Uploading the main structure

node_modules/@parcel/watcher/src/Debounce.cc

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+#include "Debounce.hh"
+
+#ifdef __wasm32__
+extern "C" void on_timeout(void *ctx) {
+  Debounce *debounce = (Debounce *)ctx;
+  debounce->notify();
+}
+#endif
+
+std::shared_ptr<Debounce> Debounce::getShared() {
+  static std::weak_ptr<Debounce> sharedInstance;
+  std::shared_ptr<Debounce> shared = sharedInstance.lock();
+  if (!shared) {
+    shared = std::make_shared<Debounce>();
+    sharedInstance = shared;
+  }
+
+  return shared;
+}
+
+Debounce::Debounce() {
+  mRunning = true;
+  #ifndef __wasm32__
+    mThread = std::thread([this] () {
+      loop();
+    });
+  #endif
+}
+
+Debounce::~Debounce() {
+  mRunning = false;
+  #ifndef __wasm32__
+    mWaitSignal.notify();
+    mThread.join();
+  #endif
+}
+
+void Debounce::add(void *key, std::function<void()> cb) {
+  std::unique_lock<std::mutex> lock(mMutex);
+  mCallbacks.emplace(key, cb);
+}
+
+void Debounce::remove(void *key) {
+  std::unique_lock<std::mutex> lock(mMutex);
+  mCallbacks.erase(key);
+}
+
+void Debounce::trigger() {
+  std::unique_lock<std::mutex> lock(mMutex);
+  #ifdef __wasm32__
+    notifyIfReady();
+  #else
+    mWaitSignal.notify();
+  #endif
+}
+
+#ifndef __wasm32__
+void Debounce::loop() {
+  while (mRunning) {
+    mWaitSignal.wait();
+    if (!mRunning) {
+      break;
+    }
+
+    notifyIfReady();
+  }
+}
+#endif
+
+void Debounce::notifyIfReady() {
+  if (!mRunning) {
+    return;
+  }
+
+  // If we haven't seen an event in more than the maximum wait time, notify callbacks immediately
+  // to ensure that we don't wait forever. Otherwise, wait for the minimum wait time and batch
+  // subsequent fast changes. This also means the first file change in a batch is notified immediately,
+  // separately from the rest of the batch. This seems like an acceptable tradeoff if the common case
+  // is that only a single file was updated at a time.
+  auto time = std::chrono::steady_clock::now();
+  if ((time - mLastTime) > std::chrono::milliseconds(MAX_WAIT_TIME)) {
+    mLastTime = time;
+    notify();
+  } else {
+    wait();
+  }
+}
+
+void Debounce::wait() {
+  #ifdef __wasm32__
+    clear_timeout(mTimeout);
+    mTimeout = set_timeout(MIN_WAIT_TIME, this);
+  #else
+    auto status = mWaitSignal.waitFor(std::chrono::milliseconds(MIN_WAIT_TIME));
+    if (mRunning && (status == std::cv_status::timeout)) {
+      notify();
+    }
+  #endif
+}
+
+void Debounce::notify() {
+  std::unique_lock<std::mutex> lock(mMutex);
+
+  mLastTime = std::chrono::steady_clock::now();
+  for (auto it = mCallbacks.begin(); it != mCallbacks.end(); it++) {
+    auto cb = it->second;
+    cb();
+  }
+
+  #ifndef __wasm32__
+    mWaitSignal.reset();
+  #endif
+}