From 5d7cbec34cd5e473d5768b39054d99bc72ddad62 Mon Sep 17 00:00:00 2001
From: jacqueline <me@jacqueline.id.au>
Date: Thu, 27 Apr 2023 12:55:30 +1000
Subject: Move DB interactions to a background thread

---
 src/database/db_task.cpp | 91 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 src/database/db_task.cpp

(limited to 'src/database/db_task.cpp')

diff --git a/src/database/db_task.cpp b/src/database/db_task.cpp
new file mode 100644
index 00000000..ce1cd98a
--- /dev/null
+++ b/src/database/db_task.cpp
@@ -0,0 +1,91 @@
+#include "db_task.hpp"
+
+#include <functional>
+
+#include "esp_heap_caps.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/portmacro.h"
+#include "freertos/projdefs.h"
+#include "freertos/queue.h"
+#include "freertos/task.h"
+
+namespace database {
+
+static const std::size_t kDbStackSize = 256 * 1024;
+static StaticTask_t sDbStaticTask;
+static StackType_t* sDbStack = nullptr;
+
+static std::atomic<bool> sTaskRunning(false);
+static QueueHandle_t sWorkQueue;
+
+struct WorkItem {
+  std::function<void(void)>* fn;
+  bool quit;
+};
+
+auto SendToDbTask(std::function<void(void)> fn) -> void {
+  WorkItem item{
+      .fn = new std::function<void(void)>(fn),
+      .quit = false,
+  };
+  xQueueSend(sWorkQueue, &item, portMAX_DELAY);
+}
+
+template <>
+auto RunOnDbTask(std::function<void(void)> fn) -> std::future<void> {
+  std::shared_ptr<std::promise<void>> promise =
+      std::make_shared<std::promise<void>>();
+  SendToDbTask([=]() {
+    std::invoke(fn);
+    promise->set_value();
+  });
+  return promise->get_future();
+}
+
+void DatabaseTaskMain(void* args) {
+  while (true) {
+    WorkItem item;
+    if (xQueueReceive(sWorkQueue, &item, portMAX_DELAY)) {
+      if (item.quit) {
+        break;
+      }
+      if (item.fn != nullptr) {
+        std::invoke(*item.fn);
+        delete item.fn;
+      }
+    }
+  }
+  vQueueDelete(sWorkQueue);
+  sTaskRunning.store(false);
+  vTaskDelete(NULL);
+}
+
+auto StartDbTask() -> bool {
+  if (sTaskRunning.exchange(true)) {
+    return false;
+  }
+  if (sDbStack == nullptr) {
+    sDbStack = reinterpret_cast<StackType_t*>(
+        heap_caps_malloc(kDbStackSize, MALLOC_CAP_SPIRAM));
+  }
+  sWorkQueue = xQueueCreate(8, sizeof(std::function<void(void)>*));
+  xTaskCreateStatic(&DatabaseTaskMain, "DB", kDbStackSize, NULL, 1, sDbStack,
+                    &sDbStaticTask);
+  return true;
+}
+
+auto QuitDbTask() -> void {
+  if (!sTaskRunning.load()) {
+    return;
+  }
+  WorkItem item{
+      .fn = nullptr,
+      .quit = true,
+  };
+  xQueueSend(sWorkQueue, &item, portMAX_DELAY);
+  while (sTaskRunning.load()) {
+    vTaskDelay(pdMS_TO_TICKS(1));
+  }
+}
+
+}  // namespace database
-- 
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