Merge pull request #581 from kevmoo/polymer

lib/src/code_printer.dart

-// Copyright (c) 2012, 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.
-
-library code_printer;
-
-import 'dart:utf' show stringToCodepoints;
-import 'package:source_maps/source_maps.dart';
-
-/**
- * Helper class to format generated code and keep track of source map
- * information.
- */
-class CodePrinter {
-
-  /**
-   * Items recoded by this printer, which can be [String] literals,
-   * other printing helpers such as [Declarations] and [CodePrinter],
-   * and source map information like [Location] and [Span].
-   */
-  List _items = [];
-
-  /** Internal buffer to merge consecutive strings added to this printer. */
-  StringBuffer _buff;
-
-  /** Current indentation, which can be updated from outside this class. */
-  int indent = 0;
-
-  /**
-   * Item used to indicate that the following item is copied from the original
-   * source code, and hence we should preserve source-maps on every new line.
-   */
-  static final _ORIGINAL = new Object();
-
-  CodePrinter(this.indent);
-
-  /**
-   * Adds [object] to this printer. [object] can be a [String], [Declarations],
-   * or a [CodePrinter]. If [object] is a [String], the value is appended
-   * directly, without doing any formatting changes. If you wish to add a line
-   * of code with automatic indentation, use [addLine] instead. [Declarations]
-   * and [CodePrinter] are not processed until [build] gets called later on.
-   * We ensure that [build] emits every object in the order that they were added
-   * to this printer.
-   *
-   * The [location] and [span] parameters indicate the corresponding source map
-   * location of [object] in the original input. Only one, [location] or
-   * [span], should be provided at a time.
-   *
-   * Indicate [isOriginal] when [object] is copied directly from the user code.
-   * Setting [isOriginal] will make this printer propagate source map locations
-   * on every line-break.
-   */
-  void add(object, {Location location, Span span, bool isOriginal: false}) {
-    if (object is! String || location != null || span != null || isOriginal) {
-      _flush();
-      assert(location == null || span == null);
-      if (location != null) _items.add(location);
-      if (span != null) _items.add(span);
-      if (isOriginal) _items.add(_ORIGINAL);
-    }
-
-    if (object is String) {
-      _appendString(object);
-    } else {
-      _items.add(object);
-    }
-  }
-
-  /** Append `2 * indent` spaces to this printer. */
-  void insertIndent() => _indent(indent);
-
-  /**
-   * Add a [line], autoindenting to the current value of [indent]. Note,
-   * indentation is not inferred, so if a line opens or closes an indentation
-   * block, you need to also update [indent] accordingly. Also, indentation is
-   * not adapted for nested code printers. If you add a [CodePrinter] to this
-   * printer, its indentation is set separately and will not include any
-   * the indentation set here.
-   *
-   * The [location] and [span] parameters indicate the corresponding source map
-   * location of [object] in the original input. Only one, [location] or
-   * [span], should be provided at a time.
-   */
-  void addLine(String line, {Location location, Span span}) {
-    if (location != null || span != null) {
-      _flush();
-      assert(location == null || span == null);
-      if (location != null) _items.add(location);
-      if (span != null) _items.add(span);
-    }
-    if (line == null) return;
-    if (line != '') {
-      // We don't indent empty lines.
-      _indent(indent);
-      _appendString(line);
-    }
-    _appendString('\n');
-  }
-
-  /** Appends a string merging it with any previous strings, if possible. */
-  void _appendString(String s) {
-    if (_buff == null) _buff = new StringBuffer();
-    _buff.write(s);
-  }
-
-  /** Adds all of the current [_buff] contents as a string item. */
-  void _flush() {
-    if (_buff != null) {
-      _items.add(_buff.toString());
-      _buff = null;
-    }
-  }
-
-  void _indent(int indent) {
-    for (int i = 0; i < indent; i++) _appendString('  ');
-  }
-
-  /**
-   * Returns a string representation of all the contents appended to this
-   * printer, including source map location tokens.
-   */
-  String toString() {
-    _flush();
-    return (new StringBuffer()..writeAll(_items)).toString();
-  }
-
-  /** [Printer] used during the last call to [build], if any. */
-  Printer _printer;
-
-  /** Returns the text produced after calling [build]. */
-  String get text => _printer.text;
-
-  /** Returns the source-map information produced after calling [build]. */
-  String get map => _printer.map;
-
-  /**
-   * Builds the output of this printer and source map information. After calling
-   * this function, you can use [text] and [map] to retrieve the geenrated code
-   * and source map information, respectively.
-   */
-  void build(String filename) {
-    _build(_printer = new Printer(filename));
-  }
-
-  void _build(Printer printer) {
-    _flush();
-    bool propagate = false;
-    for (var item in _items) {
-      if (item is Declarations) {
-        item._build(printer);
-      } else if (item is CodePrinter) {
-        item._build(printer);
-      } else if (item is String) {
-        printer.add(item, projectMarks: propagate);
-        propagate = false;
-      } else if (item is Location || item is Span) {
-        printer.mark(item);
-      } else if (item == _ORIGINAL) {
-        // we insert booleans when we are about to quote text that was copied
-        // from the original source. In such case, we will propagate marks on
-        // every new-line.
-        propagate = true;
-      } else {
-        throw new UnsupportedError('Unknown item type: $item');
-      }
-    }
-  }
-}
-
-/** A declaration of a field or local variable. */
-class Declaration implements Comparable {
-  final String type;
-  final String name;
-  final Span sourceSpan;
-  final String initializer;
-
-  Declaration(this.type, this.name, this.sourceSpan, [this.initializer]);
-
-  /**
-   * Sort declarations by type, so they can be merged together in a declaration
-   * group.
-   */
-  int compareTo(Declaration other) {
-    if (type != other.type) return type.compareTo(other.type);
-    return name.compareTo(other.name);
-  }
-}
-
-/** A set of declarations grouped together. */
-class Declarations {
-
-  /** All declarations in this group. */
-  final List<Declaration> declarations = <Declaration>[];
-
-  /** Indentation associated with this declaration group. */
-  final int indent;
-
-  /** Whether these declarations are local variables or fields in a class. */
-  final bool isLocal;
-
-  /** Whether types should be prefixed with the "static" keyword. */
-  final bool staticKeyword;
-
-  Declarations(this.indent, {this.isLocal: false, this.staticKeyword: false});
-
-  /** Add a declaration to this group. */
-  void add(String type, String identifier, Span sourceSpan, [String init]) {
-    declarations.add(
-        new Declaration(isLocal ? 'var' : type, identifier, sourceSpan, init));
-  }
-
-  String toString() {
-    var printer = new Printer(null);
-    _build(printer);
-    return printer.text;
-  }
-
-  void _build(Printer printer) {
-    if (declarations.length == 0) return;
-    declarations.sort();
-    var lastType = null;
-    printer.addSpaces(2 * indent);
-    for (var d in declarations) {
-      if (d.type != lastType) {
-        if (lastType != null) {
-          printer.add(';\n');
-          printer.addSpaces(2 * indent);
-        }
-        if (staticKeyword) printer.add('static ');
-        printer.add(d.type);
-        lastType = d.type;
-      } else {
-        printer.add(',');
-      }
-      printer.add(' ');
-      if (d.sourceSpan != null) printer.mark(d.sourceSpan);
-      printer.add(d.name);
-      if (d.initializer != null) {
-        printer..add(' = ')..add(d.initializer);
-      }
-    }
-    printer.add(';\n');
-  }
-}