diff options
Diffstat (limited to 'python/helpers/coverage/templite.py')
| -rw-r--r-- | python/helpers/coverage/templite.py | 228 |
1 files changed, 135 insertions, 93 deletions
diff --git a/python/helpers/coverage/templite.py b/python/helpers/coverage/templite.py index c39e061efd92..e5c0bafefb77 100644 --- a/python/helpers/coverage/templite.py +++ b/python/helpers/coverage/templite.py @@ -2,7 +2,53 @@ # Coincidentally named the same as http://code.activestate.com/recipes/496702/ -import re, sys +import re + +from coverage.backward import set # pylint: disable=W0622 + + +class CodeBuilder(object): + """Build source code conveniently.""" + + def __init__(self, indent=0): + self.code = [] + self.indent_amount = indent + + def add_line(self, line): + """Add a line of source to the code. + + Don't include indentations or newlines. + + """ + self.code.append(" " * self.indent_amount) + self.code.append(line) + self.code.append("\n") + + def add_section(self): + """Add a section, a sub-CodeBuilder.""" + sect = CodeBuilder(self.indent_amount) + self.code.append(sect) + return sect + + def indent(self): + """Increase the current indent for following lines.""" + self.indent_amount += 4 + + def dedent(self): + """Decrease the current indent for following lines.""" + self.indent_amount -= 4 + + def __str__(self): + return "".join([str(c) for c in self.code]) + + def get_function(self, fn_name): + """Compile the code, and return the function `fn_name`.""" + assert self.indent_amount == 0 + g = {} + code_text = str(self) + exec(code_text, g) + return g[fn_name] + class Templite(object): """A simple template renderer, for a nano-subset of Django syntax. @@ -39,53 +85,104 @@ class Templite(object): for context in contexts: self.context.update(context) + # We construct a function in source form, then compile it and hold onto + # it, and execute it to render the template. + code = CodeBuilder() + + code.add_line("def render(ctx, dot):") + code.indent() + vars_code = code.add_section() + self.all_vars = set() + self.loop_vars = set() + code.add_line("result = []") + code.add_line("a = result.append") + code.add_line("e = result.extend") + code.add_line("s = str") + + buffered = [] + def flush_output(): + """Force `buffered` to the code builder.""" + if len(buffered) == 1: + code.add_line("a(%s)" % buffered[0]) + elif len(buffered) > 1: + code.add_line("e([%s])" % ",".join(buffered)) + del buffered[:] + # Split the text to form a list of tokens. toks = re.split(r"(?s)({{.*?}}|{%.*?%}|{#.*?#})", text) - # Parse the tokens into a nested list of operations. Each item in the - # list is a tuple with an opcode, and arguments. They'll be - # interpreted by TempliteEngine. - # - # When parsing an action tag with nested content (if, for), the current - # ops list is pushed onto ops_stack, and the parsing continues in a new - # ops list that is part of the arguments to the if or for op. - ops = [] ops_stack = [] for tok in toks: if tok.startswith('{{'): - # Expression: ('exp', expr) - ops.append(('exp', tok[2:-2].strip())) + # An expression to evaluate. + buffered.append("s(%s)" % self.expr_code(tok[2:-2].strip())) elif tok.startswith('{#'): # Comment: ignore it and move on. continue elif tok.startswith('{%'): # Action tag: split into words and parse further. + flush_output() words = tok[2:-2].strip().split() if words[0] == 'if': - # If: ('if', (expr, body_ops)) - if_ops = [] + # An if statement: evaluate the expression to determine if. assert len(words) == 2 - ops.append(('if', (words[1], if_ops))) - ops_stack.append(ops) - ops = if_ops + ops_stack.append('if') + code.add_line("if %s:" % self.expr_code(words[1])) + code.indent() elif words[0] == 'for': - # For: ('for', (varname, listexpr, body_ops)) + # A loop: iterate over expression result. assert len(words) == 4 and words[2] == 'in' - for_ops = [] - ops.append(('for', (words[1], words[3], for_ops))) - ops_stack.append(ops) - ops = for_ops + ops_stack.append('for') + self.loop_vars.add(words[1]) + code.add_line( + "for c_%s in %s:" % ( + words[1], + self.expr_code(words[3]) + ) + ) + code.indent() elif words[0].startswith('end'): # Endsomething. Pop the ops stack - ops = ops_stack.pop() - assert ops[-1][0] == words[0][3:] + end_what = words[0][3:] + if ops_stack[-1] != end_what: + raise SyntaxError("Mismatched end tag: %r" % end_what) + ops_stack.pop() + code.dedent() else: - raise SyntaxError("Don't understand tag %r" % words) + raise SyntaxError("Don't understand tag: %r" % words[0]) else: - ops.append(('lit', tok)) + # Literal content. If it isn't empty, output it. + if tok: + buffered.append("%r" % tok) + flush_output() - assert not ops_stack, "Unmatched action tag: %r" % ops_stack[-1][0] - self.ops = ops + for var_name in self.all_vars - self.loop_vars: + vars_code.add_line("c_%s = ctx[%r]" % (var_name, var_name)) + + if ops_stack: + raise SyntaxError("Unmatched action tag: %r" % ops_stack[-1]) + + code.add_line("return ''.join(result)") + code.dedent() + self.render_function = code.get_function('render') + + def expr_code(self, expr): + """Generate a Python expression for `expr`.""" + if "|" in expr: + pipes = expr.split("|") + code = self.expr_code(pipes[0]) + for func in pipes[1:]: + self.all_vars.add(func) + code = "c_%s(%s)" % (func, code) + elif "." in expr: + dots = expr.split(".") + code = self.expr_code(dots[0]) + args = [repr(d) for d in dots[1:]] + code = "dot(%s, %s)" % (code, ", ".join(args)) + else: + self.all_vars.add(expr) + code = "c_%s" % expr + return code def render(self, context=None): """Render this template by applying it to `context`. @@ -97,70 +194,15 @@ class Templite(object): ctx = dict(self.context) if context: ctx.update(context) - - # Run it through an engine, and return the result. - engine = _TempliteEngine(ctx) - engine.execute(self.ops) - return "".join(engine.result) - - -class _TempliteEngine(object): - """Executes Templite objects to produce strings.""" - def __init__(self, context): - self.context = context - self.result = [] - - def execute(self, ops): - """Execute `ops` in the engine. - - Called recursively for the bodies of if's and loops. - - """ - for op, args in ops: - if op == 'lit': - self.result.append(args) - elif op == 'exp': - try: - self.result.append(str(self.evaluate(args))) - except: - exc_class, exc, _ = sys.exc_info() - new_exc = exc_class("Couldn't evaluate {{ %s }}: %s" - % (args, exc)) - raise new_exc - elif op == 'if': - expr, body = args - if self.evaluate(expr): - self.execute(body) - elif op == 'for': - var, lis, body = args - vals = self.evaluate(lis) - for val in vals: - self.context[var] = val - self.execute(body) - else: - raise AssertionError("TempliteEngine doesn't grok op %r" % op) - - def evaluate(self, expr): - """Evaluate an expression. - - `expr` can have pipes and dots to indicate data access and filtering. - - """ - if "|" in expr: - pipes = expr.split("|") - value = self.evaluate(pipes[0]) - for func in pipes[1:]: - value = self.evaluate(func)(value) - elif "." in expr: - dots = expr.split('.') - value = self.evaluate(dots[0]) - for dot in dots[1:]: - try: - value = getattr(value, dot) - except AttributeError: - value = value[dot] - if hasattr(value, '__call__'): - value = value() - else: - value = self.context[expr] + return self.render_function(ctx, self.do_dots) + + def do_dots(self, value, *dots): + """Evaluate dotted expressions at runtime.""" + for dot in dots: + try: + value = getattr(value, dot) + except AttributeError: + value = value[dot] + if hasattr(value, '__call__'): + value = value() return value |