1 files changed, 77 insertions, 0 deletions
diff --git a/pw_sync_freertos/public/pw_sync_freertos/counting_semaphore_inline.h b/pw_sync_freertos/public/pw_sync_freertos/counting_semaphore_inline.h
new file mode 100644
index 000000000..e5fb3776a
--- /dev/null
+++ b/pw_sync_freertos/public/pw_sync_freertos/counting_semaphore_inline.h
@@ -0,0 +1,77 @@
+// 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 "FreeRTOS.h"
+#include "pw_assert/light.h"
+#include "pw_chrono/system_clock.h"
+#include "pw_chrono_freertos/system_clock_constants.h"
+#include "pw_interrupt/context.h"
+#include "pw_sync/counting_semaphore.h"
+#include "semphr.h"
+
+namespace pw::sync {
+
+inline CountingSemaphore::CountingSemaphore() : native_type_() {
+  const SemaphoreHandle_t handle =
+      xSemaphoreCreateCountingStatic(max(), 0, &native_type_);
+  // This should never fail since the pointer provided was not null and it
+  // should return a pointer to the StaticSemaphore_t.
+  PW_DASSERT(handle == &native_type_);
+}
+
+inline CountingSemaphore::~CountingSemaphore() {
+  vSemaphoreDelete(&native_type_);
+}
+
+inline void CountingSemaphore::acquire() {
+  PW_ASSERT(!interrupt::InInterruptContext());
+#if INCLUDE_vTaskSuspend == 1  // This means portMAX_DELAY is indefinite.
+  const BaseType_t result = xSemaphoreTake(&native_type_, portMAX_DELAY);
+  PW_DASSERT(result == pdTRUE);
+#else
+  // In case we need to block for longer than the FreeRTOS delay can represent
+  // repeatedly hit take until success.
+  while (xSemaphoreTake(&native_type_, chrono::freertos::kMaxTimeout.count()) ==
+         pdFALSE) {
+  }
+#endif  // INCLUDE_vTaskSuspend
+}
+
+inline bool CountingSemaphore::try_acquire() noexcept {
+  if (interrupt::InInterruptContext()) {
+    BaseType_t woke_higher_task = pdFALSE;
+    const bool success =
+        xSemaphoreTakeFromISR(&native_type_, &woke_higher_task) == pdTRUE;
+    portYIELD_FROM_ISR(woke_higher_task);
+    return success;
+  }
+
+  // Task Context
+  return xSemaphoreTake(&native_type_, 0) == pdTRUE;
+}
+
+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