Keep bus length when failed

In the event that a Bus fails to initialize, or the memory validation
fails, keep the configuration around so the settings contents don't
change out from under the user.

Author: willmmiles

wled00/FX_fcn.cpp

@@ -1181,14 +1181,14 @@ void WS2812FX::finalizeInit() {
   // create buses/outputs
   unsigned mem = 0;
   for (auto bus : busConfigs) {
-    unsigned busMemUsage = bus.memUsage(Bus::isDigital(bus.type) && !Bus::is2Pin(bus.type) ? digitalCount : 0);
-    // if memory exceeds limit, add it anyway but reduce LED count to default if it is larger (a bit dangerous, but prevents no buses being created at all)
-    if (mem + busMemUsage > MAX_LED_MEMORY) {
-      bus.count = min((int)bus.count, DEFAULT_LED_COUNT);
-      DEBUG_PRINTF_P(PSTR("Bus %d memory usage exceeds limit, setting count to %d\n"), (int)bus.type, bus.count);
+    bool use_placeholder = false;
+    unsigned busMemUsage = bus.memUsage(Bus::isDigital(bus.type) && !Bus::is2Pin(bus.type) ? digitalCount : 0);    
+    if (mem + busMemUsage > MAX_LED_MEMORY) {      
+      DEBUG_PRINTF_P(PSTR("Bus %d with %d LEDS memory usage exceeds limit\n"), (int)bus.type, bus.count);
+      use_placeholder = true;
     }
-    if (BusManager::add(bus) != -1) {
-      mem += bus.memUsage(Bus::isDigital(bus.type) && !Bus::is2Pin(bus.type) ? digitalCount : 0);
+    if (BusManager::add(bus, use_placeholder) != -1) {
+      mem += BusManager::busses.back()->getBusSize();
       if (Bus::isDigital(bus.type) && !Bus::is2Pin(bus.type)) digitalCount++;
     } else break;
   }
@@ -1807,7 +1807,7 @@ void WS2812FX::makeAutoSegments(bool forceReset) {
 
     for (size_t i = s; i < BusManager::getNumBusses(); i++) {
       const Bus *bus = BusManager::getBus(i);
-      if (!bus || !bus->isOk()) break;
+      if (!bus) break;
 
       segStarts[s] = bus->getStart();
       segStops[s]  = segStarts[s] + bus->getLength();

wled00/bus_manager.cpp

@@ -755,6 +755,26 @@ void BusNetwork::cleanup() {
 }
 
 
+BusPlaceholder::BusPlaceholder(const BusConfig &bc) 
+: Bus(bc.type, bc.start, bc.autoWhite, bc.count, bc.reversed, bc.refreshReq)
+, _colorOrder(bc.colorOrder)
+, _skipAmount(bc.skipAmount)
+, _frequency(bc.frequency)
+, _milliAmpsPerLed(bc.milliAmpsPerLed)
+, _milliAmpsMax(bc.milliAmpsMax)
+, _text(bc.text)
+{
+  memcpy(_pins, bc.pins, sizeof(_pins));
+}
+
+size_t BusPlaceholder::getPins(uint8_t* pinArray) const {
+  size_t nPins = Bus::getNumberOfPins(_type);
+  if (pinArray) {
+    for (size_t i = 0; i < nPins; i++) pinArray[i] = _pins[i];
+  }
+  return nPins;
+}
+
 //utility to get the approx. memory usage of a given BusConfig
 size_t BusConfig::memUsage(unsigned nr) const {
   if (Bus::isVirtual(type)) {
@@ -797,7 +817,7 @@ size_t BusManager::memUsage() {
   return size + maxI2S;
 }
 
-int BusManager::add(const BusConfig &bc) {
+int BusManager::add(const BusConfig &bc, bool placeholder) {
   DEBUGBUS_PRINTF_P(PSTR("Bus: Adding bus (p:%d v:%d)\n"), getNumBusses(), getNumVirtualBusses());
   unsigned digital = 0;
   unsigned analog  = 0;
@@ -807,8 +827,10 @@ int BusManager::add(const BusConfig &bc) {
     if (bus->isDigital() && !bus->is2Pin()) digital++;
     if (bus->is2Pin()) twoPin++;
   }
-  if (digital > WLED_MAX_DIGITAL_CHANNELS || analog > WLED_MAX_ANALOG_CHANNELS) return -1;
-  if (Bus::isVirtual(bc.type)) {
+  if (digital > WLED_MAX_DIGITAL_CHANNELS || analog > WLED_MAX_ANALOG_CHANNELS) placeholder = true;
+  if (placeholder) {
+    busses.push_back(make_unique<BusPlaceholder>(bc));
+  } else if (Bus::isVirtual(bc.type)) {
     busses.push_back(make_unique<BusNetwork>(bc));
   } else if (Bus::isDigital(bc.type)) {
     busses.push_back(make_unique<BusDigital>(bc, Bus::is2Pin(bc.type) ? twoPin : digital));
@@ -907,7 +929,7 @@ void BusManager::on() {
   if (PinManager::getPinOwner(LED_BUILTIN) == PinOwner::BusDigital) {
     for (auto &bus : busses) {
       uint8_t pins[2] = {255,255};
-      if (bus->isDigital() && bus->getPins(pins)) {
+      if (bus->isDigital() && bus->getPins(pins) && bus->isOk()) {
         if (pins[0] == LED_BUILTIN || pins[1] == LED_BUILTIN) {
           BusDigital &b = static_cast<BusDigital&>(*bus);
           b.begin();
@@ -1002,7 +1024,7 @@ void BusManager::initializeABL() {
       _useABL = true; // at least one bus has ABL set
       uint32_t ESPshare = MA_FOR_ESP / numABLbuses; // share of ESP current per ABL bus
       for (auto &bus : busses) {
-        if (bus->isDigital()) {
+        if (bus->isDigital() && bus->isOk()) {
           BusDigital &busd = static_cast<BusDigital&>(*bus);
           uint32_t busLength = busd.getLength();
           uint32_t busDemand = busLength * busd.getLEDCurrent();

wled00/bus_manager.h

@@ -125,7 +125,7 @@ class Bus {
     virtual void     setColorOrder(uint8_t co)                  {}
     virtual uint32_t getPixelColor(unsigned pix) const          { return 0; }
     virtual size_t   getPins(uint8_t* pinArray = nullptr) const { return 0; }
-    virtual uint16_t getLength() const                          { return isOk() ? _len : 0; }
+    virtual uint16_t getLength() const                          { return _len; }
     virtual uint8_t  getColorOrder() const                      { return COL_ORDER_RGB; }
     virtual unsigned skippedLeds() const                        { return 0; }
     virtual uint16_t getFrequency() const                       { return 0U; }
@@ -363,6 +363,37 @@ class BusNetwork : public Bus {
     #endif
 };
 
+// Placeholder for buses that we can't construct due to resource limitations
+// This preserves the configuration so it can be read back to the settings pages
+class BusPlaceholder : public Bus {
+  public:
+    BusPlaceholder(const BusConfig &bc);
+
+    // Actual calls are stubbed out
+    void setPixelColor(unsigned pix, uint32_t c) override {};
+    void show() override {};
+
+    // Accessors
+    uint8_t  getColorOrder() const override  { return _colorOrder; }
+    size_t   getPins(uint8_t* pinArray) const override;
+    unsigned skippedLeds() const override    { return _skipAmount; }
+    uint16_t getFrequency() const override   { return _frequency; }
+    uint16_t getLEDCurrent() const override  { return _milliAmpsPerLed; }
+    uint16_t getMaxCurrent() const override  { return _milliAmpsMax; }
+    const String getCustomText() const override { return _text; }
+
+    size_t   getBusSize() const override   { return sizeof(BusPlaceholder); }
+
+  private:
+    uint8_t _colorOrder;
+    uint8_t _skipAmount;
+    uint8_t _pins[5];
+    uint16_t _frequency;
+    uint8_t _milliAmpsPerLed;
+    uint16_t _milliAmpsMax;
+    String _text;
+};
+
 
 //temporary struct for passing bus configuration to bus
 struct BusConfig {
@@ -464,7 +495,7 @@ namespace BusManager {
 
   //do not call this method from system context (network callback)
   void removeAll();
-  int  add(const BusConfig &bc);
+  int  add(const BusConfig &bc, bool placeholder);
 
   void on();
   void off();

wled00/cfg.cpp

@@ -973,7 +973,7 @@ void serializeConfig(JsonObject root) {
   for (size_t s = 0; s < BusManager::getNumBusses(); s++) {
     DEBUG_PRINTF_P(PSTR("Cfg: Saving bus #%u\n"), s);
     const Bus *bus = BusManager::getBus(s);
-    if (!bus || !bus->isOk()) break;
+    if (!bus) break;  // Memory corruption, iterator invalid
     DEBUG_PRINTF_P(PSTR("  (%d-%d, type:%d, CO:%d, rev:%d, skip:%d, AW:%d kHz:%d, mA:%d/%d)\n"),
       (int)bus->getStart(), (int)(bus->getStart()+bus->getLength()),
       (int)(bus->getType() & 0x7F),

wled00/xml.cpp

@@ -314,7 +314,7 @@ void getSettingsJS(byte subPage, Print& settingsScript)
     unsigned sumMa = 0;
     for (size_t s = 0; s < BusManager::getNumBusses(); s++) {
       const Bus *bus = BusManager::getBus(s);
-      if (!bus || !bus->isOk()) break; // should not happen but for safety
+      if (!bus) break; // should not happen but for safety
       int offset = s < 10 ? '0' : 'A' - 10;
       char lp[4] = "L0"; lp[2] = offset+s; lp[3] = 0; //ascii 0-9 //strip data pin
       char lc[4] = "LC"; lc[2] = offset+s; lc[3] = 0; //strip length