Merge branch 'feat/remove-unecessray-condition-in-usj-read' into 'master'

fix(driver): remove unecessary if conditions in the read function

Closes IDF-13166

See merge request espressif/esp-idf!39523

Author: SoucheSouche

components/esp_driver_usb_serial_jtag/include/driver/usb_serial_jtag_select.h

@@ -1,6 +1,6 @@
 
 /*
- * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -27,6 +27,13 @@ typedef void (*usj_select_notif_callback_t)(usj_select_notif_t usb_serial_jtag_s
  */
 void usb_serial_jtag_set_select_notif_callback(usj_select_notif_callback_t usb_serial_jtag_select_notif_callback);
 
+/**
+ * @brief Return the number of bytes available for reading
+ *
+ * @return the number of bytes available for reading in the buffer
+ */
+size_t usb_serial_jtag_get_read_bytes_available(void);
+
 /**
  * @brief Return the readiness status of the driver for read operation
  *

components/esp_driver_usb_serial_jtag/src/usb_serial_jtag.c

@@ -366,12 +366,23 @@ void usb_serial_jtag_set_select_notif_callback(usj_select_notif_callback_t usj_s
     }
 }
 
-bool usb_serial_jtag_read_ready(void)
+size_t usb_serial_jtag_get_read_bytes_available(void)
 {
     // sign the the driver is read ready is that data is waiting in the RX ringbuffer
-    UBaseType_t items_waiting = 0;
-    vRingbufferGetInfo(p_usb_serial_jtag_obj->rx_ring_buf, NULL, NULL, NULL, NULL, &items_waiting);
-    return items_waiting != 0;
+    UBaseType_t bytes_available = 0;
+    if (usb_serial_jtag_is_driver_installed()) {
+        vRingbufferGetInfo(p_usb_serial_jtag_obj->rx_ring_buf, NULL, NULL, NULL, NULL, &bytes_available);
+        if (bytes_available <= 0) {
+            return 0;
+        }
+    }
+
+    return (size_t)bytes_available;
+}
+
+bool usb_serial_jtag_read_ready(void)
+{
+    return usb_serial_jtag_get_read_bytes_available() != 0;
 }
 
 bool usb_serial_jtag_write_ready(void)

components/esp_driver_usb_serial_jtag/src/usb_serial_jtag_vfs.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -226,40 +226,69 @@ static void usb_serial_jtag_return_char(int fd, int c)
 
 static ssize_t usb_serial_jtag_read(int fd, void* data, size_t size)
 {
+    assert(fd == USJ_LOCAL_FD);
     char *data_c = (char *) data;
     size_t received = 0;
+    size_t available_size = 0;
+    int c = NONE; // store the read char
     _lock_acquire_recursive(&s_ctx.read_lock);
-    while (received < size) {
-        int c = usb_serial_jtag_read_char(fd);
-        if (c == '\r') {
-            if (s_ctx.rx_mode == ESP_LINE_ENDINGS_CR) {
-                c = '\n';
-            } else if (s_ctx.rx_mode == ESP_LINE_ENDINGS_CRLF) {
-                /* look ahead */
-                int c2 = usb_serial_jtag_read_char(fd);
-                if (c2 == NONE) {
-                    /* could not look ahead, put the current character back */
-                    usb_serial_jtag_return_char(fd, c);
-                    break;
-                }
-                if (c2 == '\n') {
-                    /* this was \r\n sequence. discard \r, return \n */
+
+    // if blocking read, wait for data to  be available
+    if (!s_ctx.non_blocking) {
+        c = usb_serial_jtag_read_char(fd);
+    }
+
+    // find the actual fetch size
+    available_size += usb_serial_jtag_get_read_bytes_available();
+    if (c != NONE) {
+        available_size++;
+    }
+    if (s_ctx.peek_char != NONE) {
+        available_size++;
+    }
+    size_t fetch_size = MIN(available_size, size);
+
+    if (fetch_size > 0) {
+        do {
+            if (c == NONE) { // for non-O_NONBLOCK mode, there is already a pre-fetched char
+                c = usb_serial_jtag_read_char(fd);
+            }
+            assert(c != NONE);
+
+            if (c == '\r') {
+                if (s_ctx.rx_mode == ESP_LINE_ENDINGS_CR) {
                     c = '\n';
-                } else {
-                    /* \r followed by something else. put the second char back,
-                     * it will be processed on next iteration. return \r now.
-                     */
-                    usb_serial_jtag_return_char(fd, c2);
+                } else if (s_ctx.rx_mode == ESP_LINE_ENDINGS_CRLF) {
+                    /* look ahead */
+                    int c2 = usb_serial_jtag_read_char(fd);
+                    fetch_size--;
+                    if (c2 == NONE) {
+                        /* could not look ahead, put the current character back */
+                        usb_serial_jtag_return_char(fd, c);
+                        c = NONE;
+                        break;
+                    }
+                    if (c2 == '\n') {
+                        /* this was \r\n sequence. discard \r, return \n */
+                        c = '\n';
+                    } else {
+                        /* \r followed by something else. put the second char back,
+                         * it will be processed on next iteration. return \r now.
+                         */
+                        usb_serial_jtag_return_char(fd, c2);
+                        fetch_size++;
+                    }
                 }
             }
-        } else if (c == NONE) {
-            break;
-        }
-        data_c[received] = (char) c;
-        ++received;
-        if (c == '\n') {
-            break;
-        }
+
+            data_c[received] = (char) c;
+            ++received;
+            c = NONE;
+        } while (received < fetch_size);
+    }
+
+    if (c != NONE) { // fetched, but not used
+        usb_serial_jtag_return_char(fd, c);
     }
     _lock_release_recursive(&s_ctx.read_lock);
     if (received > 0) {
@@ -455,7 +484,7 @@ static esp_err_t usb_serial_jtag_start_select(int nfds, fd_set *readfds, fd_set
     bool trigger_select = false;
 
     // check if the select should return instantly if the bus is read ready
-    if (FD_ISSET(USJ_LOCAL_FD, &args->readfds_orig) && usb_serial_jtag_read_ready()) {
+    if (FD_ISSET(USJ_LOCAL_FD, &args->readfds_orig) && (usb_serial_jtag_get_read_bytes_available() > 0)) {
         // signal immediately when data is buffered
         FD_SET(USJ_LOCAL_FD, readfds);
         trigger_select = true;

components/esp_driver_usb_serial_jtag/test_apps/usb_serial_jtag_vfs/main/test_vfs_usb_serial_jtag.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -23,11 +23,6 @@
 #include "test_utils.h"
 #include "sdkconfig.h"
 
-struct task_arg_t {
-    FILE* stream;
-    SemaphoreHandle_t done;
-};
-
 static int read_bytes_with_select(FILE *stream, void *buf, size_t buf_len, struct timeval tv)
 {
 
@@ -74,7 +69,7 @@ static int read_bytes_with_select(FILE *stream, void *buf, size_t buf_len, struc
  * write calls. At the end of the test, the variable is check to make sure the select returned
  * for each of the write calls.
  */
-TEST_CASE("test select read, write and timeout", "[usb_serial_jtag]")
+TEST_CASE("test select read, write and timeout", "[usb_serial_jtag vfs]")
 {
     struct timeval tv;
     tv.tv_sec = 1;
@@ -128,3 +123,86 @@ TEST_CASE("test select read, write and timeout", "[usb_serial_jtag]")
     usb_serial_jtag_vfs_use_nonblocking();
     usb_serial_jtag_driver_uninstall();
 }
+
+/* Test that the read function does not return prematurely when receiving a new line character
+ */
+TEST_CASE("read does not return on new line character", "[usb serial jtag vfs]")
+{
+    // Send a string with length less than the read requested length
+    const char in_buffer[] = "!(@*#&(!*@&#((SDasdkjhad\nce"; // read should not early return on \n
+    const size_t in_buffer_len = sizeof(in_buffer);
+
+    const size_t out_buffer_len = in_buffer_len - 1; // don't compare the null character at the end of in_buffer string
+    char out_buffer[out_buffer_len] = {};
+
+    usb_serial_jtag_driver_config_t usj_config = USB_SERIAL_JTAG_DRIVER_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK(usb_serial_jtag_driver_install(&usj_config));
+    usb_serial_jtag_vfs_use_driver();
+
+    usb_serial_jtag_vfs_set_rx_line_endings(ESP_LINE_ENDINGS_LF);
+    usb_serial_jtag_vfs_set_tx_line_endings(ESP_LINE_ENDINGS_LF);
+
+    int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
+    fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
+
+    // trigger the test environment to send the test message
+    char ready_msg[] = "ready to receive\n";
+    write(fileno(stdout), ready_msg, sizeof(ready_msg));
+
+    // wait for the string to be sent and buffered
+    vTaskDelay(pdMS_TO_TICKS(500));
+
+    char *out_buffer_ptr = out_buffer;
+    size_t bytes_read = 0;
+    do {
+        int nread = read(STDIN_FILENO, out_buffer_ptr, out_buffer_len);
+        printf("%d\n", nread);
+        if (nread > 0) {
+            out_buffer_ptr += nread;
+            bytes_read += nread;
+        }
+    } while (bytes_read < in_buffer_len);
+
+    // string compare
+    for (size_t i = 0; i < out_buffer_len; i++) {
+        TEST_ASSERT_EQUAL(in_buffer[i], out_buffer[i]);
+    }
+
+    usb_serial_jtag_vfs_use_nonblocking();
+    fcntl(STDIN_FILENO, F_SETFL, flags);
+    usb_serial_jtag_vfs_set_rx_line_endings(ESP_LINE_ENDINGS_CRLF);
+    usb_serial_jtag_vfs_set_tx_line_endings(ESP_LINE_ENDINGS_CRLF);
+    ESP_ERROR_CHECK(usb_serial_jtag_driver_uninstall());
+    vTaskDelay(2);  // wait for tasks to exit
+}
+
+TEST_CASE("blocking read returns with available data", "[usb serial jtag vfs]")
+{
+    const size_t out_buffer_len = 32;
+    char out_buffer[out_buffer_len] = {};
+
+    usb_serial_jtag_driver_config_t usj_config = USB_SERIAL_JTAG_DRIVER_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK(usb_serial_jtag_driver_install(&usj_config));
+    usb_serial_jtag_vfs_use_driver();
+
+    usb_serial_jtag_vfs_set_rx_line_endings(ESP_LINE_ENDINGS_LF);
+    usb_serial_jtag_vfs_set_tx_line_endings(ESP_LINE_ENDINGS_LF);
+
+    int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
+    fcntl(STDIN_FILENO, F_SETFL, flags & (~O_NONBLOCK));
+
+    // trigger the test environment to send the test message
+    char ready_msg[] = "ready to receive\n";
+    write(fileno(stdout), ready_msg, sizeof(ready_msg));
+
+    const int nread = read(STDIN_FILENO, out_buffer, out_buffer_len);
+    TEST_ASSERT(nread > 0);
+    TEST_ASSERT(nread < out_buffer_len);
+
+    usb_serial_jtag_vfs_use_nonblocking();
+    fcntl(STDIN_FILENO, F_SETFL, flags);
+    usb_serial_jtag_vfs_set_rx_line_endings(ESP_LINE_ENDINGS_CRLF);
+    usb_serial_jtag_vfs_set_tx_line_endings(ESP_LINE_ENDINGS_CRLF);
+    ESP_ERROR_CHECK(usb_serial_jtag_driver_uninstall());
+    vTaskDelay(2);  // wait for tasks to exit
+}

components/esp_driver_usb_serial_jtag/test_apps/usb_serial_jtag_vfs/pytest_usb_serial_jtag_vfs.py

@@ -15,10 +15,46 @@
 )
 @pytest.mark.parametrize('test_message', ['test123456789!@#%^&*'])
 @idf_parametrize('target', ['esp32s3', 'esp32c3', 'esp32c6', 'esp32h2'], indirect=['target'])
-def test_usj_vfs_release(dut: Dut, test_message: list) -> None:
+def test_usj_vfs_select(dut: Dut, test_message: list) -> None:
     dut.expect_exact('Press ENTER to see the list of tests')
     dut.write('"test select read, write and timeout"')
     dut.expect_exact('select timed out', timeout=2)
     dut.write(test_message)
     dut.expect_exact(test_message, timeout=2)
     dut.expect(r'\d{1} Tests 0 Failures 0 Ignored', timeout=10)
+
+
+@pytest.mark.usb_serial_jtag
+@pytest.mark.parametrize(
+    'port, flash_port, config',
+    [
+        pytest.param('/dev/serial_ports/ttyACM-esp32', '/dev/serial_ports/ttyUSB-esp32', 'release'),
+    ],
+    indirect=True,
+)
+@pytest.mark.parametrize('test_message', ['!(@*#&(!*@&#((SDasdkjhad\nce'])
+@idf_parametrize('target', ['esp32s3', 'esp32c3', 'esp32c6', 'esp32h2'], indirect=['target'])
+def test_usj_vfs_read_return(dut: Dut, test_message: list) -> None:
+    dut.expect_exact('Press ENTER to see the list of tests')
+    dut.write('"read does not return on new line character"')
+    dut.expect_exact('ready to receive', timeout=2)
+    dut.write(test_message)
+    dut.expect(r'\d{1} Tests 0 Failures 0 Ignored', timeout=10)
+
+
+@pytest.mark.usb_serial_jtag
+@pytest.mark.parametrize(
+    'port, flash_port, config',
+    [
+        pytest.param('/dev/serial_ports/ttyACM-esp32', '/dev/serial_ports/ttyUSB-esp32', 'release'),
+    ],
+    indirect=True,
+)
+@pytest.mark.parametrize('test_message', ['testdata'])
+@idf_parametrize('target', ['esp32s3', 'esp32c3', 'esp32c6', 'esp32h2'], indirect=['target'])
+def test_usj_vfs_read_blocking(dut: Dut, test_message: list) -> None:
+    dut.expect_exact('Press ENTER to see the list of tests')
+    dut.write('"blocking read returns with available data"')
+    dut.expect_exact('ready to receive', timeout=2)
+    dut.write(test_message)
+    dut.expect(r'\d{1} Tests 0 Failures 0 Ignored', timeout=10)