When profiling ngcc it is notable that a large amount of time
is spent dealing with an exception that is thrown (and handled
internally by fs) when checking the existence of a file.
We check file existence a lot in both finding entry-points
and when TS is compiling code. This commit adds a simple
cached `FileSystem`, which wraps a real `FileSystem` delegate.
This will reduce the number of calls through to `fs.exists()` and
`fs.readFile()` on the delegate.
Initial benchmarks indicate that the cache is miss to hit ratio
for `exists()` is about 2:1, which means that we save about 1/3
of the calls to `fs.existsSync()`.
Note that this implements a "non-expiring" cache, so it is not suitable
for a long lived `FileSystem`, where files may be modified externally.
The cache will be updated if a file is changed or moved via
calls to `FileSystem` methods but it will not be aware of changes
to the files system from outside the `FileSystem` service.
For ngcc we must create a new `FileSystem` service
for each run of `mainNgcc` and ensure that all file operations
(including TS compilation) use the `FileSystem` service.
This ensures that it is very unlikely that a file will change
externally during `mainNgcc` processing.
PR Close#30525
To improve cross platform support, all file access (and path manipulation)
is now done through a well known interface (`FileSystem`).
For testing a number of `MockFileSystem` implementations are provided.
These provide an in-memory file-system which emulates operating systems
like OS/X, Unix and Windows.
The current file system is always available via the static method,
`FileSystem.getFileSystem()`. This is also used by a number of static
methods on `AbsoluteFsPath` and `PathSegment`, to avoid having to pass
`FileSystem` objects around all the time. The result of this is that one
must be careful to ensure that the file-system has been initialized before
using any of these static methods. To prevent this happening accidentally
the current file system always starts out as an instance of `InvalidFileSystem`,
which will throw an error if any of its methods are called.
You can set the current file-system by calling `FileSystem.setFileSystem()`.
During testing you can call the helper function `initMockFileSystem(os)`
which takes a string name of the OS to emulate, and will also monkey-patch
aspects of the TypeScript library to ensure that TS is also using the
current file-system.
Finally there is the `NgtscCompilerHost` to be used for any TypeScript
compilation, which uses a given file-system.
All tests that interact with the file-system should be tested against each
of the mock file-systems. A series of helpers have been provided to support
such tests:
* `runInEachFileSystem()` - wrap your tests in this helper to run all the
wrapped tests in each of the mock file-systems.
* `addTestFilesToFileSystem()` - use this to add files and their contents
to the mock file system for testing.
* `loadTestFilesFromDisk()` - use this to load a mirror image of files on
disk into the in-memory mock file-system.
* `loadFakeCore()` - use this to load a fake version of `@angular/core`
into the mock file-system.
All ngcc and ngtsc source and tests now use this virtual file-system setup.
PR Close#30921
Now the public API does not contain internal types, such as `AbsoluteFsPath` and
`EntryPointJsonProperty`. Instead we just accept strings and then guard them in
`mainNgcc` as appropriate.
A new public API function (`hasBeenProcessed`) has been exported to allow programmatic
checking of the build marker when the package.json contents are already known.
PR Close#29092
By default ngcc will compile all the format properties specified. With this
change you can configure ngcc so that it will stop compiling an entry-point
after the first property that matches the `propertiesToConsider`.
PR Close#29092
Now that we are using package.json properties to indicate which
entry-point format to compile, it turns out that we don't really
need to distinguish between flat and non-flat formats, unless we
are compiling `@angular/core`.
PR Close#29092
You can now specify a list of properties in the package.json that
should be considered (in order) to find the path to the format to compile.
The build marker system has been updated to store the markers in
the package.json rather than an additional external file.
Also instead of tracking the underlying bundle format that was compiled,
it now tracks the package.json property.
BREAKING CHANGE:
The `proertiesToConsider` option replaces the previous `formats` option,
which specified the final bundle format, rather than the property in the
package.json.
If you were using this option to compile only specific bundle formats,
you must now modify your usage to pass in the properties in the package.json
that map to the format that you wish to compile.
In the CLI, the `--formats` is no longer available. Instead use the
`--properties` option.
FW-1120
PR Close#29092
The `mainNgcc()` function has been refactored to make it easier to call
ngcc from JavaScript, rather than via the command line.
For example, the `yargs` argument parsing and the exception
handling/logging have moved to the `main-ngcc.ts`
file so that it is only used for the command line version.
FW-1118
PR Close#29092
Pete Bacon Darwin