Move WriteUtf8String functionality to stream_base.cpp

Summary:
Moved WriteUtf8String functionality to stream_base.cpp
because the same write functionality is used for both
tty and pipe. This move was primarily made to mirror
the file structure that node uses.

Additionally, since uv_write is async, the data string
and the uv_write_t object need to survive past the
end of the function. Thus we created a callback where
these allocated objects are freed, and added the uv_run
line to ensure that the callback is called.

Reviewed By: avp

Differential Revision: D29909965

fbshipit-source-id: e6b0b469eca26671d3051d201e85587c454ba767

tools/node-hermes/CMakeLists.txt

@@ -19,7 +19,7 @@ if(HERMES_BUILD_NODE_HERMES)
     node-hermes.cpp RuntimeState.cpp InternalBindings/buffer.cpp
     InternalBindings/constants.cpp InternalBindings/file.cpp
     InternalBindings/util.cpp InternalBindings/tty_wrap.cpp
-    InternalBindings/pipe_wrap.cpp
+    InternalBindings/pipe_wrap.cpp InternalBindings/stream_base.cpp
     ${ALL_HEADER_FILES}
     LINK_LIBS hermesapi hermesNodeBytecode uv_a
     )

tools/node-hermes/InternalBindings/pipe_wrap.cpp

@@ -7,6 +7,7 @@
 
 #include "InternalBindings.h"
 #include "hermes/hermes.h"
+#include "stream_base.h"
 
 #include "uv.h"
 

tools/node-hermes/InternalBindings/stream_base.cpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "stream_base.h"
+#include "../RuntimeState.h"
+#include "hermes/hermes.h"
+
+#include "uv.h"
+
+using namespace facebook;
+
+class WriteContext {
+ public:
+  std::string data_;
+  WriteContext(std::string data) {
+    data_ = data;
+  }
+};
+
+/// Callback for cleaning up the allocations made in streamBaseWriteUtf8String.
+/// Necessary because uv_write can be async.
+static void afterWrite(uv_write_t *req, int status) {
+  WriteContext *context = reinterpret_cast<WriteContext *>(req->data);
+  delete context;
+  free(req);
+}
+
+int facebook::streamBaseWriteUtf8String(
+    RuntimeState &rs,
+    const jsi::Value &arg,
+    uv_stream_t *stream) {
+  jsi::Runtime &rt = rs.getRuntime();
+
+  WriteContext *writeContext = new WriteContext(arg.toString(rt).utf8(rt));
+  uv_write_t *writeReq = (uv_write_t *)malloc(sizeof(uv_write_t));
+  writeReq->data = writeContext;
+  uv_buf_t buf =
+      uv_buf_init(&writeContext->data_[0], writeContext->data_.size());
+
+  int err = uv_write(writeReq, stream, &buf, 1, afterWrite);
+  return err;
+}

tools/node-hermes/InternalBindings/stream_base.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "../RuntimeState.h"
+#include "hermes/hermes.h"
+
+namespace facebook {
+/// Given the data argument, initializes a uv_buf and
+/// writes to the stream associated with the object this
+/// function is defined on.
+int streamBaseWriteUtf8String(
+    RuntimeState &rs,
+    const jsi::Value &arg,
+    uv_stream_t *stream);
+} // namespace facebook

tools/node-hermes/InternalBindings/tty_wrap.cpp

@@ -7,6 +7,7 @@
 
 #include "InternalBindings.h"
 #include "hermes/hermes.h"
+#include "stream_base.h"
 
 #include "uv.h"
 

tools/node-hermes/node-hermes.cpp

@@ -318,6 +318,7 @@ int main(int argc, char **argv) {
   try {
     initialize(rs, builtinModules, intBinding);
     auto result = rt.evaluateJavaScript(jsiBuffer, srcPath);
+    uv_run(rs.getLoop(), UV_RUN_DEFAULT);
 
   } catch (const jsi::JSIException &e) {
     llvh::errs() << "JavaScript terminated via uncaught exception: " << e.what()