buffer, client: fix deadlock with send() calls

This is an ancient bug, but it got much easier to trigger with mouse
scrolling support so it's time to fix it.

(The bug itself was that since both the client and buffer ends of the
controlling stream are blocking, they could get stuck when both were
trying to send() data to the other end but the buffer was full. So now
we set the client end to non-blocking.)

1 files changed, 20 insertions, 13 deletions

diff --git a/src/server/buffer.nim b/src/server/buffer.nim
index 26ce08db..c0efeb65 100644
--- a/src/server/buffer.nim
+++ b/src/server/buffer.nim
@@ -26,6 +26,7 @@ import html/dom
 import html/enums
 import html/env
 import html/event
+import io/bufstream
 import io/posixstream
 import io/promise
 import io/serialize
@@ -127,26 +128,29 @@ type
     map: PromiseMap
     packetid: int
     opaque: InterfaceOpaque
-    stream*: Stream
+    stream*: BufStream
 
 proc getFromOpaque[T](opaque: pointer, res: var T) =
   let opaque = cast[InterfaceOpaque](opaque)
   if opaque.len != 0:
     opaque.stream.sread(res)
 
-proc newBufferInterface*(stream: Stream): BufferInterface =
+proc newBufferInterface*(stream: SocketStream, registerFun: proc(fd: int)):
+    BufferInterface =
   let opaque = InterfaceOpaque(stream: stream)
   result = BufferInterface(
     map: newPromiseMap(cast[pointer](opaque)),
     packetid: 1, # ids below 1 are invalid
     opaque: opaque,
-    stream: stream
+    stream: newBufStream(stream, registerFun)
   )
 
 # After cloning a buffer, we need a new interface to the new buffer process.
 # Here we create a new interface for that clone.
-proc cloneInterface*(stream: Stream): BufferInterface =
-  let iface = newBufferInterface(stream)
+proc cloneInterface*(stream: SocketStream, registerFun: proc(fd: int)):
+    BufferInterface =
+  let iface = newBufferInterface(stream, registerFun)
+  #TODO buffered data should probably be copied here
   # We have just fork'ed the buffer process inside an interface function,
   # from which the new buffer is going to return as well. So we must also
   # consume the return value of the clone function, which is the pid 0.
@@ -180,7 +184,8 @@ proc buildInterfaceProc(fun: NimNode, funid: string): tuple[fun, name: NimNode]
   let thisval = this2[0]
   body.add(quote do:
     `thisval`.stream.swrite(BufferCommand.`nup`)
-    `thisval`.stream.swrite(`thisval`.packetid))
+    `thisval`.stream.swrite(`thisval`.packetid)
+  )
   var params2: seq[NimNode]
   var retval2: NimNode
   var addfun: NimNode
@@ -196,6 +201,7 @@ proc buildInterfaceProc(fun: NimNode, funid: string): tuple[fun, name: NimNode]
       retval)
   params2.add(retval2)
   params2.add(this2)
+  # flatten args
   for i in 2 ..< params.len:
     let param = params[i]
     for i in 0 ..< param.len - 2:
@@ -205,15 +211,16 @@ proc buildInterfaceProc(fun: NimNode, funid: string): tuple[fun, name: NimNode]
     let s = params2[i][0] # sym e.g. url
     body.add(quote do:
       when typeof(`s`) is FileHandle:
-        SocketStream(`thisval`.stream).sendFileHandle(`s`)
+        #TODO flush or something
+        SocketStream(`thisval`.stream.source).sendFileHandle(`s`)
       else:
-        `thisval`.stream.swrite(`s`))
-  body.add(quote do:
-    `thisval`.stream.flush())
+        `thisval`.stream.swrite(`s`)
+    )
   body.add(quote do:
     let promise = `addfun`
     inc `thisval`.packetid
-    return promise)
+    return promise
+  )
   var pragmas: NimNode
   if retval.kind == nnkEmpty:
     pragmas = newNimNode(nnkPragma).add(ident("discardable"))
@@ -1749,14 +1756,14 @@ macro bufferDispatcher(funs: static ProxyMap, buffer: Buffer,
         let len = slen(`packetid`)
         buffer.pstream.swrite(len)
         buffer.pstream.swrite(`packetid`)
-        buffer.pstream.flush())
+      )
     else:
       resolve.add(quote do:
         let len = slen(`packetid`) + slen(`rval`)
         buffer.pstream.swrite(len)
         buffer.pstream.swrite(`packetid`)
         buffer.pstream.swrite(`rval`)
-        buffer.pstream.flush())
+      )
     if v.istask:
       let en = v.ename
       stmts.add(quote do: