unify request object to use uv_queue_work for both corefoundation + curl

src/platform/request.cpp

@@ -0,0 +1,44 @@
+#include <llmr/platform/request.hpp>
+#include <llmr/platform/platform.hpp>
+#include <uv.h>
+
+using namespace llmr::platform;
+
+Request::Request(const std::string &url,
+                 std::function<void(Response *)> background_function,
+                 std::function<void()> foreground_callback)
+    : url(url),
+      background_function(background_function),
+      foreground_callback(foreground_callback) {
+
+    // Add a check handle without a callback to keep the default loop running.
+    // We don't have a real handler attached to the default loop right from the
+    // beginning, because we're using asynchronous messaging to perform the actual
+    // request in the request thread. Only after the request is complete, we
+    // create an actual work request that is attached to the default loop.
+    check = new uv_check_t();
+    uv_check_init(uv_default_loop(), check);
+    uv_check_start(check, [](uv_check_t *) {});
+}
+
+Request::~Request() {
+    // We need to remove our no-op handle again to allow the main event loop to exit.
+    uv_check_stop(check);
+}
+
+void Request::work_callback(uv_work_t *work) {
+    std::shared_ptr<Request> *req = static_cast<std::shared_ptr<Request> *>(work->data);
+    (*req)->background_function((*req)->res.get());
+}
+
+// This callback is executed in the main loop.
+void Request::after_work_callback(uv_work_t *work, int /*status*/) {
+    std::shared_ptr<Request> *req = static_cast<std::shared_ptr<Request> *>(work->data);
+
+    (*req)->foreground_callback();
+
+    // This finally deletes the *pointer* to the shared pointer we've been holding on since we
+    // pushed it on the add_queue on request creation.
+    delete req;
+    delete work;
+}