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-rw-r--r--src/tree_sitter/get_changed_ranges.c482
1 files changed, 482 insertions, 0 deletions
diff --git a/src/tree_sitter/get_changed_ranges.c b/src/tree_sitter/get_changed_ranges.c
new file mode 100644
index 0000000000..5bd1d814bd
--- /dev/null
+++ b/src/tree_sitter/get_changed_ranges.c
@@ -0,0 +1,482 @@
+#include "./get_changed_ranges.h"
+#include "./subtree.h"
+#include "./language.h"
+#include "./error_costs.h"
+#include "./tree_cursor.h"
+#include <assert.h>
+
+// #define DEBUG_GET_CHANGED_RANGES
+
+static void ts_range_array_add(TSRangeArray *self, Length start, Length end) {
+ if (self->size > 0) {
+ TSRange *last_range = array_back(self);
+ if (start.bytes <= last_range->end_byte) {
+ last_range->end_byte = end.bytes;
+ last_range->end_point = end.extent;
+ return;
+ }
+ }
+
+ if (start.bytes < end.bytes) {
+ TSRange range = { start.extent, end.extent, start.bytes, end.bytes };
+ array_push(self, range);
+ }
+}
+
+bool ts_range_array_intersects(const TSRangeArray *self, unsigned start_index,
+ uint32_t start_byte, uint32_t end_byte) {
+ for (unsigned i = start_index; i < self->size; i++) {
+ TSRange *range = &self->contents[i];
+ if (range->end_byte > start_byte) {
+ if (range->start_byte >= end_byte) break;
+ return true;
+ }
+ }
+ return false;
+}
+
+void ts_range_array_get_changed_ranges(
+ const TSRange *old_ranges, unsigned old_range_count,
+ const TSRange *new_ranges, unsigned new_range_count,
+ TSRangeArray *differences
+) {
+ unsigned new_index = 0;
+ unsigned old_index = 0;
+ Length current_position = length_zero();
+ bool in_old_range = false;
+ bool in_new_range = false;
+
+ while (old_index < old_range_count || new_index < new_range_count) {
+ const TSRange *old_range = &old_ranges[old_index];
+ const TSRange *new_range = &new_ranges[new_index];
+
+ Length next_old_position;
+ if (in_old_range) {
+ next_old_position = (Length) {old_range->end_byte, old_range->end_point};
+ } else if (old_index < old_range_count) {
+ next_old_position = (Length) {old_range->start_byte, old_range->start_point};
+ } else {
+ next_old_position = LENGTH_MAX;
+ }
+
+ Length next_new_position;
+ if (in_new_range) {
+ next_new_position = (Length) {new_range->end_byte, new_range->end_point};
+ } else if (new_index < new_range_count) {
+ next_new_position = (Length) {new_range->start_byte, new_range->start_point};
+ } else {
+ next_new_position = LENGTH_MAX;
+ }
+
+ if (next_old_position.bytes < next_new_position.bytes) {
+ if (in_old_range != in_new_range) {
+ ts_range_array_add(differences, current_position, next_old_position);
+ }
+ if (in_old_range) old_index++;
+ current_position = next_old_position;
+ in_old_range = !in_old_range;
+ } else if (next_new_position.bytes < next_old_position.bytes) {
+ if (in_old_range != in_new_range) {
+ ts_range_array_add(differences, current_position, next_new_position);
+ }
+ if (in_new_range) new_index++;
+ current_position = next_new_position;
+ in_new_range = !in_new_range;
+ } else {
+ if (in_old_range != in_new_range) {
+ ts_range_array_add(differences, current_position, next_new_position);
+ }
+ if (in_old_range) old_index++;
+ if (in_new_range) new_index++;
+ in_old_range = !in_old_range;
+ in_new_range = !in_new_range;
+ current_position = next_new_position;
+ }
+ }
+}
+
+typedef struct {
+ TreeCursor cursor;
+ const TSLanguage *language;
+ unsigned visible_depth;
+ bool in_padding;
+} Iterator;
+
+static Iterator iterator_new(TreeCursor *cursor, const Subtree *tree, const TSLanguage *language) {
+ array_clear(&cursor->stack);
+ array_push(&cursor->stack, ((TreeCursorEntry){
+ .subtree = tree,
+ .position = length_zero(),
+ .child_index = 0,
+ .structural_child_index = 0,
+ }));
+ return (Iterator) {
+ .cursor = *cursor,
+ .language = language,
+ .visible_depth = 1,
+ .in_padding = false,
+ };
+}
+
+static bool iterator_done(Iterator *self) {
+ return self->cursor.stack.size == 0;
+}
+
+static Length iterator_start_position(Iterator *self) {
+ TreeCursorEntry entry = *array_back(&self->cursor.stack);
+ if (self->in_padding) {
+ return entry.position;
+ } else {
+ return length_add(entry.position, ts_subtree_padding(*entry.subtree));
+ }
+}
+
+static Length iterator_end_position(Iterator *self) {
+ TreeCursorEntry entry = *array_back(&self->cursor.stack);
+ Length result = length_add(entry.position, ts_subtree_padding(*entry.subtree));
+ if (self->in_padding) {
+ return result;
+ } else {
+ return length_add(result, ts_subtree_size(*entry.subtree));
+ }
+}
+
+static bool iterator_tree_is_visible(const Iterator *self) {
+ TreeCursorEntry entry = *array_back(&self->cursor.stack);
+ if (ts_subtree_visible(*entry.subtree)) return true;
+ if (self->cursor.stack.size > 1) {
+ Subtree parent = *self->cursor.stack.contents[self->cursor.stack.size - 2].subtree;
+ const TSSymbol *alias_sequence = ts_language_alias_sequence(
+ self->language,
+ parent.ptr->production_id
+ );
+ return alias_sequence && alias_sequence[entry.structural_child_index] != 0;
+ }
+ return false;
+}
+
+static void iterator_get_visible_state(const Iterator *self, Subtree *tree,
+ TSSymbol *alias_symbol, uint32_t *start_byte) {
+ uint32_t i = self->cursor.stack.size - 1;
+
+ if (self->in_padding) {
+ if (i == 0) return;
+ i--;
+ }
+
+ for (; i + 1 > 0; i--) {
+ TreeCursorEntry entry = self->cursor.stack.contents[i];
+
+ if (i > 0) {
+ const Subtree *parent = self->cursor.stack.contents[i - 1].subtree;
+ const TSSymbol *alias_sequence = ts_language_alias_sequence(
+ self->language,
+ parent->ptr->production_id
+ );
+ if (alias_sequence) {
+ *alias_symbol = alias_sequence[entry.structural_child_index];
+ }
+ }
+
+ if (ts_subtree_visible(*entry.subtree) || *alias_symbol) {
+ *tree = *entry.subtree;
+ *start_byte = entry.position.bytes;
+ break;
+ }
+ }
+}
+
+static void iterator_ascend(Iterator *self) {
+ if (iterator_done(self)) return;
+ if (iterator_tree_is_visible(self) && !self->in_padding) self->visible_depth--;
+ if (array_back(&self->cursor.stack)->child_index > 0) self->in_padding = false;
+ self->cursor.stack.size--;
+}
+
+static bool iterator_descend(Iterator *self, uint32_t goal_position) {
+ if (self->in_padding) return false;
+
+ bool did_descend;
+ do {
+ did_descend = false;
+ TreeCursorEntry entry = *array_back(&self->cursor.stack);
+ Length position = entry.position;
+ uint32_t structural_child_index = 0;
+ for (uint32_t i = 0, n = ts_subtree_child_count(*entry.subtree); i < n; i++) {
+ const Subtree *child = &entry.subtree->ptr->children[i];
+ Length child_left = length_add(position, ts_subtree_padding(*child));
+ Length child_right = length_add(child_left, ts_subtree_size(*child));
+
+ if (child_right.bytes > goal_position) {
+ array_push(&self->cursor.stack, ((TreeCursorEntry){
+ .subtree = child,
+ .position = position,
+ .child_index = i,
+ .structural_child_index = structural_child_index,
+ }));
+
+ if (iterator_tree_is_visible(self)) {
+ if (child_left.bytes > goal_position) {
+ self->in_padding = true;
+ } else {
+ self->visible_depth++;
+ }
+ return true;
+ }
+
+ did_descend = true;
+ break;
+ }
+
+ position = child_right;
+ if (!ts_subtree_extra(*child)) structural_child_index++;
+ }
+ } while (did_descend);
+
+ return false;
+}
+
+static void iterator_advance(Iterator *self) {
+ if (self->in_padding) {
+ self->in_padding = false;
+ if (iterator_tree_is_visible(self)) {
+ self->visible_depth++;
+ } else {
+ iterator_descend(self, 0);
+ }
+ return;
+ }
+
+ for (;;) {
+ if (iterator_tree_is_visible(self)) self->visible_depth--;
+ TreeCursorEntry entry = array_pop(&self->cursor.stack);
+ if (iterator_done(self)) return;
+
+ const Subtree *parent = array_back(&self->cursor.stack)->subtree;
+ uint32_t child_index = entry.child_index + 1;
+ if (ts_subtree_child_count(*parent) > child_index) {
+ Length position = length_add(entry.position, ts_subtree_total_size(*entry.subtree));
+ uint32_t structural_child_index = entry.structural_child_index;
+ if (!ts_subtree_extra(*entry.subtree)) structural_child_index++;
+ const Subtree *next_child = &parent->ptr->children[child_index];
+
+ array_push(&self->cursor.stack, ((TreeCursorEntry){
+ .subtree = next_child,
+ .position = position,
+ .child_index = child_index,
+ .structural_child_index = structural_child_index,
+ }));
+
+ if (iterator_tree_is_visible(self)) {
+ if (ts_subtree_padding(*next_child).bytes > 0) {
+ self->in_padding = true;
+ } else {
+ self->visible_depth++;
+ }
+ } else {
+ iterator_descend(self, 0);
+ }
+ break;
+ }
+ }
+}
+
+typedef enum {
+ IteratorDiffers,
+ IteratorMayDiffer,
+ IteratorMatches,
+} IteratorComparison;
+
+static IteratorComparison iterator_compare(const Iterator *old_iter, const Iterator *new_iter) {
+ Subtree old_tree = NULL_SUBTREE;
+ Subtree new_tree = NULL_SUBTREE;
+ uint32_t old_start = 0;
+ uint32_t new_start = 0;
+ TSSymbol old_alias_symbol = 0;
+ TSSymbol new_alias_symbol = 0;
+ iterator_get_visible_state(old_iter, &old_tree, &old_alias_symbol, &old_start);
+ iterator_get_visible_state(new_iter, &new_tree, &new_alias_symbol, &new_start);
+
+ if (!old_tree.ptr && !new_tree.ptr) return IteratorMatches;
+ if (!old_tree.ptr || !new_tree.ptr) return IteratorDiffers;
+
+ if (
+ old_alias_symbol == new_alias_symbol &&
+ ts_subtree_symbol(old_tree) == ts_subtree_symbol(new_tree)
+ ) {
+ if (old_start == new_start &&
+ !ts_subtree_has_changes(old_tree) &&
+ ts_subtree_symbol(old_tree) != ts_builtin_sym_error &&
+ ts_subtree_size(old_tree).bytes == ts_subtree_size(new_tree).bytes &&
+ ts_subtree_parse_state(old_tree) != TS_TREE_STATE_NONE &&
+ ts_subtree_parse_state(new_tree) != TS_TREE_STATE_NONE &&
+ (ts_subtree_parse_state(old_tree) == ERROR_STATE) ==
+ (ts_subtree_parse_state(new_tree) == ERROR_STATE)) {
+ return IteratorMatches;
+ } else {
+ return IteratorMayDiffer;
+ }
+ }
+
+ return IteratorDiffers;
+}
+
+#ifdef DEBUG_GET_CHANGED_RANGES
+static inline void iterator_print_state(Iterator *self) {
+ TreeCursorEntry entry = *array_back(&self->cursor.stack);
+ TSPoint start = iterator_start_position(self).extent;
+ TSPoint end = iterator_end_position(self).extent;
+ const char *name = ts_language_symbol_name(self->language, ts_subtree_symbol(*entry.subtree));
+ printf(
+ "(%-25s %s\t depth:%u [%u, %u] - [%u, %u])",
+ name, self->in_padding ? "(p)" : " ",
+ self->visible_depth,
+ start.row + 1, start.column,
+ end.row + 1, end.column
+ );
+}
+#endif
+
+unsigned ts_subtree_get_changed_ranges(const Subtree *old_tree, const Subtree *new_tree,
+ TreeCursor *cursor1, TreeCursor *cursor2,
+ const TSLanguage *language,
+ const TSRangeArray *included_range_differences,
+ TSRange **ranges) {
+ TSRangeArray results = array_new();
+
+ Iterator old_iter = iterator_new(cursor1, old_tree, language);
+ Iterator new_iter = iterator_new(cursor2, new_tree, language);
+
+ unsigned included_range_difference_index = 0;
+
+ Length position = iterator_start_position(&old_iter);
+ Length next_position = iterator_start_position(&new_iter);
+ if (position.bytes < next_position.bytes) {
+ ts_range_array_add(&results, position, next_position);
+ position = next_position;
+ } else if (position.bytes > next_position.bytes) {
+ ts_range_array_add(&results, next_position, position);
+ next_position = position;
+ }
+
+ do {
+ #ifdef DEBUG_GET_CHANGED_RANGES
+ printf("At [%-2u, %-2u] Compare ", position.extent.row + 1, position.extent.column);
+ iterator_print_state(&old_iter);
+ printf("\tvs\t");
+ iterator_print_state(&new_iter);
+ puts("");
+ #endif
+
+ // Compare the old and new subtrees.
+ IteratorComparison comparison = iterator_compare(&old_iter, &new_iter);
+
+ // Even if the two subtrees appear to be identical, they could differ
+ // internally if they contain a range of text that was previously
+ // excluded from the parse, and is now included, or vice-versa.
+ if (comparison == IteratorMatches && ts_range_array_intersects(
+ included_range_differences,
+ included_range_difference_index,
+ position.bytes,
+ iterator_end_position(&old_iter).bytes
+ )) {
+ comparison = IteratorMayDiffer;
+ }
+
+ bool is_changed = false;
+ switch (comparison) {
+ // If the subtrees are definitely identical, move to the end
+ // of both subtrees.
+ case IteratorMatches:
+ next_position = iterator_end_position(&old_iter);
+ break;
+
+ // If the subtrees might differ internally, descend into both
+ // subtrees, finding the first child that spans the current position.
+ case IteratorMayDiffer:
+ if (iterator_descend(&old_iter, position.bytes)) {
+ if (!iterator_descend(&new_iter, position.bytes)) {
+ is_changed = true;
+ next_position = iterator_end_position(&old_iter);
+ }
+ } else if (iterator_descend(&new_iter, position.bytes)) {
+ is_changed = true;
+ next_position = iterator_end_position(&new_iter);
+ } else {
+ next_position = length_min(
+ iterator_end_position(&old_iter),
+ iterator_end_position(&new_iter)
+ );
+ }
+ break;
+
+ // If the subtrees are different, record a change and then move
+ // to the end of both subtrees.
+ case IteratorDiffers:
+ is_changed = true;
+ next_position = length_min(
+ iterator_end_position(&old_iter),
+ iterator_end_position(&new_iter)
+ );
+ break;
+ }
+
+ // Ensure that both iterators are caught up to the current position.
+ while (
+ !iterator_done(&old_iter) &&
+ iterator_end_position(&old_iter).bytes <= next_position.bytes
+ ) iterator_advance(&old_iter);
+ while (
+ !iterator_done(&new_iter) &&
+ iterator_end_position(&new_iter).bytes <= next_position.bytes
+ ) iterator_advance(&new_iter);
+
+ // Ensure that both iterators are at the same depth in the tree.
+ while (old_iter.visible_depth > new_iter.visible_depth) {
+ iterator_ascend(&old_iter);
+ }
+ while (new_iter.visible_depth > old_iter.visible_depth) {
+ iterator_ascend(&new_iter);
+ }
+
+ if (is_changed) {
+ #ifdef DEBUG_GET_CHANGED_RANGES
+ printf(
+ " change: [[%u, %u] - [%u, %u]]\n",
+ position.extent.row + 1, position.extent.column,
+ next_position.extent.row + 1, next_position.extent.column
+ );
+ #endif
+
+ ts_range_array_add(&results, position, next_position);
+ }
+
+ position = next_position;
+
+ // Keep track of the current position in the included range differences
+ // array in order to avoid scanning the entire array on each iteration.
+ while (included_range_difference_index < included_range_differences->size) {
+ const TSRange *range = &included_range_differences->contents[
+ included_range_difference_index
+ ];
+ if (range->end_byte <= position.bytes) {
+ included_range_difference_index++;
+ } else {
+ break;
+ }
+ }
+ } while (!iterator_done(&old_iter) && !iterator_done(&new_iter));
+
+ Length old_size = ts_subtree_total_size(*old_tree);
+ Length new_size = ts_subtree_total_size(*new_tree);
+ if (old_size.bytes < new_size.bytes) {
+ ts_range_array_add(&results, old_size, new_size);
+ } else if (new_size.bytes < old_size.bytes) {
+ ts_range_array_add(&results, new_size, old_size);
+ }
+
+ *cursor1 = old_iter.cursor;
+ *cursor2 = new_iter.cursor;
+ *ranges = results.contents;
+ return results.size;
+}
generated by cgit (git 2.34.1) at 2025-05-29 05:45:29 +0000