1 files changed, 96 insertions, 0 deletions
diff --git a/devtools/client/shared/source-map-loader/utils/sourceMapRequests.js b/devtools/client/shared/source-map-loader/utils/sourceMapRequests.js
new file mode 100644
index 0000000000..95f0420cba
--- /dev/null
+++ b/devtools/client/shared/source-map-loader/utils/sourceMapRequests.js
@@ -0,0 +1,96 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+"use strict";
+
+const {
+  generatedToOriginalId,
+} = require("resource://devtools/client/shared/source-map-loader/utils/index.js");
+
+const sourceMapRequests = new Map();
+
+function clearSourceMaps() {
+  for (const [, metadataPromise] of sourceMapRequests) {
+    // The source-map module leaks memory unless `.destroy` is called on
+    // the consumer instances when they are no longer being used.
+    metadataPromise.then(
+      metadata => {
+        if (metadata) {
+          metadata.map.destroy();
+        }
+      },
+      // We don't want this to cause any unhandled rejection errors.
+      () => {}
+    );
+  }
+
+  sourceMapRequests.clear();
+}
+
+/**
+ * For a given generated source, retrieve an object with many attributes:
+ * @param {String} generatedSourceId
+ *        The id of the generated source
+ *
+ * @return {Object} Meta data object with many attributes
+ *     - map: The SourceMapConsumer or WasmRemap instance
+ *     - urlsById Map of Original Source ID (string) to Source URL (string)
+ *     - sources: Array of object with the two following attributes:
+ *       - id: Original Source ID (string)
+ *       - url: Original Source URL (string)
+ */
+function getSourceMapWithMetadata(generatedSourceId) {
+  return sourceMapRequests.get(generatedSourceId);
+}
+
+/**
+ * Retrieve the SourceMapConsumer or WasmRemap instance for a given generated source.
+ *
+ * @param {String} generatedSourceId
+ *        The id of the generated source
+ *
+ * @return null | Promise<SourceMapConsumer | WasmRemap>
+ */
+function getSourceMap(generatedSourceId) {
+  const request = getSourceMapWithMetadata(generatedSourceId);
+  if (!request) {
+    return null;
+  }
+
+  return request.then(result => result?.map);
+}
+
+/**
+ * Record the SourceMapConsumer or WasmRemap instance for a given generated source.
+ *
+ * @param {String} generatedId
+ *        The generated source ID.
+ * @param {Promise<SourceMapConsumer or WasmRemap>} request
+ *        A promise which should resolve to either a SourceMapConsume or WasmRemap instance.
+ */
+function setSourceMap(generatedId, request) {
+  sourceMapRequests.set(
+    generatedId,
+    request.then(map => {
+      if (!map || !map.sources) {
+        return null;
+      }
+
+      const urlsById = new Map();
+
+      for (const url of map.sources) {
+        const id = generatedToOriginalId(generatedId, url);
+        urlsById.set(id, url);
+      }
+      return { map, urlsById };
+    })
+  );
+}
+
+module.exports = {
+  clearSourceMaps,
+  getSourceMapWithMetadata,
+  getSourceMap,
+  setSourceMap,
+};