…the overwritten one (#32427)

In order to prevent `ngcc`'d packages (e.g. libraries) from getting
accidentally published, `ngcc` overwrites the `prepublishOnly` npm
script to log a warning and exit with an error. In case we want to
restore the original script (e.g. "undo" `ngcc` processing), we keep a
backup of the original `prepublishOnly` script.

Previously, running `ngcc` a second time (e.g. for a different format)
would create a backup of the overwritten `prepublishOnly` script (if
there was originally no `prepublishOnly` script). As a result, if we
ever tried to "undo" `ngcc` processing and restore the original
`prepublishOnly` script, the error-throwing script would be restored
instead.

This commit fixes it by ensuring that we only back up a `prepublishOnly`
script, iff it is not the one we created ourselves (i.e. the
error-throwing one).

PR Close #32427

…rface (#32427)

To persist some of its state, `ngcc` needs to update `package.json`
files (both in memory and on disk).

This refactoring abstracts these operations behind the
`PackageJsonUpdater` interface, making it easier to orchestrate them
from different contexts (e.g. when running tasks in parallel on multiple
processes).

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd

PR Close #32427

…face (#32427)

This change does not alter the current behavior, but makes it easier to
introduce new types of `Executors` , for example to do the required work
in parallel (on multiple processes).

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd

PR Close #32427

Previously, `ngcc`'s programmatic API would run and complete
synchronously. This was necessary for specific usecases (such as how the
`@angular/cli` invokes `ngcc` as part of the TypeScript module
resolution process), but not for others (e.g. running `ivy-ngcc` as a
`postinstall` script).

This commit adds a new option (`async`) that enables turning on
asynchronous execution. I.e. it signals that the caller is OK with the
function call to complete asynchronously, which allows `ngcc` to
potentially run in a more efficient mode.

Currently, there is no difference in the way tasks are executed in sync
vs async mode, but this change sets the ground for adding new execution
options (that require asynchronous operation), such as processing tasks
in parallel on multiple processes.

NOTE:
When using the programmatic API, the default value for `async` is
`false`, thus retaining backwards compatibility.
When running `ngcc` from the command line (i.e. via the `ivy-ngcc`
script), it runs in async mode (to be able to take advantage of future
optimizations), but that is transparent to the caller.

PR Close #32427

…ty processability (#32427)

In the past, a task's processability didn't use to be known in advance.
It was possible that a task would be created and added to the queue
during the analysis phase and then later (during the compilation phase)
it would be found out that the task (i.e. the associated format
property) was not processable.

As a result, certain checks had to be delayed, until a task's processing
had started or even until all tasks had been processed. Examples of
checks that had to be delayed are:
- Whether a task can be skipped due to `compileAllFormats: false`.
- Whether there were entry-points for which no format at all was
  successfully processed.

It turns out that (as made clear by the refactoring in 9537b2f), once
a task starts being processed it is expected to either complete
successfully (with the associated format being processed) or throw an
error (in which case the process will exit). In other words, a task's
processability is known in advance.

This commit takes advantage of this fact by moving certain checks
earlier in the process (e.g. in the analysis phase instead of the
compilation phase), which in turn allows avoiding some unnecessary work.
More specifically:

- When `compileAllFormats` is `false`, tasks are created _only_ for the
  first suitable format property for each entry-point, since the rest of
  the tasks would have been skipped during the compilation phase anyway.
  This has the following advantages:
  1. It avoids the slight overhead of generating extraneous tasks and
     then starting to process them (before realizing they should be
     skipped).
  2. In a potential future parallel execution mode, unnecessary tasks
     might start being processed at the same time as the first (useful)
     task, even if their output would be later discarded, wasting
     resources. Alternatively, extra logic would have to be added to
     prevent this from happening. The change in this commit avoids these
     issues.
- When an entry-point is not processable, an error will be thrown
  upfront without having to wait for other tasks to be processed before
  failing.

PR Close #32427

… types (#32427)

Previously, `ngcc` needed to store some metadata related to the
processing of each entry-point. This metadata was stored in a `Map`, in
the form of `EntryPointProcessingMetadata` and passed around as needed.

After some recent refactorings, it turns out that this metadata (with
its only remaining property, `hasProcessedTypings`) was no longer used,
because the relevant information was extracted from other sources (such
as the `processDts` property on `Task`s).

This commit cleans up the code by removing the unused code and types.

PR Close #32427

This change does not alter the current behavior, but makes it easier to
introduce `TaskQueue`s implementing different task selection algorithms,
for example to support executing multiple tasks in parallel (while
respecting interdependencies between them).

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd

PR Close #32427

…32427)

This commit adds a new `TaskQueue` implementation that supports
executing multiple tasks in parallel (while respecting interdependencies
between them).

This new implementation is currently not used, thus the behavior of
`ngcc` is not affected by this change. The parallel `TaskQueue` will be
used in a subsequent commit that will introduce parallel task execution.

PR Close #32427

`ngcc` supports both synchronous and asynchronous execution. The default
mode when using `ngcc` programmatically (which is how `@angular/cli` is
using it) is synchronous. When running `ngcc` from the command line
(i.e. via the `ivy-ngcc` script), it runs in async mode.

Previously, the work would be executed in the same way in both modes.

This commit improves the performance of `ngcc` in async mode by
processing tasks in parallel on multiple processes. It uses the Node.js
built-in [`cluster` module](https://nodejs.org/api/cluster.html) to
launch a cluster of Node.js processes and take advantage of multi-core
systems.

Preliminary comparisons indicate a 1.8x to 2.6x speed improvement when
processing the angular.io app (apparently depending on the OS, number of
available cores, system load, etc.). Further investigation is needed to
better understand these numbers and identify potential areas of
improvement.

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd
Original design doc: https://hackmd.io/uYG9CJrFQZ-6FtKqpnYJAA?view

Jira issue: [FW-1460](https://angular-team.atlassian.net/browse/FW-1460)

PR Close #32427

…tions (#32427)

This gives an overview of how much time is spent in each operation/phase
and makes it easy to do rough comparisons of how different
configurations or changes affect performance.

PR Close #32427

…ls (#32427)

PR Close #32427

…32427)

This commit addresses the review feedback from angular#32052, which was merged
before addressing the feedback there.

PR Close angular#32427

…the overwritten one (angular#32427)

In order to prevent `ngcc`'d packages (e.g. libraries) from getting
accidentally published, `ngcc` overwrites the `prepublishOnly` npm
script to log a warning and exit with an error. In case we want to
restore the original script (e.g. "undo" `ngcc` processing), we keep a
backup of the original `prepublishOnly` script.

Previously, running `ngcc` a second time (e.g. for a different format)
would create a backup of the overwritten `prepublishOnly` script (if
there was originally no `prepublishOnly` script). As a result, if we
ever tried to "undo" `ngcc` processing and restore the original
`prepublishOnly` script, the error-throwing script would be restored
instead.

This commit fixes it by ensuring that we only back up a `prepublishOnly`
script, iff it is not the one we created ourselves (i.e. the
error-throwing one).

PR Close angular#32427

…rface (angular#32427)

To persist some of its state, `ngcc` needs to update `package.json`
files (both in memory and on disk).

This refactoring abstracts these operations behind the
`PackageJsonUpdater` interface, making it easier to orchestrate them
from different contexts (e.g. when running tasks in parallel on multiple
processes).

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd

PR Close angular#32427

…face (angular#32427)

This change does not alter the current behavior, but makes it easier to
introduce new types of `Executors` , for example to do the required work
in parallel (on multiple processes).

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd

PR Close angular#32427

Previously, `ngcc`'s programmatic API would run and complete
synchronously. This was necessary for specific usecases (such as how the
`@angular/cli` invokes `ngcc` as part of the TypeScript module
resolution process), but not for others (e.g. running `ivy-ngcc` as a
`postinstall` script).

This commit adds a new option (`async`) that enables turning on
asynchronous execution. I.e. it signals that the caller is OK with the
function call to complete asynchronously, which allows `ngcc` to
potentially run in a more efficient mode.

Currently, there is no difference in the way tasks are executed in sync
vs async mode, but this change sets the ground for adding new execution
options (that require asynchronous operation), such as processing tasks
in parallel on multiple processes.

NOTE:
When using the programmatic API, the default value for `async` is
`false`, thus retaining backwards compatibility.
When running `ngcc` from the command line (i.e. via the `ivy-ngcc`
script), it runs in async mode (to be able to take advantage of future
optimizations), but that is transparent to the caller.

PR Close angular#32427

…ty processability (angular#32427)

In the past, a task's processability didn't use to be known in advance.
It was possible that a task would be created and added to the queue
during the analysis phase and then later (during the compilation phase)
it would be found out that the task (i.e. the associated format
property) was not processable.

As a result, certain checks had to be delayed, until a task's processing
had started or even until all tasks had been processed. Examples of
checks that had to be delayed are:
- Whether a task can be skipped due to `compileAllFormats: false`.
- Whether there were entry-points for which no format at all was
  successfully processed.

It turns out that (as made clear by the refactoring in 9537b2f), once
a task starts being processed it is expected to either complete
successfully (with the associated format being processed) or throw an
error (in which case the process will exit). In other words, a task's
processability is known in advance.

This commit takes advantage of this fact by moving certain checks
earlier in the process (e.g. in the analysis phase instead of the
compilation phase), which in turn allows avoiding some unnecessary work.
More specifically:

- When `compileAllFormats` is `false`, tasks are created _only_ for the
  first suitable format property for each entry-point, since the rest of
  the tasks would have been skipped during the compilation phase anyway.
  This has the following advantages:
  1. It avoids the slight overhead of generating extraneous tasks and
     then starting to process them (before realizing they should be
     skipped).
  2. In a potential future parallel execution mode, unnecessary tasks
     might start being processed at the same time as the first (useful)
     task, even if their output would be later discarded, wasting
     resources. Alternatively, extra logic would have to be added to
     prevent this from happening. The change in this commit avoids these
     issues.
- When an entry-point is not processable, an error will be thrown
  upfront without having to wait for other tasks to be processed before
  failing.

PR Close angular#32427

… types (angular#32427)

Previously, `ngcc` needed to store some metadata related to the
processing of each entry-point. This metadata was stored in a `Map`, in
the form of `EntryPointProcessingMetadata` and passed around as needed.

After some recent refactorings, it turns out that this metadata (with
its only remaining property, `hasProcessedTypings`) was no longer used,
because the relevant information was extracted from other sources (such
as the `processDts` property on `Task`s).

This commit cleans up the code by removing the unused code and types.

PR Close angular#32427

…32427)

This change does not alter the current behavior, but makes it easier to
introduce `TaskQueue`s implementing different task selection algorithms,
for example to support executing multiple tasks in parallel (while
respecting interdependencies between them).

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd

PR Close angular#32427

…ngular#32427)

This commit adds a new `TaskQueue` implementation that supports
executing multiple tasks in parallel (while respecting interdependencies
between them).

This new implementation is currently not used, thus the behavior of
`ngcc` is not affected by this change. The parallel `TaskQueue` will be
used in a subsequent commit that will introduce parallel task execution.

PR Close angular#32427

`ngcc` supports both synchronous and asynchronous execution. The default
mode when using `ngcc` programmatically (which is how `@angular/cli` is
using it) is synchronous. When running `ngcc` from the command line
(i.e. via the `ivy-ngcc` script), it runs in async mode.

Previously, the work would be executed in the same way in both modes.

This commit improves the performance of `ngcc` in async mode by
processing tasks in parallel on multiple processes. It uses the Node.js
built-in [`cluster` module](https://nodejs.org/api/cluster.html) to
launch a cluster of Node.js processes and take advantage of multi-core
systems.

Preliminary comparisons indicate a 1.8x to 2.6x speed improvement when
processing the angular.io app (apparently depending on the OS, number of
available cores, system load, etc.). Further investigation is needed to
better understand these numbers and identify potential areas of
improvement.

Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bd
Original design doc: https://hackmd.io/uYG9CJrFQZ-6FtKqpnYJAA?view

Jira issue: [FW-1460](https://angular-team.atlassian.net/browse/FW-1460)

PR Close angular#32427

…tions (angular#32427)

This gives an overview of how much time is spent in each operation/phase
and makes it easy to do rough comparisons of how different
configurations or changes affect performance.

PR Close angular#32427

…ls (angular#32427)

PR Close angular#32427