fix(node): use source encoding in getText()

Author: ObserverOfTime

src/main/java/io/github/treesitter/jtreesitter/Node.java

@@ -21,6 +21,7 @@ public final class Node {
     private final Tree tree;
     private @Nullable List<Node> children;
     private final Arena arena = Arena.ofAuto();
+    private boolean wasEdited = false;
 
     Node(MemorySegment self, Tree tree) {
         this.self = self;
@@ -409,10 +410,7 @@ public Optional<Node> getChildWithDescendant(Node descendant) {
 
     /** Get the source code of the node, if available. */
     public @Nullable String getText() {
-        var text = tree.getText();
-        if (text == null) return null;
-        var endByte = Math.min(getEndByte(), text.length());
-        return text.substring(getStartByte(), endByte);
+        return !wasEdited ? tree.getRegion(getStartByte(), getEndByte()) : null;
     }
 
     /**
@@ -426,6 +424,7 @@ public Optional<Node> getChildWithDescendant(Node descendant) {
      */
     public void edit(InputEdit edit) {
         ts_node_edit(self, edit.into(arena));
+        wasEdited = true;
         children = null;
     }
 

src/main/java/io/github/treesitter/jtreesitter/Parser.java

@@ -244,7 +244,7 @@ public Optional<Tree> parse(String source, InputEncoding encoding, @Nullable Tre
             var old = oldTree == null ? MemorySegment.NULL : oldTree.segment();
             var tree = ts_parser_parse_string_encoding(self, old, string, bytes.length, encoding.ordinal());
             if (tree.equals(MemorySegment.NULL)) return Optional.empty();
-            return Optional.of(new Tree(tree, language, source));
+            return Optional.of(new Tree(tree, language, source, encoding.charset()));
         }
     }
 
@@ -299,7 +299,7 @@ public Optional<Tree> parse(ParseCallback callback, InputEncoding encoding, @Nul
         var old = oldTree == null ? MemorySegment.NULL : oldTree.segment();
         var tree = ts_parser_parse(self, old, input);
         if (tree.equals(MemorySegment.NULL)) return Optional.empty();
-        return Optional.of(new Tree(tree, language, null));
+        return Optional.of(new Tree(tree, language, null, null));
     }
 
     /**

src/main/java/io/github/treesitter/jtreesitter/Tree.java

@@ -5,6 +5,7 @@
 import io.github.treesitter.jtreesitter.internal.TSRange;
 import io.github.treesitter.jtreesitter.internal.TreeSitter;
 import java.lang.foreign.*;
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -15,16 +16,18 @@
 @NullMarked
 public final class Tree implements AutoCloseable, Cloneable {
     private final MemorySegment self;
-    private @Nullable String source;
+    private byte[] source;
+    private @Nullable Charset charset;
     private final Arena arena;
     private final Language language;
     private @Nullable List<Range> includedRanges;
 
-    Tree(MemorySegment self, Language language, @Nullable String source) {
+    Tree(MemorySegment self, Language language, @Nullable String source, @Nullable Charset charset) {
         arena = Arena.ofShared();
         this.self = self.reinterpret(arena, TreeSitter::ts_tree_delete);
         this.language = language;
-        this.source = source;
+        this.source = source != null && charset != null ? source.getBytes(charset) : new byte[] {};
+        this.charset = charset;
     }
 
     private Tree(Tree tree) {
@@ -33,21 +36,28 @@ private Tree(Tree tree) {
         self = copy.reinterpret(arena, TreeSitter::ts_tree_delete);
         language = tree.language;
         source = tree.source;
+        charset = tree.charset;
         includedRanges = tree.includedRanges;
     }
 
     MemorySegment segment() {
         return self;
     }
 
+    @Nullable
+    String getRegion(@Unsigned int start, @Unsigned int end) {
+        var length = Math.min(end, source.length) - start;
+        return charset != null ? new String(source, start, length, charset) : null;
+    }
+
     /** Get the language that was used to parse the syntax tree. */
     public Language getLanguage() {
         return language;
     }
 
     /** Get the source code of the syntax tree, if available. */
     public @Nullable String getText() {
-        return source;
+        return charset != null ? new String(source, charset) : null;
     }
 
     /** Get the root node of the syntax tree. */
@@ -122,7 +132,8 @@ public void edit(InputEdit edit) {
         try (var alloc = Arena.ofConfined()) {
             ts_tree_edit(self, edit.into(alloc));
         } finally {
-            source = null;
+            source = new byte[] {};
+            charset = null;
         }
     }