stream_base: introduce StreamBase
StreamBase is a brand new way to write C++ streams. The class itself is
for separting StreamWrap (with the methods like .writeAsciiString,
.writeBuffer, .writev, etc) from the HandleWrap class, making
possible writing abstract C++ streams that are not bound to any uv
socket.
Important part of the abstraction is following methods (which mimics libuv's stream API):
- Events:
OnAlloc(size_t size, uv_buf_t*)OnRead(ssize_t nread, const uv_buf_t*, uv_handle_type pending)OnAfterWrite(WriteWrap*)
- Wrappers:
DoShutdown(ShutdownWrap*)DoTryWrite(uv_buf_t** bufs, size_t* count)DoWrite(WriteWrap*, uv_buf_t*, size_t count, uv_stream_t* handle)Error()ClearError()
The implementation should provide all of these methods, thus providing the access to the underlying resource (be it uv handle, TLS socket, or anything else).
A C++ stream may consume input of other stream by replacing the event
callbacks and proxying the writes. This kind of API is actually used now
for the TLSWrap implementation, making possible to wrap TLS stream into
another TLS stream. Thus legacy API calls are no longer required in
_tls_wrap.js.
PR-URL: nodejs/node#840
Reviewed-By: Trevor Norris [email protected]
Reviewed-By: Chris Dickinson [email protected]