widget_surveyor.dart

import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:surveyor/src/analysis.dart';
import 'package:surveyor/src/driver.dart';
import 'package:surveyor/src/visitors.dart';

/// Gathers and displays widget 2-grams.
///
/// Run like so:
///
/// dart bin/widget_surveyor.dart <source dir>
main(List<String> args) async {
  var driver = Driver.forArgs(args);
  driver.visitor = WidgetCollector();

  await driver.analyze();
}

class TwoGram implements Comparable<TwoGram> {
  String parent;
  String child;

  TwoGram(DartType parent, DartType child)
      : parent = parent?.name ?? 'null',
        child = child?.name ?? 'null';

  @override
  int get hashCode => child.hashCode * 13 + parent.hashCode;

  @override
  bool operator ==(other) =>
      other is TwoGram && other.child == child && other.parent == parent;

  @override
  int compareTo(TwoGram other) =>
      child.compareTo(other.child) * 2 + parent.compareTo(other.parent);

  @override
  String toString() => '$child->$parent';
}

class TwoGrams {
  Map<TwoGram, int> map = <TwoGram, int>{};

  void add(TwoGram twoGram) {
    map.update(twoGram, (v) => v + 1, ifAbsent: () => 1);
  }

  @override
  String toString() {
    var sb = StringBuffer();
    for (var entry in map.entries.toList()
      ..sort((a, b) => a.key.compareTo(b.key))) {
      sb.writeln('${entry.key} : ${entry.value}');
    }
    return sb.toString();
  }
}

class WidgetCollector extends RecursiveAstVisitor implements PostVisitCallback {
  TwoGrams twoGrams = TwoGrams();

  DartType previousEnclosingWidget;
  DartType enclosingWidget;

  @override
  void onVisitFinished() {
    print('2 Grams:');
    print(twoGrams);
  }

  @override
  visitInstanceCreationExpression(InstanceCreationExpression node) {
    final type = node.staticType;
    if (isWidgetType(type)) {
      twoGrams.add(TwoGram(enclosingWidget, type));
      previousEnclosingWidget = enclosingWidget;
      enclosingWidget = type;
    }

    // Visit children.
    super.visitInstanceCreationExpression(node);

    // Reset parent.
    enclosingWidget = previousEnclosingWidget;
  }
}