Merge flask framework and other stuff from master

1 files changed, 256 insertions, 0 deletions

diff --git a/python/jinja2/asyncsupport.py b/python/jinja2/asyncsupport.py
new file mode 100644
index 0000000..b1e7b5c
--- /dev/null
+++ b/python/jinja2/asyncsupport.py
@@ -0,0 +1,256 @@
+# -*- coding: utf-8 -*-
+"""
+    jinja2.asyncsupport
+    ~~~~~~~~~~~~~~~~~~~
+
+    Has all the code for async support which is implemented as a patch
+    for supported Python versions.
+
+    :copyright: (c) 2017 by the Jinja Team.
+    :license: BSD, see LICENSE for more details.
+"""
+import sys
+import asyncio
+import inspect
+from functools import update_wrapper
+
+from jinja2.utils import concat, internalcode, Markup
+from jinja2.environment import TemplateModule
+from jinja2.runtime import LoopContextBase, _last_iteration
+
+
+async def concat_async(async_gen):
+    rv = []
+    async def collect():
+        async for event in async_gen:
+            rv.append(event)
+    await collect()
+    return concat(rv)
+
+
+async def generate_async(self, *args, **kwargs):
+    vars = dict(*args, **kwargs)
+    try:
+        async for event in self.root_render_func(self.new_context(vars)):
+            yield event
+    except Exception:
+        exc_info = sys.exc_info()
+    else:
+        return
+    yield self.environment.handle_exception(exc_info, True)
+
+
+def wrap_generate_func(original_generate):
+    def _convert_generator(self, loop, args, kwargs):
+        async_gen = self.generate_async(*args, **kwargs)
+        try:
+            while 1:
+                yield loop.run_until_complete(async_gen.__anext__())
+        except StopAsyncIteration:
+            pass
+    def generate(self, *args, **kwargs):
+        if not self.environment.is_async:
+            return original_generate(self, *args, **kwargs)
+        return _convert_generator(self, asyncio.get_event_loop(), args, kwargs)
+    return update_wrapper(generate, original_generate)
+
+
+async def render_async(self, *args, **kwargs):
+    if not self.environment.is_async:
+        raise RuntimeError('The environment was not created with async mode '
+                           'enabled.')
+
+    vars = dict(*args, **kwargs)
+    ctx = self.new_context(vars)
+
+    try:
+        return await concat_async(self.root_render_func(ctx))
+    except Exception:
+        exc_info = sys.exc_info()
+    return self.environment.handle_exception(exc_info, True)
+
+
+def wrap_render_func(original_render):
+    def render(self, *args, **kwargs):
+        if not self.environment.is_async:
+            return original_render(self, *args, **kwargs)
+        loop = asyncio.get_event_loop()
+        return loop.run_until_complete(self.render_async(*args, **kwargs))
+    return update_wrapper(render, original_render)
+
+
+def wrap_block_reference_call(original_call):
+    @internalcode
+    async def async_call(self):
+        rv = await concat_async(self._stack[self._depth](self._context))
+        if self._context.eval_ctx.autoescape:
+            rv = Markup(rv)
+        return rv
+
+    @internalcode
+    def __call__(self):
+        if not self._context.environment.is_async:
+            return original_call(self)
+        return async_call(self)
+
+    return update_wrapper(__call__, original_call)
+
+
+def wrap_macro_invoke(original_invoke):
+    @internalcode
+    async def async_invoke(self, arguments, autoescape):
+        rv = await self._func(*arguments)
+        if autoescape:
+            rv = Markup(rv)
+        return rv
+
+    @internalcode
+    def _invoke(self, arguments, autoescape):
+        if not self._environment.is_async:
+            return original_invoke(self, arguments, autoescape)
+        return async_invoke(self, arguments, autoescape)
+    return update_wrapper(_invoke, original_invoke)
+
+
+@internalcode
+async def get_default_module_async(self):
+    if self._module is not None:
+        return self._module
+    self._module = rv = await self.make_module_async()
+    return rv
+
+
+def wrap_default_module(original_default_module):
+    @internalcode
+    def _get_default_module(self):
+        if self.environment.is_async:
+            raise RuntimeError('Template module attribute is unavailable '
+                               'in async mode')
+        return original_default_module(self)
+    return _get_default_module
+
+
+async def make_module_async(self, vars=None, shared=False, locals=None):
+    context = self.new_context(vars, shared, locals)
+    body_stream = []
+    async for item in self.root_render_func(context):
+        body_stream.append(item)
+    return TemplateModule(self, context, body_stream)
+
+
+def patch_template():
+    from jinja2 import Template
+    Template.generate = wrap_generate_func(Template.generate)
+    Template.generate_async = update_wrapper(
+        generate_async, Template.generate_async)
+    Template.render_async = update_wrapper(
+        render_async, Template.render_async)
+    Template.render = wrap_render_func(Template.render)
+    Template._get_default_module = wrap_default_module(
+        Template._get_default_module)
+    Template._get_default_module_async = get_default_module_async
+    Template.make_module_async = update_wrapper(
+        make_module_async, Template.make_module_async)
+
+
+def patch_runtime():
+    from jinja2.runtime import BlockReference, Macro
+    BlockReference.__call__ = wrap_block_reference_call(
+        BlockReference.__call__)
+    Macro._invoke = wrap_macro_invoke(Macro._invoke)
+
+
+def patch_filters():
+    from jinja2.filters import FILTERS
+    from jinja2.asyncfilters import ASYNC_FILTERS
+    FILTERS.update(ASYNC_FILTERS)
+
+
+def patch_all():
+    patch_template()
+    patch_runtime()
+    patch_filters()
+
+
+async def auto_await(value):
+    if inspect.isawaitable(value):
+        return await value
+    return value
+
+
+async def auto_aiter(iterable):
+    if hasattr(iterable, '__aiter__'):
+        async for item in iterable:
+            yield item
+        return
+    for item in iterable:
+        yield item
+
+
+class AsyncLoopContext(LoopContextBase):
+
+    def __init__(self, async_iterator, undefined, after, length, recurse=None,
+                 depth0=0):
+        LoopContextBase.__init__(self, undefined, recurse, depth0)
+        self._async_iterator = async_iterator
+        self._after = after
+        self._length = length
+
+    @property
+    def length(self):
+        if self._length is None:
+            raise TypeError('Loop length for some iterators cannot be '
+                            'lazily calculated in async mode')
+        return self._length
+
+    def __aiter__(self):
+        return AsyncLoopContextIterator(self)
+
+
+class AsyncLoopContextIterator(object):
+    __slots__ = ('context',)
+
+    def __init__(self, context):
+        self.context = context
+
+    def __aiter__(self):
+        return self
+
+    async def __anext__(self):
+        ctx = self.context
+        ctx.index0 += 1
+        if ctx._after is _last_iteration:
+            raise StopAsyncIteration()
+        ctx._before = ctx._current
+        ctx._current = ctx._after
+        try:
+            ctx._after = await ctx._async_iterator.__anext__()
+        except StopAsyncIteration:
+            ctx._after = _last_iteration
+        return ctx._current, ctx
+
+
+async def make_async_loop_context(iterable, undefined, recurse=None, depth0=0):
+    # Length is more complicated and less efficient in async mode.  The
+    # reason for this is that we cannot know if length will be used
+    # upfront but because length is a property we cannot lazily execute it
+    # later.  This means that we need to buffer it up and measure :(
+    #
+    # We however only do this for actual iterators, not for async
+    # iterators as blocking here does not seem like the best idea in the
+    # world.
+    try:
+        length = len(iterable)
+    except (TypeError, AttributeError):
+        if not hasattr(iterable, '__aiter__'):
+            iterable = tuple(iterable)
+            length = len(iterable)
+        else:
+            length = None
+    async_iterator = auto_aiter(iterable)
+    try:
+        after = await async_iterator.__anext__()
+    except StopAsyncIteration:
+        after = _last_iteration
+    return AsyncLoopContext(async_iterator, undefined, after, length, recurse,
+                            depth0)