Extensions Docs Server: Faster Handlebar

third_party/handlebar/handlebar.py

Index: third_party/handlebar/handlebar.py
diff --git a/third_party/handlebar/handlebar.py b/third_party/handlebar/handlebar.py
index 3e7b5a535d334ff3ef267acbbe22570ff6eddff6..c5a2c101629ab0ed9e25444a9d053d941982b7bd 100644
--- a/third_party/handlebar/handlebar.py
+++ b/third_party/handlebar/handlebar.py
@@ -43,9 +43,6 @@ class CustomContext(object):
 print(Handlebar('hello {{world}}').render(CustomContext()).text)
 """
 
-def _SafeStr(obj):
-  return obj if isinstance(obj, basestring) else str(obj)
-
 class ParseException(Exception):
   """ Exception thrown while parsing the template.
   """
@@ -65,22 +62,24 @@ class StringBuilder(object):
   """
   def __init__(self):
     self._buf = []
-    self._length = 0
 
   def __len__(self):
-    return self._length
+    self._Collapse()
+    return len(self._buf[0])
 
-  def append(self, obj):
-    string = _SafeStr(obj)
+  def append(self, string):
     self._buf.append(string)
-    self._length += len(string)
 
   def toString(self):
-    return u''.join(self._buf)
+    self._Collapse()
+    return self._buf[0]
 
   def __str__(self):
     return self.toString()
 
+  def _Collapse(self):
+    self._buf = [u''.join(self._buf)]
+
 class RenderState(object):
   """ The state of a render call.
   """
@@ -110,7 +109,7 @@ class RenderState(object):
       return self
     buf = StringBuilder()
     for message in messages:
-      buf.append(message)
+      buf.append(str(message))
     self.errors.append(buf.toString())
     return self
 
@@ -144,16 +143,16 @@ class Identifier(object):
       return self._resolveFromContext(renderState.getFirstContext())
 
     resolved = self._resolveFromContexts(renderState.localContexts)
-    if resolved == None:
+    if resolved is None:
       resolved = self._resolveFromContexts(renderState.globalContexts)
-    if resolved == None:
+    if resolved is None:
       renderState.addError("Couldn't resolve identifier ", self._path)
     return resolved
 
   def _resolveFromContexts(self, contexts):
     for context in contexts:
       resolved = self._resolveFromContext(context)
-      if resolved != None:
+      if resolved is not None:
         return resolved
     return None
 
@@ -162,7 +161,7 @@ class Identifier(object):
     for next in self._path:
       # Only require that contexts provide a get method, meaning that callers
       # can provide dict-like contexts (for example, to populate values lazily).
-      if result == None or not getattr(result, "get", None):
+      if result is None or not getattr(result, "get", None):
         return None
       result = result.get(next)
     return result
@@ -236,32 +235,26 @@ class InlineNode(DecoratorNode):
     self._content.render(contentRenderState)
 
     renderState.errors.extend(contentRenderState.errors)
-
-    for c in contentRenderState.text.toString():
-      if c != '\n':
-        renderState.text.append(c)
+    renderState.text.append(
+        contentRenderState.text.toString().replace('\n', ''))
 
 class IndentedNode(DecoratorNode):
   def __init__(self, content, indentation):
     DecoratorNode.__init__(self, content)
-    self._indentation = indentation
+    self._indent_str = ' ' * indentation
 
   def render(self, renderState):
     contentRenderState = renderState.inSameContext()
     self._content.render(contentRenderState)
 
     renderState.errors.extend(contentRenderState.errors)
-
-    self._indent(renderState.text)
-    for i, c in enumerate(contentRenderState.text.toString()):
-      renderState.text.append(c)
-      if c == '\n' and i < len(contentRenderState.text) - 1:
-        self._indent(renderState.text)
+    renderState.text.append(self._indent_str)
+    # TODO: this might introduce an extra \n at the end? need test.
+    renderState.text.append(
+        contentRenderState.text.toString().replace('\n',
+                                                   '\n' + self._indent_str))
     renderState.text.append('\n')
 
-  def _indent(self, buf):
-    buf.append(' ' * self._indentation)
-
 class BlockNode(DecoratorNode):
   def __init__(self, content):
     DecoratorNode.__init__(self, content)
@@ -354,19 +347,13 @@ class EscapedVariableNode(LeafNode):
 
   def render(self, renderState):
     value = self._id.resolve(renderState)
-    if value != None:
-      self._appendEscapedHtml(renderState.text, _SafeStr(value))
-
-  def _appendEscapedHtml(self, escaped, unescaped):
-    for c in unescaped:
-      if c == '<':
-        escaped.append("&lt;")
-      elif c == '>':
-        escaped.append("&gt;")
-      elif c == '&':
-        escaped.append("&amp;")
-      else:
-        escaped.append(c)
+    if value is None:
+      return
+
+    string = value if isinstance(value, basestring) else str(value)
+    renderState.text.append(string.replace('&', '&amp;')
+                                  .replace('<', '&lt;')
+                                  .replace('>', '&gt;'))
 
 class UnescapedVariableNode(LeafNode):
   """ {{{foo}}}
@@ -377,8 +364,10 @@ class UnescapedVariableNode(LeafNode):
 
   def render(self, renderState):
     value = self._id.resolve(renderState)
-    if value != None:
-      renderState.text.append(value)
+    if value is None:
+      return
+    renderState.text.append(
+        value if isinstance(value, basestring) else str(value))
 
 class SectionNode(DecoratorNode):
   """ {{#foo}} ... {{/}}
@@ -389,7 +378,7 @@ class SectionNode(DecoratorNode):
 
   def render(self, renderState):
     value = self._id.resolve(renderState)
-    if value == None:
+    if value is None:
       return
 
     if isinstance(value, list):
@@ -420,7 +409,7 @@ class VertedSectionNode(DecoratorNode):
       renderState.localContexts.pop(0)
 
 def _VertedSectionNodeShouldRender(value):
-  if value == None:
+  if value is None:
     return False
   if isinstance(value, bool):
     return value
@@ -457,8 +446,9 @@ class JsonNode(LeafNode):
 
   def render(self, renderState):
     value = self._id.resolve(renderState)
-    if value != None:
-      renderState.text.append(json.dumps(value, separators=(',',':')))
+    if value is None:
+      return
+    renderState.text.append(json.dumps(value, separators=(',',':')))
 
 class PartialNode(LeafNode):
   """ {{+foo}}
@@ -549,7 +539,7 @@ class TokenStream(object):
     self.advance()
 
   def hasNext(self):
-    return self.nextToken != None
+    return self.nextToken is not None
 
   def advance(self):
     if self.nextContents == '\n':