[Pkg-telepathy-commits] [libnice] 83/265: agent: Add a nice_agent_recv_nonblocking() function
Simon McVittie
smcv at debian.org
Wed May 14 12:04:55 UTC 2014
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smcv pushed a commit to branch debian
in repository libnice.
commit 6d3a32a0573db6e3fe4a1ad92c3f0678083c5cc3
Author: Philip Withnall <philip.withnall at collabora.co.uk>
Date: Thu Jan 9 17:59:11 2014 +0000
agent: Add a nice_agent_recv_nonblocking() function
This is a non-blocking variant of nice_agent_recv(), and will be used
internally by the GPollableInputStream implementation. External
implementations may use it as well.
It reserves the right to iterate the main context, but doesn’t currently
do so.
---
agent/agent.c | 175 ++++++++++++++++++++++++++++
agent/agent.h | 10 ++
docs/reference/libnice/libnice-sections.txt | 1 +
nice/libnice.sym | 1 +
4 files changed, 187 insertions(+)
diff --git a/agent/agent.c b/agent/agent.c
index 231f5b4..0669b9c 100644
--- a/agent/agent.c
+++ b/agent/agent.c
@@ -2637,6 +2637,181 @@ done:
}
/**
+ * nice_agent_recv_nonblocking:
+ * @agent: a #NiceAgent
+ * @stream_id: the ID of the stream to receive on
+ * @component_id: the ID of the component to receive on
+ * @buf: (array length=buf_len) (out caller-allocates): caller-allocated buffer
+ * to write the received data into, of length at least @buf_len
+ * @buf_len: length of @buf
+ * @cancellable: (allow-none): a #GCancellable to allow the operation to be
+ * cancelled from another thread, or %NULL
+ * @error: (allow-none): return location for a #GError, or %NULL
+ *
+ * Try to receive data from the given stream/component combination on @agent,
+ * without blocking. If receiving data would block, -1 is returned and a
+ * %G_IO_ERROR_WOULD_BLOCK is set in @error. If any other error occurs, -1 is
+ * returned. Otherwise, 0 is returned if (and only if) @buf_len is 0. In all
+ * other cases, the number of bytes read into @buf is returned, and will be
+ * greater than 0.
+ *
+ * For a reliable @agent, this function will receive as many bytes as possible
+ * up to @buf_len. For a non-reliable @agent, it will receive a single message.
+ * In this case, @buf must be big enough to contain the entire message (65536
+ * bytes), or any excess data may be silently dropped.
+ *
+ * As this function is non-blocking, @cancellable is included only for parity
+ * with nice_agent_recv(). If @cancellable is cancelled before this function is
+ * called, a %G_IO_ERROR_CANCELLED error will be returned immediately.
+ *
+ * This must not be used in combination with nice_agent_attach_recv() on the
+ * same stream/component pair.
+ *
+ * Internally, this may iterate the current thread’s default main context.
+ *
+ * If the stream/component pair doesn’t exist, or if a suitable candidate socket
+ * hasn’t yet been selected for it, a %G_IO_ERROR_BROKEN_PIPE error will be
+ * returned. A %G_IO_ERROR_CANCELLED error will be returned if the operation was
+ * cancelled. %G_IO_ERROR_FAILED will be returned for other errors.
+ *
+ * Returns: the number of bytes received into @buf on success (guaranteed to be
+ * greater than 0 unless @buf_len is 0), or -1 on error
+ *
+ * Since: 0.1.5
+ */
+NICEAPI_EXPORT gssize
+nice_agent_recv_nonblocking (NiceAgent *agent, guint stream_id,
+ guint component_id, guint8 *buf, gsize buf_len, GCancellable *cancellable,
+ GError **error)
+{
+ Component *component;
+ Stream *stream;
+ gssize total_len = 0;
+ gboolean received_enough = FALSE, error_reported = FALSE;
+ gboolean all_sockets_would_block = FALSE;
+ GError *child_error = NULL;
+
+ if (buf_len == 0)
+ return 0;
+
+ /* Support cancellation at the beginning only. */
+ if (g_cancellable_set_error_if_cancelled (cancellable, error))
+ return -1;
+
+ /* Try and receive some data. */
+ agent_lock ();
+
+ if (!agent_find_component (agent, stream_id, component_id,
+ &stream, &component)) {
+ g_set_error (&child_error, G_IO_ERROR, G_IO_ERROR_BROKEN_PIPE,
+ "Invalid stream/component.");
+ total_len = -1;
+ goto done;
+ }
+
+ /* For a reliable stream, grab any data from the pseudo-TCP input buffer
+ * before trying the sockets (which we try to see if there’s any more data
+ * available to read without blocking). */
+ if (agent->reliable && component->tcp != NULL &&
+ pseudo_tcp_socket_get_available_bytes (component->tcp) > 0) {
+ gssize len;
+
+ len = pseudo_tcp_socket_recv (component->tcp, (gchar *) buf, buf_len);
+ adjust_tcp_clock (agent, stream, component);
+
+ nice_debug ("%s: Received %" G_GSSIZE_FORMAT " bytes from pseudo-TCP read "
+ "buffer.", G_STRFUNC, len);
+
+ if (len < 0 &&
+ pseudo_tcp_socket_get_error (component->tcp) == EWOULDBLOCK) {
+ len = 0;
+ } else if (len < 0 &&
+ pseudo_tcp_socket_get_error (component->tcp) == ENOTCONN) {
+ g_set_error (&child_error, G_IO_ERROR, G_IO_ERROR_BROKEN_PIPE,
+ "Error reading data from pseudo-TCP socket: not connected.");
+ } else if (len < 0) {
+ g_set_error (&child_error, G_IO_ERROR, G_IO_ERROR_FAILED,
+ "Error reading data from pseudo-TCP socket.");
+ } else if (len > 0) {
+ /* Got some data! */
+ buf += len;
+ buf_len -= len;
+ total_len += len;
+ }
+
+ received_enough = ((gsize) total_len == buf_len);
+ error_reported = (len < 0);
+ }
+
+ /* Each call to agent_recv_locked() will either receive some data or a socket
+ * error (including EWOULDBLOCK). (Cancellation is not supported.) If *any*
+ * socket returns an error, discard all the data in @buf and return an error
+ * from nice_agent_recv_nonblocking() overall.
+ *
+ * In reliable mode, iterate the loop enough to receive at least one byte.
+ * In non-reliable mode, iterate the loop to receive a single message. */
+ while (!received_enough && !error_reported && !all_sockets_would_block) {
+ GSList *i;
+ gssize len = 0;
+
+ for (i = component->socket_sources; i != NULL; i = i->next) {
+ SocketSource *socket_source = i->data;
+
+ /* Actually read the data. This will return 0 if the data has already been
+ * handled (e.g. for STUN control packets). */
+ len = agent_recv_locked (agent, stream, component,
+ socket_source->socket, buf, buf_len);
+
+ nice_debug ("%s: Received %" G_GSSIZE_FORMAT " bytes from socket %p.",
+ G_STRFUNC, len, socket_source->socket);
+
+ if (len < 0) {
+ g_set_error (&child_error, G_IO_ERROR, G_IO_ERROR_FAILED,
+ "Unable to receive from socket %p. Detaching.",
+ socket_source->socket);
+
+ break;
+ } else if (len > 0) {
+ /* Got some data! */
+ buf += len;
+ buf_len -= len;
+ total_len += len;
+
+ break;
+ }
+ }
+
+ received_enough =
+ ((agent->reliable && (gsize) total_len == buf_len) ||
+ (!agent->reliable && total_len > 0));
+ error_reported = (len < 0);
+ all_sockets_would_block = (len == 0);
+ }
+
+ nice_debug ("%s: total_len: %" G_GSSIZE_FORMAT ", buf_len: %" G_GSIZE_FORMAT,
+ G_STRFUNC, total_len, buf_len);
+
+ if (error_reported) {
+ total_len = -1;
+ } else if (total_len == 0 && all_sockets_would_block) {
+ g_set_error_literal (&child_error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK,
+ g_strerror (EAGAIN));
+ total_len = -1;
+ }
+
+done:
+ g_assert ((child_error != NULL) == (total_len == -1));
+ g_assert (total_len != 0);
+
+ if (child_error != NULL)
+ g_propagate_error (error, child_error);
+
+ agent_unlock ();
+
+ return total_len;
+}
+
+/**
* nice_agent_send_full:
* @agent: a #NiceAgent
* @stream_id: the ID of the stream to send to
diff --git a/agent/agent.h b/agent/agent.h
index f7e808b..8b4c974 100644
--- a/agent/agent.h
+++ b/agent/agent.h
@@ -711,6 +711,16 @@ nice_agent_recv (
GCancellable *cancellable,
GError **error);
+gssize
+nice_agent_recv_nonblocking (
+ NiceAgent *agent,
+ guint stream_id,
+ guint component_id,
+ guint8 *buf,
+ gsize buf_len,
+ GCancellable *cancellable,
+ GError **error);
+
/**
* nice_agent_set_selected_pair:
* @agent: The #NiceAgent Object
diff --git a/docs/reference/libnice/libnice-sections.txt b/docs/reference/libnice/libnice-sections.txt
index 74fdb24..f763133 100644
--- a/docs/reference/libnice/libnice-sections.txt
+++ b/docs/reference/libnice/libnice-sections.txt
@@ -25,6 +25,7 @@ nice_agent_get_selected_pair
nice_agent_send
nice_agent_send_full
nice_agent_recv
+nice_agent_recv_nonblocking
nice_agent_attach_recv
nice_agent_set_selected_pair
nice_agent_set_selected_remote_candidate
diff --git a/nice/libnice.sym b/nice/libnice.sym
index bc25f66..f075a57 100644
--- a/nice/libnice.sym
+++ b/nice/libnice.sym
@@ -17,6 +17,7 @@ nice_address_to_string
nice_agent_add_local_address
nice_agent_add_stream
nice_agent_recv
+nice_agent_recv_nonblocking
nice_agent_attach_recv
nice_agent_gather_candidates
nice_agent_generate_local_candidate_sdp
--
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