refactor(change_detect): Abstract name logic into NameRegistry

Create `NameRegistry`, responsible for understanding how names are
generated for change detector fields and variables.

Use `NameRegistry` for both JS Jit & Dart pre-generated detectors.
Making progress on #3248

modules/angular2/src/change_detection/codegen_name_util.ts

@@ -0,0 +1,134 @@
+import {RegExpWrapper, StringWrapper} from 'angular2/src/facade/lang';
+import {List, ListWrapper} from 'angular2/src/facade/collection';
+
+import {DirectiveIndex} from './directive_record';
+
+import {ProtoRecord} from './proto_record';
+
+// `context` is always the first field.
+var _CONTEXT_IDX = 0;
+
+var _whiteSpaceRegExp = RegExpWrapper.create("\\W", "g");
+
+/**
+ * Returns `s` with all non-identifier characters removed.
+ */
+export function sanitizeName(s: string): string {
+  return StringWrapper.replaceAll(s, _whiteSpaceRegExp, '');
+}
+
+/**
+ * Class responsible for providing field and local variable names for change detector classes.
+ * Also provides some convenience functions, for example, declaring variables, destroying pipes,
+ * and dehydrating the detector.
+ */
+export class CodegenNameUtil {
+  /**
+   * Record names sanitized for use as fields.
+   * See [sanitizeName] for details.
+   */
+  _sanitizedNames: List<string>;
+
+  constructor(public records: List<ProtoRecord>, public directiveRecords: List<any>,
+              public fieldPrefix: string, public utilName: string) {
+    this._sanitizedNames = ListWrapper.createFixedSize(this.records.length + 1);
+    this._sanitizedNames[_CONTEXT_IDX] = 'context';
+    for (var i = 0, iLen = this.records.length; i < iLen; ++i) {
+      this._sanitizedNames[i + 1] = sanitizeName(`${this.records[i].name}${i}`);
+    }
+  }
+
+  getContextName(): string { return this.getFieldName(_CONTEXT_IDX); }
+
+  getLocalName(idx: int): string { return this._sanitizedNames[idx]; }
+
+  getChangeName(idx: int): string { return `c_${this._sanitizedNames[idx]}`; }
+
+  /**
+   * Generate a statement initializing local variables used when detecting changes.
+   */
+  genInitLocals(): string {
+    var declarations = [];
+    var assignments = [];
+    for (var i = 0, iLen = this.getFieldCount(); i < iLen; ++i) {
+      var changeName = this.getChangeName(i);
+      declarations.push(`${this.getLocalName(i)},${changeName}`);
+      assignments.push(changeName);
+    }
+    return `var ${ListWrapper.join(declarations, ',')};` +
+           `${ListWrapper.join(assignments, '=')} = false;`;
+  }
+
+  getFieldCount(): int { return this._sanitizedNames.length; }
+
+  getFieldName(idx: int): string { return `${this.fieldPrefix}${this._sanitizedNames[idx]}`; }
+
+  getAllFieldNames(): List<string> {
+    var fieldList = [];
+    for (var k = 0, kLen = this.getFieldCount(); k < kLen; ++k) {
+      fieldList.push(this.getFieldName(k));
+    }
+    for (var i = 0, iLen = this.records.length; i < iLen; ++i) {
+      var rec = this.records[i];
+      if (rec.isPipeRecord()) {
+        fieldList.push(this.getPipeName(rec.selfIndex));
+      }
+    }
+    for (var j = 0, jLen = this.directiveRecords.length; j < jLen; ++j) {
+      var dRec = this.directiveRecords[j];
+      fieldList.push(this.getDirectiveName(dRec.directiveIndex));
+      if (dRec.isOnPushChangeDetection()) {
+        fieldList.push(this.getDetectorName(dRec.directiveIndex));
+      }
+    }
+    return fieldList;
+  }
+
+  /**
+   * Generates a statement which declares all fields.
+   * This is only necessary for Dart change detectors.
+   */
+  genDeclareFields(): string {
+    var fields = this.getAllFieldNames();
+    ListWrapper.removeAt(fields, _CONTEXT_IDX);
+    return ListWrapper.isEmpty(fields) ? '' : `var ${ListWrapper.join(fields, ', ')};`;
+  }
+
+  /**
+   * Generates statements which clear all fields so that the change detector is dehydrated.
+   */
+  genDehydrateFields(): string {
+    var fields = this.getAllFieldNames();
+    ListWrapper.removeAt(fields, _CONTEXT_IDX);
+    if (!ListWrapper.isEmpty(fields)) {
+      // At least one assignment.
+      fields.push(`${this.utilName}.uninitialized();`);
+    }
+    return `${this.getContextName()} = null; ${ListWrapper.join(fields, ' = ')}`;
+  }
+
+  /**
+   * Generates statements destroying all pipe variables.
+   */
+  genPipeOnDestroy(): string {
+    return ListWrapper.join(ListWrapper.map(ListWrapper.filter(this.records, (r) => {
+      return r.isPipeRecord();
+    }), (r) => { return `${this.getPipeName(r.selfIndex)}.onDestroy();`; }), '\n');
+  }
+
+  getPipeName(idx: int): string { return `${this.fieldPrefix}${this._sanitizedNames[idx]}_pipe`; }
+
+  getAllDirectiveNames(): List<string> {
+    return ListWrapper.map(this.directiveRecords, d => this.getDirectiveName(d.directiveIndex));
+  }
+
+  getDirectiveName(d: DirectiveIndex): string { return `${this.fieldPrefix}directive_${d.name}`; }
+
+  getAllDetectorNames(): List<string> {
+    return ListWrapper.map(
+        ListWrapper.filter(this.directiveRecords, r => r.isOnPushChangeDetection()),
+        (d) => this.getDetectorName(d.directiveIndex));
+  }
+
+  getDetectorName(d: DirectiveIndex): string { return `${this.fieldPrefix}detector_${d.name}`; }
+}

modules/angular2/test/transform/integration/two_annotations_files/expected/bar.ng_deps.dart

@@ -30,13 +30,15 @@ class _MyComponent_ChangeDetector0 extends _gen.AbstractChangeDetector {
   dynamic _locals = null;
   dynamic _alreadyChecked = false;
   dynamic currentProto = null;
-  MyComponent _context = null;
-  dynamic _myNum0 = _gen.ChangeDetectionUtil.uninitialized();
-  dynamic _interpolate1 = _gen.ChangeDetectionUtil.uninitialized();
+  MyComponent _context;
+  var _myNum0, _interpolate1;
 
   _MyComponent_ChangeDetector0(
       dynamic dispatcher, this._protos, this._directiveRecords)
-      : super("MyComponent_comp_0", dispatcher);
+      : super("MyComponent_comp_0", dispatcher) {
+    _context = null;
+    _myNum0 = _interpolate1 = _gen.ChangeDetectionUtil.uninitialized();
+  }
 
   void detectChangesInRecords(throwOnChange) {
     if (!hydrated()) {
@@ -50,12 +52,8 @@ class _MyComponent_ChangeDetector0 extends _gen.AbstractChangeDetector {
   }
 
   void __detectChangesInRecords(throwOnChange) {
-    var context = null;
-    var myNum0 = null;
-    var interpolate1 = null;
-    var change_context = false;
-    var change_myNum0 = false;
-    var change_interpolate1 = false;
+    var context, c_context, myNum0, c_myNum0, interpolate1, c_interpolate1;
+    c_context = c_myNum0 = c_interpolate1 = false;
     var isChanged = false;
     currentProto = null;
     var changes = null;
@@ -64,15 +62,15 @@ class _MyComponent_ChangeDetector0 extends _gen.AbstractChangeDetector {
     currentProto = _protos[0];
     myNum0 = context.myNum;
     if (!_gen.looseIdentical(myNum0, _myNum0)) {
-      change_myNum0 = true;
+      c_myNum0 = true;
 
       _myNum0 = myNum0;
     }
-    if (change_myNum0) {
+    if (c_myNum0) {
       currentProto = _protos[1];
       interpolate1 = "Salad: " "${myNum0 == null ? "" : myNum0}" " is awesome";
       if (!_gen.looseIdentical(interpolate1, _interpolate1)) {
-        change_interpolate1 = true;
+        c_interpolate1 = true;
         if (throwOnChange) {
           _gen.ChangeDetectionUtil.throwOnChange(currentProto,
               _gen.ChangeDetectionUtil.simpleChange(
@@ -108,8 +106,7 @@ class _MyComponent_ChangeDetector0 extends _gen.AbstractChangeDetector {
 
   void dehydrate() {
     _context = null;
-    _myNum0 = _gen.ChangeDetectionUtil.uninitialized();
-    _interpolate1 = _gen.ChangeDetectionUtil.uninitialized();
+    _myNum0 = _interpolate1 = _gen.ChangeDetectionUtil.uninitialized();
     _locals = null;
     _pipes = null;
   }