feat: parallelize downloads from TS compiler (#2949)

9 files changed, 137 insertions, 78 deletions

diff --git a/cli/ops/compiler.rs b/cli/ops/compiler.rs
index 40d25aa74..975e01ee1 100644
--- a/cli/ops/compiler.rs
+++ b/cli/ops/compiler.rs
@@ -33,39 +33,49 @@ pub fn op_cache(
 }
 
 #[derive(Deserialize)]
-struct FetchSourceFileArgs {
-  specifier: String,
+struct FetchSourceFilesArgs {
+  specifiers: Vec<String>,
   referrer: String,
 }
 
-pub fn op_fetch_source_file(
+pub fn op_fetch_source_files(
   state: &ThreadSafeState,
   args: Value,
   _zero_copy: Option<PinnedBuf>,
 ) -> Result<JsonOp, ErrBox> {
-  let args: FetchSourceFileArgs = serde_json::from_value(args)?;
+  let args: FetchSourceFilesArgs = serde_json::from_value(args)?;
 
   // TODO(ry) Maybe a security hole. Only the compiler worker should have access
   // to this. Need a test to demonstrate the hole.
   let is_dyn_import = false;
 
-  let resolved_specifier =
-    state.resolve(&args.specifier, &args.referrer, false, is_dyn_import)?;
-
-  let fut = state
-    .file_fetcher
-    .fetch_source_file_async(&resolved_specifier);
+  let mut futures = vec![];
+  for specifier in &args.specifiers {
+    let resolved_specifier =
+      state.resolve(specifier, &args.referrer, false, is_dyn_import)?;
+    let fut = state
+      .file_fetcher
+      .fetch_source_file_async(&resolved_specifier);
+    futures.push(fut);
+  }
 
   // WARNING: Here we use tokio_util::block_on() which starts a new Tokio
-  // runtime for executing the future. This is so we don't inadvernently run
+  // runtime for executing the future. This is so we don't inadvertently run
   // out of threads in the main runtime.
-  let out = tokio_util::block_on(fut)?;
-  Ok(JsonOp::Sync(json!({
-    "moduleName": out.url.to_string(),
-    "filename": out.filename.to_str().unwrap(),
-    "mediaType": out.media_type as i32,
-    "sourceCode": String::from_utf8(out.source_code).unwrap(),
-  })))
+  let files = tokio_util::block_on(futures::future::join_all(futures))?;
+  let res: Vec<serde_json::value::Value> = files
+    .into_iter()
+    .map(|file| {
+      json!({
+        "moduleName": file.url.to_string(),
+        "filename": file.filename.to_str().unwrap(),
+        "mediaType": file.media_type as i32,
+        "sourceCode": String::from_utf8(file.source_code).unwrap(),
+      })
+    })
+    .collect();
+
+  Ok(JsonOp::Sync(json!(res)))
 }
 
 #[derive(Deserialize)]
diff --git a/cli/ops/mod.rs b/cli/ops/mod.rs
index 1f07acc65..7a2e9c9f4 100644
--- a/cli/ops/mod.rs
+++ b/cli/ops/mod.rs
@@ -37,7 +37,7 @@ pub const OP_START: OpId = 10;
 pub const OP_APPLY_SOURCE_MAP: OpId = 11;
 pub const OP_FORMAT_ERROR: OpId = 12;
 pub const OP_CACHE: OpId = 13;
-pub const OP_FETCH_SOURCE_FILE: OpId = 14;
+pub const OP_FETCH_SOURCE_FILES: OpId = 14;
 pub const OP_OPEN: OpId = 15;
 pub const OP_CLOSE: OpId = 16;
 pub const OP_SEEK: OpId = 17;
@@ -133,8 +133,8 @@ pub fn dispatch(
     OP_CACHE => {
       dispatch_json::dispatch(compiler::op_cache, state, control, zero_copy)
     }
-    OP_FETCH_SOURCE_FILE => dispatch_json::dispatch(
-      compiler::op_fetch_source_file,
+    OP_FETCH_SOURCE_FILES => dispatch_json::dispatch(
+      compiler::op_fetch_source_files,
       state,
       control,
       zero_copy,
diff --git a/js/compiler.ts b/js/compiler.ts
index 41f23bcd2..1e1fe3dd3 100644
--- a/js/compiler.ts
+++ b/js/compiler.ts
@@ -136,18 +136,25 @@ function fetchAsset(name: string): string {
   return sendSync(dispatch.OP_FETCH_ASSET, { name });
 }
 
-/** Ops to Rust to resolve and fetch a modules meta data. */
-function fetchSourceFile(specifier: string, referrer: string): SourceFile {
-  util.log("compiler.fetchSourceFile", { specifier, referrer });
-  const res = sendSync(dispatch.OP_FETCH_SOURCE_FILE, {
-    specifier,
+/** Ops to Rust to resolve and fetch modules meta data. */
+function fetchSourceFiles(
+  specifiers: string[],
+  referrer: string
+): SourceFile[] {
+  util.log("compiler.fetchSourceFiles", { specifiers, referrer });
+  const res = sendSync(dispatch.OP_FETCH_SOURCE_FILES, {
+    specifiers,
     referrer
   });
 
-  return {
-    ...res,
-    typeDirectives: parseTypeDirectives(res.sourceCode)
-  };
+  return res.map(
+    (sourceFile: SourceFile): SourceFile => {
+      return {
+        ...sourceFile,
+        typeDirectives: parseTypeDirectives(sourceFile.sourceCode)
+      };
+    }
+  );
 }
 
 /** Utility function to turn the number of bytes into a human readable
@@ -219,34 +226,69 @@ class Host implements ts.CompilerHost {
 
   private _sourceFileCache: Record<string, SourceFile> = {};
 
+  private _getAsset(specifier: string): SourceFile {
+    const moduleName = specifier.split("/").pop()!;
+    if (moduleName in this._sourceFileCache) {
+      return this._sourceFileCache[moduleName];
+    }
+    const assetName = moduleName.includes(".")
+      ? moduleName
+      : `${moduleName}.d.ts`;
+    const sourceCode = fetchAsset(assetName);
+    const sourceFile = {
+      moduleName,
+      filename: specifier,
+      mediaType: MediaType.TypeScript,
+      sourceCode
+    };
+    this._sourceFileCache[moduleName] = sourceFile;
+    return sourceFile;
+  }
+
   private _resolveModule(specifier: string, referrer: string): SourceFile {
-    util.log("host._resolveModule", { specifier, referrer });
-    // Handle built-in assets specially.
-    if (specifier.startsWith(ASSETS)) {
-      const moduleName = specifier.split("/").pop()!;
-      if (moduleName in this._sourceFileCache) {
-        return this._sourceFileCache[moduleName];
+    return this._resolveModules([specifier], referrer)[0];
+  }
+
+  private _resolveModules(
+    specifiers: string[],
+    referrer: string
+  ): SourceFile[] {
+    util.log("host._resolveModules", { specifiers, referrer });
+    const resolvedModules: Array<SourceFile | undefined> = [];
+    const modulesToRequest = [];
+
+    for (const specifier of specifiers) {
+      // Firstly built-in assets are handled specially, so they should
+      // be removed from array of files that we'll be requesting from Rust.
+      if (specifier.startsWith(ASSETS)) {
+        const assetFile = this._getAsset(specifier);
+        resolvedModules.push(assetFile);
+      } else if (specifier in this._sourceFileCache) {
+        const module = this._sourceFileCache[specifier];
+        resolvedModules.push(module);
+      } else {
+        // Temporarily fill with undefined, after fetching file from
+        // Rust it will be filled with proper value.
+        resolvedModules.push(undefined);
+        modulesToRequest.push(specifier);
       }
-      const assetName = moduleName.includes(".")
-        ? moduleName
-        : `${moduleName}.d.ts`;
-      const sourceCode = fetchAsset(assetName);
-      const sourceFile = {
-        moduleName,
-        filename: specifier,
-        mediaType: MediaType.TypeScript,
-        sourceCode
-      };
-      this._sourceFileCache[moduleName] = sourceFile;
-      return sourceFile;
     }
-    const sourceFile = fetchSourceFile(specifier, referrer);
-    assert(sourceFile.moduleName != null);
-    const { moduleName } = sourceFile;
-    if (!(moduleName! in this._sourceFileCache)) {
-      this._sourceFileCache[moduleName!] = sourceFile;
+
+    // Now get files from Rust.
+    const sourceFiles = fetchSourceFiles(modulesToRequest, referrer);
+
+    for (const sourceFile of sourceFiles) {
+      assert(sourceFile.moduleName != null);
+      const { moduleName } = sourceFile;
+      if (!(moduleName! in this._sourceFileCache)) {
+        this._sourceFileCache[moduleName!] = sourceFile;
+      }
+      // And fill temporary `undefined`s with actual files.
+      const index = resolvedModules.indexOf(undefined);
+      resolvedModules[index] = sourceFile;
     }
-    return sourceFile;
+
+    return resolvedModules as SourceFile[];
   }
 
   /* Deno specific APIs */
@@ -371,22 +413,25 @@ class Host implements ts.CompilerHost {
       containingFile in this._sourceFileCache
         ? this._sourceFileCache[containingFile].typeDirectives
         : undefined;
-    return moduleNames.map(
-      (moduleName): ts.ResolvedModuleFull | undefined => {
-        const mappedModuleName = getMappedModuleName(
-          moduleName,
-          containingFile,
-          typeDirectives
-        );
-        const sourceFile = this._resolveModule(
-          mappedModuleName,
-          containingFile
-        );
+
+    const mappedModuleNames = moduleNames.map(
+      (moduleName: string): string => {
+        return getMappedModuleName(moduleName, containingFile, typeDirectives);
+      }
+    );
+
+    return this._resolveModules(mappedModuleNames, containingFile).map(
+      (
+        sourceFile: SourceFile,
+        index: number
+      ): ts.ResolvedModuleFull | undefined => {
         if (sourceFile.moduleName) {
           const resolvedFileName = sourceFile.moduleName;
           // This flags to the compiler to not go looking to transpile functional
           // code, anything that is in `/$asset$/` is just library code
-          const isExternalLibraryImport = moduleName.startsWith(ASSETS);
+          const isExternalLibraryImport = mappedModuleNames[index].startsWith(
+            ASSETS
+          );
           const extension = getExtension(
             resolvedFileName,
             sourceFile.mediaType
diff --git a/js/dispatch.ts b/js/dispatch.ts
index 1a60a5363..a15da69f4 100644
--- a/js/dispatch.ts
+++ b/js/dispatch.ts
@@ -16,7 +16,7 @@ export const OP_START = 10;
 export const OP_APPLY_SOURCE_MAP = 11;
 export const OP_FORMAT_ERROR = 12;
 export const OP_CACHE = 13;
-export const OP_FETCH_SOURCE_FILE = 14;
+export const OP_FETCH_SOURCE_FILES = 14;
 export const OP_OPEN = 15;
 export const OP_CLOSE = 16;
 export const OP_SEEK = 17;
diff --git a/tests/error_004_missing_module.ts.out b/tests/error_004_missing_module.ts.out
index db56f51a5..c2a0d0208 100644
--- a/tests/error_004_missing_module.ts.out
+++ b/tests/error_004_missing_module.ts.out
@@ -3,10 +3,10 @@
     at DenoError ([WILDCARD]errors.ts:[WILDCARD])
     at unwrapResponse ([WILDCARD]dispatch_json.ts:[WILDCARD])
     at sendSync[WILDCARD] ([WILDCARD]dispatch_json.ts:[WILDCARD])
-    at fetchSourceFile ([WILDCARD]compiler.ts:[WILDCARD])
-    at _resolveModule ([WILDCARD]compiler.ts:[WILDCARD])
-    at [WILDCARD]compiler.ts:[WILDCARD]
+    at fetchSourceFiles ([WILDCARD]compiler.ts:[WILDCARD])
+    at _resolveModules ([WILDCARD]compiler.ts:[WILDCARD])
     at resolveModuleNames ([WILDCARD]compiler.ts:[WILDCARD])
     at resolveModuleNamesWorker ([WILDCARD]typescript.js:[WILDCARD])
     at resolveModuleNamesReusingOldState ([WILDCARD]typescript.js:[WILDCARD])
     at processImportedModules ([WILDCARD]typescript.js:[WILDCARD])
+    at findSourceFile ([WILDCARD]typescript.js:[WILDCARD])
diff --git a/tests/error_005_missing_dynamic_import.ts.out b/tests/error_005_missing_dynamic_import.ts.out
index eb1d7b7b1..ec1468b09 100644
--- a/tests/error_005_missing_dynamic_import.ts.out
+++ b/tests/error_005_missing_dynamic_import.ts.out
@@ -3,9 +3,10 @@
     at DenoError ([WILDCARD]errors.ts:[WILDCARD])
     at unwrapResponse ([WILDCARD]dispatch_json.ts:[WILDCARD])
     at sendSync[WILDCARD] ([WILDCARD]dispatch_json.ts:[WILDCARD])
-    at fetchSourceFile ([WILDCARD]compiler.ts:[WILDCARD])
-    at _resolveModule ([WILDCARD]compiler.ts:[WILDCARD])
+    at fetchSourceFiles ([WILDCARD]compiler.ts:[WILDCARD])
+    at _resolveModules ([WILDCARD]compiler.ts:[WILDCARD])
     at [WILDCARD]compiler.ts:[WILDCARD]
     at resolveModuleNamesWorker ([WILDCARD])
     at resolveModuleNamesReusingOldState ([WILDCARD]typescript.js:[WILDCARD])
     at processImportedModules ([WILDCARD]typescript.js:[WILDCARD])
+    at findSourceFile ([WILDCARD]typescript.js:[WILDCARD])
diff --git a/tests/error_006_import_ext_failure.ts.out b/tests/error_006_import_ext_failure.ts.out
index d0e14520b..aa82c10aa 100644
--- a/tests/error_006_import_ext_failure.ts.out
+++ b/tests/error_006_import_ext_failure.ts.out
@@ -3,9 +3,10 @@
     at DenoError ([WILDCARD]errors.ts:[WILDCARD])
     at unwrapResponse ([WILDCARD]dispatch_json.ts:[WILDCARD])
     at sendSync[WILDCARD] ([WILDCARD]dispatch_json.ts:[WILDCARD])
-    at fetchSourceFile ([WILDCARD]compiler.ts:[WILDCARD])
-    at _resolveModule ([WILDCARD]compiler.ts:[WILDCARD])
+    at fetchSourceFiles ([WILDCARD]compiler.ts:[WILDCARD])
+    at _resolveModules ([WILDCARD]compiler.ts:[WILDCARD])
     at [WILDCARD]compiler.ts:[WILDCARD]
     at resolveModuleNamesWorker ([WILDCARD])
     at resolveModuleNamesReusingOldState ([WILDCARD]typescript.js:[WILDCARD])
     at processImportedModules ([WILDCARD]typescript.js:[WILDCARD])
+    at findSourceFile ([WILDCARD]typescript.js:[WILDCARD])
diff --git a/tests/error_011_bad_module_specifier.ts.out b/tests/error_011_bad_module_specifier.ts.out
index 9918c503c..97f59f2ca 100644
--- a/tests/error_011_bad_module_specifier.ts.out
+++ b/tests/error_011_bad_module_specifier.ts.out
@@ -3,9 +3,10 @@
     at DenoError ([WILDCARD]errors.ts:[WILDCARD])
     at unwrapResponse ([WILDCARD]dispatch_json.ts:[WILDCARD])
     at sendSync[WILDCARD] ([WILDCARD]dispatch_json.ts:[WILDCARD])
-    at fetchSourceFile ([WILDCARD]compiler.ts:[WILDCARD])
-    at _resolveModule ([WILDCARD]compiler.ts:[WILDCARD])
+    at fetchSourceFiles ([WILDCARD]compiler.ts:[WILDCARD])
+    at _resolveModules ([WILDCARD]compiler.ts:[WILDCARD])
     at [WILDCARD]compiler.ts:[WILDCARD]
     at resolveModuleNamesWorker ([WILDCARD])
     at resolveModuleNamesReusingOldState ([WILDCARD]typescript.js:[WILDCARD])
     at processImportedModules ([WILDCARD]typescript.js:[WILDCARD])
+    at findSourceFile ([WILDCARD]typescript.js:[WILDCARD])
diff --git a/tests/error_012_bad_dynamic_import_specifier.ts.out b/tests/error_012_bad_dynamic_import_specifier.ts.out
index 9918c503c..97f59f2ca 100644
--- a/tests/error_012_bad_dynamic_import_specifier.ts.out
+++ b/tests/error_012_bad_dynamic_import_specifier.ts.out
@@ -3,9 +3,10 @@
     at DenoError ([WILDCARD]errors.ts:[WILDCARD])
     at unwrapResponse ([WILDCARD]dispatch_json.ts:[WILDCARD])
     at sendSync[WILDCARD] ([WILDCARD]dispatch_json.ts:[WILDCARD])
-    at fetchSourceFile ([WILDCARD]compiler.ts:[WILDCARD])
-    at _resolveModule ([WILDCARD]compiler.ts:[WILDCARD])
+    at fetchSourceFiles ([WILDCARD]compiler.ts:[WILDCARD])
+    at _resolveModules ([WILDCARD]compiler.ts:[WILDCARD])
     at [WILDCARD]compiler.ts:[WILDCARD]
     at resolveModuleNamesWorker ([WILDCARD])
     at resolveModuleNamesReusingOldState ([WILDCARD]typescript.js:[WILDCARD])
     at processImportedModules ([WILDCARD]typescript.js:[WILDCARD])
+    at findSourceFile ([WILDCARD]typescript.js:[WILDCARD])