1 files changed, 179 insertions, 0 deletions
diff --git a/cli/js/compiler_imports.ts b/cli/js/compiler_imports.ts
new file mode 100644
index 000000000..d861f8ddc
--- /dev/null
+++ b/cli/js/compiler_imports.ts
@@ -0,0 +1,179 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+import {
+  MediaType,
+  SourceFile,
+  SourceFileJson
+} from "./compiler_sourcefile.ts";
+import { cwd } from "./dir.ts";
+import * as dispatch from "./dispatch.ts";
+import { sendAsync, sendSync } from "./dispatch_json.ts";
+import { assert } from "./util.ts";
+import * as util from "./util.ts";
+
+/** Resolve a path to the final path segment passed. */
+function resolvePath(...pathSegments: string[]): string {
+  let resolvedPath = "";
+  let resolvedAbsolute = false;
+
+  for (let i = pathSegments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
+    let path: string;
+
+    if (i >= 0) path = pathSegments[i];
+    else path = cwd();
+
+    // Skip empty entries
+    if (path.length === 0) {
+      continue;
+    }
+
+    resolvedPath = `${path}/${resolvedPath}`;
+    resolvedAbsolute = path.charCodeAt(0) === util.CHAR_FORWARD_SLASH;
+  }
+
+  // At this point the path should be resolved to a full absolute path, but
+  // handle relative paths to be safe (might happen when cwd() fails)
+
+  // Normalize the path
+  resolvedPath = util.normalizeString(
+    resolvedPath,
+    !resolvedAbsolute,
+    "/",
+    code => code === util.CHAR_FORWARD_SLASH
+  );
+
+  if (resolvedAbsolute) {
+    if (resolvedPath.length > 0) return `/${resolvedPath}`;
+    else return "/";
+  } else if (resolvedPath.length > 0) return resolvedPath;
+  else return ".";
+}
+
+/** Resolve a relative specifier based on the referrer.  Used when resolving
+ * modules internally within the runtime compiler API. */
+function resolveSpecifier(specifier: string, referrer: string): string {
+  if (!specifier.startsWith(".")) {
+    return specifier;
+  }
+  const pathParts = referrer.split("/");
+  pathParts.pop();
+  let path = pathParts.join("/");
+  path = path.endsWith("/") ? path : `${path}/`;
+  return resolvePath(path, specifier);
+}
+
+/** Ops to Rust to resolve modules' URLs. */
+export function resolveModules(
+  specifiers: string[],
+  referrer?: string
+): string[] {
+  util.log("compiler_imports::resolveModules", { specifiers, referrer });
+  return sendSync(dispatch.OP_RESOLVE_MODULES, { specifiers, referrer });
+}
+
+/** Ops to Rust to fetch modules meta data. */
+function fetchSourceFiles(
+  specifiers: string[],
+  referrer?: string
+): Promise<SourceFileJson[]> {
+  util.log("compiler_imports::fetchSourceFiles", { specifiers, referrer });
+  return sendAsync(dispatch.OP_FETCH_SOURCE_FILES, {
+    specifiers,
+    referrer
+  });
+}
+
+/** Given a filename, determine the media type based on extension.  Used when
+ * resolving modules internally in a runtime compile. */
+function getMediaType(filename: string): MediaType {
+  const maybeExtension = /\.([a-zA-Z]+)$/.exec(filename);
+  if (!maybeExtension) {
+    util.log(`!!! Could not identify valid extension: "${filename}"`);
+    return MediaType.Unknown;
+  }
+  const [, extension] = maybeExtension;
+  switch (extension.toLowerCase()) {
+    case "js":
+      return MediaType.JavaScript;
+    case "jsx":
+      return MediaType.JSX;
+    case "json":
+      return MediaType.Json;
+    case "ts":
+      return MediaType.TypeScript;
+    case "tsx":
+      return MediaType.TSX;
+    case "wasm":
+      return MediaType.Wasm;
+    default:
+      util.log(`!!! Unknown extension: "${extension}"`);
+      return MediaType.Unknown;
+  }
+}
+
+/** Recursively process the imports of modules from within the supplied sources,
+ * generating `SourceFile`s of any imported files.
+ *
+ * Specifiers are supplied in an array of tuples where the first is the
+ * specifier that will be requested in the code and the second is the specifier
+ * that should be actually resolved. */
+export function processLocalImports(
+  sources: Record<string, string>,
+  specifiers: Array<[string, string]>,
+  referrer?: string
+): string[] {
+  if (!specifiers.length) {
+    return [];
+  }
+  const moduleNames = specifiers.map(
+    referrer
+      ? ([, specifier]): string => resolveSpecifier(specifier, referrer)
+      : ([, specifier]): string => specifier
+  );
+  for (let i = 0; i < moduleNames.length; i++) {
+    const moduleName = moduleNames[i];
+    assert(moduleName in sources, `Missing module in sources: "${moduleName}"`);
+    const sourceFile =
+      SourceFile.get(moduleName) ||
+      new SourceFile({
+        url: moduleName,
+        filename: moduleName,
+        sourceCode: sources[moduleName],
+        mediaType: getMediaType(moduleName)
+      });
+    sourceFile.cache(specifiers[i][0], referrer);
+    if (!sourceFile.processed) {
+      processLocalImports(sources, sourceFile.imports(), sourceFile.url);
+    }
+  }
+  return moduleNames;
+}
+
+/** Recursively process the imports of modules, generating `SourceFile`s of any
+ * imported files.
+ *
+ * Specifiers are supplied in an array of tuples where the first is the
+ * specifier that will be requested in the code and the second is the specifier
+ * that should be actually resolved. */
+export async function processImports(
+  specifiers: Array<[string, string]>,
+  referrer?: string
+): Promise<string[]> {
+  if (!specifiers.length) {
+    return [];
+  }
+  const sources = specifiers.map(([, moduleSpecifier]) => moduleSpecifier);
+  const resolvedSources = resolveModules(sources, referrer);
+  const sourceFiles = await fetchSourceFiles(resolvedSources, referrer);
+  assert(sourceFiles.length === specifiers.length);
+  for (let i = 0; i < sourceFiles.length; i++) {
+    const sourceFileJson = sourceFiles[i];
+    const sourceFile =
+      SourceFile.get(sourceFileJson.url) || new SourceFile(sourceFileJson);
+    sourceFile.cache(specifiers[i][0], referrer);
+    if (!sourceFile.processed) {
+      await processImports(sourceFile.imports(), sourceFile.url);
+    }
+  }
+  return resolvedSources;
+}