mirror of
https://github.com/denoland/deno
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![Bartek Iwańczuk](/assets/img/avatar_default.png)
This commit adds `--unstable-hmr` flag, that enabled Hot Module Replacement. This flag works like `--watch` and accepts the same arguments. If HMR is not possible the process will be restarted instead. Currently HMR is only supported in `deno run` subcommand. Upon HMR a `CustomEvent("hmr")` will be dispatched that contains information which file was changed in its `details` property. --------- Co-authored-by: Valentin Anger <syrupthinker@gryphno.de> Co-authored-by: David Sherret <dsherret@gmail.com>
134 lines
3.7 KiB
Rust
134 lines
3.7 KiB
Rust
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
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use crate::cache::EmitCache;
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use crate::cache::FastInsecureHasher;
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use crate::cache::ParsedSourceCache;
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use deno_core::error::AnyError;
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use deno_core::ModuleCode;
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use deno_core::ModuleSpecifier;
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use deno_graph::MediaType;
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use deno_graph::Module;
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use deno_graph::ModuleGraph;
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use std::sync::Arc;
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pub struct Emitter {
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emit_cache: EmitCache,
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parsed_source_cache: Arc<ParsedSourceCache>,
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emit_options: deno_ast::EmitOptions,
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// cached hash of the emit options
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emit_options_hash: u64,
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}
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impl Emitter {
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pub fn new(
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emit_cache: EmitCache,
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parsed_source_cache: Arc<ParsedSourceCache>,
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emit_options: deno_ast::EmitOptions,
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) -> Self {
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let emit_options_hash = FastInsecureHasher::hash(&emit_options);
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Self {
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emit_cache,
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parsed_source_cache,
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emit_options,
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emit_options_hash,
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}
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}
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pub fn cache_module_emits(
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&self,
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graph: &ModuleGraph,
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) -> Result<(), AnyError> {
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for module in graph.modules() {
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if let Module::Esm(module) = module {
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let is_emittable = matches!(
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module.media_type,
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MediaType::TypeScript
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| MediaType::Mts
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| MediaType::Cts
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| MediaType::Jsx
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| MediaType::Tsx
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);
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if is_emittable {
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self.emit_parsed_source(
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&module.specifier,
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module.media_type,
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&module.source,
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)?;
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}
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}
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}
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Ok(())
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}
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/// Gets a cached emit if the source matches the hash found in the cache.
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pub fn maybe_cached_emit(
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&self,
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specifier: &ModuleSpecifier,
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source: &str,
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) -> Option<String> {
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let source_hash = self.get_source_hash(source);
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self.emit_cache.get_emit_code(specifier, source_hash)
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}
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pub fn emit_parsed_source(
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&self,
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specifier: &ModuleSpecifier,
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media_type: MediaType,
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source: &Arc<str>,
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) -> Result<ModuleCode, AnyError> {
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let source_hash = self.get_source_hash(source);
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if let Some(emit_code) =
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self.emit_cache.get_emit_code(specifier, source_hash)
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{
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Ok(emit_code.into())
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} else {
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// this will use a cached version if it exists
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let parsed_source = self.parsed_source_cache.get_or_parse_module(
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specifier,
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source.clone(),
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media_type,
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)?;
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let transpiled_source = parsed_source.transpile(&self.emit_options)?;
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debug_assert!(transpiled_source.source_map.is_none());
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self.emit_cache.set_emit_code(
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specifier,
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source_hash,
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&transpiled_source.text,
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);
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Ok(transpiled_source.text.into())
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}
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}
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/// Expects a file URL, panics otherwise.
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pub async fn load_and_emit_for_hmr(
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&self,
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specifier: &ModuleSpecifier,
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) -> Result<String, AnyError> {
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let media_type = MediaType::from_specifier(specifier);
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let source_code = tokio::fs::read_to_string(
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ModuleSpecifier::to_file_path(specifier).unwrap(),
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)
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.await?;
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let source_arc: Arc<str> = source_code.into();
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let parsed_source = self
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.parsed_source_cache
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.get_or_parse_module(specifier, source_arc, media_type)?;
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let mut options = self.emit_options.clone();
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options.inline_source_map = false;
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let transpiled_source = parsed_source.transpile(&options)?;
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Ok(transpiled_source.text)
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}
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/// A hashing function that takes the source code and uses the global emit
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/// options then generates a string hash which can be stored to
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/// determine if the cached emit is valid or not.
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fn get_source_hash(&self, source_text: &str) -> u64 {
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FastInsecureHasher::new()
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.write_str(source_text)
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.write_u64(self.emit_options_hash)
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.finish()
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}
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}
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