1"""The code for async support. Importing this patches Jinja."""
2import asyncio
3import inspect
4from functools import update_wrapper
5
6from markupsafe import Markup
7
8from .environment import TemplateModule
9from .runtime import LoopContext
10from .utils import concat
11from .utils import internalcode
12from .utils import missing
13
14
15async def concat_async(async_gen):
16    rv = []
17
18    async def collect():
19        async for event in async_gen:
20            rv.append(event)
21
22    await collect()
23    return concat(rv)
24
25
26async def generate_async(self, *args, **kwargs):
27    vars = dict(*args, **kwargs)
28    try:
29        async for event in self.root_render_func(self.new_context(vars)):
30            yield event
31    except Exception:
32        yield self.environment.handle_exception()
33
34
35def wrap_generate_func(original_generate):
36    def _convert_generator(self, loop, args, kwargs):
37        async_gen = self.generate_async(*args, **kwargs)
38        try:
39            while 1:
40                yield loop.run_until_complete(async_gen.__anext__())
41        except StopAsyncIteration:
42            pass
43
44    def generate(self, *args, **kwargs):
45        if not self.environment.is_async:
46            return original_generate(self, *args, **kwargs)
47        return _convert_generator(self, asyncio.get_event_loop(), args, kwargs)
48
49    return update_wrapper(generate, original_generate)
50
51
52async def render_async(self, *args, **kwargs):
53    if not self.environment.is_async:
54        raise RuntimeError("The environment was not created with async mode enabled.")
55
56    vars = dict(*args, **kwargs)
57    ctx = self.new_context(vars)
58
59    try:
60        return await concat_async(self.root_render_func(ctx))
61    except Exception:
62        return self.environment.handle_exception()
63
64
65def wrap_render_func(original_render):
66    def render(self, *args, **kwargs):
67        if not self.environment.is_async:
68            return original_render(self, *args, **kwargs)
69        loop = asyncio.get_event_loop()
70        return loop.run_until_complete(self.render_async(*args, **kwargs))
71
72    return update_wrapper(render, original_render)
73
74
75def wrap_block_reference_call(original_call):
76    @internalcode
77    async def async_call(self):
78        rv = await concat_async(self._stack[self._depth](self._context))
79        if self._context.eval_ctx.autoescape:
80            rv = Markup(rv)
81        return rv
82
83    @internalcode
84    def __call__(self):
85        if not self._context.environment.is_async:
86            return original_call(self)
87        return async_call(self)
88
89    return update_wrapper(__call__, original_call)
90
91
92def wrap_macro_invoke(original_invoke):
93    @internalcode
94    async def async_invoke(self, arguments, autoescape):
95        rv = await self._func(*arguments)
96        if autoescape:
97            rv = Markup(rv)
98        return rv
99
100    @internalcode
101    def _invoke(self, arguments, autoescape):
102        if not self._environment.is_async:
103            return original_invoke(self, arguments, autoescape)
104        return async_invoke(self, arguments, autoescape)
105
106    return update_wrapper(_invoke, original_invoke)
107
108
109@internalcode
110async def get_default_module_async(self):
111    if self._module is not None:
112        return self._module
113    self._module = rv = await self.make_module_async()
114    return rv
115
116
117def wrap_default_module(original_default_module):
118    @internalcode
119    def _get_default_module(self, ctx=None):
120        if self.environment.is_async:
121            raise RuntimeError("Template module attribute is unavailable in async mode")
122        return original_default_module(self, ctx)
123
124    return _get_default_module
125
126
127async def make_module_async(self, vars=None, shared=False, locals=None):
128    context = self.new_context(vars, shared, locals)
129    body_stream = []
130    async for item in self.root_render_func(context):
131        body_stream.append(item)
132    return TemplateModule(self, context, body_stream)
133
134
135def patch_template():
136    from . import Template
137
138    Template.generate = wrap_generate_func(Template.generate)
139    Template.generate_async = update_wrapper(generate_async, Template.generate_async)
140    Template.render_async = update_wrapper(render_async, Template.render_async)
141    Template.render = wrap_render_func(Template.render)
142    Template._get_default_module = wrap_default_module(Template._get_default_module)
143    Template._get_default_module_async = get_default_module_async
144    Template.make_module_async = update_wrapper(
145        make_module_async, Template.make_module_async
146    )
147
148
149def patch_runtime():
150    from .runtime import BlockReference, Macro
151
152    BlockReference.__call__ = wrap_block_reference_call(BlockReference.__call__)
153    Macro._invoke = wrap_macro_invoke(Macro._invoke)
154
155
156def patch_filters():
157    from .filters import FILTERS
158    from .asyncfilters import ASYNC_FILTERS
159
160    FILTERS.update(ASYNC_FILTERS)
161
162
163def patch_all():
164    patch_template()
165    patch_runtime()
166    patch_filters()
167
168
169async def auto_await(value):
170    if inspect.isawaitable(value):
171        return await value
172    return value
173
174
175async def auto_aiter(iterable):
176    if hasattr(iterable, "__aiter__"):
177        async for item in iterable:
178            yield item
179        return
180    for item in iterable:
181        yield item
182
183
184class AsyncLoopContext(LoopContext):
185    _to_iterator = staticmethod(auto_aiter)
186
187    @property
188    async def length(self):
189        if self._length is not None:
190            return self._length
191
192        try:
193            self._length = len(self._iterable)
194        except TypeError:
195            iterable = [x async for x in self._iterator]
196            self._iterator = self._to_iterator(iterable)
197            self._length = len(iterable) + self.index + (self._after is not missing)
198
199        return self._length
200
201    @property
202    async def revindex0(self):
203        return await self.length - self.index
204
205    @property
206    async def revindex(self):
207        return await self.length - self.index0
208
209    async def _peek_next(self):
210        if self._after is not missing:
211            return self._after
212
213        try:
214            self._after = await self._iterator.__anext__()
215        except StopAsyncIteration:
216            self._after = missing
217
218        return self._after
219
220    @property
221    async def last(self):
222        return await self._peek_next() is missing
223
224    @property
225    async def nextitem(self):
226        rv = await self._peek_next()
227
228        if rv is missing:
229            return self._undefined("there is no next item")
230
231        return rv
232
233    def __aiter__(self):
234        return self
235
236    async def __anext__(self):
237        if self._after is not missing:
238            rv = self._after
239            self._after = missing
240        else:
241            rv = await self._iterator.__anext__()
242
243        self.index0 += 1
244        self._before = self._current
245        self._current = rv
246        return rv, self
247
248
249patch_all()
250