Add python coverage 3.7 to depot tools.

third_party/coverage/templite.py

+"""A simple Python template renderer, for a nano-subset of Django syntax."""
+
+# Coincidentally named the same as http://code.activestate.com/recipes/496702/
+
+import re, sys
+
+class Templite(object):
+    """A simple template renderer, for a nano-subset of Django syntax.
+
+    Supported constructs are extended variable access::
+
+        {{var.modifer.modifier|filter|filter}}
+
+    loops::
+
+        {% for var in list %}...{% endfor %}
+
+    and ifs::
+
+        {% if var %}...{% endif %}
+
+    Comments are within curly-hash markers::
+
+        {# This will be ignored #}
+
+    Construct a Templite with the template text, then use `render` against a
+    dictionary context to create a finished string.
+
+    """
+    def __init__(self, text, *contexts):
+        """Construct a Templite with the given `text`.
+
+        `contexts` are dictionaries of values to use for future renderings.
+        These are good for filters and global values.
+
+        """
+        self.text = text
+        self.context = {}
+        for context in contexts:
+            self.context.update(context)
+
+        # 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()))
+            elif tok.startswith('{#'):
+                # Comment: ignore it and move on.
+                continue
+            elif tok.startswith('{%'):
+                # Action tag: split into words and parse further.
+                words = tok[2:-2].strip().split()
+                if words[0] == 'if':
+                    # If: ('if', (expr, body_ops))
+                    if_ops = []
+                    assert len(words) == 2
+                    ops.append(('if', (words[1], if_ops)))
+                    ops_stack.append(ops)
+                    ops = if_ops
+                elif words[0] == 'for':
+                    # For: ('for', (varname, listexpr, body_ops))
+                    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
+                elif words[0].startswith('end'):
+                    # Endsomething.  Pop the ops stack
+                    ops = ops_stack.pop()
+                    assert ops[-1][0] == words[0][3:]
+                else:
+                    raise SyntaxError("Don't understand tag %r" % words)
+            else:
+                ops.append(('lit', tok))
+
+        assert not ops_stack, "Unmatched action tag: %r" % ops_stack[-1][0]
+        self.ops = ops
+
+    def render(self, context=None):
+        """Render this template by applying it to `context`.
+
+        `context` is a dictionary of values to use in this rendering.
+
+        """
+        # Make the complete context we'll use.
+        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 value