removed require to define available, tell, seek in ioLib

res/modules/internal/stream_providers/bytearray.lua

@@ -98,10 +98,6 @@ function lib.tell(descriptor)
     return positions[descriptor]
 end
 
-function lib.flush(descriptor)
-    requireDescriptor(descriptor)
-end
-
 function lib.available(descriptor)
     requireDescriptor(descriptor)
 

res/modules/internal/stream_providers/named_pipe_unix.lua

@@ -60,18 +60,6 @@ function lib.write(fd, bytearray)
     end
 end
 
-function lib.seek(fd, mode, offset)
-    error("cannot seek the named pipe")
-end
-
-function lib.tell(fd)
-    error("cannot tell the named pipe")
-end
-
-function lib.flush(fd)
-    -- no flush on unix
-end
-
 function lib.available(fd)
     if fd == nil or fd < 0 then return 0 end
 

res/modules/internal/stream_providers/named_pipe_windows.lua

@@ -97,14 +97,6 @@ function lib.write(handle, bytearray)
     end
 end
 
-function lib.seek(handle, mode, offset)
-    error("cannot seek the named pipe")
-end
-
-function lib.tell(handle)
-    error("cannot tell the named pipe")
-end
-
 function lib.flush(handle)
     C.FlushFileBuffers(handle)
 end

res/modules/internal/stream_providers/socket.lua

@@ -32,18 +32,6 @@ function lib.write(descriptor, data)
     sockets[descriptor]:send(data)
 end
 
-function lib.seek(descriptor, mode, offset)
-    error("cannot seek socket")
-end
-
-function lib.tell(descriptor)
-    error("cannot tell socket")
-end
-
-function lib.flush(descriptor)
-    requireDescriptor(descriptor)
-end
-
 function lib.available(descriptor)
     requireDescriptor(descriptor)
 

res/modules/io_stream.lua

@@ -47,15 +47,14 @@ binaryMode - if enabled, most methods will expect bytes instead of strings
 ioLib - I/O library. Should include the following functions:
     read(descriptor: int, length: int) -> Bytearray
         May return bytearray with a smaller size if bytes have not arrived yet or have run out
+        May throw error if descriptor isn't readable
     write(descriptor: int, data: Bytearray)
-    seek(descriptor: int, mode: string, offset: int)
+        May throw error if descriptor isn't writeable
+    [optional] seek(descriptor: int, mode: string, offset: int)
         Mode may be 'b' (relative begin), 'c' (relative current), 'e' (relative end + 1)
-        May throw error if environment is not support seek
+    [optional] tell(descriptor: int) -> int
-    tell(descriptor: int) -> int
+    [optional] flush(descriptor: int)
-        May throw error if environment is not support tell
+    [optional] available(descriptor: int) -> int
-    flush(descriptor: int)
-    available(descriptor: int) -> int
-        May return 0 if environment is not support available method
     is_alive(descriptor: int) -> bool
     close(descriptor: int)
 --]]
@@ -135,7 +134,7 @@ function io_stream:available(length)
 
         available = #self.readBuffer
     else
-        available = self.ioLib.available(self.descriptor)
+        available = self.ioLib.available and self.ioLib.available(self.descriptor) or 0
     end
 
     if not length then
@@ -388,10 +387,18 @@ function io_stream:write(arg, ...)
 end
 
 function io_stream:seek(mode, offset)
+    if not self.ioLib.seek then
+        error("cannot seek this stream")
+    end
+
     self.ioLib.seek(self.descriptor, mode, offset)
 end
 
 function io_stream:tell()
+    if not self.ioLib.tell then
+        error("cannot tell this stream")
+    end
+
     return self.ioLib.tell(self.descriptor)
 end
 
@@ -418,7 +425,11 @@ function io_stream:flush()
         self.writeBuffer:clear()
     end
 
-    if self.flushMode ~= FLUSH_MODE_ONLY_BUFFER then self.ioLib.flush(self.descriptor) end
+    if self.flushMode ~= FLUSH_MODE_ONLY_BUFFER then
+        if self.ioLib.flush then
+            self.ioLib.flush(self.descriptor)
+        elseif self:is_closed() then error("stream is closed") end
+    end
 end
 
 return io_stream