Protocol running.

src/Logging.cpp

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+#include "EggDuino.h"
+
+namespace {
+constexpr size_t kLogCapacity = 80;
+constexpr size_t kLogLineLength = 160;
+
+char g_logLines[kLogCapacity][kLogLineLength];
+uint32_t g_logSeq[kLogCapacity];
+size_t g_logWritePos = 0;
+uint32_t g_nextLogSeq = 1;
+
+void appendJsonEscaped(String &out, const char *text) {
+	out += "\"";
+	for (size_t i = 0; text[i] != '\0'; ++i) {
+		const char c = text[i];
+		switch (c) {
+			case '\\':
+				out += "\\\\";
+				break;
+			case '"':
+				out += "\\\"";
+				break;
+			case '\n':
+				out += "\\n";
+				break;
+			case '\r':
+				out += "\\r";
+				break;
+			case '\t':
+				out += "\\t";
+				break;
+			default:
+				if (static_cast<unsigned char>(c) < 0x20) {
+					out += '?';
+				} else {
+					out += c;
+				}
+				break;
+		}
+	}
+	out += "\"";
+}
+} // namespace
+
+void Log(const String &message) {
+	const String trimmed = message.substring(0, kLogLineLength - 1);
+	trimmed.toCharArray(g_logLines[g_logWritePos], kLogLineLength);
+	g_logSeq[g_logWritePos] = g_nextLogSeq++;
+	g_logWritePos = (g_logWritePos + 1) % kLogCapacity;
+}
+
+void Log(const char *message) {
+	Log(String(message));
+}
+
+String buildLogsJson(uint32_t sinceSeq) {
+	String output;
+	output.reserve(2048);
+	output += "{\"logs\":[";
+	uint32_t lastSeq = sinceSeq;
+	bool first = true;
+
+	for (size_t i = 0; i < kLogCapacity; ++i) {
+		const size_t idx = (g_logWritePos + i) % kLogCapacity;
+		const uint32_t seq = g_logSeq[idx];
+		if (seq == 0 || seq <= sinceSeq) {
+			continue;
+		}
+
+		if (!first) {
+			output += ",";
+		}
+		first = false;
+		output += "{\"seq\":";
+		output += String(seq);
+		output += ",\"text\":";
+		appendJsonEscaped(output, g_logLines[idx]);
+		output += "}";
+		lastSeq = seq;
+	}
+
+	output += "],\"lastSeq\":";
+	output += String(lastSeq);
+	output += "}";
+	return output;
+}