Update networking layer w/ CURL and emscripten impl

2025-11-08 01:50:36 +11:00
parent a17925904d
commit f6874dc55a
4105 changed files with 694617 additions and 179 deletions
@@ -0,0 +1,104 @@
+---
+c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+SPDX-License-Identifier: curl
+Title: CURLOPT_INTERLEAVEFUNCTION
+Section: 3
+Source: libcurl
+See-also:
+  - CURLOPT_INTERLEAVEDATA (3)
+  - CURLOPT_RTSP_REQUEST (3)
+Protocol:
+  - RTSP
+Added-in: 7.20.0
+---
+
+# NAME
+
+CURLOPT_INTERLEAVEFUNCTION - callback for RTSP interleaved data
+
+# SYNOPSIS
+
+~~~c
+#include <curl/curl.h>
+
+size_t interleave_callback(void *ptr, size_t size, size_t nmemb,
+                           void *userdata);
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_INTERLEAVEFUNCTION,
+                          interleave_callback);
+~~~
+
+# DESCRIPTION
+
+Pass a pointer to your callback function, which should match the prototype
+shown above.
+
+This callback function gets called by libcurl as soon as it has received
+interleaved RTP data. This function gets called for each $ block and therefore
+contains exactly one upper-layer protocol unit (e.g. one RTP packet). curl
+writes the interleaved header as well as the included data for each call. The
+first byte is always an ASCII dollar sign. The dollar sign is followed by a
+one byte channel identifier and then a 2 byte integer length in network byte
+order. See RFC 2326 Section 10.12 for more information on how RTP interleaving
+behaves. If unset or set to NULL, curl uses the default write function.
+
+Interleaved RTP poses some challenges for the client application. Since the
+stream data is sharing the RTSP control connection, it is critical to service
+the RTP in a timely fashion. If the RTP data is not handled quickly,
+subsequent response processing may become unreasonably delayed and the
+connection may close. The application may use *CURL_RTSPREQ_RECEIVE* to
+service RTP data when no requests are desired. If the application makes a
+request, (e.g. *CURL_RTSPREQ_PAUSE*) then the response handler processes
+any pending RTP data before marking the request as finished.
+
+The CURLOPT_INTERLEAVEDATA(3) is passed in the *userdata* argument in
+the callback.
+
+Your callback should return the number of bytes actually taken care of. If
+that amount differs from the amount passed to your callback function, it
+signals an error condition to the library. This causes the transfer to abort
+and the libcurl function used returns *CURLE_WRITE_ERROR*.
+
+You can also abort the transfer by returning CURL_WRITEFUNC_ERROR. (7.87.0)
+
+# DEFAULT
+
+NULL, the interleave data is then passed to the regular write function:
+CURLOPT_WRITEFUNCTION(3).
+
+# %PROTOCOLS%
+
+# EXAMPLE
+
+~~~c
+struct local {
+  void *custom;
+};
+
+static size_t rtp_write(void *ptr, size_t size, size_t nmemb, void *userp)
+{
+  struct local *l = userp;
+  printf("our ptr: %p\n", l->custom);
+  /* take care of the packet in 'ptr', then return... */
+  return size * nmemb;
+}
+
+int main(void)
+{
+  struct local rtp_data;
+  CURL *curl = curl_easy_init();
+  if(curl) {
+    curl_easy_setopt(curl, CURLOPT_INTERLEAVEFUNCTION, rtp_write);
+    curl_easy_setopt(curl, CURLOPT_INTERLEAVEDATA, &rtp_data);
+  }
+}
+~~~
+
+# %AVAILABILITY%
+
+# RETURN VALUE
+
+curl_easy_setopt(3) returns a CURLcode indicating success or error.
+
+CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
+libcurl-errors(3).