Make tree-sitter read function utilize faster rope reading

- By removing any allocations/deallocation that the function would have used

include/editor.h

@@ -104,11 +104,6 @@ struct Editor {
                                         // - built by tree-sitter helpers
 };
 
-typedef struct TSLoad {
-  Editor *editor;
-  char *prev = nullptr;
-} TSLoad;
-
 Editor *new_editor(const char *filename, Coord position, Coord size);
 void free_editor(Editor *editor);
 void render_editor(Editor *editor);

include/rope.h

@@ -36,6 +36,7 @@ typedef struct LeafIterator {
   Knot *node;
   uint8_t top;
   uint32_t offset;
+  uint32_t adjustment;
   Knot *stack[64];
 } LeafIterator;
 
@@ -122,13 +123,15 @@ char *next_line(LineIterator *it);
 // Used to start an iterator over leaf data
 // root is the root of the rope
 // the caller must free the iterator after use
-LeafIterator *begin_k_iter(Knot *root);
+// start_offset is the byte from which the iterator should start
+LeafIterator *begin_k_iter(Knot *root, uint32_t start_offset);
 
 // Returns the next leaf data as a null terminated string
 // `it` is the iterator returned from begin_k_iter
 // ! Strings returned must never be freed by the caller !
 // to mutate the string a copy must be made
-char *next_leaf(LeafIterator *it);
+// `out_len` is set to the length of the returned string
+char *next_leaf(LeafIterator *it, uint32_t *out_len);
 
 // Used to start an iterator over byte data (one byte at a time)
 // Uses leaf iterator internally
@@ -140,6 +143,13 @@ ByteIterator *begin_b_iter(Knot *root);
 // `it` is the iterator returned from begin_b_iter
 char next_byte(ByteIterator *it);
 
+// Returns a leaf data as a null terminated string
+// root is the root of the rope
+// start_offset is the byte from which the leaf data should start
+// `out_len` is set to the length of the returned string
+// return value must never be freed
+char *leaf_from_offset(Knot *root, uint32_t start_offset, uint32_t *out_len);
+
 // Used to search for a pattern in the rope
 // Pattern is a null terminated string representing a regular expression (DFA
 // compliant) I.e some forms of backtracking etc. are not supported

src/rope.cc

@@ -570,31 +570,32 @@ char *next_line(LineIterator *it) {
   return nullptr;
 }
 
-LeafIterator *begin_k_iter(Knot *root) {
+LeafIterator *begin_k_iter(Knot *root, uint32_t start_offset) {
   if (!root)
     return nullptr;
   LeafIterator *it = (LeafIterator *)malloc(sizeof(LeafIterator));
   if (!it)
     return nullptr;
   it->top = 0;
+  it->adjustment = 0;
   Knot *curr = root;
   while (curr) {
     it->stack[it->top++] = curr;
     if (!curr->left && !curr->right) {
+      if (start_offset > curr->char_count) {
+        free(it);
+        return nullptr;
+      }
       it->node = curr;
+      it->adjustment = start_offset;
       return it;
     }
+    uint32_t left_size = (curr->left) ? curr->left->char_count : 0;
+    if (start_offset < left_size) {
       curr = curr->left;
-    if (!curr) {
+    } else {
-      curr = it->stack[--it->top]->right;
+      start_offset -= left_size;
-      Knot *temp = it->stack[it->top];
+      curr = curr->right;
-      it->stack[it->top++] = temp;
-      curr = temp->left ? temp->left : temp->right;
-      Knot *parent = it->stack[it->top - 1];
-      curr = parent->left;
-      if (!curr) {
-        curr = parent->right;
-      }
     }
   }
   free(it);
@@ -602,11 +603,14 @@ LeafIterator *begin_k_iter(Knot *root) {
 }
 
 // Caller must never free the returned string
-char *next_leaf(LeafIterator *it) {
+char *next_leaf(LeafIterator *it, uint32_t *out_len) {
   if (!it || !it->node)
     return nullptr;
-  char *data_to_return = it->node->data;
+  char *data_to_return = it->node->data + it->adjustment;
-  data_to_return[it->node->char_count] = '\0';
+  if (out_len)
+    *out_len = it->node->char_count - it->adjustment;
+  it->node->data[it->node->char_count] = '\0';
+  it->adjustment = 0;
   Knot *prev_leaf = it->node;
   Knot *parent = nullptr;
   while (it->top > 0) {
@@ -632,7 +636,7 @@ char *next_leaf(LeafIterator *it) {
 
 ByteIterator *begin_b_iter(Knot *root) {
   ByteIterator *b_it = (ByteIterator *)malloc(sizeof(ByteIterator));
-  LeafIterator *l_it = begin_k_iter(root);
+  LeafIterator *l_it = begin_k_iter(root, 0);
   b_it->it = l_it;
   b_it->offset_g = 0;
   b_it->offset_l = 0;
@@ -647,21 +651,46 @@ char next_byte(ByteIterator *it) {
   } else {
     it->offset_g += it->offset_l;
     it->offset_l = 1;
-    char *data = next_leaf(it->it);
+    char *data = next_leaf(it->it, &it->char_count);
     if (!data)
       return '\0';
-    it->char_count = strlen(data);
     while (it->char_count <= 0) {
-      data = next_leaf(it->it);
+      data = next_leaf(it->it, &it->char_count);
       if (!data)
         return '\0';
-      it->char_count = strlen(data);
     }
     it->data = data;
     return *it->data;
   }
 }
 
+// Caller must NOT free returned string.
+// Returns nullptr if offset is invalid or no leaf found.
+char *leaf_from_offset(Knot *root, uint32_t start_offset, uint32_t *out_len) {
+  if (!root)
+    return nullptr;
+  Knot *curr = root;
+  while (curr) {
+    if (!curr->left && !curr->right) {
+      if (start_offset > curr->char_count)
+        return nullptr;
+      char *result = curr->data + start_offset;
+      if (out_len)
+        *out_len = curr->char_count - start_offset;
+      curr->data[curr->char_count] = '\0';
+      return result;
+    }
+    uint32_t left_size = curr->left ? curr->left->char_count : 0;
+    if (start_offset < left_size) {
+      curr = curr->left;
+    } else {
+      start_offset -= left_size;
+      curr = curr->right;
+    }
+  }
+  return nullptr;
+}
+
 std::vector<std::pair<size_t, size_t>> search_rope(Knot *root,
                                                    const char *pattern) {
   std::vector<std::pair<size_t, size_t>> results;
@@ -675,7 +704,7 @@ std::vector<std::pair<size_t, size_t>> search_rope(Knot *root,
   }
   pcre2_match_data *mdata = pcre2_match_data_create(128, nullptr);
   int workspace[PCRE_WORKSPACE_SIZE];
-  LeafIterator *it = begin_k_iter(root);
+  LeafIterator *it = begin_k_iter(root, 0);
   if (!it) {
     pcre2_code_free(re);
     pcre2_match_data_free(mdata);
@@ -686,7 +715,7 @@ std::vector<std::pair<size_t, size_t>> search_rope(Knot *root,
   bool match_in_progress = false;
   int flags = PCRE2_PARTIAL_SOFT;
   while (1) {
-    const char *chunk_start = next_leaf(it);
+    const char *chunk_start = next_leaf(it, nullptr);
     if (!chunk_start)
       break;
     size_t chunk_len = strlen(chunk_start);

src/ts.cc

@@ -141,24 +141,12 @@ const char *read_ts(void *payload, uint32_t byte_index, TSPoint,
     *bytes_read = 0;
     return "";
   }
-  TSLoad *load = (TSLoad *)payload;
+  Editor *editor = (Editor *)payload;
-  Knot *root = load->editor->root;
+  if (byte_index >= editor->root->char_count) {
-  if (load->prev)
-    free(load->prev);
-  if (byte_index >= root->char_count) {
     *bytes_read = 0;
-    load->prev = nullptr;
     return "";
   }
-  uint32_t chunk_size = 4096;
+  return leaf_from_offset(editor->root, byte_index, bytes_read);
-  uint32_t remaining = root->char_count - byte_index;
-  uint32_t len_to_read = remaining > chunk_size ? chunk_size : remaining;
-  std::shared_lock lock(load->editor->knot_mtx);
-  char *buffer = read(root, byte_index, len_to_read);
-  lock.unlock();
-  load->prev = buffer;
-  *bytes_read = len_to_read;
-  return buffer;
 }
 
 static inline Highlight *safe_get(std::vector<Highlight> &vec, size_t index) {
@@ -170,9 +158,8 @@ static inline Highlight *safe_get(std::vector<Highlight> &vec, size_t index) {
 void ts_collect_spans(Editor *editor) {
   if (!editor->parser || !editor->root || !editor->query)
     return;
-  TSLoad load = {editor, nullptr};
   TSInput tsinput = {
-      .payload = &load,
+      .payload = editor,
       .read = read_ts,
       .encoding = TSInputEncodingUTF8,
       .decode = nullptr,
@@ -196,7 +183,9 @@ void ts_collect_spans(Editor *editor) {
     return;
   }
   editor->spans.mid_parse = true;
+  std::shared_lock lock(editor->knot_mtx);
   tree = ts_parser_parse(editor->parser, copy, tsinput);
+  lock.unlock();
   if (copy)
     ts_tree_delete(copy);
   knot_mtx.lock();
@@ -228,8 +217,6 @@ void ts_collect_spans(Editor *editor) {
   }
   ts_query_cursor_delete(cursor);
   ts_tree_delete(copy);
-  if (load.prev)
-    free(load.prev);
   if (!running)
     return;
   std::sort(new_spans.begin(), new_spans.end());