Remove excess data from page line serialization

lib/Epub/Epub/Page.cpp

@@ -7,12 +7,12 @@ void PageLine::render(GfxRenderer& renderer, const int fontId, const int xOffset
   block->render(renderer, fontId, xPos + xOffset, yPos + yOffset);
 }
 
-void PageLine::serialize(File& file) {
+bool PageLine::serialize(File &file) {
   serialization::writePod(file, xPos);
   serialization::writePod(file, yPos);
 
   // serialize TextBlock pointed to by PageLine
-  block->serialize(file);
+  return block->serialize(file);
 }
 
 std::unique_ptr<PageLine> PageLine::deserialize(File& file) {
@@ -31,15 +31,19 @@ void Page::render(GfxRenderer& renderer, const int fontId, const int xOffset, co
   }
 }
 
-void Page::serialize(File& file) const {
+bool Page::serialize(File& file) const {
   const uint32_t count = elements.size();
   serialization::writePod(file, count);
 
   for (const auto& el : elements) {
     // Only PageLine exists currently
     serialization::writePod(file, static_cast<uint8_t>(TAG_PageLine));
-    el->serialize(file);
+    if (!el->serialize(file)) {
+      return false;
+    }
   }
+
+  return true;
 }
 
 std::unique_ptr<Page> Page::deserialize(File& file) {

lib/Epub/Epub/Page.h

@@ -18,7 +18,7 @@ class PageElement {
   explicit PageElement(const int16_t xPos, const int16_t yPos) : xPos(xPos), yPos(yPos) {}
   virtual ~PageElement() = default;
   virtual void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) = 0;
-  virtual void serialize(File& file) = 0;
+  virtual bool serialize(File &file) = 0;
 };
 
 // a line from a block element
@@ -29,7 +29,7 @@ class PageLine final : public PageElement {
   PageLine(std::shared_ptr<TextBlock> block, const int16_t xPos, const int16_t yPos)
       : PageElement(xPos, yPos), block(std::move(block)) {}
   void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) override;
-  void serialize(File& file) override;
+  bool serialize(File &file) override;
   static std::unique_ptr<PageLine> deserialize(File& file);
 };
 
@@ -38,6 +38,6 @@ class Page {
   // the list of block index and line numbers on this page
   std::vector<std::shared_ptr<PageElement>> elements;
   void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) const;
-  void serialize(File& file) const;
+  bool serialize(File& file) const;
   static std::unique_ptr<Page> deserialize(File& file);
 };

lib/Epub/Epub/Section.cpp

@@ -18,8 +18,12 @@ size_t Section::onPageComplete(std::unique_ptr<Page> page) {
     Serial.printf("[%lu] [SCT] File not open for writing page %d\n", millis(), pageCount);
     return 0;
   }
+
   const auto position = file.position();
-  page->serialize(file);
+  if (!page->serialize(file)) {
+    Serial.printf("[%lu] [SCT] Failed to serialize page %d\n", millis(), pageCount);
+    return 0;
+  }
   Serial.printf("[%lu] [SCT] Page %d processed\n", millis(), pageCount);
 
   pageCount++;
@@ -174,10 +178,23 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
   }
 
   const auto lutOffset = file.position();
+  bool hasFailedLutRecords = false;
   // Write LUT
   for (const auto& pos : lut) {
+    if (pos == 0) {
+      hasFailedLutRecords = true;
+      break;
+    }
     serialization::writePod(file, pos);
   }
+
+  if (hasFailedLutRecords) {
+    Serial.printf("[%lu] [SCT] Failed to write LUT due to invalid page positions\n", millis());
+    file.close();
+    SD.remove(filePath.c_str());
+    return false;
+  }
+
   // Go back and write LUT offset
   file.seek(HEADER_SIZE - sizeof(size_t) - sizeof(pageCount));
   serialization::writePod(file, pageCount);

lib/Epub/Epub/blocks/TextBlock.cpp

@@ -24,34 +24,33 @@ void TextBlock::render(const GfxRenderer& renderer, const int fontId, const int
   }
 }
 
-void TextBlock::serialize(File& file) const {
-  // words
-  const uint32_t wc = words.size();
-  serialization::writePod(file, wc);
+bool TextBlock::serialize(File &file) const {
+  if (words.size() != wordXpos.size() || words.size() != wordStyles.size()) {
+    Serial.printf("[%lu] [TXB] Serialization failed: size mismatch (words=%u, xpos=%u, styles=%u)\n", millis(),
+                  words.size(), wordXpos.size(), wordStyles.size());
+    return false;
+  }
+
+  // Word data
+  serialization::writePod(file, static_cast<uint32_t>(words.size()));
   for (const auto& w : words) serialization::writeString(file, w);
-
-  // wordXpos
-  const uint32_t xc = wordXpos.size();
-  serialization::writePod(file, xc);
   for (auto x : wordXpos) serialization::writePod(file, x);
-
-  // wordStyles
-  const uint32_t sc = wordStyles.size();
-  serialization::writePod(file, sc);
   for (auto s : wordStyles) serialization::writePod(file, s);
 
-  // style
+  // Block style
   serialization::writePod(file, style);
+
+  return true;
 }
 
 std::unique_ptr<TextBlock> TextBlock::deserialize(File& file) {
-  uint32_t wc, xc, sc;
+  uint32_t wc;
   std::list<std::string> words;
   std::list<uint16_t> wordXpos;
   std::list<EpdFontStyle> wordStyles;
   BLOCK_STYLE style;
 
-  // words
+  // Word count
   serialization::readPod(file, wc);
 
   // Sanity check: prevent allocation of unreasonably large lists (max 10000 words per block)
@@ -60,27 +59,15 @@ std::unique_ptr<TextBlock> TextBlock::deserialize(File& file) {
     return nullptr;
   }
 
+  // Word data
   words.resize(wc);
+  wordXpos.resize(wc);
+  wordStyles.resize(wc);
   for (auto& w : words) serialization::readString(file, w);
-
-  // wordXpos
-  serialization::readPod(file, xc);
-  wordXpos.resize(xc);
   for (auto& x : wordXpos) serialization::readPod(file, x);
-
-  // wordStyles
-  serialization::readPod(file, sc);
-  wordStyles.resize(sc);
   for (auto& s : wordStyles) serialization::readPod(file, s);
 
-  // Validate data consistency: all three lists must have the same size
-  if (wc != xc || wc != sc) {
-    Serial.printf("[%lu] [TXB] Deserialization failed: size mismatch (words=%u, xpos=%u, styles=%u)\n", millis(), wc,
-                  xc, sc);
-    return nullptr;
-  }
-
-  // style
+  // Block style
   serialization::readPod(file, style);
 
   return std::unique_ptr<TextBlock>(new TextBlock(std::move(words), std::move(wordXpos), std::move(wordStyles), style));

lib/Epub/Epub/blocks/TextBlock.h

@@ -36,6 +36,6 @@ class TextBlock final : public Block {
   // given a renderer works out where to break the words into lines
   void render(const GfxRenderer& renderer, int fontId, int x, int y) const;
   BlockType getType() override { return TEXT_BLOCK; }
-  void serialize(File& file) const;
+  bool serialize(File &file) const;
   static std::unique_ptr<TextBlock> deserialize(File& file);
 };