Standardize File handling with FsHelpers (#110)

## Summary

* Standardize File handling with FsHelpers
* Better central place to manage to logic of if files exist/open for
reading/writing

src/CrossPointSettings.cpp

@@ -1,26 +1,28 @@
 #include "CrossPointSettings.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
 #include <SD.h>
 #include <Serialization.h>
 
-#include <cstdint>
-#include <fstream>
-
 // Initialize the static instance
 CrossPointSettings CrossPointSettings::instance;
 
 namespace {
 constexpr uint8_t SETTINGS_FILE_VERSION = 1;
 constexpr uint8_t SETTINGS_COUNT = 3;
-constexpr char SETTINGS_FILE[] = "/sd/.crosspoint/settings.bin";
+constexpr char SETTINGS_FILE[] = "/.crosspoint/settings.bin";
 }  // namespace
 
 bool CrossPointSettings::saveToFile() const {
   // Make sure the directory exists
   SD.mkdir("/.crosspoint");
 
-  std::ofstream outputFile(SETTINGS_FILE);
+  File outputFile;
+  if (!FsHelpers::openFileForWrite("CPS", SETTINGS_FILE, outputFile)) {
+    return false;
+  }
+
   serialization::writePod(outputFile, SETTINGS_FILE_VERSION);
   serialization::writePod(outputFile, SETTINGS_COUNT);
   serialization::writePod(outputFile, sleepScreen);
@@ -33,13 +35,11 @@ bool CrossPointSettings::saveToFile() const {
 }
 
 bool CrossPointSettings::loadFromFile() {
-  if (!SD.exists(SETTINGS_FILE + 3)) {  // +3 to skip "/sd" prefix
-    Serial.printf("[%lu] [CPS] Settings file does not exist, using defaults\n", millis());
+  File inputFile;
+  if (!FsHelpers::openFileForRead("CPS", SETTINGS_FILE, inputFile)) {
     return false;
   }
 
-  std::ifstream inputFile(SETTINGS_FILE);
-
   uint8_t version;
   serialization::readPod(inputFile, version);
   if (version != SETTINGS_FILE_VERSION) {

src/CrossPointState.cpp

@@ -1,20 +1,22 @@
 #include "CrossPointState.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
-#include <SD.h>
 #include <Serialization.h>
 
-#include <fstream>
-
 namespace {
 constexpr uint8_t STATE_FILE_VERSION = 1;
-constexpr char STATE_FILE[] = "/sd/.crosspoint/state.bin";
+constexpr char STATE_FILE[] = "/.crosspoint/state.bin";
 }  // namespace
 
 CrossPointState CrossPointState::instance;
 
 bool CrossPointState::saveToFile() const {
-  std::ofstream outputFile(STATE_FILE);
+  File outputFile;
+  if (!FsHelpers::openFileForWrite("CPS", STATE_FILE, outputFile)) {
+    return false;
+  }
+
   serialization::writePod(outputFile, STATE_FILE_VERSION);
   serialization::writeString(outputFile, openEpubPath);
   outputFile.close();
@@ -22,7 +24,10 @@ bool CrossPointState::saveToFile() const {
 }
 
 bool CrossPointState::loadFromFile() {
-  std::ifstream inputFile(STATE_FILE);
+  File inputFile;
+  if (!FsHelpers::openFileForRead("CPS", STATE_FILE, inputFile)) {
+    return false;
+  }
 
   uint8_t version;
   serialization::readPod(inputFile, version);

src/WifiCredentialStore.cpp

@@ -1,11 +1,10 @@
 #include "WifiCredentialStore.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
 #include <SD.h>
 #include <Serialization.h>
 
-#include <fstream>
-
 // Initialize the static instance
 WifiCredentialStore WifiCredentialStore::instance;
 
@@ -14,7 +13,7 @@ namespace {
 constexpr uint8_t WIFI_FILE_VERSION = 1;
 
 // WiFi credentials file path
-constexpr char WIFI_FILE[] = "/sd/.crosspoint/wifi.bin";
+constexpr char WIFI_FILE[] = "/.crosspoint/wifi.bin";
 
 // Obfuscation key - "CrossPoint" in ASCII
 // This is NOT cryptographic security, just prevents casual file reading
@@ -33,9 +32,8 @@ bool WifiCredentialStore::saveToFile() const {
   // Make sure the directory exists
   SD.mkdir("/.crosspoint");
 
-  std::ofstream file(WIFI_FILE, std::ios::binary);
-  if (!file) {
-    Serial.printf("[%lu] [WCS] Failed to open wifi.bin for writing\n", millis());
+  File file;
+  if (!FsHelpers::openFileForWrite("WCS", WIFI_FILE, file)) {
     return false;
   }
 
@@ -62,14 +60,8 @@ bool WifiCredentialStore::saveToFile() const {
 }
 
 bool WifiCredentialStore::loadFromFile() {
-  if (!SD.exists(WIFI_FILE + 3)) {  // +3 to skip "/sd" prefix
-    Serial.printf("[%lu] [WCS] WiFi credentials file does not exist\n", millis());
-    return false;
-  }
-
-  std::ifstream file(WIFI_FILE, std::ios::binary);
-  if (!file) {
-    Serial.printf("[%lu] [WCS] Failed to open wifi.bin for reading\n", millis());
+  File file;
+  if (!FsHelpers::openFileForRead("WCS", WIFI_FILE, file)) {
     return false;
   }
 

src/activities/boot_sleep/SleepActivity.cpp

@@ -1,6 +1,7 @@
 #include "SleepActivity.h"
 
 #include <Epub.h>
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
 #include <SD.h>
 
@@ -76,8 +77,8 @@ void SleepActivity::renderCustomSleepScreen() const {
       // Generate a random number between 1 and numFiles
       const auto randomFileIndex = random(numFiles);
       const auto filename = "/sleep/" + files[randomFileIndex];
-      auto file = SD.open(filename.c_str());
-      if (file) {
+      File file;
+      if (FsHelpers::openFileForRead("SLP", filename, file)) {
         Serial.printf("[%lu] [SLP] Randomly loading: /sleep/%s\n", millis(), files[randomFileIndex].c_str());
         delay(100);
         Bitmap bitmap(file);
@@ -93,8 +94,8 @@ void SleepActivity::renderCustomSleepScreen() const {
 
   // Look for sleep.bmp on the root of the sd card to determine if we should
   // render a custom sleep screen instead of the default.
-  auto file = SD.open("/sleep.bmp");
-  if (file) {
+  File file;
+  if (FsHelpers::openFileForRead("SLP", "/sleep.bmp", file)) {
     Bitmap bitmap(file);
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
       Serial.printf("[%lu] [SLP] Loading: /sleep.bmp\n", millis());
@@ -186,8 +187,8 @@ void SleepActivity::renderCoverSleepScreen() const {
     return renderDefaultSleepScreen();
   }
 
-  auto file = SD.open(lastEpub.getCoverBmpPath().c_str(), FILE_READ);
-  if (file) {
+  File file;
+  if (FsHelpers::openFileForRead("SLP", lastEpub.getCoverBmpPath(), file)) {
     Bitmap bitmap(file);
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
       renderBitmapSleepScreen(bitmap);

src/activities/reader/EpubReaderActivity.cpp

@@ -1,9 +1,9 @@
 #include "EpubReaderActivity.h"
 
 #include <Epub/Page.h>
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
 #include <InputManager.h>
-#include <SD.h>
 
 #include "Battery.h"
 #include "CrossPointSettings.h"
@@ -37,8 +37,8 @@ void EpubReaderActivity::onEnter() {
 
   epub->setupCacheDir();
 
-  File f = SD.open((epub->getCachePath() + "/progress.bin").c_str());
-  if (f) {
+  File f;
+  if (FsHelpers::openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     if (f.read(data, 4) == 4) {
       currentSpineIndex = data[0] + (data[1] << 8);
@@ -282,14 +282,16 @@ void EpubReaderActivity::renderScreen() {
     Serial.printf("[%lu] [ERS] Rendered page in %dms\n", millis(), millis() - start);
   }
 
-  File f = SD.open((epub->getCachePath() + "/progress.bin").c_str(), FILE_WRITE);
-  uint8_t data[4];
-  data[0] = currentSpineIndex & 0xFF;
-  data[1] = (currentSpineIndex >> 8) & 0xFF;
-  data[2] = section->currentPage & 0xFF;
-  data[3] = (section->currentPage >> 8) & 0xFF;
-  f.write(data, 4);
-  f.close();
+  File f;
+  if (FsHelpers::openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
+    uint8_t data[4];
+    data[0] = currentSpineIndex & 0xFF;
+    data[1] = (currentSpineIndex >> 8) & 0xFF;
+    data[2] = section->currentPage & 0xFF;
+    data[3] = (section->currentPage >> 8) & 0xFF;
+    f.write(data, 4);
+    f.close();
+  }
 }
 
 void EpubReaderActivity::renderContents(std::unique_ptr<Page> page) {

src/main.cpp

@@ -160,7 +160,12 @@ void onGoHome() {
 
 void setup() {
   t1 = millis();
-  Serial.begin(115200);
+
+  // Only start serial if USB connected
+  pinMode(UART0_RXD, INPUT);
+  if (digitalRead(UART0_RXD) == HIGH) {
+    Serial.begin(115200);
+  }
 
   Serial.printf("[%lu] [   ] Starting CrossPoint version " CROSSPOINT_VERSION "\n", millis());
 

src/network/CrossPointWebServer.cpp

@@ -1,6 +1,7 @@
 #include "CrossPointWebServer.h"
 
 #include <ArduinoJson.h>
+#include <FsHelpers.h>
 #include <SD.h>
 #include <WiFi.h>
 
@@ -339,8 +340,7 @@ void CrossPointWebServer::handleUpload() const {
     }
 
     // Open file for writing
-    uploadFile = SD.open(filePath.c_str(), FILE_WRITE);
-    if (!uploadFile) {
+    if (!FsHelpers::openFileForWrite("WEB", filePath, uploadFile)) {
       uploadError = "Failed to create file on SD card";
       Serial.printf("[%lu] [WEB] [UPLOAD] FAILED to create file: %s\n", millis(), filePath.c_str());
       return;