Begin generating code for summary serialization/deserialization.

pkg/analyzer/tool/summary/generate.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/**
+ * This file contains code to generate serialization/deserialization logic for
+ * summaries based on an "IDL" description of the summary format (written in
+ * stylized Dart).
+ *
+ * For each class in the "IDL" input, two corresponding classes are generated:
+ * - A class with the same name which represents deserialized summary data in
+ *   memory.  This class has read-only semantics.
+ * - A "builder" class which can be used to generate serialized summary data.
+ *   This class has write-only semantics.
+ *
+ * Each of the "builder" classess has a single `finish` method which finalizes
+ * the entity being built and returns it as an [Object].  This object should
+ * only be passed to other builders (or to [BuilderContext.getBuffer]);
+ * otherwise the client should treat it as opaque, since it exposes
+ * implementation details of the underlying summary infrastructure.
+ */
+library analyzer.tool.summary.generate;
+
+import 'dart:convert';
+import 'dart:io' hide File;
+
+import 'package:analyzer/analyzer.dart';
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/file_system/physical_file_system.dart';
+import 'package:analyzer/src/codegen/tools.dart';
+import 'package:analyzer/src/generated/parser.dart';
+import 'package:analyzer/src/generated/scanner.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:path/path.dart';
+
+import 'idl_model.dart' as idlModel;
+
+main() {
+  String script = Platform.script.toFilePath(windows: Platform.isWindows);
+  String pkgPath = normalize(join(dirname(script), '..', '..'));
+  GeneratedContent.generateAll(pkgPath, <GeneratedContent>[target]);
+}
+
+final GeneratedFile target =
+    new GeneratedFile('lib/src/summary/format.dart', (String pkgPath) {
+  // Parse the input "IDL" file and pass it to the [_CodeGenerator].
+  PhysicalResourceProvider provider = new PhysicalResourceProvider(
+      PhysicalResourceProvider.NORMALIZE_EOL_ALWAYS);
+  String idlPath = join(pkgPath, 'tool', 'summary', 'idl.dart');
+  File idlFile = provider.getFile(idlPath);
+  Source idlSource = provider.getFile(idlPath).createSource();
+  String idlText = idlFile.readAsStringSync();
+  BooleanErrorListener errorListener = new BooleanErrorListener();
+  CharacterReader idlReader = new CharSequenceReader(idlText);
+  Scanner scanner = new Scanner(idlSource, idlReader, errorListener);
+  Token tokenStream = scanner.tokenize();
+  Parser parser = new Parser(idlSource, new BooleanErrorListener());
+  CompilationUnit idlParsed = parser.parseCompilationUnit(tokenStream);
+  _CodeGenerator codeGenerator = new _CodeGenerator();
+  codeGenerator.processCompilationUnit(idlParsed);
+  return codeGenerator._outBuffer.toString();
+});
+
+class _CodeGenerator {
+  /**
+   * Buffer in which generated code is accumulated.
+   */
+  final StringBuffer _outBuffer = new StringBuffer();
+
+  /**
+   * Current indentation level.
+   */
+  String _indentation = '';
+
+  /**
+   * Semantic model of the "IDL" input file.
+   */
+  idlModel.Idl _idl;
+
+  /**
+   * Perform basic sanity checking of the IDL (over and above that done by
+   * [extractIdl]).
+   */
+  void checkIdl() {
+    _idl.classes.forEach((String name, idlModel.ClassDeclaration cls) {
+      cls.fields.forEach((String fieldName, idlModel.FieldType type) {
+        if (type.isList) {
+          if (_idl.classes.containsKey(type.typeName)) {
+            // List of classes is ok
+          } else if (type.typeName == 'int') {
+            // List of ints is ok
+          } else {
+            throw new Exception(
+                '$name.$fieldName: illegal type (list of ${type.typeName})');
+          }
+        }
+      });
+    });
+  }
+
+  /**
+   * Generate a string representing the Dart type which should be used to
+   * represent [type] when deserialized.
+   */
+  String dartType(idlModel.FieldType type) {
+    if (type.isList) {
+      return 'List<${type.typeName}>';
+    } else {
+      return type.typeName;
+    }
+  }
+
+  /**
+   * Generate a Dart expression representing the default value for a field
+   * having the given [type], or `null` if there is no default value.
+   */
+  String defaultValue(idlModel.FieldType type) {
+    if (type.isList) {
+      return 'const <${type.typeName}>[]';
+    } else if (_idl.enums.containsKey(type.typeName)) {
+      return '${type.typeName}.${_idl.enums[type.typeName].values[0]}';
+    } else if (type.typeName == 'int') {
+      return '0';
+    } else if (type.typeName == 'String') {
+      return "''";
+    } else if (type.typeName == 'bool') {
+      return 'false';
+    } else {
+      return null;
+    }
+  }
+
+  /**
+   * Generate a string representing the Dart type which should be used to
+   * represent [type] while building a serialized data structure.
+   */
+  String encodedType(idlModel.FieldType type) {
+    if (type.isList) {
+      if (type.typeName == 'int') {
+        return 'List<int>';
+      } else {
+        return 'List<Object>';
+      }
+    } else if (_idl.classes.containsKey(type.typeName)) {
+      return 'Object';
+    } else {
+      return dartType(type);
+    }
+  }
+
+  /**
+   * Process the AST in [idlParsed] and store the resulting semantic model in
+   * [_idl].  Also perform some error checking.
+   */
+  void extractIdl(CompilationUnit idlParsed) {
+    _idl = new idlModel.Idl();
+    for (CompilationUnitMember decl in idlParsed.declarations) {
+      if (decl is ClassDeclaration) {
+        idlModel.ClassDeclaration cls = new idlModel.ClassDeclaration();
+        _idl.classes[decl.name.name] = cls;
+        for (ClassMember classMember in decl.members) {
+          if (classMember is FieldDeclaration) {
+            TypeName type = classMember.fields.type;
+            bool isList = false;
+            if (type.name.name == 'List' &&
+                type.typeArguments != null &&
+                type.typeArguments.arguments.length == 1) {
+              isList = true;
+              type = type.typeArguments.arguments[0];
+            }
+            if (type.typeArguments != null) {
+              throw new Exception('Cannot handle type arguments in `$type`');
+            }
+            idlModel.FieldType fieldType =
+                new idlModel.FieldType(type.name.name, isList);
+            for (VariableDeclaration field in classMember.fields.variables) {
+              cls.fields[field.name.name] = fieldType;
+            }
+          } else {
+            throw new Exception('Unexpected class member `$classMember`');
+          }
+        }
+      } else if (decl is EnumDeclaration) {
+        idlModel.EnumDeclaration enm = new idlModel.EnumDeclaration();
+        _idl.enums[decl.name.name] = enm;
+        for (EnumConstantDeclaration constDecl in decl.constants) {
+          enm.values.add(constDecl.name.name);
+        }
+      } else if (decl is TopLevelVariableDeclaration) {
+        // Ignore top leve variable declarations; they are present just to make
+        // the IDL analyze without warnings.
+      } else {
+        throw new Exception('Unexpected declaration `$decl`');
+      }
+    }
+  }
+
+  /**
+   * Execute [callback] with two spaces added to [_indentation].
+   */
+  void indent(void callback()) {
+    String oldIndentation = _indentation;
+    try {
+      _indentation += '  ';
+      callback();
+    } finally {
+      _indentation = oldIndentation;
+    }
+  }
+
+  /**
+   * Add the string [s] to the output as a single line, indenting as
+   * appropriate.
+   */
+  void out([String s = '']) {
+    if (s == '') {
+      _outBuffer.writeln('');
+    } else {
+      _outBuffer.writeln('$_indentation$s');
+    }
+  }
+
+  /**
+   * Entry point to the code generator.  Interpret the AST in [idlParsed],
+   * generate code, and output it to [_outBuffer].
+   */
+  void processCompilationUnit(CompilationUnit idlParsed) {
+    extractIdl(idlParsed);
+    checkIdl();
+    out('// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file');
+    out('// for details. All rights reserved. Use of this source code is governed by a');
+    out('// BSD-style license that can be found in the LICENSE file.');
+    out('//');
+    out('// This file has been automatically generated.  Please do not edit it manually.');
+    out('// To regenerate the file, use the script "pkg/analyzer/tool/generate_files".');
+    out();
+    out('library analyzer.src.summary.format;');
+    out();
+    out("import 'builder.dart' as builder;");
+    out();
+    _idl.enums.forEach((String name, idlModel.EnumDeclaration enm) {
+      out('enum $name {');
+      indent(() {
+        for (String value in enm.values) {
+          out('$value,');
+        }
+      });
+      out('}');
+      out();
+    });
+    _idl.classes.forEach((String name, idlModel.ClassDeclaration cls) {
+      out('class $name {');
+      indent(() {
+        cls.fields.forEach((String fieldName, idlModel.FieldType type) {
+          out('${dartType(type)} _$fieldName;');
+        });
+        out();
+        out('$name.fromJson(Map json)');
+        indent(() {
+          List<String> initializers = <String>[];
+          cls.fields.forEach((String fieldName, idlModel.FieldType type) {
+            String convert = 'json[${quoted(fieldName)}]';
+            if (type.isList && type.typeName == 'int') {
+              // No conversion necessary.
+            } else if (type.isList) {
+              convert =
+                  '$convert?.map((x) => new ${type.typeName}.fromJson(x))?.toList()';
+            } else if (_idl.classes.containsKey(type.typeName)) {
+              convert =
+                  '$convert == null ? null : new ${type.typeName}.fromJson($convert)';
+            } else if (_idl.enums.containsKey(type.typeName)) {
+              convert =
+                  '$convert == null ? null : ${type.typeName}.values[$convert]';
+            }
+            initializers.add('_$fieldName = $convert');
+          });
+          for (int i = 0; i < initializers.length; i++) {
+            String prefix = i == 0 ? ': ' : '  ';
+            String suffix = i == initializers.length - 1 ? ';' : ',';
+            out('$prefix${initializers[i]}$suffix');
+          }
+        });
+        out();
+        cls.fields.forEach((String fieldName, idlModel.FieldType type) {
+          String def = defaultValue(type);
+          String defaultSuffix = def == null ? '' : ' ?? $def';
+          out('${dartType(type)} get $fieldName => _$fieldName$defaultSuffix;');
+        });
+      });
+      out('}');
+      out();
+      List<String> builderParams = <String>[];
+      out('class ${name}Builder {');
+      indent(() {
+        out('final Map _json = {};');
+        out();
+        out('${name}Builder(builder.BuilderContext context);');
+        cls.fields.forEach((String fieldName, idlModel.FieldType type) {
+          out();
+          String conversion = '_value';
+          String condition = '';
+          if (type.isList) {
+            conversion = '$conversion.toList()';
+            condition = ' || _value.isEmpty';
+          } else if (_idl.enums.containsKey(type.typeName)) {
+            conversion = '$conversion.index';
+            condition = ' || _value == ${defaultValue(type)}';
+          }
+          builderParams.add('${encodedType(type)} $fieldName');
+          out('void set $fieldName(${encodedType(type)} _value) {');
+          indent(() {
+            out('assert(!_json.containsKey(${quoted(fieldName)}));');
+            out('if (_value != null$condition) {');
+            indent(() {
+              out('_json[${quoted(fieldName)}] = $conversion;');
+            });
+            out('}');
+          });
+          out('}');
+        });
+        out();
+        out('Object finish() => _json;');
+      });
+      out('}');
+      out();
+      out('Object encode$name(builder.BuilderContext builderContext, {${builderParams.join(', ')}}) {');
+      indent(() {
+        out('${name}Builder builder = new ${name}Builder(builderContext);');
+        cls.fields.forEach((String fieldName, idlModel.FieldType type) {
+          out('builder.$fieldName = $fieldName;');
+        });
+        out('return builder.finish();');
+      });
+      out('}');
+      out();
+    });
+  }
+
+  /**
+   * Enclose [s] in quotes, escaping as necessary.
+   */
+  String quoted(String s) {
+    return JSON.encode(s);
+  }
+}