Rearrange code and cleanup

include/editor/spans.h

@@ -0,0 +1,85 @@
+#ifndef EDITOR_SPANS_H
+#define EDITOR_SPANS_H
+
+#include "editor/decl.h"
+#include "utils/utils.h"
+
+struct Spans {
+  std::vector<Span> spans;
+  Queue<std::pair<uint32_t, int64_t>> edits;
+  bool mid_parse = false;
+  std::shared_mutex mtx;
+};
+
+struct SpanCursor {
+  Spans &spans;
+  size_t index = 0;
+  std::vector<Span *> active;
+  std::shared_lock<std::shared_mutex> lock;
+
+  SpanCursor(Spans &s) : spans(s) {}
+  Highlight *get_highlight(uint32_t byte_offset) {
+    for (int i = (int)active.size() - 1; i >= 0; i--)
+      if (active[i]->end <= byte_offset)
+        active.erase(active.begin() + i);
+    while (index < spans.spans.size() &&
+           spans.spans[index].start <= byte_offset) {
+      if (spans.spans[index].end > byte_offset)
+        active.push_back(const_cast<Span *>(&spans.spans[index]));
+      index++;
+    }
+    Highlight *best = nullptr;
+    int max_prio = -1;
+    for (auto *s : active)
+      if (s->hl->priority > max_prio) {
+        max_prio = s->hl->priority;
+        best = s->hl;
+      }
+    return best;
+  }
+  void sync(uint32_t byte_offset) {
+    lock = std::shared_lock(spans.mtx);
+    active.clear();
+    size_t left = 0, right = spans.spans.size();
+    while (left < right) {
+      size_t mid = (left + right) / 2;
+      if (spans.spans[mid].start <= byte_offset)
+        left = mid + 1;
+      else
+        right = mid;
+    }
+    index = left;
+    while (left > 0) {
+      left--;
+      if (spans.spans[left].end > byte_offset)
+        active.push_back(const_cast<Span *>(&spans.spans[left]));
+      else if (byte_offset - spans.spans[left].end > 1000)
+        break;
+    }
+  }
+};
+
+inline void apply_edit(std::vector<Span> &spans, uint32_t x, int64_t y) {
+  Span key{.start = x, .end = 0, .hl = nullptr};
+  auto it = std::lower_bound(
+      spans.begin(), spans.end(), key,
+      [](const Span &a, const Span &b) { return a.start < b.start; });
+  size_t idx = std::distance(spans.begin(), it);
+  while (idx > 0 && spans.at(idx - 1).end >= x)
+    --idx;
+  for (size_t i = idx; i < spans.size();) {
+    Span &s = spans.at(i);
+    if (s.start < x && s.end >= x) {
+      s.end += y;
+    } else if (s.start > x) {
+      s.start += y;
+      s.end += y;
+    }
+    if (s.end <= s.start)
+      spans.erase(spans.begin() + i);
+    else
+      ++i;
+  }
+}
+
+#endif