platform/lib/transformer.dart
2017-03-08 17:47:58 -05:00

98 lines
2.7 KiB
Dart

import 'dart:async';
import 'dart:convert';
import 'package:barback/barback.dart';
import 'package:analyzer/analyzer.dart';
import 'package:angel_framework/angel_framework.dart';
import 'angel_configuration.dart';
class ConfigurationTransformer extends Transformer {
final BarbackSettings _settings;
@override
String get allowedExtensions => ".dart";
ConfigurationTransformer.asPlugin(this._settings) {}
Future apply(Transform transform) async {
try {
var app = new Angel();
await app.configure(loadConfigurationFile(
directoryPath: _settings.configuration["dir"] ?? "./config",
overrideEnvironmentName: _settings.configuration["env"]));
var text = await transform.primaryInput.readAsString();
var compilationUnit = parseCompilationUnit(text);
var visitor = new ConfigAstVisitor(app.properties);
visitor.visitCompilationUnit(compilationUnit);
await for (Map replaced in visitor.onReplaced) {
text = text.replaceAll(replaced["needle"], replaced["with"]);
}
transform
.addOutput(new Asset.fromString(transform.primaryInput.id, text));
} catch (e) {
// Fail silently...
}
}
}
class ConfigAstVisitor extends GeneralizingAstVisitor {
Map _config;
var _onReplaced = new StreamController<Map>();
String _prefix = "";
Stream<Map> get onReplaced => _onReplaced.stream;
ConfigAstVisitor(this._config);
bool isConfigMethod(Expression function) =>
function is SimpleIdentifier && function.name == "${_prefix}config";
resolveItem(String key) {
var split = key.split(".");
var parent = _config;
for (int i = 0; i < split.length; i++) {
if (parent != null && parent is Map) parent = parent[split[i]];
}
return parent;
}
@override
visitCompilationUnit(CompilationUnit ctx) {
var result = super.visitCompilationUnit(ctx);
_onReplaced.close();
return result;
}
@override
visitImportDirective(ImportDirective ctx) {
String uri = ctx.uri.stringValue;
if (uri == "package:angel_configuration/browser.dart") {
_onReplaced.add({"needle": ctx.toString(), "with": ""});
if (ctx.asKeyword != null) {
_prefix = ctx.prefix.name;
}
}
return super.visitImportDirective(ctx);
}
@override
visitExpression(Expression ctx) {
if (ctx is MethodInvocation) {
if (isConfigMethod(ctx.function)) {
StringLiteral key = ctx.argumentList.arguments[0];
var resolved = resolveItem(key.stringValue);
_onReplaced
.add({"needle": ctx.toString(), "with": JSON.encode(resolved)});
}
}
return super.visitExpression(ctx);
}
}