feat: emit files on demand and fix racy emit (#15220)

cli/module_loader.rs

@@ -1,20 +1,36 @@
 // Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
 
+use crate::emit::emit_parsed_source;
 use crate::emit::TsTypeLib;
+use crate::graph_util::ModuleEntry;
 use crate::proc_state::ProcState;
+use crate::text_encoding::code_without_source_map;
+use crate::text_encoding::source_map_from_code;
 
+use deno_ast::MediaType;
+use deno_core::anyhow::anyhow;
 use deno_core::error::AnyError;
 use deno_core::futures::future::FutureExt;
 use deno_core::futures::Future;
+use deno_core::resolve_url;
 use deno_core::ModuleLoader;
+use deno_core::ModuleSource;
 use deno_core::ModuleSpecifier;
+use deno_core::ModuleType;
 use deno_core::OpState;
+use deno_core::SourceMapGetter;
 use deno_runtime::permissions::Permissions;
 use std::cell::RefCell;
 use std::pin::Pin;
 use std::rc::Rc;
 use std::str;
 
+struct ModuleCodeSource {
+  pub code: String,
+  pub found_url: ModuleSpecifier,
+  pub media_type: MediaType,
+}
+
 pub struct CliModuleLoader {
   pub lib: TsTypeLib,
   /// The initial set of permissions used to resolve the static imports in the
@@ -40,6 +56,65 @@ impl CliModuleLoader {
       ps,
     })
   }
+
+  fn load_prepared_module(
+    &self,
+    specifier: &ModuleSpecifier,
+  ) -> Result<ModuleCodeSource, AnyError> {
+    let graph_data = self.ps.graph_data.read();
+    let found_url = graph_data.follow_redirect(specifier);
+    match graph_data.get(&found_url) {
+      Some(ModuleEntry::Module {
+        code,
+        media_type,
+        maybe_parsed_source,
+        ..
+      }) => {
+        let code = match media_type {
+          MediaType::JavaScript
+          | MediaType::Unknown
+          | MediaType::Cjs
+          | MediaType::Mjs
+          | MediaType::Json => {
+            if let Some(source) = graph_data.get_cjs_esm_translation(specifier)
+            {
+              source.to_owned()
+            } else {
+              code.to_string()
+            }
+          }
+          MediaType::Dts | MediaType::Dcts | MediaType::Dmts => "".to_string(),
+          MediaType::TypeScript
+          | MediaType::Mts
+          | MediaType::Cts
+          | MediaType::Jsx
+          | MediaType::Tsx => {
+            // get emit text
+            let parsed_source = maybe_parsed_source.as_ref().unwrap(); // should always be set
+            emit_parsed_source(
+              &self.ps.emit_cache,
+              &found_url,
+              parsed_source,
+              &self.ps.emit_options,
+              self.ps.emit_options_hash,
+            )?
+          }
+          MediaType::TsBuildInfo | MediaType::Wasm | MediaType::SourceMap => {
+            panic!("Unexpected media type {} for {}", media_type, found_url)
+          }
+        };
+        Ok(ModuleCodeSource {
+          code,
+          found_url,
+          media_type: *media_type,
+        })
+      }
+      _ => Err(anyhow!(
+        "Loading unprepared module: {}",
+        specifier.to_string()
+      )),
+    }
+  }
 }
 
 impl ModuleLoader for CliModuleLoader {
@@ -54,18 +129,35 @@ impl ModuleLoader for CliModuleLoader {
 
   fn load(
     &self,
-    module_specifier: &ModuleSpecifier,
-    maybe_referrer: Option<ModuleSpecifier>,
-    is_dynamic: bool,
+    specifier: &ModuleSpecifier,
+    _maybe_referrer: Option<ModuleSpecifier>,
+    _is_dynamic: bool,
   ) -> Pin<Box<deno_core::ModuleSourceFuture>> {
-    let module_specifier = module_specifier.clone();
-    let ps = self.ps.clone();
-
     // NOTE: this block is async only because of `deno_core` interface
     // requirements; module was already loaded when constructing module graph
-    // during call to `prepare_load`.
-    async move { ps.load(module_specifier, maybe_referrer, is_dynamic) }
-      .boxed_local()
+    // during call to `prepare_load` so we can load it synchronously.
+    let result = self.load_prepared_module(specifier).map(|code_source| {
+      let code = if self.ps.options.is_inspecting() {
+        // we need the code with the source map in order for
+        // it to work with --inspect or --inspect-brk
+        code_source.code
+      } else {
+        // reduce memory and throw away the source map
+        // because we don't need it
+        code_without_source_map(code_source.code)
+      };
+      ModuleSource {
+        code: code.into_bytes().into_boxed_slice(),
+        module_url_specified: specifier.to_string(),
+        module_url_found: code_source.found_url.to_string(),
+        module_type: match code_source.media_type {
+          MediaType::Json => ModuleType::Json,
+          _ => ModuleType::JavaScript,
+        },
+      }
+    });
+
+    Box::pin(deno_core::futures::future::ready(result))
   }
 
   fn prepare_load(
@@ -103,3 +195,47 @@ impl ModuleLoader for CliModuleLoader {
     .boxed_local()
   }
 }
+
+impl SourceMapGetter for CliModuleLoader {
+  fn get_source_map(&self, file_name: &str) -> Option<Vec<u8>> {
+    if let Ok(specifier) = resolve_url(file_name) {
+      match specifier.scheme() {
+        // we should only be looking for emits for schemes that denote external
+        // modules, which the disk_cache supports
+        "wasm" | "file" | "http" | "https" | "data" | "blob" => (),
+        _ => return None,
+      }
+      if let Ok(source) = self.load_prepared_module(&specifier) {
+        source_map_from_code(&source.code)
+      } else {
+        None
+      }
+    } else {
+      None
+    }
+  }
+
+  fn get_source_line(
+    &self,
+    file_name: &str,
+    line_number: usize,
+  ) -> Option<String> {
+    let graph_data = self.ps.graph_data.read();
+    let specifier = graph_data.follow_redirect(&resolve_url(file_name).ok()?);
+    let code = match graph_data.get(&specifier) {
+      Some(ModuleEntry::Module { code, .. }) => code,
+      _ => return None,
+    };
+    // Do NOT use .lines(): it skips the terminating empty line.
+    // (due to internally using_terminator() instead of .split())
+    let lines: Vec<&str> = code.split('\n').collect();
+    if line_number >= lines.len() {
+      Some(format!(
+        "{} Couldn't format source line: Line {} is out of bounds (source may have changed at runtime)",
+        crate::colors::yellow("Warning"), line_number + 1,
+      ))
+    } else {
+      Some(lines[line_number].to_string())
+    }
+  }
+}