From ce6107480256b3251b0d069f5c678b09bc36d90e Mon Sep 17 00:00:00 2001
From: Adam Coddington <me@adamcoddington.net>
Date: Mon, 17 Sep 2018 12:16:18 -0700
Subject: [PATCH] Add functionality allowing rxBuffer of HardwareSerial to be
 changed in size via HardwareSerial::setRxBufferSize. (#1855)

---
 cores/esp32/HardwareSerial.cpp |  4 ++++
 cores/esp32/HardwareSerial.h   |  1 +
 cores/esp32/esp32-hal-uart.c   | 20 ++++++++++++++++++++
 cores/esp32/esp32-hal-uart.h   |  2 ++
 4 files changed, 27 insertions(+)

diff --git a/cores/esp32/HardwareSerial.cpp b/cores/esp32/HardwareSerial.cpp
index e46c7a02..920e4abd 100644
--- a/cores/esp32/HardwareSerial.cpp
+++ b/cores/esp32/HardwareSerial.cpp
@@ -46,6 +46,10 @@ void HardwareSerial::end()
     _uart = 0;
 }
 
+size_t HardwareSerial::setRxBufferSize(size_t new_size) {
+    return uartResizeRxBuffer(_uart, new_size);
+}
+
 void HardwareSerial::setDebugOutput(bool en)
 {
     if(_uart == 0) {
diff --git a/cores/esp32/HardwareSerial.h b/cores/esp32/HardwareSerial.h
index f1e04e90..a5a3f671 100644
--- a/cores/esp32/HardwareSerial.h
+++ b/cores/esp32/HardwareSerial.h
@@ -70,6 +70,7 @@ public:
     uint32_t baudRate();
     operator bool() const;
 
+    size_t setRxBufferSize(size_t);
     void setDebugOutput(bool);
 
 protected:
diff --git a/cores/esp32/esp32-hal-uart.c b/cores/esp32/esp32-hal-uart.c
index d8d13295..8fdb0cc3 100644
--- a/cores/esp32/esp32-hal-uart.c
+++ b/cores/esp32/esp32-hal-uart.c
@@ -240,6 +240,26 @@ void uartEnd(uart_t* uart)
     uartDetachTx(uart);
 }
 
+size_t uartResizeRxBuffer(uart_t * uart, size_t new_size) {
+    if(uart == NULL) {
+        return;
+    }
+
+    UART_MUTEX_LOCK();
+    if(uart->queue != NULL) {
+        uint8_t c;
+        while(xQueueReceive(uart->queue, &c, 0));
+        vQueueDelete(uart->queue);
+        uart->queue = xQueueCreate(new_size, sizeof(uint8_t));
+        if(uart->queue == NULL) {
+            return NULL;
+        }
+    }
+    UART_MUTEX_UNLOCK();
+
+    return new_size;
+}
+
 uint32_t uartAvailable(uart_t* uart)
 {
     if(uart == NULL || uart->queue == NULL) {
diff --git a/cores/esp32/esp32-hal-uart.h b/cores/esp32/esp32-hal-uart.h
index 5cd6e965..e3023a1c 100644
--- a/cores/esp32/esp32-hal-uart.h
+++ b/cores/esp32/esp32-hal-uart.h
@@ -67,6 +67,8 @@ void uartFlush(uart_t* uart);
 void uartSetBaudRate(uart_t* uart, uint32_t baud_rate);
 uint32_t uartGetBaudRate(uart_t* uart);
 
+size_t uartResizeRxBuffer(uart_t* uart, size_t new_size);
+
 void uartSetDebug(uart_t* uart);
 int uartGetDebug();