fix(mdns): Refactor freertos linux compat layers

Move it to a separate component that could be shared by multiple network
libs.

common_components/linux_compat/freertos/osal/event_group.cpp

@@ -0,0 +1,111 @@
+/*
+ * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <mutex>
+#include <condition_variable>
+#include "osal_api.h"
+
+struct SignalGroupInternal {
+    std::condition_variable notify;
+    std::mutex m;
+    uint32_t flags{ 0 };
+};
+
+using SignalT = std::unique_ptr<SignalGroupInternal>;
+
+class SignalGroup {
+public:
+
+    explicit SignalGroup(): event_group(std::make_unique<SignalGroupInternal>()) {}
+
+    void set(uint32_t bits)
+    {
+        std::unique_lock<std::mutex> lock(event_group->m);
+        event_group->flags |= bits;
+        event_group->notify.notify_all();
+    }
+
+    uint32_t get()
+    {
+        return event_group->flags;
+    }
+
+    void clear(uint32_t bits)
+    {
+        std::unique_lock<std::mutex> lock(event_group->m);
+        event_group->flags &= ~bits;
+        event_group->notify.notify_all();
+    }
+
+    // waiting for all and clearing if set
+    bool wait(uint32_t flags, uint32_t time_ms)
+    {
+        std::unique_lock<std::mutex> lock(event_group->m);
+        return event_group->notify.wait_for(lock, std::chrono::milliseconds(time_ms), [&] {
+            if ((flags & event_group->flags) == flags)
+            {
+                event_group->flags &= ~flags;
+                return true;
+            }
+            return false;
+        });
+    }
+
+
+    // waiting for any bit, not clearing them
+    bool wait_any(uint32_t flags, uint32_t time_ms)
+    {
+        std::unique_lock<std::mutex> lock(event_group->m);
+        return event_group->notify.wait_for(lock, std::chrono::milliseconds(time_ms), [&] { return flags & event_group->flags; });
+    }
+
+    ~SignalGroup() = default;
+
+private:
+    SignalT event_group;
+};
+
+
+void *osal_signal_create()
+{
+    auto signal = new SignalGroup;
+    return signal;
+}
+
+void osal_signal_delete(void *s)
+{
+    delete static_cast<SignalGroup *>(s);
+}
+
+uint32_t osal_signal_clear(void *s, uint32_t bits)
+{
+    auto signal = static_cast<SignalGroup *>(s);
+    signal->clear(bits);
+    return signal->get();
+}
+
+uint32_t osal_signal_set(void *s, uint32_t bits)
+{
+    auto signal = static_cast<SignalGroup *>(s);
+    signal->set(bits);
+    return signal->get();
+}
+
+uint32_t osal_signal_get(void *s)
+{
+    auto signal = static_cast<SignalGroup *>(s);
+    return signal->get();
+}
+
+uint32_t osal_signal_wait(void *s, uint32_t flags, bool all, uint32_t timeout)
+{
+    auto signal = static_cast<SignalGroup *>(s);
+    if (all) {
+        signal->wait(flags, timeout);
+    } else {
+        signal->wait_any(flags, timeout);
+    }
+    return signal->get();
+}