Change Serial logging to flexible logging (#690)

* Add Logging class
Add Logging class which inherits from Print class, to be able to route logging to USB Serial or to memory for display in the webpage. Adds a log webpage only visible when DEBUG_VIA_WEB is defined.

Software/src/devboard/utils/logging.cpp

@@ -0,0 +1,86 @@
+#include "logging.h"
+#include "../../datalayer/datalayer.h"
+
+size_t Logging::write(const uint8_t* buffer, size_t size) {
+#ifdef DEBUG_LOG
+  char* message_string = datalayer.system.info.logged_can_messages;
+  int offset = datalayer.system.info.logged_can_messages_offset;  // Keeps track of the current position in the buffer
+  size_t message_string_size = sizeof(datalayer.system.info.logged_can_messages);
+  unsigned long currentTime = millis();
+#ifdef DEBUG_VIA_USB
+  size_t n = 0;
+  while (size--) {
+    if (Serial.write(*buffer++))
+      n++;
+    else
+      break;
+  }
+  return n;
+#endif
+#ifdef DEBUG_VIA_WEB
+  if (datalayer.system.info.can_logging_active) {
+    return 0;
+  }
+  if (offset + size + 13 > sizeof(datalayer.system.info.logged_can_messages)) {
+    offset = 0;
+  }
+  if (buffer[0] != '\r' && buffer[0] != '\n' &&
+      (offset == 0 || message_string[offset - 1] == '\r' || message_string[offset - 1] == '\n')) {
+    offset += snprintf(message_string + offset, message_string_size - offset - 1, "%8lu.%03lu ", currentTime / 1000,
+                       currentTime % 1000);
+  }
+  memcpy(message_string + offset, buffer, size);
+  datalayer.system.info.logged_can_messages_offset = offset + size;  // Update offset in buffer
+  return size;
+#endif  // DEBUG_VIA_WEB
+#endif  // DEBUG_LOG
+  return 0;
+}
+
+void Logging::printf(const char* fmt, ...) {
+#ifdef DEBUG_LOG
+  char* message_string = datalayer.system.info.logged_can_messages;
+  int offset = datalayer.system.info.logged_can_messages_offset;  // Keeps track of the current position in the buffer
+  size_t message_string_size = sizeof(datalayer.system.info.logged_can_messages);
+#ifdef DEBUG_VIA_USB
+  static char buf[128];
+  message_string = buf;
+  offset = 0;
+  message_string_size = sizeof(buf);
+#endif
+#ifdef DEBUG_VIA_WEB
+  if (datalayer.system.info.can_logging_active) {
+    return;
+  }
+  message_string = datalayer.system.info.logged_can_messages;
+  offset = datalayer.system.info.logged_can_messages_offset;  // Keeps track of the current position in the buffer
+  message_string_size = sizeof(datalayer.system.info.logged_can_messages);
+#endif
+  if (offset + 128 > sizeof(datalayer.system.info.logged_can_messages)) {
+    // Not enough space, reset and start from the beginning
+    offset = 0;
+  }
+  unsigned long currentTime = millis();
+  // Add timestamp
+  offset += snprintf(message_string + offset, message_string_size - offset - 1, "%8lu.%03lu ", currentTime / 1000,
+                     currentTime % 1000);
+
+  va_list(args);
+  va_start(args, fmt);
+  offset += vsnprintf(message_string + offset, message_string_size - offset - 1, fmt, args);
+  va_end(args);
+
+  if (datalayer.system.info.can_logging_active) {
+    size_t size = offset;
+    size_t n = 0;
+    while (size--) {
+      if (Serial.write(*message_string++))
+        n++;
+      else
+        break;
+    }
+  } else {
+    datalayer.system.info.logged_can_messages_offset = offset;  // Update offset in buffer
+  }
+#endif  // DEBUG_LOG
+}