Less low-level operations to manage receive buffer.

[simgrid.git] / src / mc / remote / Channel.cpp

diff --git a/src/mc/remote/Channel.cpp b/src/mc/remote/Channel.cpp
index dfd07e5..c7d57fe 100644 (file)
--- a/src/mc/remote/Channel.cpp
+++ b/src/mc/remote/Channel.cpp
@@ -1,5 +1,4 @@
-/* Copyright (c) 2015-2023. The SimGrid Team.
- * All rights reserved.                                                     */
+/* Copyright (c) 2015-2023. The SimGrid Team.  All rights reserved.         */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
@@ -13,9 +12,13 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_Channel, mc, "MC interprocess communication");
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_channel, mc, "MC interprocess communication");
 
 namespace simgrid::mc {
+Channel::Channel(int sock, Channel const& other) : socket_(sock), buffer_(other.buffer_)
+{
+  XBT_DEBUG("Adopt %zu bytes buffered by father channel.", buffer_.size());
+}
 
 Channel::~Channel()
 {
@@ -26,34 +29,61 @@ Channel::~Channel()
 /** @brief Send a message; returns 0 on success or errno on failure */
 int Channel::send(const void* message, size_t size) const
 {
+  if (size >= sizeof(int) && is_valid_MessageType(*static_cast<const int*>(message))) {
+    XBT_DEBUG("Sending %s (%zu bytes sent)", to_c_str(*static_cast<const MessageType*>(message)), size);
+  } else {
+    XBT_DEBUG("Sending bytes directly (from address %p) (%zu bytes sent)", message, size);
+    if (size == 0)
+      XBT_WARN("Request to send a 0-sized message! Proceeding anyway.");
+  }
+
   while (::send(this->socket_, message, size, 0) == -1) {
     if (errno != EINTR) {
       XBT_ERROR("Channel::send failure: %s", strerror(errno));
       return errno;
     }
   }
-
-  if (is_valid_MessageType(*static_cast<const int*>(message))) {
-    XBT_DEBUG("Sending %s (%zu bytes sent)", to_c_str(*static_cast<const MessageType*>(message)), size);
-  } else {
-    XBT_DEBUG("Sending bytes directly (from address %p) (%zu bytes sent)", message, size);
-  }
-
   return 0;
 }
 
-ssize_t Channel::receive(void* message, size_t size, bool block) const
+ssize_t Channel::receive(void* message, size_t size, int flags)
 {
-  ssize_t res = recv(this->socket_, message, size, block ? 0 : MSG_DONTWAIT);
-  if (res != -1) {
-    if (is_valid_MessageType(*static_cast<int*>(message))) {
-      XBT_DEBUG("Receive %s (requested %zu; received %zd)", to_c_str(*static_cast<MessageType*>(message)), size, res);
-    } else {
-      XBT_DEBUG("Receive %zd bytes", res);
+  size_t bufsize = buffer_.size();
+  ssize_t copied = 0;
+  char* whereto  = static_cast<char*>(message);
+  size_t todo    = size;
+  if (bufsize > 0) {
+    XBT_DEBUG("%d %zu bytes (of %zu expected) are already in buffer", getpid(), bufsize, size);
+    copied = std::min(size, bufsize);
+    std::copy_n(begin(buffer_), copied, whereto);
+    buffer_.erase(begin(buffer_), begin(buffer_) + copied);
+    todo -= copied;
+    whereto += copied;
+  }
+  ssize_t res = 0;
+  if (todo > 0) {
+    errno = 0;
+    res   = recv(this->socket_, whereto, todo, flags);
+    xbt_assert(res != -1 || errno == EAGAIN, "Channel::receive failure: %s", strerror(errno));
+    if (res == -1) {
+      res = 0;
     }
+  }
+  XBT_DEBUG("%d Wanted %zu; Got %zd from buffer and %zd from network", getpid(), size, copied, res);
+  res += copied;
+  if (static_cast<size_t>(res) >= sizeof(int) && is_valid_MessageType(*static_cast<const int*>(message))) {
+    XBT_DEBUG("%d Receive %s (requested %zu; received %zd at %p)", getpid(),
+              to_c_str(*static_cast<const MessageType*>(message)), size, res, message);
   } else {
-    XBT_ERROR("Channel::receive failure: %s", strerror(errno));
+    XBT_DEBUG("Receive %zd bytes", res);
   }
   return res;
 }
+
+void Channel::reinject(const char* data, size_t size)
+{
+  xbt_assert(size > 0, "Cannot reinject less than one char (size: %lu)", size);
+  XBT_DEBUG("%d Reinject %zu bytes on top of %zu pre-existing bytes", getpid(), size, buffer_.size());
+  buffer_.insert(end(buffer_), data, data + size);
+}
 } // namespace simgrid::mc