From f8ec5242c98649cb590e24667dd3791a5f6b6df1 Mon Sep 17 00:00:00 2001
From: Kevin Ahrendt <kahrendt@gmail.com>
Date: Mon, 2 Sep 2024 20:47:54 -0400
Subject: [PATCH] Better support for task blocking ring buffer reads and writes
 (#7390)

---
 esphome/core/ring_buffer.cpp | 15 ++++++++--
 esphome/core/ring_buffer.h   | 56 ++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/esphome/core/ring_buffer.cpp b/esphome/core/ring_buffer.cpp
index 9bd3d9d853..d8ca831de0 100644
--- a/esphome/core/ring_buffer.cpp
+++ b/esphome/core/ring_buffer.cpp
@@ -20,13 +20,20 @@ std::unique_ptr<RingBuffer> RingBuffer::create(size_t len) {
     return nullptr;
   }
 
-  rb->handle_ = xStreamBufferCreateStatic(len + 1, 0, rb->storage_, &rb->structure_);
+  rb->handle_ = xStreamBufferCreateStatic(len + 1, 1, rb->storage_, &rb->structure_);
   ESP_LOGD(TAG, "Created ring buffer with size %u", len);
   return rb;
 }
 
 size_t RingBuffer::read(void *data, size_t len, TickType_t ticks_to_wait) {
-  return xStreamBufferReceive(this->handle_, data, len, ticks_to_wait);
+  if (ticks_to_wait > 0)
+    xStreamBufferSetTriggerLevel(this->handle_, len);
+
+  size_t bytes_read = xStreamBufferReceive(this->handle_, data, len, ticks_to_wait);
+
+  xStreamBufferSetTriggerLevel(this->handle_, 1);
+
+  return bytes_read;
 }
 
 size_t RingBuffer::write(void *data, size_t len) {
@@ -39,6 +46,10 @@ size_t RingBuffer::write(void *data, size_t len) {
   return xStreamBufferSend(this->handle_, data, len, 0);
 }
 
+size_t RingBuffer::write_without_replacement(void *data, size_t len, TickType_t ticks_to_wait) {
+  return xStreamBufferSend(this->handle_, data, len, ticks_to_wait);
+}
+
 size_t RingBuffer::available() const { return xStreamBufferBytesAvailable(this->handle_); }
 
 size_t RingBuffer::free() const { return xStreamBufferSpacesAvailable(this->handle_); }
diff --git a/esphome/core/ring_buffer.h b/esphome/core/ring_buffer.h
index e602068844..97ffefcefa 100644
--- a/esphome/core/ring_buffer.h
+++ b/esphome/core/ring_buffer.h
@@ -12,13 +12,69 @@ namespace esphome {
 
 class RingBuffer {
  public:
+  /**
+   * @brief Reads from the ring buffer, waiting up to a specified number of ticks if necessary.
+   *
+   * Available bytes are read into the provided data pointer. If not enough bytes are available,
+   * the function will wait up to `ticks_to_wait` FreeRTOS ticks before reading what is available.
+   *
+   * @param data Pointer to copy read data into
+   * @param len Number of bytes to read
+   * @param ticks_to_wait Maximum number of FreeRTOS ticks to wait (default: 0)
+   * @return Number of bytes read
+   */
   size_t read(void *data, size_t len, TickType_t ticks_to_wait = 0);
 
+  /**
+   * @brief Writes to the ring buffer, overwriting oldest data if necessary.
+   *
+   * The provided data is written to the ring buffer. If not enough space is available,
+   * the function will overwrite the oldest data in the ring buffer.
+   *
+   * @param data Pointer to data for writing
+   * @param len Number of bytes to write
+   * @return Number of bytes written
+   */
   size_t write(void *data, size_t len);
 
+  /**
+   * @brief Writes to the ring buffer without overwriting oldest data.
+   *
+   * The provided data is written to the ring buffer. If not enough space is available,
+   * the function will wait up to `ticks_to_wait` FreeRTOS ticks before writing as much as possible.
+   *
+   * @param data Pointer to data for writing
+   * @param len Number of bytes to write
+   * @param ticks_to_wait Maximum number of FreeRTOS ticks to wait (default: 0)
+   * @return Number of bytes written
+   */
+  size_t write_without_replacement(void *data, size_t len, TickType_t ticks_to_wait = 0);
+
+  /**
+   * @brief Returns the number of available bytes in the ring buffer.
+   *
+   * This function provides the number of bytes that can be read from the ring buffer
+   * without blocking the calling FreeRTOS task.
+   *
+   * @return Number of available bytes
+   */
   size_t available() const;
+
+  /**
+   * @brief Returns the number of free bytes in the ring buffer.
+   *
+   * This function provides the number of bytes that can be written to the ring buffer
+   * without overwriting data or blocking the calling FreeRTOS task.
+   *
+   * @return Number of free bytes
+   */
   size_t free() const;
 
+  /**
+   * @brief Resets the ring buffer, discarding all stored data.
+   *
+   * @return pdPASS if successful, pdFAIL otherwise
+   */
   BaseType_t reset();
 
   static std::unique_ptr<RingBuffer> create(size_t len);