added Stream::tryWrite

src/uvw/stream.hpp

@@ -1,6 +1,10 @@
 #pragma once
 
 
+#include <iterator>
+#include <cstddef>
+#include <memory>
+#include <array>
 #include <uv.h>
 #include "handle.hpp"
 #include "loop.hpp"
@@ -9,6 +13,37 @@
 namespace uvw {
 
 
+template<typename T>
+class Stream;
+
+
+class Buffer final {
+    template<typename>
+    friend class Stream;
+
+    uv_buf_t uvBuf() const noexcept {
+        return uv_buf_init(data.get(), size);
+    }
+
+public:
+    Buffer(std::unique_ptr<char[]> dt, std::size_t s)
+        : data{std::move(dt)}, size{s}
+    { }
+
+    Buffer(Buffer &&) = default;
+    Buffer& operator=(Buffer &&) = default;
+
+    void reset(std::unique_ptr<char[]> dt, std::size_t s) noexcept {
+        data.swap(dt);
+        size = s;
+    }
+
+private:
+    std::unique_ptr<char[]> data;
+    std::size_t size;
+};
+
+
 template<typename T>
 class Stream: public Handle<T> {
     static constexpr unsigned int DEFAULT_BACKLOG = 128;
@@ -50,7 +85,20 @@ public:
     }
 
     // TODO write
-    // TODO tryWrite
+
+    UVWOptionalData<int> tryWrite(Buffer buf) noexcept {
+        Buffer data[] = { std::move(buf) };
+        return tryWrite(std::begin(data), std::end(data));
+    }
+
+    template<typename It>
+    UVWOptionalData<int> tryWrite(It first, It last) noexcept {
+        uv_buf_t data[last - first];
+        std::size_t pos = 0;
+        while(first != last) { data[pos++] = (first++)->uvBuf(); }
+        auto bw = uv_try_write(this->template get<uv_stream_t>(), data, pos);
+        return (bw >= 0 ? bw : UVWError{bw});
+    }
 
     bool readable() const noexcept {
         return (uv_is_readable(this->template get<uv_stream_t>()) == 1);

test/main.cpp

@@ -62,7 +62,18 @@ void conn(uvw::Loop &loop) {
     auto cb = [](uvw::UVWError err, uvw::Tcp &tcp) mutable {
         std::cout << "connect: " << ((bool)err) << std::endl;
 
-        auto cb = [](uvw::UVWError err, uvw::Tcp &tcp) mutable {
+        auto data = std::unique_ptr<char[]>(new char[1]);
+        data[0] = 42;
+        uvw::Buffer buf{std::move(data), 1};
+        uvw::UVWOptionalData<int> bw = tcp.tryWrite(std::move(buf));
+
+        if(bw) {
+            std::cout << "written: " << ((int)bw) << std::endl;
+        } else {
+            std::cout << "written err: " << ((int)bw) << std::endl;
+        }
+
+        auto cb = [](uvw::UVWError err, uvw::Tcp &) mutable {
             std::cout << "close: " << ((bool)err) << std::endl;
         };