Only write to remote socket when we know they are writable

Buffer data (in an horribly innefficient way for now), and use the
event manager to watch for the socket being ready for a write.

Fixes #945

1 files changed, 10 insertions, 0 deletions

diff --git a/src/file.cc b/src/file.cc
index 1455624b..64061d09 100644
--- a/src/file.cc
+++ b/src/file.cc
@@ -143,6 +143,16 @@ bool fd_readable(int fd)
     return select(fd+1, &rfds, nullptr, nullptr, &tv) == 1;
 }
 
+bool fd_writable(int fd)
+{
+    fd_set  rfds;
+    FD_ZERO(&rfds);
+    FD_SET(fd, &rfds);
+
+    timeval tv{0,0};
+    return select(fd+1, nullptr, &rfds, nullptr, &tv) == 1;
+}
+
 String read_fd(int fd, bool text)
 {
     String content;