22// Licensed under the MIT license. See LICENSE file in the project root for full license information.
33
44using System ;
5+ using System . Collections . Generic ;
6+ using System . Diagnostics ;
57using System . Runtime . InteropServices ;
8+ using System . Threading ;
9+
10+ using size_t = System . IntPtr ;
11+ using libc = Interop . libc ;
12+ using libcurl = Interop . libcurl ;
13+ using PollFlags = Interop . libc . PollFlags ;
614
715internal static partial class Interop
816{
@@ -30,16 +38,48 @@ public static void DisposeAndClearHandle(ref SafeCurlHandle curlHandle)
3038
3139 protected override bool ReleaseHandle ( )
3240 {
33- Interop . libcurl . curl_easy_cleanup ( this . handle ) ;
41+ libcurl . curl_easy_cleanup ( this . handle ) ;
3442 return true ;
3543 }
3644 }
3745
3846 internal sealed class SafeCurlMultiHandle : SafeHandle
3947 {
48+ private bool _pollCancelled = true ;
49+ private readonly int [ ] _specialFds = new int [ 2 ] ;
50+ private readonly HashSet < int > _fdSet = new HashSet < int > ( ) ;
51+ private int _requestCount = 0 ;
52+ private Timer _timer ;
53+
54+ internal bool PollCancelled
55+ {
56+ get { return _pollCancelled ; }
57+ set { _pollCancelled = value ; }
58+ }
59+
60+ internal int RequestCount
61+ {
62+ get { return _requestCount ; }
63+ set { _requestCount = value ; }
64+ }
65+
66+ internal Timer Timer
67+ {
68+ get { return _timer ; }
69+ set { _timer = value ; }
70+ }
71+
72+
4073 public SafeCurlMultiHandle ( )
4174 : base ( IntPtr . Zero , true )
4275 {
76+ unsafe
77+ {
78+ fixed( int * fds = _specialFds )
79+ {
80+ while ( Interop . CheckIo ( libc . pipe ( fds ) ) ) ;
81+ }
82+ }
4383 }
4484
4585 public override bool IsInvalid
@@ -56,11 +96,169 @@ public static void DisposeAndClearHandle(ref SafeCurlMultiHandle curlHandle)
5696 }
5797 }
5898
99+ internal void PollFds ( List < libc . pollfd > readyFds )
100+ {
101+ int count ;
102+ libc . pollfd [ ] pollFds ;
103+
104+ readyFds . Clear ( ) ;
105+
106+ lock ( this )
107+ {
108+ // TODO: Avoid the allocation when count is in 100s
109+ count = _fdSet . Count + 1 ;
110+ pollFds = new libc . pollfd [ count ] ;
111+
112+ // Always include special fd in the poll set. This is used to
113+ // return from the poll in case any fds have been added or
114+ // removed to the set of fds being polled. This prevents starvation
115+ // in case current set of fds have no activity but the new fd
116+ // is ready for a read/write. The special fd is the read end of a pipe
117+ // Whenever an fd is added/removed in _fdSet, a write happens to the
118+ // write end of the pipe thus causing the poll to return.
119+ pollFds [ 0 ] . fd = _specialFds [ libc . ReadEndOfPipe ] ;
120+ pollFds [ 0 ] . events = PollFlags . POLLIN | PollFlags . POLLOUT ;
121+ int i = 1 ;
122+ foreach ( int fd in _fdSet )
123+ {
124+ pollFds [ i ] . fd = fd ;
125+ pollFds [ i ] . events = PollFlags . POLLIN | PollFlags . POLLOUT ;
126+ i ++ ;
127+ }
128+ }
129+
130+ unsafe
131+ {
132+ fixed ( libc . pollfd * fds = pollFds )
133+ {
134+ int numFds = libc . poll ( fds , ( uint ) count , - 1 ) ;
135+ if ( numFds <= 0 )
136+ {
137+ Debug . Assert ( numFds != 0 ) ; // Since timeout is infinite
138+
139+ // TODO: How to handle errors?
140+ throw new InvalidOperationException ( "Poll failure: " + Marshal . GetLastWin32Error ( ) ) ;
141+ }
142+
143+ lock ( this )
144+ {
145+ if ( 0 == _requestCount )
146+ {
147+ return ;
148+ }
149+ }
150+
151+ // Check for any fdset changes
152+ if ( fds [ 0 ] . revents != 0 )
153+ {
154+ if ( ReadSpecialFd ( fds [ 0 ] . revents ) < 0 )
155+ {
156+ // TODO: How to handle errors?
157+ throw new InvalidOperationException ( "Cannot read data: " + Marshal . GetLastWin32Error ( ) ) ;
158+ }
159+ numFds -- ;
160+ }
161+
162+ // Now check for events on the remaining fds
163+ for ( int i = 1 ; i < count && numFds > 0 ; i ++ )
164+ {
165+ if ( fds [ i ] . revents == 0 )
166+ {
167+ continue ;
168+ }
169+ readyFds . Add ( fds [ i ] ) ;
170+ numFds -- ;
171+ }
172+ }
173+ }
174+ }
175+
176+ internal void SignalFdSetChange ( int fd , bool isRemove )
177+ {
178+ Debug . Assert ( Monitor . IsEntered ( this ) ) ;
179+
180+ bool changed = isRemove ? _fdSet . Remove ( fd ) : _fdSet . Add ( fd ) ;
181+ if ( ! changed )
182+ {
183+ return ;
184+ }
185+
186+ unsafe
187+ {
188+ // Write to special fd
189+ byte * dummyBytes = stackalloc byte [ 1 ] ;
190+ if ( ( int ) libc . write ( _specialFds [ libc . WriteEndOfPipe ] , dummyBytes , ( size_t ) 1 ) <= 0 )
191+ {
192+ // TODO: How to handle errors?
193+ throw new InvalidOperationException ( "Cannot write data: " + Marshal . GetLastWin32Error ( ) ) ;
194+ }
195+ }
196+ }
197+
198+ protected override void Dispose ( bool disposing )
199+ {
200+ if ( disposing )
201+ {
202+ if ( null != _timer )
203+ {
204+ _timer . Dispose ( ) ;
205+ }
206+ }
207+ base . Dispose ( disposing ) ;
208+ }
209+
59210 protected override bool ReleaseHandle ( )
60211 {
61- Interop . libcurl . curl_multi_cleanup ( this . handle ) ;
212+ Debug . Assert ( 0 == _fdSet . Count ) ;
213+ Debug . Assert ( 0 == _requestCount ) ;
214+ Debug . Assert ( _pollCancelled ) ;
215+
216+ libc . close ( _specialFds [ libc . ReadEndOfPipe ] ) ;
217+ libc . close ( _specialFds [ libc . WriteEndOfPipe ] ) ;
218+ libcurl . curl_multi_cleanup ( this . handle ) ;
219+
62220 return true ;
63221 }
222+
223+ private int ReadSpecialFd ( PollFlags revents )
224+ {
225+ PollFlags badEvents = PollFlags . POLLERR | PollFlags . POLLHUP | PollFlags . POLLNVAL ;
226+ if ( ( revents & badEvents ) != 0 )
227+ {
228+ return - 1 ;
229+ }
230+ int pipeReadFd = _specialFds [ libc . ReadEndOfPipe ] ;
231+ int bytesRead = 0 ;
232+ unsafe
233+ {
234+ do
235+ {
236+ // Read available data from the pipe
237+ int bufferLength = 1024 ;
238+ byte * dummyBytes = stackalloc byte [ bufferLength ] ;
239+ int numBytes = ( int ) libc . read ( pipeReadFd , dummyBytes , ( size_t ) bufferLength ) ;
240+ if ( numBytes <= 0 )
241+ {
242+ return - 1 ;
243+ }
244+ bytesRead += numBytes ;
245+
246+ // Check if more data is available
247+ PollFlags outFlags ;
248+ int retVal = libc . poll ( pipeReadFd , PollFlags . POLLIN , 0 , out outFlags ) ;
249+ if ( retVal < 0 )
250+ {
251+ return - 1 ;
252+ }
253+ else if ( 0 == retVal )
254+ {
255+ break ;
256+ }
257+ }
258+ while ( true ) ;
259+ }
260+ return bytesRead ;
261+ }
64262 }
65263
66264 internal sealed class SafeCurlSlistHandle : SafeHandle
@@ -91,7 +289,7 @@ public static void DisposeAndClearHandle(ref SafeCurlSlistHandle curlHandle)
91289
92290 protected override bool ReleaseHandle ( )
93291 {
94- Interop . libcurl . curl_slist_free_all ( this . handle ) ;
292+ libcurl . curl_slist_free_all ( this . handle ) ;
95293 return true ;
96294 }
97295 }
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