refactor(platform-browser): move platform-browser/animations to animations/browser (#15130)

Closes: #15130

packages/animations/browser/src/dsl/animation_trigger.ts

@@ -0,0 +1,115 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {AnimationAnimateMetadata, AnimationGroupMetadata, AnimationKeyframesSequenceMetadata, AnimationMetadata, AnimationSequenceMetadata, AnimationStateMetadata, AnimationStyleMetadata, AnimationTransitionMetadata, ɵStyleData} from '@angular/animations';
+
+import {copyStyles, normalizeStyles} from '../util';
+
+import {AnimationDslVisitor, visitAnimationNode} from './animation_dsl_visitor';
+import {parseTransitionExpr} from './animation_transition_expr';
+import {AnimationTransitionFactory} from './animation_transition_factory';
+import {AnimationTransitionInstruction, createTransitionInstruction} from './animation_transition_instruction';
+import {validateAnimationSequence} from './animation_validator_visitor';
+
+
+/**
+ * @experimental Animation support is experimental.
+ */
+export function buildTrigger(name: string, definitions: AnimationMetadata[]): AnimationTrigger {
+  return new AnimationTriggerVisitor().buildTrigger(name, definitions);
+}
+
+/**
+* @experimental Animation support is experimental.
+*/
+export class AnimationTrigger {
+  public transitionFactories: AnimationTransitionFactory[] = [];
+  public states: {[stateName: string]: ɵStyleData} = {};
+
+  constructor(
+      public name: string, states: {[stateName: string]: ɵStyleData},
+      private _transitionAsts: AnimationTransitionMetadata[]) {
+    Object.keys(states).forEach(
+        stateName => { this.states[stateName] = copyStyles(states[stateName], false); });
+
+    const errors: string[] = [];
+    _transitionAsts.forEach(ast => {
+      const exprs = parseTransitionExpr(ast.expr, errors);
+      const sequenceErrors = validateAnimationSequence(ast);
+      if (sequenceErrors.length) {
+        errors.push(...sequenceErrors);
+      } else {
+        this.transitionFactories.push(
+            new AnimationTransitionFactory(this.name, ast, exprs, states));
+      }
+    });
+
+    if (errors.length) {
+      const LINE_START = '\n - ';
+      throw new Error(
+          `Animation parsing for the ${name} trigger have failed:${LINE_START}${errors.join(LINE_START)}`);
+    }
+  }
+
+  createFallbackInstruction(currentState: any, nextState: any): AnimationTransitionInstruction {
+    const backupStateStyles = this.states['*'] || {};
+    const currentStateStyles = this.states[currentState] || backupStateStyles;
+    const nextStateStyles = this.states[nextState] || backupStateStyles;
+    return createTransitionInstruction(
+        this.name, currentState, nextState, nextState == 'void', currentStateStyles,
+        nextStateStyles, []);
+  }
+
+  matchTransition(currentState: any, nextState: any): AnimationTransitionInstruction {
+    for (let i = 0; i < this.transitionFactories.length; i++) {
+      let result = this.transitionFactories[i].match(currentState, nextState);
+      if (result) return result;
+    }
+  }
+}
+
+class AnimationTriggerContext {
+  public errors: string[] = [];
+  public states: {[stateName: string]: ɵStyleData} = {};
+  public transitions: AnimationTransitionMetadata[] = [];
+}
+
+class AnimationTriggerVisitor implements AnimationDslVisitor {
+  buildTrigger(name: string, definitions: AnimationMetadata[]): AnimationTrigger {
+    const context = new AnimationTriggerContext();
+    definitions.forEach(def => visitAnimationNode(this, def, context));
+    return new AnimationTrigger(name, context.states, context.transitions);
+  }
+
+  visitState(ast: AnimationStateMetadata, context: any): any {
+    context.states[ast.name] = normalizeStyles(ast.styles.styles);
+  }
+
+  visitTransition(ast: AnimationTransitionMetadata, context: any): any {
+    context.transitions.push(ast);
+  }
+
+  visitSequence(ast: AnimationSequenceMetadata, context: any) {
+    // these values are not visited in this AST
+  }
+
+  visitGroup(ast: AnimationGroupMetadata, context: any) {
+    // these values are not visited in this AST
+  }
+
+  visitAnimate(ast: AnimationAnimateMetadata, context: any) {
+    // these values are not visited in this AST
+  }
+
+  visitStyle(ast: AnimationStyleMetadata, context: any) {
+    // these values are not visited in this AST
+  }
+
+  visitKeyframeSequence(ast: AnimationKeyframesSequenceMetadata, context: any) {
+    // these values are not visited in this AST
+  }
+}