visit_Name(self, node): |
| """All assignments to names go through this function.""" |
| if node.ctx in ('store', 'param'): |
| self.identifiers.declared_locally.add(node.name) |
| elif node.ctx == 'load': |
| if not self.identifiers.is_declared(node.name): |
| self.identifiers.undeclared.add(node.name) |
| |
| def visit_Macro(self, node): |
| """Macros set local.""" |
| self.identifiers.declared_locally.add(node.name) |
| |
| # stop traversing at instructions that have their own scope. |
| visit_Block = visit_Call = visit_FilterBlock = \ |
| visit_For = lambda s, n: None |
| |
| |
| class CodeGenerator(NodeVisitor): |
| |
| def __init__(self, is_child, filename, stream=None): |
| if stream is None: |
| stream = StringIO() |
| self.is_child = is_child |
| self.filename = filename |
| self.stream = stream |
| self.blocks = {} |
| self.indentation = 0 |
| self.new_lines = 0 |
| self.last_identifier = 0 |
| self._last_line = 0 |
| self._first_write = True |
| |
| def temporary_identifier(self): |
| self.last_identifier += 1 |
| return 't%d' % self.last_identifier |
| |
| def indent(self): |
| self.indentation += 1 |
| |
| def outdent(self): |
| self.indentation -= 1 |
| |
| def blockvisit(self, nodes, frame, force_generator=False): |
| self.indent() |
| if force_generator: |
| self.writeline('if 0: yield None') |
| for node in nodes: |
| self.visit(node, frame) |
| self.outdent() |
| |
| def write(self, x): |
| if self.new_lines: |
| if not self._first_write: |
| self.stream.write('\n' * self.new_lines) |
| 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): |
| self.newline(node, extra) |
| self.write(x) |
| |
| def newline(self, node=None, extra=0): |
| self.new_lines = max(self.new_lines, 1 + extra) |
| if node is not None and node.lineno != self._last_line: |
| self.write('# line: %s' % node.lineno) |
| self.new_lines = 1 |
| self._last_line = node.lineno |
| |
| def pull_locals(self, frame, no_indent=False): |
| if not no_indent: |
| self.indent() |
| for name in frame.identifiers.undeclared: |
| self.writeline('l_%s = context[%r]' % (name, name)) |
| if not no_indent: |
| self.outdent() |
| |
| # -- Visitors |
| |
| def visit_Template(self, node, frame=None): |
| assert frame is None, 'no root frame allowed' |
| self.writeline('from jinja2.runtime import *') |
| self.writeline('filename = %r' % self.filename) |
| self.writeline('context = TemplateContext(global_context, ' |
| 'make_undefined, filename)') |
| |
| # generate the body render function. |
| self.writeline('def body(context=context):', extra=1) |
| frame = Frame() |
| frame.inspect(node.body) |
| self.pull_locals(frame) |
| self.blockvisit(node.body, frame, True) |
| |
| # top level changes to locals are pushed back to the |
| # context of *this* template for include. |
| self.indent() |
| self.writeline('context.from_locals(locals())') |
| self.outdent() |
| |
| # at this point we now have the blocks collected and can visit them too. |
| for name, block in self.blocks.iteritems(): |
| block_frame = Frame() |
| block_frame.inspect(block.body) |
| self.writeline('def block_%s(context=context):' % name, block, 1) |
| self.pull_locals(block_frame) |
| self.blockvisit(block.body, block_frame, True) |
| |
| def visit_Block(self, node, frame): |
| """Call a block and register it for the template.""" |
| if node.name in self.blocks: |
| raise TemplateAssertionError("the block '%s' was already defined" % |
| node.name, node.lineno, |
| self.filename) |
| self.blocks[node.name] = node |
| self.writeline('for event in block_%s():' % node.name) |
| self.indent() |
| self.writeline('yield event') |
| self.outdent() |
| |
| def visit_Extends(self, node, frame): |
| """Calls the extender.""" |
| self.writeline('extends(', node, 1) |
| self.visit(node.template) |
| self.write(', globals())') |
| |
| def visit_For(self, node, frame): |
| loop_frame = frame.inner() |
| loop_frame.inspect(node.iter_child_nodes()) |
| loop_frame.identifiers.add_special('loop') |
| extended_loop = bool(node.else_) or \ |
| 'loop' in loop_frame.identifiers.undeclared |
| |
| # make sure we "backup" overridden, local identifiers |
| # TODO: we should probably optimize this and check if the |
| # identifier is in use afterwards. |
| aliases = {} |
| for name in loop_frame.identifiers.find_shadowed(): |
| aliases[name] = ident = self.temporary_identifier() |
| self.writeline('%s = l_%s' % (ident, name)) |
| |
| self.pull_locals(loop_frame, True) |
| |
| self.newline(node) |
| if node.else_: |
| self.writeline('l_loop = None') |
| self.write('for ') |
| self.visit(node.target, loop_frame) |
| self.write(extended_loop and ', l_loop in looper(' or ' in ') |
| self.visit(node.iter, loop_frame) |
| self.write(extended_loop and '):' or ':') |
| self.blockvisit(node.body, loop_frame) |
| |
| if node.else_: |
| self.writeline('if l_loop is None:') |
| self.blockvisit(node.else_, loop_frame) |
| |
| # reset the aliases and clean them up |
| for name, alias in aliases.iteritems(): |
| self.writeline('l_%s = %s; del %s' % (name, alias, alias)) |
| |
| def visit_If(self, node, frame): |
| self.writeline('if ', node) |
| self.visit(node.test, frame) |
| self.write(':') |
| self.blockvisit(node.body, frame) |
| if node.else_: |
| self.writeline('else:') |
| self.blockvisit(node.else_, frame) |
| |
| def visit_ExprStmt(self, node, frame): |
| self.newline(node) |
| self.visit(node, frame) |
| |
| def visit_Output(self, node, frame): |
| self.newline(node) |
| |
| # try to evaluate as many chunks as possible into a static |
| # string at compile time. |
| body = [] |
| for child in node.nodes: |
| try: |
| const = unicode(child.as_const()) |
| except: |
| 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 we just yield them |
| if len(body) < 3: |
| for item in body: |
| if isinstance(item, list): |
| self.writeline('yield %s' % repr(u''.join(item))) |
| else: |
| self.newline(item) |
| self.write('yield unicode(') |
| self.visit(item, frame) |
| self.write(')') |
| |
| # 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(u''.join(item).replace('%', '%%')) |
| else: |
| format.append('%s') |
| arguments.append(item) |
| self.writeline('yield %r %% (' % u''.join(format)) |
| idx = -1 |
| for idx, argument in enumerate(arguments): |
| if idx: |
| self.write(', ') |
| self.visit(argument, frame) |
| self.write(idx == 0 and ',)' or ')') |
| |
| def visit_Name(self, node, frame): |
| # at this point we should only have locals left as the |
| # blocks, macros and template body ensure that they are set. |
| self.write('l_' + node.name) |
| |
| def visit_Const(self, node, frame): |
| val = node.value |
| if isinstance(val, float): |
| # XXX: add checks for infinity and nan |
| self.write(str(val)) |
| else: |
| self.write(repr(val)) |
| |
| 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) |
| 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_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_Subscript(self, node, frame): |
| self.write('subscript(') |
| self.visit(node.node, frame) |
| self.write(', ') |
| self.visit(node.arg, frame) |
| self.write(')') |