1 files changed, 75 insertions, 0 deletions
diff --git a/pw_sync_threadx/public/pw_sync_threadx/counting_semaphore_inline.h b/pw_sync_threadx/public/pw_sync_threadx/counting_semaphore_inline.h
new file mode 100644
index 000000000..7125e0169
--- /dev/null
+++ b/pw_sync_threadx/public/pw_sync_threadx/counting_semaphore_inline.h
@@ -0,0 +1,75 @@
+// Copyright 2020 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+#pragma once
+
+#include <algorithm>
+
+#include "pw_assert/light.h"
+#include "pw_chrono/system_clock.h"
+#include "pw_interrupt/context.h"
+#include "pw_sync/counting_semaphore.h"
+#include "tx_api.h"
+
+namespace pw::sync {
+namespace backend {
+
+inline constexpr char kCountingSemaphoreName[] = "pw::CountingSemaphore";
+
+}  // namespace backend
+
+inline CountingSemaphore::CountingSemaphore() : native_type_() {
+  PW_ASSERT(
+      tx_semaphore_create(&native_type_,
+                          const_cast<char*>(backend::kCountingSemaphoreName),
+                          0) == TX_SUCCESS);
+}
+
+inline CountingSemaphore::~CountingSemaphore() {
+  PW_ASSERT(tx_semaphore_delete(&native_type_) == TX_SUCCESS);
+}
+
+inline void CountingSemaphore::release(ptrdiff_t update) {
+  for (; update > 0; --update) {
+    PW_ASSERT(tx_semaphore_put(&native_type_) == TX_SUCCESS);
+  }
+}
+
+inline void CountingSemaphore::acquire() {
+  // Enforce the pw::sync::CountingSemaphore IRQ contract.
+  PW_DASSERT(!interrupt::InInterruptContext());
+  PW_ASSERT(tx_semaphore_get(&native_type_, TX_WAIT_FOREVER) == TX_SUCCESS);
+}
+
+inline bool CountingSemaphore::try_acquire() noexcept {
+  const UINT result = tx_semaphore_get(&native_type_, TX_NO_WAIT);
+  if (result == TX_NO_INSTANCE) {
+    return false;
+  }
+  PW_ASSERT(result == TX_SUCCESS);
+  return true;
+}
+
+inline bool CountingSemaphore::try_acquire_until(
+    chrono::SystemClock::time_point until_at_least) {
+  // Note that if this deadline is in the future, it will get rounded up by
+  // one whole tick due to how try_acquire_for is implemented.
+  return try_acquire_for(until_at_least - chrono::SystemClock::now());
+}
+
+inline CountingSemaphore::native_handle_type
+CountingSemaphore::native_handle() {
+  return native_type_;
+}
+
+}  // namespace pw::sync