Beginnings of a debugger wire protocol

runtime/bin/fdutils_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 
 #include "bin/fdutils.h"
 
 
 bool FDUtils::SetNonBlocking(intptr_t fd) {
   intptr_t status;
   status = TEMP_FAILURE_RETRY(fcntl(fd, F_GETFL));
   if (status < 0) {
     perror("fcntl F_GETFL failed");
     return false;
   }
   status = (status | O_NONBLOCK);
   if (TEMP_FAILURE_RETRY(fcntl(fd, F_SETFL, status)) < 0) {
     perror("fcntl F_SETFL failed");
     return false;
   }
   return true;
 }
 
 
+bool FDUtils::SetBlocking(intptr_t fd) {
+  intptr_t status;
+  status = TEMP_FAILURE_RETRY(fcntl(fd, F_GETFL));
+  if (status < 0) {
+    perror("fcntl F_GETFL failed");
+    return false;
+  }
+  status = (status & ~O_NONBLOCK);
+  if (TEMP_FAILURE_RETRY(fcntl(fd, F_SETFL, status)) < 0) {
+    perror("fcntl F_SETFL failed");
+    return false;
+  }
+  return true;

[siva, 2012/05/03 22:52:08]

The code in SetNonBlocking and SetBlocking can be factored into a single helper
function:
bool SetBlockingState(intptr_t fd, intptr_t state);
SetBlocking would be SetBlockingState(fd, ~O_NONBLOCK);
SetNonBlocking would be SetBlockingState(fd, O_NONBLOCK);

[hausner, 2012/05/03 23:52:00]

Not quite. The bit operation is | in one case and & in the other.
But built a helper function along the same idea.

On 2012/05/03 22:52:08, asiva wrote:

+}
+
+
 bool FDUtils::IsBlocking(intptr_t fd, bool* is_blocking) {
   intptr_t status;
   status = TEMP_FAILURE_RETRY(fcntl(fd, F_GETFL));
   if (status < 0) {
     perror("fcntl F_GETFL failed");
     return false;
   }
   *is_blocking = (status & O_NONBLOCK) == 0;
   return true;
 }
@@ skipping 60 matching lines @@
       ASSERT(errno != EWOULDBLOCK);
       return -1;
     } else {
       ASSERT(bytes_written > 0);
       remaining -= bytes_written;
       buffer_pos += bytes_written;
     }
   }
   return count;
 }