perf(grid): allocation-light selection export (#1524)

lib/features/workspace/grid/grid_selection_manager.dart

@@ -66,23 +66,22 @@ class ResultGridSelection {
   String toTsv(List<List<String>> rows, {List<String>? columns}) {
     if (rows.isEmpty) return '';
     final buffer = StringBuffer();
+    // Cells go straight into the buffer: no per-row list and join (#1524).
     if (columns != null && columns.isNotEmpty) {
-      final headerCells = <String>[];
       for (var c = startColumn; c <= endColumn; c++) {
-        final col = c < columns.length ? columns[c] : '';
-        headerCells.add(_escapeTsv(col));
+        if (c > startColumn) buffer.write('\t');
+        buffer.write(_escapeTsv(c < columns.length ? columns[c] : ''));
       }
-      buffer.writeln(headerCells.join('\t'));
+      buffer.writeln();
     }
     for (var r = startRow; r <= endRow; r++) {
       if (r < 0 || r >= rows.length) continue;
       final rowData = rows[r];
-      final cells = <String>[];
       for (var c = startColumn; c <= endColumn; c++) {
-        final val = c < rowData.length ? rowData[c] : '';
-        cells.add(_escapeTsv(val));
+        if (c > startColumn) buffer.write('\t');
+        buffer.write(_escapeTsv(c < rowData.length ? rowData[c] : ''));
       }
-      buffer.writeln(cells.join('\t'));
+      buffer.writeln();
     }
     return buffer.toString().trimRight();
   }
@@ -93,22 +92,20 @@ class ResultGridSelection {
     if (rows.isEmpty) return '';
     final buffer = StringBuffer();
     if (columns != null && columns.isNotEmpty) {
-      final headerCells = <String>[];
       for (var c = startColumn; c <= endColumn; c++) {
-        final col = c < columns.length ? columns[c] : '';
-        headerCells.add(_escapeCsv(col));
+        if (c > startColumn) buffer.write(',');
+        buffer.write(_escapeCsv(c < columns.length ? columns[c] : ''));
       }
-      buffer.writeln(headerCells.join(','));
+      buffer.writeln();
     }
     for (var r = startRow; r <= endRow; r++) {
       if (r < 0 || r >= rows.length) continue;
       final rowData = rows[r];
-      final cells = <String>[];
       for (var c = startColumn; c <= endColumn; c++) {
-        final val = c < rowData.length ? rowData[c] : '';
-        cells.add(_escapeCsv(val));
+        if (c > startColumn) buffer.write(',');
+        buffer.write(_escapeCsv(c < rowData.length ? rowData[c] : ''));
       }
-      buffer.writeln(cells.join(','));
+      buffer.writeln();
     }
     return buffer.toString().trimRight();
   }
@@ -127,13 +124,13 @@ class ResultGridSelection {
         final val = c < rowData.length ? rowData[c] : '';
         if (val == 'NULL') {
           map[colName] = null;
-        } else if (RegExp(r'^0\d+$').hasMatch(val.trim())) {
+        } else if (_hasLeadingZeroDigits(val.trim())) {
           // Preserve numeric strings with leading zeros (e.g. '01234', '007')
           map[colName] = val;
-        } else if (int.tryParse(val) != null) {
-          map[colName] = int.parse(val);
-        } else if (double.tryParse(val) != null) {
-          map[colName] = double.parse(val);
+        } else if (int.tryParse(val) case final asInt?) {
+          map[colName] = asInt;
+        } else if (double.tryParse(val) case final asDouble?) {
+          map[colName] = asDouble;
         } else if (val.toLowerCase() == 'true') {
           map[colName] = true;
         } else if (val.toLowerCase() == 'false') {
@@ -150,6 +147,16 @@ class ResultGridSelection {
     return const JsonEncoder.withIndent('  ').convert(result);
   }
 
+  /// `^0\d+$`: a zero followed by one or more ASCII digits and nothing else.
+  static bool _hasLeadingZeroDigits(String s) {
+    if (s.length < 2 || s.codeUnitAt(0) != 0x30) return false;
+    for (var i = 1; i < s.length; i++) {
+      final c = s.codeUnitAt(i);
+      if (c < 0x30 || c > 0x39) return false;
+    }
+    return true;
+  }
+
   static String _escapeTsv(String val) {
     if (val.contains('\t') ||
         val.contains('\n') ||

test/features/workspace/grid_selection_export_test.dart

@@ -0,0 +1,114 @@
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/features/workspace/grid/grid_selection_manager.dart';
+
+void main() {
+  group('ResultGridSelection clipboard export (#1524)', () {
+    const columns = ['x', 'y', 'z'];
+    const rows = [
+      ['a', 'b c', 'd,e'],
+      ['1', '', '"q"'],
+    ];
+    const all = ResultGridSelection(
+      startRow: 0,
+      startColumn: 0,
+      endRow: 1,
+      endColumn: 2,
+    );
+
+    test('CSV: header, quoting and row order', () {
+      expect(
+        all.toCsv(rows, columns: columns),
+        'x,y,z\na,b c,"d,e"\n1,,"""q"""',
+      );
+      expect(all.toCsv(rows), 'a,b c,"d,e"\n1,,"""q"""');
+    });
+
+    test('TSV: header, quoting and row order', () {
+      expect(
+        all.toTsv(rows, columns: columns),
+        'x\ty\tz\na\tb c\td,e\n1\t\t"""q"""',
+      );
+      expect(all.toTsv(rows), 'a\tb c\td,e\n1\t\t"""q"""');
+    });
+
+    test('a column sub-range and rows past the end', () {
+      const sub = ResultGridSelection(
+        startRow: 1,
+        startColumn: 1,
+        endRow: 5,
+        endColumn: 3,
+      );
+      // Column 3 does not exist: an empty cell; row 5 does not exist: skipped.
+      expect(sub.toCsv(rows, columns: columns), 'y,z,\n,"""q""",');
+      expect(sub.toTsv(rows), '\t"""q"""');
+    });
+
+    test('trailing empty cells of the last row are trimmed in TSV only', () {
+      const one = ResultGridSelection(
+        startRow: 0,
+        startColumn: 0,
+        endRow: 0,
+        endColumn: 1,
+      );
+      const data = [
+        ['a', ''],
+      ];
+      expect(one.toTsv(data), 'a');
+      expect(one.toCsv(data), 'a,');
+    });
+
+    test('empty input gives an empty string', () {
+      expect(all.toCsv(const []), '');
+      expect(all.toTsv(const []), '');
+    });
+
+    test('JSON keeps leading zeros, nulls and booleans', () {
+      const sel = ResultGridSelection(
+        startRow: 0,
+        startColumn: 0,
+        endRow: 0,
+        endColumn: 9,
+      );
+      final json = sel.toJson(
+        ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'],
+        const [
+          ['007', '12', '1.5', 'NULL', 'true', 'FALSE', 'x', ' 007 ', '0', '0.5'],
+        ],
+      );
+      expect(jsonDecode(json), {
+        'a': '007',
+        'b': 12,
+        'c': 1.5,
+        'd': null,
+        'e': true,
+        'f': false,
+        'g': 'x',
+        'h': ' 007 ',
+        'i': 0,
+        'j': 0.5,
+      });
+    });
+
+    test('JSON of several rows is an array', () {
+      const sel = ResultGridSelection(
+        startRow: 0,
+        startColumn: 0,
+        endRow: 1,
+        endColumn: 0,
+      );
+      final json = sel.toJson(
+        ['n'],
+        const [
+          ['1'],
+          ['2'],
+        ],
+      );
+      expect(jsonDecode(json), [
+        {'n': 1},
+        {'n': 2},
+      ]);
+    });
+  });
+}