Refactor and extend docs

lib/KOReaderSync/ChapterXPathIndexerState.h

@@ -0,0 +1,104 @@
+#pragma once
+
+#include "ChapterXPathIndexerInternal.h"
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace ChapterXPathIndexerInternal {
+
+// Shared parser state used by both forward and reverse mappers.
+// It centralizes DOM-stack bookkeeping and XPath reconstruction so each mapper
+// only implements its own match/emit logic.
+
+struct StackNode {
+  std::string tag;
+  int index = 1;
+  bool hasText = false;
+};
+
+struct StackState {
+  int skipDepth = -1;
+  size_t totalTextBytes = 0;
+  std::vector<StackNode> stack;
+  std::vector<std::unordered_map<std::string, int>> siblingCounters;
+
+  StackState() { siblingCounters.emplace_back(); }
+
+  void pushElement(const XML_Char* rawName) {
+    std::string name = toLowerStr(rawName ? rawName : "");
+    const size_t depth = stack.size();
+    if (siblingCounters.size() <= depth) {
+      siblingCounters.resize(depth + 1);
+    }
+    const int sibIdx = ++siblingCounters[depth][name];
+    stack.push_back({name, sibIdx, false});
+    siblingCounters.emplace_back();
+    if (skipDepth < 0 && isSkippableTag(name)) {
+      skipDepth = static_cast<int>(stack.size()) - 1;
+    }
+  }
+
+  void popElement() {
+    if (stack.empty()) {
+      return;
+    }
+    if (skipDepth == static_cast<int>(stack.size()) - 1) {
+      skipDepth = -1;
+    }
+    stack.pop_back();
+    if (!siblingCounters.empty()) {
+      siblingCounters.pop_back();
+    }
+  }
+
+  int bodyIdx() const {
+    for (int i = static_cast<int>(stack.size()) - 1; i >= 0; i--) {
+      if (stack[i].tag == "body") {
+        return i;
+      }
+    }
+    return -1;
+  }
+
+  bool insideBody() const { return bodyIdx() >= 0; }
+
+  std::string currentXPath(const int spineIndex) const {
+    const int bi = bodyIdx();
+    std::string xpath = "/body/DocFragment[" + std::to_string(spineIndex + 1) + "]/body";
+    if (bi < 0) {
+      return xpath;
+    }
+    for (size_t i = static_cast<size_t>(bi + 1); i < stack.size(); i++) {
+      xpath += "/" + stack[i].tag + "[" + std::to_string(stack[i].index) + "]";
+    }
+    return xpath;
+  }
+
+  bool shouldSkipText(const int len) const { return skipDepth >= 0 || len <= 0 || !insideBody(); }
+};
+
+template <typename StateT>
+void XMLCALL parserStartCb(void* ud, const XML_Char* name, const XML_Char**) {
+  static_cast<StateT*>(ud)->onStartElement(name);
+}
+
+template <typename StateT>
+void XMLCALL parserEndCb(void* ud, const XML_Char*) {
+  static_cast<StateT*>(ud)->onEndElement();
+}
+
+template <typename StateT>
+void XMLCALL parserCharCb(void* ud, const XML_Char* text, const int len) {
+  static_cast<StateT*>(ud)->onCharData(text, len);
+}
+
+template <typename StateT>
+void XMLCALL parserDefaultCb(void* ud, const XML_Char* text, const int len) {
+  if (isEntityRef(text, len)) {
+    static_cast<StateT*>(ud)->onCharData(text, len);
+  }
+}
+
+}  // namespace ChapterXPathIndexerInternal