From 93048392bf1996354a65de82d519b6aea86482bb Mon Sep 17 00:00:00 2001
From: Mitch Bradley <wmb@firmworks.com>
Date: Wed, 6 Sep 2023 19:17:34 -1000
Subject: [PATCH] Store startup log in RTC DRAM

... so it can be preserved across panic resets
---
 FluidNC/esp32/StartupLog.cpp    | 52 +++++++++++++++++++++++++++++++++
 FluidNC/src/Main.cpp            |  2 ++
 FluidNC/src/ProcessSettings.cpp |  2 +-
 FluidNC/src/StartupLog.cpp      | 21 -------------
 FluidNC/src/StartupLog.h        | 13 ++++-----
 5 files changed, 60 insertions(+), 30 deletions(-)
 create mode 100644 FluidNC/esp32/StartupLog.cpp
 delete mode 100644 FluidNC/src/StartupLog.cpp

diff --git a/FluidNC/esp32/StartupLog.cpp b/FluidNC/esp32/StartupLog.cpp
new file mode 100644
index 000000000..034e10d2b
--- /dev/null
+++ b/FluidNC/esp32/StartupLog.cpp
@@ -0,0 +1,52 @@
+// Copyright (c) 2023 - Mitch Bradley
+// Use of this source code is governed by a GPLv3 license that can be found in the LICENSE file.
+
+#include "src/StartupLog.h"
+#include "src/Protocol.h"  // send_line()
+#include <sstream>
+
+// The startup log is stored in RTC RAM that is preserved across
+// resets.  That lets us show the previous startup log if the
+// system panics and resets.
+
+// The size is limited by the size of RTC RAM minus system usage thereof
+static const size_t           _maxlen = 7000;
+static RTC_NOINIT_ATTR char   _messages[_maxlen];
+static RTC_NOINIT_ATTR size_t _len;
+static bool                   _paniced;
+
+void StartupLog::init() {
+    if (esp_reset_reason() == ESP_RST_PANIC) {
+        _paniced = true;
+    } else {
+        _paniced = false;
+        _len     = 0;
+    }
+}
+size_t StartupLog::write(uint8_t data) {
+    if (_paniced || _len >= _maxlen) {
+        return 0;
+    }
+    _messages[_len++] = (char)data;
+    return 1;
+}
+void StartupLog::dump(Channel& out) {
+    if (_paniced) {
+        log_error_to(out, "Showing startup log from previous panic");
+    }
+    for (size_t i = 0; i < _len;) {
+        std::string line;
+        while (i < _len) {
+            char c = _messages[i++];
+            if (c == '\n') {
+                break;
+            }
+            line += c;
+        }
+        log_to(out, line);
+    }
+}
+
+StartupLog::~StartupLog() {}
+
+StartupLog startupLog;
diff --git a/FluidNC/src/Main.cpp b/FluidNC/src/Main.cpp
index 6da6ed47e..aed6a8608 100644
--- a/FluidNC/src/Main.cpp
+++ b/FluidNC/src/Main.cpp
@@ -34,6 +34,8 @@ void setup() {
         uartInit();       // Setup serial port
         Uart0.println();  // create some white space after ESP32 boot info
 
+        StartupLog::init();
+
         // Setup input polling loop after loading the configuration,
         // because the polling may depend on the config
         allChannels.init();
diff --git a/FluidNC/src/ProcessSettings.cpp b/FluidNC/src/ProcessSettings.cpp
index 467556244..4c2a29dab 100644
--- a/FluidNC/src/ProcessSettings.cpp
+++ b/FluidNC/src/ProcessSettings.cpp
@@ -705,7 +705,7 @@ static Error showChannelInfo(const char* value, WebUI::AuthenticationLevel auth_
 }
 
 static Error showStartupLog(const char* value, WebUI::AuthenticationLevel auth_level, Channel& out) {
-    startupLog.dump(out);
+    StartupLog::dump(out);
     return Error::Ok;
 }
 
diff --git a/FluidNC/src/StartupLog.cpp b/FluidNC/src/StartupLog.cpp
deleted file mode 100644
index 0e36e71fb..000000000
--- a/FluidNC/src/StartupLog.cpp
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "StartupLog.h"
-#include <sstream>
-#include "Protocol.h"  // send_line()
-
-size_t StartupLog::write(uint8_t data) {
-    _messages += (char)data;
-    return 1;
-}
-std::string StartupLog::messages() {
-    return _messages;
-}
-void StartupLog::dump(Channel& out) {
-    std::istringstream iss(_messages);
-    for (std::string line; std::getline(iss, line);) {
-        log_to(out, line);
-    }
-}
-
-StartupLog::~StartupLog() {}
-
-StartupLog startupLog("Startup Log");
diff --git a/FluidNC/src/StartupLog.h b/FluidNC/src/StartupLog.h
index 51176a2e8..fd678f127 100644
--- a/FluidNC/src/StartupLog.h
+++ b/FluidNC/src/StartupLog.h
@@ -6,19 +6,16 @@
 #include "Config.h"
 
 #include "Channel.h"
-#include <queue>
 
 class StartupLog : public Channel {
-private:
-    std::string _messages;
-
 public:
-    StartupLog(const char* name) : Channel(name) {}
+    StartupLog() : Channel("Startup Log") {}
     virtual ~StartupLog();
 
-    size_t      write(uint8_t data) override;
-    std::string messages();
-    void        dump(Channel& channel);
+    size_t write(uint8_t data) override;
+
+    static void init();
+    static void dump(Channel& channel);
 };
 
 extern StartupLog startupLog;