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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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4
packages/compiler/src/render3/r3_identifiers.ts
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@ -115,8 +115,6 @@ export class Identifiers {
static styleSanitizer: o.ExternalReference = {name: 'ɵɵstyleSanitizer', moduleName: CORE};
static elementHostAttrs: o.ExternalReference = {name: 'ɵɵelementHostAttrs', moduleName: CORE};
static containerCreate: o.ExternalReference = {name: 'ɵɵcontainer', moduleName: CORE};
static nextContext: o.ExternalReference = {name: 'ɵɵnextContext', moduleName: CORE};
@ -129,8 +127,6 @@ export class Identifiers {
static disableBindings: o.ExternalReference = {name: 'ɵɵdisableBindings', moduleName: CORE};
static allocHostVars: o.ExternalReference = {name: 'ɵɵallocHostVars', moduleName: CORE};
static getCurrentView: o.ExternalReference = {name: 'ɵɵgetCurrentView', moduleName: CORE};
static textInterpolate: o.ExternalReference = {name: 'ɵɵtextInterpolate', moduleName: CORE};