Add resolver trait and placeholders (#9725)

Author: MonicaOlejniczak

crates/parcel_core/src/bundle_graph.rs

@@ -0,0 +1 @@
+pub struct BundleGraph {}

crates/parcel_core/src/lib.rs

@@ -1,6 +1,8 @@
 //! Core re-implementation in Rust
 
+pub mod bundle_graph;
 pub mod hash;
+pub mod plugin;
 pub mod types;
 
 /// New-type for paths relative to a project-root

crates/parcel_core/src/plugin.rs

@@ -0,0 +1,38 @@
+mod bundler;
+pub use bundler::*;
+
+mod compressor;
+pub use compressor::*;
+
+mod namer;
+pub use namer::*;
+
+mod optimizer;
+pub use optimizer::*;
+
+mod packager;
+pub use packager::*;
+
+mod reporter;
+pub use reporter::*;
+
+mod resolver;
+pub use resolver::*;
+
+mod runtime;
+pub use runtime::*;
+
+mod transformer;
+pub use transformer::*;
+
+mod validator;
+pub use validator::*;
+
+pub struct PluginContext {
+  pub options: PluginOptions,
+  pub logger: PluginLogger,
+}
+
+pub struct PluginLogger {}
+
+pub struct PluginOptions {}

crates/parcel_core/src/plugin/bundler.rs

@@ -0,0 +1,8 @@
+/// Converts an asset graph into a BundleGraph
+///
+/// Bundlers accept the entire asset graph and modify it to add bundle nodes that group the assets
+/// into output bundles.
+///
+/// Bundle and optimize run in series and are functionally identitical.
+///
+pub trait BundlerPlugin {}

crates/parcel_core/src/plugin/compressor.rs

@@ -0,0 +1,2 @@
+/// Compresses the input file stream
+pub trait CompressorPlugin {}

crates/parcel_core/src/plugin/namer.rs

@@ -0,0 +1,5 @@
+/// Determines the output filename for a bundle
+///
+/// Namers run in a pipeline until one returns a result.
+///
+pub trait NamerPlugin {}

crates/parcel_core/src/plugin/optimizer.rs

@@ -0,0 +1,11 @@
+/// Optimises a bundle
+///
+/// Optimizers are commonly used to implement minification, tree shaking, dead code elimination,
+/// and other size reduction techniques that need a full bundle to be effective. However,
+/// optimizers can also be used for any type of bundle transformation, such as prepending license
+/// headers, converting inline bundles to base 64, etc.
+///
+/// Multiple optimizer plugins may run in series, and the result of each optimizer is passed to
+/// the next.
+///
+pub trait OptimizerPlugin: Send + Sync {}

crates/parcel_core/src/plugin/packager.rs

@@ -0,0 +1,6 @@
+/// Combines all the assets in a bundle together into an output file
+///
+/// Packagers are also responsible for resolving URL references, bundle inlining, and generating
+/// source maps.
+///
+pub trait PackagerPlugin: Send + Sync {}

crates/parcel_core/src/plugin/reporter.rs

@@ -0,0 +1,6 @@
+/// Receives events from Parcel as they occur throughout the build process
+///
+/// For example, reporters may write status information to stdout, run a dev server, or generate a
+/// bundle analysis report at the end of a build.
+///
+pub trait ReporterPlugin {}

crates/parcel_core/src/plugin/resolver.rs

@@ -0,0 +1,55 @@
+use std::path::PathBuf;
+
+use super::PluginContext;
+use crate::types::Dependency;
+use crate::types::JSONObject;
+use crate::types::Priority;
+
+// TODO Diagnostics and invalidations
+
+pub struct Resolution {
+  /// Whether this dependency can be deferred by Parcel itself
+  pub can_defer: bool,
+
+  /// The code of the resolved asset
+  ///
+  /// If provided, this is used rather than reading the file from disk.
+  ///
+  pub code: Option<String>,
+
+  /// An absolute path to the resolved file
+  pub file_path: PathBuf,
+
+  /// Whether the resolved file should be excluded from the build
+  pub is_excluded: bool,
+
+  /// Is spread (shallowly merged) onto the request's dependency.meta
+  pub meta: JSONObject,
+
+  /// An optional named pipeline to use to compile the resolved file
+  pub pipeline: Option<String>,
+
+  /// Overrides the priority set on the dependency
+  pub priority: Option<Priority>,
+
+  /// Corresponds to the asset side effects
+  pub side_effects: bool,
+
+  /// Query parameters to be used by transformers when compiling the resolved file
+  pub query: Option<String>,
+}
+
+/// Converts a dependency specifier into a file path that will be processed by transformers
+///
+/// Resolvers run in a pipeline until one of them return a result.
+///
+pub trait ResolverPlugin: Send + Sync {
+  /// Determines what the dependency specifier resolves to
+  fn resolve(
+    &self,
+    specifier: &str,
+    dependency: &Dependency,
+    pipeline: Option<&str>,
+    context: &PluginContext,
+  ) -> Result<Resolution, anyhow::Error>;
+}

crates/parcel_core/src/plugin/runtime.rs

@@ -0,0 +1,2 @@
+/// Programmatically insert assets into bundles
+pub trait RuntimePlugin {}

crates/parcel_core/src/plugin/transformer.rs

@@ -0,0 +1,6 @@
+/// Compile a single asset, discover dependencies, or convert the asset to a different format
+///
+/// Many transformers are wrappers around other tools such as compilers and preprocessors, and are
+/// designed to integrate with Parcel.
+///
+pub trait TransformerPlugin: Send + Sync {}

crates/parcel_core/src/plugin/validator.rs

@@ -0,0 +1,13 @@
+/// Analyzes assets to ensure they are in a valid state
+///
+/// Validators may throw errors or log warnings to indicate an asset is invalid. They can be used
+/// to verify linting, type safety, etc and are run after a build has completed. This enables more
+/// important compilation errors to occur first.
+///
+/// When Parcel runs in watch mode, the built bundles are served even if a validator throws an
+/// error. But when running a build, Parcel exits with a failure and status code to ensure code is
+/// not deployed for assets that do not meet the validation criteria. This ensures developers
+/// remain productive, and do not have to worry about every small typing or linting issue while
+/// trying to solve a problem.
+///
+pub trait ValidatorPlugin {}

crates/parcel_core/src/types/source.rs

@@ -25,3 +25,5 @@ pub struct SourceLocation {
   /// The final location in the source code
   pub end: Location,
 }
+
+pub struct SourceMap {}