1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
//! This is an implementation of [`Reader`] for reading from a [`AsyncBufRead`]
//! as underlying byte stream. This reader fully implements async/await so reading
//! can use non-blocking I/O.

use std::pin::Pin;
use std::task::{Context, Poll};

use tokio::io::{self, AsyncBufRead, AsyncBufReadExt, AsyncRead, ReadBuf};

use crate::errors::{Error, Result, SyntaxError};
use crate::events::Event;
use crate::name::{QName, ResolveResult};
use crate::parser::{ElementParser, Parser, PiParser};
use crate::reader::buffered_reader::impl_buffered_source;
use crate::reader::{BangType, BinaryStream, NsReader, ParseState, ReadTextResult, Reader, Span};
use crate::utils::is_whitespace;

/// A struct for read XML asynchronously from an [`AsyncBufRead`].
///
/// Having own struct allows us to implement anything without risk of name conflicts
/// and does not suffer from the impossibility of having `async` in traits.
struct TokioAdapter<'a, R>(&'a mut R);

impl<'a, R: AsyncBufRead + Unpin> TokioAdapter<'a, R> {
    impl_buffered_source!('b, 0, async, await);
}

////////////////////////////////////////////////////////////////////////////////////////////////////

impl<'r, R> AsyncRead for BinaryStream<'r, R>
where
    R: AsyncRead + Unpin,
{
    fn poll_read(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &mut ReadBuf<'_>,
    ) -> Poll<io::Result<()>> {
        let start = buf.remaining();
        let this = self.get_mut();
        let poll = Pin::new(&mut *this.inner).poll_read(cx, buf);

        // If something was read, update offset
        if let Poll::Ready(Ok(_)) = poll {
            let amt = start - buf.remaining();
            *this.offset += amt as u64;
        }
        poll
    }
}

impl<'r, R> AsyncBufRead for BinaryStream<'r, R>
where
    R: AsyncBufRead + Unpin,
{
    #[inline]
    fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
        Pin::new(&mut *self.get_mut().inner).poll_fill_buf(cx)
    }

    #[inline]
    fn consume(self: Pin<&mut Self>, amt: usize) {
        let this = self.get_mut();
        this.inner.consume(amt);
        *this.offset += amt as u64;
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////

impl<R: AsyncBufRead + Unpin> Reader<R> {
    /// An asynchronous version of [`read_event_into()`]. Reads the next event into
    /// given buffer.
    ///
    /// This is the main entry point for reading XML `Event`s when using an async reader.
    ///
    /// See the documentation of [`read_event_into()`] for more information.
    ///
    /// # Examples
    ///
    /// ```
    /// # tokio_test::block_on(async {
    /// # use pretty_assertions::assert_eq;
    /// use quick_xml::events::Event;
    /// use quick_xml::reader::Reader;
    ///
    /// // This explicitly uses `from_reader("...".as_bytes())` to use a buffered
    /// // reader instead of relying on the zero-copy optimizations for reading
    /// // from byte slices, which is provides the sync interface anyway.
    /// let mut reader = Reader::from_reader(r#"
    ///     <tag1 att1 = "test">
    ///        <tag2><!--Test comment-->Test</tag2>
    ///        <tag2>Test 2</tag2>
    ///     </tag1>
    /// "#.as_bytes());
    /// reader.config_mut().trim_text(true);
    ///
    /// let mut count = 0;
    /// let mut buf = Vec::new();
    /// let mut txt = Vec::new();
    /// loop {
    ///     match reader.read_event_into_async(&mut buf).await {
    ///         Ok(Event::Start(_)) => count += 1,
    ///         Ok(Event::Text(e)) => txt.push(e.unescape().unwrap().into_owned()),
    ///         Err(e) => panic!("Error at position {}: {:?}", reader.error_position(), e),
    ///         Ok(Event::Eof) => break,
    ///         _ => (),
    ///     }
    ///     buf.clear();
    /// }
    /// assert_eq!(count, 3);
    /// assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
    /// # }) // tokio_test::block_on
    /// ```
    ///
    /// [`read_event_into()`]: Reader::read_event_into
    pub async fn read_event_into_async<'b>(
        &mut self,
        mut buf: &'b mut Vec<u8>,
    ) -> Result<Event<'b>> {
        read_event_impl!(
            self, buf,
            TokioAdapter(&mut self.reader),
            read_until_close_async,
            await
        )
    }

    /// An asynchronous version of [`read_to_end_into()`].
    /// Reads asynchronously until end element is found using provided buffer as
    /// intermediate storage for events content. This function is supposed to be
    /// called after you already read a [`Start`] event.
    ///
    /// See the documentation of [`read_to_end_into()`] for more information.
    ///
    /// # Examples
    ///
    /// This example shows, how you can skip XML content after you read the
    /// start event.
    ///
    /// ```
    /// # tokio_test::block_on(async {
    /// # use pretty_assertions::assert_eq;
    /// use quick_xml::events::{BytesStart, Event};
    /// use quick_xml::reader::Reader;
    ///
    /// let mut reader = Reader::from_reader(r#"
    ///     <outer>
    ///         <inner>
    ///             <inner></inner>
    ///             <inner/>
    ///             <outer></outer>
    ///             <outer/>
    ///         </inner>
    ///     </outer>
    /// "#.as_bytes());
    /// reader.config_mut().trim_text(true);
    /// let mut buf = Vec::new();
    ///
    /// let start = BytesStart::new("outer");
    /// let end   = start.to_end().into_owned();
    ///
    /// // First, we read a start event...
    /// assert_eq!(reader.read_event_into_async(&mut buf).await.unwrap(), Event::Start(start));
    ///
    /// // ...then, we could skip all events to the corresponding end event.
    /// // This call will correctly handle nested <outer> elements.
    /// // Note, however, that this method does not handle namespaces.
    /// reader.read_to_end_into_async(end.name(), &mut buf).await.unwrap();
    ///
    /// // At the end we should get an Eof event, because we ate the whole XML
    /// assert_eq!(reader.read_event_into_async(&mut buf).await.unwrap(), Event::Eof);
    /// # }) // tokio_test::block_on
    /// ```
    ///
    /// [`read_to_end_into()`]: Self::read_to_end_into
    /// [`Start`]: Event::Start
    pub async fn read_to_end_into_async<'n>(
        &mut self,
        // We should name that lifetime due to https://github.com/rust-lang/rust/issues/63033`
        end: QName<'n>,
        buf: &mut Vec<u8>,
    ) -> Result<Span> {
        Ok(read_to_end!(self, end, buf, read_event_into_async, { buf.clear(); }, await))
    }

    /// Private function to read until `>` is found. This function expects that
    /// it was called just after encounter a `<` symbol.
    async fn read_until_close_async<'b>(&mut self, buf: &'b mut Vec<u8>) -> Result<Event<'b>> {
        read_until_close!(self, buf, TokioAdapter(&mut self.reader), await)
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////

impl<R: AsyncBufRead + Unpin> NsReader<R> {
    /// An asynchronous version of [`read_event_into()`]. Reads the next event into
    /// given buffer.
    ///
    /// This method manages namespaces but doesn't resolve them automatically.
    /// You should call [`resolve_element()`] if you want to get a namespace.
    ///
    /// You also can use [`read_resolved_event_into_async()`] instead if you want
    /// to resolve namespace as soon as you get an event.
    ///
    /// # Examples
    ///
    /// ```
    /// # tokio_test::block_on(async {
    /// # use pretty_assertions::assert_eq;
    /// use quick_xml::events::Event;
    /// use quick_xml::name::{Namespace, ResolveResult::*};
    /// use quick_xml::reader::NsReader;
    ///
    /// let mut reader = NsReader::from_reader(r#"
    ///     <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
    ///        <y:tag2><!--Test comment-->Test</y:tag2>
    ///        <y:tag2>Test 2</y:tag2>
    ///     </x:tag1>
    /// "#.as_bytes());
    /// reader.config_mut().trim_text(true);
    ///
    /// let mut count = 0;
    /// let mut buf = Vec::new();
    /// let mut txt = Vec::new();
    /// loop {
    ///     match reader.read_event_into_async(&mut buf).await.unwrap() {
    ///         Event::Start(e) => {
    ///             count += 1;
    ///             let (ns, local) = reader.resolve_element(e.name());
    ///             match local.as_ref() {
    ///                 b"tag1" => assert_eq!(ns, Bound(Namespace(b"www.xxxx"))),
    ///                 b"tag2" => assert_eq!(ns, Bound(Namespace(b"www.yyyy"))),
    ///                 _ => unreachable!(),
    ///             }
    ///         }
    ///         Event::Text(e) => {
    ///             txt.push(e.unescape().unwrap().into_owned())
    ///         }
    ///         Event::Eof => break,
    ///         _ => (),
    ///     }
    ///     buf.clear();
    /// }
    /// assert_eq!(count, 3);
    /// assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
    /// # }) // tokio_test::block_on
    /// ```
    ///
    /// [`read_event_into()`]: NsReader::read_event_into
    /// [`resolve_element()`]: Self::resolve_element
    /// [`read_resolved_event_into_async()`]: Self::read_resolved_event_into_async
    pub async fn read_event_into_async<'b>(&mut self, buf: &'b mut Vec<u8>) -> Result<Event<'b>> {
        self.pop();
        let event = self.reader.read_event_into_async(buf).await;
        self.process_event(event)
    }

    /// An asynchronous version of [`read_to_end_into()`].
    /// Reads asynchronously until end element is found using provided buffer as
    /// intermediate storage for events content. This function is supposed to be
    /// called after you already read a [`Start`] event.
    ///
    /// See the documentation of [`read_to_end_into()`] for more information.
    ///
    /// # Examples
    ///
    /// This example shows, how you can skip XML content after you read the
    /// start event.
    ///
    /// ```
    /// # tokio_test::block_on(async {
    /// # use pretty_assertions::assert_eq;
    /// use quick_xml::name::{Namespace, ResolveResult};
    /// use quick_xml::events::{BytesStart, Event};
    /// use quick_xml::reader::NsReader;
    ///
    /// let mut reader = NsReader::from_reader(r#"
    ///     <outer xmlns="namespace 1">
    ///         <inner xmlns="namespace 2">
    ///             <outer></outer>
    ///         </inner>
    ///         <inner>
    ///             <inner></inner>
    ///             <inner/>
    ///             <outer></outer>
    ///             <p:outer xmlns:p="ns"></p:outer>
    ///             <outer/>
    ///         </inner>
    ///     </outer>
    /// "#.as_bytes());
    /// reader.config_mut().trim_text(true);
    /// let mut buf = Vec::new();
    ///
    /// let ns = Namespace(b"namespace 1");
    /// let start = BytesStart::from_content(r#"outer xmlns="namespace 1""#, 5);
    /// let end   = start.to_end().into_owned();
    ///
    /// // First, we read a start event...
    /// assert_eq!(
    ///     reader.read_resolved_event_into_async(&mut buf).await.unwrap(),
    ///     (ResolveResult::Bound(ns), Event::Start(start))
    /// );
    ///
    /// // ...then, we could skip all events to the corresponding end event.
    /// // This call will correctly handle nested <outer> elements.
    /// // Note, however, that this method does not handle namespaces.
    /// reader.read_to_end_into_async(end.name(), &mut buf).await.unwrap();
    ///
    /// // At the end we should get an Eof event, because we ate the whole XML
    /// assert_eq!(
    ///     reader.read_resolved_event_into_async(&mut buf).await.unwrap(),
    ///     (ResolveResult::Unbound, Event::Eof)
    /// );
    /// # }) // tokio_test::block_on
    /// ```
    ///
    /// [`read_to_end_into()`]: Self::read_to_end_into
    /// [`Start`]: Event::Start
    pub async fn read_to_end_into_async<'n>(
        &mut self,
        // We should name that lifetime due to https://github.com/rust-lang/rust/issues/63033`
        end: QName<'n>,
        buf: &mut Vec<u8>,
    ) -> Result<Span> {
        // According to the https://www.w3.org/TR/xml11/#dt-etag, end name should
        // match literally the start name. See `Config::check_end_names` documentation
        self.reader.read_to_end_into_async(end, buf).await
    }

    /// An asynchronous version of [`read_resolved_event_into()`]. Reads the next
    /// event into given buffer asynchronously and resolves its namespace (if applicable).
    ///
    /// Namespace is resolved only for [`Start`], [`Empty`] and [`End`] events.
    /// For all other events the concept of namespace is not defined, so
    /// a [`ResolveResult::Unbound`] is returned.
    ///
    /// If you are not interested in namespaces, you can use [`read_event_into_async()`]
    /// which will not automatically resolve namespaces for you.
    ///
    /// # Examples
    ///
    /// ```
    /// # tokio_test::block_on(async {
    /// # use pretty_assertions::assert_eq;
    /// use quick_xml::events::Event;
    /// use quick_xml::name::{Namespace, QName, ResolveResult::*};
    /// use quick_xml::reader::NsReader;
    ///
    /// let mut reader = NsReader::from_reader(r#"
    ///     <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
    ///        <y:tag2><!--Test comment-->Test</y:tag2>
    ///        <y:tag2>Test 2</y:tag2>
    ///     </x:tag1>
    /// "#.as_bytes());
    /// reader.config_mut().trim_text(true);
    ///
    /// let mut count = 0;
    /// let mut buf = Vec::new();
    /// let mut txt = Vec::new();
    /// loop {
    ///     match reader.read_resolved_event_into_async(&mut buf).await.unwrap() {
    ///         (Bound(Namespace(b"www.xxxx")), Event::Start(e)) => {
    ///             count += 1;
    ///             assert_eq!(e.local_name(), QName(b"tag1").into());
    ///         }
    ///         (Bound(Namespace(b"www.yyyy")), Event::Start(e)) => {
    ///             count += 1;
    ///             assert_eq!(e.local_name(), QName(b"tag2").into());
    ///         }
    ///         (_, Event::Start(_)) => unreachable!(),
    ///
    ///         (_, Event::Text(e)) => {
    ///             txt.push(e.unescape().unwrap().into_owned())
    ///         }
    ///         (_, Event::Eof) => break,
    ///         _ => (),
    ///     }
    ///     buf.clear();
    /// }
    /// assert_eq!(count, 3);
    /// assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
    /// # }) // tokio_test::block_on
    /// ```
    ///
    /// [`read_resolved_event_into()`]: NsReader::read_resolved_event_into
    /// [`Start`]: Event::Start
    /// [`Empty`]: Event::Empty
    /// [`End`]: Event::End
    /// [`read_event_into_async()`]: Self::read_event_into_async
    pub async fn read_resolved_event_into_async<'ns, 'b>(
        // Name 'ns lifetime, because otherwise we get an error
        // "implicit elided lifetime not allowed here" on ResolveResult
        &'ns mut self,
        buf: &'b mut Vec<u8>,
    ) -> Result<(ResolveResult<'ns>, Event<'b>)> {
        let event = self.read_event_into_async(buf).await;
        self.resolve_event(event)
    }
}

#[cfg(test)]
mod test {
    use super::TokioAdapter;
    use crate::reader::test::check;

    check!(
        #[tokio::test]
        read_event_into_async,
        read_until_close_async,
        TokioAdapter,
        &mut Vec::new(),
        async, await
    );

    #[test]
    fn test_future_is_send() {
        // This test should just compile, no actual runtime checks are performed here.
        use super::*;
        use tokio::io::BufReader;
        fn check_send<T: Send>(_: T) {}

        let input = vec![];
        let mut reading_buf = vec![];
        let mut reader = Reader::from_reader(BufReader::new(input.as_slice()));

        check_send(reader.read_event_into_async(&mut reading_buf));
    }
}