mod: Phase 3 — Re-port unmerged upstream PRs

Re-applied upstream PRs not yet merged to upstream/master:

- #1055: Byte-level framebuffer writes (fillPhysicalHSpan*,
  optimized fillRect/drawLine/fillRectDither/fillPolygon)
- #1027: Word-width cache (FNV-1a, 128-entry) and hyphenation
  early exit in ParsedText for 7-9% layout speedup
- #1068: Already present in upstream — URL hyphenation fix
- #1019: Already present in upstream — file extensions in browser
- #1090/#1185/#1217: KOReader sync improvements — binary credential
  store, document hash caching, ChapterXPathIndexer integration
- #1209: OPDS multi-server — OpdsBookBrowserActivity accepts
  OpdsServer, directory picker for downloads, download-complete
  prompt with open/back options
- #857: Dictionary activities already ported in Phase 1/2
- #1003: Placeholder cover already integrated in Phase 2

Also fixed: STR_OFF i18n string, include paths, replaced
Epub::isValidThumbnailBmp with Storage.exists, replaced
StringUtils::checkFileExtension with FsHelpers equivalents.

Made-with: Cursor

lib/KOReaderSync/KOReaderCredentialStore.cpp

@@ -3,81 +3,73 @@
 #include <HalStorage.h>
 #include <Logging.h>
 #include <MD5Builder.h>
-#include <ObfuscationUtils.h>
 #include <Serialization.h>
 
-#include "../../src/JsonSettingsIO.h"
-
 // Initialize the static instance
 KOReaderCredentialStore KOReaderCredentialStore::instance;
 
 namespace {
-// File format version (for binary migration)
+// File format version
 constexpr uint8_t KOREADER_FILE_VERSION = 1;
 
-// File paths
-constexpr char KOREADER_FILE_BIN[] = "/.crosspoint/koreader.bin";
-constexpr char KOREADER_FILE_JSON[] = "/.crosspoint/koreader.json";
-constexpr char KOREADER_FILE_BAK[] = "/.crosspoint/koreader.bin.bak";
+// KOReader credentials file path
+constexpr char KOREADER_FILE[] = "/.crosspoint/koreader.bin";
 
 // Default sync server URL
 constexpr char DEFAULT_SERVER_URL[] = "https://sync.koreader.rocks:443";
 
-// Legacy obfuscation key - "KOReader" in ASCII (only used for binary migration)
-constexpr uint8_t LEGACY_OBFUSCATION_KEY[] = {0x4B, 0x4F, 0x52, 0x65, 0x61, 0x64, 0x65, 0x72};
-constexpr size_t LEGACY_KEY_LENGTH = sizeof(LEGACY_OBFUSCATION_KEY);
-
-void legacyDeobfuscate(std::string& data) {
-  for (size_t i = 0; i < data.size(); i++) {
-    data[i] ^= LEGACY_OBFUSCATION_KEY[i % LEGACY_KEY_LENGTH];
-  }
-}
+// Obfuscation key - "KOReader" in ASCII
+// This is NOT cryptographic security, just prevents casual file reading
+constexpr uint8_t OBFUSCATION_KEY[] = {0x4B, 0x4F, 0x52, 0x65, 0x61, 0x64, 0x65, 0x72};
+constexpr size_t KEY_LENGTH = sizeof(OBFUSCATION_KEY);
 }  // namespace
 
+void KOReaderCredentialStore::obfuscate(std::string& data) const {
+  for (size_t i = 0; i < data.size(); i++) {
+    data[i] ^= OBFUSCATION_KEY[i % KEY_LENGTH];
+  }
+}
+
 bool KOReaderCredentialStore::saveToFile() const {
+  // Make sure the directory exists
   Storage.mkdir("/.crosspoint");
-  return JsonSettingsIO::saveKOReader(*this, KOREADER_FILE_JSON);
-}
 
-bool KOReaderCredentialStore::loadFromFile() {
-  // Try JSON first
-  if (Storage.exists(KOREADER_FILE_JSON)) {
-    String json = Storage.readFile(KOREADER_FILE_JSON);
-    if (!json.isEmpty()) {
-      bool resave = false;
-      bool result = JsonSettingsIO::loadKOReader(*this, json.c_str(), &resave);
-      if (result && resave) {
-        saveToFile();
-        LOG_DBG("KRS", "Resaved KOReader credentials to update format");
-      }
-      return result;
-    }
-  }
-
-  // Fall back to binary migration
-  if (Storage.exists(KOREADER_FILE_BIN)) {
-    if (loadFromBinaryFile()) {
-      if (saveToFile()) {
-        Storage.rename(KOREADER_FILE_BIN, KOREADER_FILE_BAK);
-        LOG_DBG("KRS", "Migrated koreader.bin to koreader.json");
-        return true;
-      } else {
-        LOG_ERR("KRS", "Failed to save KOReader credentials during migration");
-        return false;
-      }
-    }
-  }
-
-  LOG_DBG("KRS", "No credentials file found");
-  return false;
-}
-
-bool KOReaderCredentialStore::loadFromBinaryFile() {
   FsFile file;
-  if (!Storage.openFileForRead("KRS", KOREADER_FILE_BIN, file)) {
+  if (!Storage.openFileForWrite("KRS", KOREADER_FILE, file)) {
     return false;
   }
 
+  // Write header
+  serialization::writePod(file, KOREADER_FILE_VERSION);
+
+  // Write username (plaintext - not particularly sensitive)
+  serialization::writeString(file, username);
+  LOG_DBG("KRS", "Saving username: %s", username.c_str());
+
+  // Write password (obfuscated)
+  std::string obfuscatedPwd = password;
+  obfuscate(obfuscatedPwd);
+  serialization::writeString(file, obfuscatedPwd);
+
+  // Write server URL
+  serialization::writeString(file, serverUrl);
+
+  // Write match method
+  serialization::writePod(file, static_cast<uint8_t>(matchMethod));
+
+  file.close();
+  LOG_DBG("KRS", "Saved KOReader credentials to file");
+  return true;
+}
+
+bool KOReaderCredentialStore::loadFromFile() {
+  FsFile file;
+  if (!Storage.openFileForRead("KRS", KOREADER_FILE, file)) {
+    LOG_DBG("KRS", "No credentials file found");
+    return false;
+  }
+
+  // Read and verify version
   uint8_t version;
   serialization::readPod(file, version);
   if (version != KOREADER_FILE_VERSION) {
@@ -86,25 +78,29 @@ bool KOReaderCredentialStore::loadFromBinaryFile() {
     return false;
   }
 
+  // Read username
   if (file.available()) {
     serialization::readString(file, username);
   } else {
     username.clear();
   }
 
+  // Read and deobfuscate password
   if (file.available()) {
     serialization::readString(file, password);
-    legacyDeobfuscate(password);
+    obfuscate(password);  // XOR is symmetric, so same function deobfuscates
   } else {
     password.clear();
   }
 
+  // Read server URL
   if (file.available()) {
     serialization::readString(file, serverUrl);
   } else {
     serverUrl.clear();
   }
 
+  // Read match method
   if (file.available()) {
     uint8_t method;
     serialization::readPod(file, method);
@@ -114,7 +110,7 @@ bool KOReaderCredentialStore::loadFromBinaryFile() {
   }
 
   file.close();
-  LOG_DBG("KRS", "Loaded KOReader credentials from binary for user: %s", username.c_str());
+  LOG_DBG("KRS", "Loaded KOReader credentials for user: %s", username.c_str());
   return true;
 }