Initial version of log history support.

platforms/common/px4_log_history.cpp

@@ -0,0 +1,147 @@
+/****************************************************************************
+ *
+ * Copyright (C) 2022 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include <px4_platform_common/log_history.h>
+
+#if defined(BOARD_ENABLE_LOG_HISTORY)
+#include <string.h>
+
+void LogHistory::print(FILE *out)
+{
+	const int buffer_length = 512;
+	char buffer[buffer_length];
+	int offset = -1;
+
+	int total_size_read = 0;
+
+	do {
+		int read_size = read(buffer, buffer_length, &offset);
+
+		if (read_size <= 0) {
+			break;
+		}
+
+		fwrite(buffer, 1, read_size, out);
+
+		if (read_size < buffer_length) {
+			break;
+		}
+
+		total_size_read += read_size;
+	} while (total_size_read < BOARD_LOG_HISTORY_SIZE);
+}
+
+// Log a null terminated string to the circular history buffer.
+void LogHistory::write(const char *buffer)
+{
+	lock(); // same rule as for printf: this cannot be used from IRQ handlers
+
+	int i = 0;
+
+	while (buffer[i] != '\0') {
+
+		_log_history[_tail] = buffer[i++];
+		_tail = (_tail + 1) % BOARD_LOG_HISTORY_SIZE;
+
+		if (_tail == _head) {
+			_head = (_head + 1) % BOARD_LOG_HISTORY_SIZE;
+		}
+	}
+
+	unlock();
+}
+
+int LogHistory::size()
+{
+	lock();
+	int size;
+
+	if (_head <= _tail) {
+		size = _tail - _head;
+
+	} else {
+		size = BOARD_LOG_HISTORY_SIZE - (_head - _tail);
+	}
+
+	unlock();
+	return size;
+}
+
+int LogHistory::read(char *buffer, int buffer_length, int *offset)
+{
+	lock();
+
+	if (*offset == -1) {
+		*offset = _head;
+	}
+
+	int size = 0;
+
+	if (*offset < _tail) {
+		size = _tail - *offset;
+
+		if (size > buffer_length) {
+			size = buffer_length;
+		}
+
+		memcpy(buffer, _log_history + *offset, size);
+
+	} else if (_tail < *offset) {
+		size = BOARD_LOG_HISTORY_SIZE - *offset;
+
+		if (size > buffer_length) {
+			size = buffer_length;
+		}
+
+		memcpy(buffer, _log_history + *offset, size);
+		buffer += size;
+		buffer_length -= size;
+
+		int size_secondary = _tail;
+
+		if (size_secondary > buffer_length) {
+			size_secondary = buffer_length;
+		}
+
+		if (size_secondary > 0) {
+			memcpy(buffer, _log_history, size_secondary);
+			size += size_secondary;
+		}
+	}
+
+	unlock();
+	*offset = (*offset + size) % BOARD_LOG_HISTORY_SIZE;
+	return size;
+}
+
+#endif