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refactor(ivy): move hostVars/hostAttrs from instruction to DirectiveDef (#34683)

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This change moves information from instructions to declarative position:
- `ɵɵallocHostVars(vars)` => `DirectiveDef.hostVars`
- `ɵɵelementHostAttrs(attrs)` => `DirectiveDef.hostAttrs`

When merging directives it is necessary to know about `hostVars` and `hostAttrs`. Before this change the information was stored in the `hostBindings` function. This was problematic, because in order to get to the information the `hostBindings` would have to be executed. In order for `hostBindings` to be executed the directives would have to be instantiated. This means that the directive instantiation would happen before we had knowledge about the `hostAttrs` and as a result the directive could observe in the constructor that not all of the `hostAttrs` have been applied. This further complicates the runtime as we have to apply `hostAttrs` in parts over many invocations.

`ɵɵallocHostVars` was unnecessarily complicated because it would have to update the `LView` (and Blueprint) while existing directives are already executing. By moving it out of `hostBindings` function we can access it statically and we can create correct `LView` (and Blueprint) in a single pass.

This change only changes how the instructions are generated, but does not change the runtime much. (We cheat by emulating the old behavior by calling `ɵɵallocHostVars` and `ɵɵelementHostAttrs`) Subsequent change will refactor the runtime to take advantage of the static information.

PR Close #34683
This commit is contained in:
Miško Hevery
2020-01-08 11:32:33 -08:00
parent 94504ff5c8
commit 2961bf06c6
33 changed files with 751 additions and 185 deletions
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6
packages/common/src/directives/ng_class.ts
View File

@ -5,7 +5,7 @@
* 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 {Directive, DoCheck, Input, ɵRenderFlags, ɵɵallocHostVars, ɵɵclassMap, ɵɵdefineDirective} from '@angular/core';
import {Directive, DoCheck, Input, ɵRenderFlags, ɵɵclassMap, ɵɵdefineDirective} from '@angular/core';
import {NgClassImpl, NgClassImplProvider} from './ng_class_impl';
@ -32,10 +32,8 @@ export const ngClassDirectiveDef__PRE_R3__ = undefined;
export const ngClassDirectiveDef__POST_R3__ = ɵɵdefineDirective({
type: function() {} as any,
selectors: null as any,
hostVars: 2,
hostBindings: function(rf: ɵRenderFlags, ctx: any, elIndex: number) {
if (rf & ɵRenderFlags.Create) {
ɵɵallocHostVars(2);
}
if (rf & ɵRenderFlags.Update) {
ɵɵclassMap(ctx.getValue());
}

6
packages/common/src/directives/ng_style.ts
View File

@ -5,7 +5,7 @@
* 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 {Directive, DoCheck, Input, ɵRenderFlags, ɵɵallocHostVars, ɵɵdefineDirective, ɵɵstyleMap} from '@angular/core';
import {Directive, DoCheck, Input, ɵRenderFlags, ɵɵdefineDirective, ɵɵstyleMap} from '@angular/core';
import {NgStyleImpl, NgStyleImplProvider} from './ng_style_impl';
@ -33,10 +33,8 @@ export const ngStyleFactoryDef__PRE_R3__ = undefined;
export const ngStyleDirectiveDef__POST_R3__ = ɵɵdefineDirective({
type: function() {} as any,
selectors: null as any,
hostVars: 2,
hostBindings: function(rf: ɵRenderFlags, ctx: any, elIndex: number) {
if (rf & ɵRenderFlags.Create) {
ɵɵallocHostVars(2);
}
if (rf & ɵRenderFlags.Update) {
ɵɵstyleMap(ctx.getValue());
}