1 files changed, 114 insertions, 0 deletions
diff --git a/devtools/shared/wasm-source-map.js b/devtools/shared/wasm-source-map.js
new file mode 100644
index 0000000000..716c794db2
--- /dev/null
+++ b/devtools/shared/wasm-source-map.js
@@ -0,0 +1,114 @@
+/* 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";
+
+/**
+ * SourceMapConsumer for WebAssembly source maps. It transposes columns with
+ * lines, which allows mapping data to be used with SpiderMonkey Debugger API.
+ */
+class WasmRemap {
+  /**
+   * @param map SourceMapConsumer
+   */
+  constructor(map) {
+    this._map = map;
+    this.version = map.version;
+    this.file = map.file;
+    this._computeColumnSpans = false;
+  }
+
+  get sources() {
+    return this._map.sources;
+  }
+
+  get sourceRoot() {
+    return this._map.sourceRoot;
+  }
+
+  /**
+   * @param url string
+   */
+  set sourceRoot(url) {
+    // important, since sources are using this.
+    this._map.sourceRoot = url;
+  }
+
+  get names() {
+    return this._map.names;
+  }
+
+  get sourcesContent() {
+    return this._map.sourcesContent;
+  }
+
+  get mappings() {
+    throw new Error("not supported");
+  }
+
+  computeColumnSpans() {
+    this._computeColumnSpans = true;
+  }
+
+  originalPositionFor(generatedPosition) {
+    const result = this._map.originalPositionFor({
+      line: 1,
+      column: generatedPosition.line,
+      bias: generatedPosition.bias,
+    });
+    return result;
+  }
+
+  _remapGeneratedPosition(position) {
+    const generatedPosition = {
+      line: position.column,
+      column: 0,
+    };
+    if (this._computeColumnSpans) {
+      generatedPosition.lastColumn = Infinity;
+    }
+    return generatedPosition;
+  }
+
+  generatedPositionFor(originalPosition) {
+    const position = this._map.generatedPositionFor(originalPosition);
+    return this._remapGeneratedPosition(position);
+  }
+
+  allGeneratedPositionsFor(originalPosition) {
+    const positions = this._map.allGeneratedPositionsFor(originalPosition);
+    return positions.map(position => {
+      return this._remapGeneratedPosition(position);
+    });
+  }
+
+  hasContentsOfAllSources() {
+    return this._map.hasContentsOfAllSources();
+  }
+
+  sourceContentFor(source, returnNullOnMissing) {
+    return this._map.sourceContentFor(source, returnNullOnMissing);
+  }
+
+  eachMapping(callback, context, order) {
+    this._map.eachMapping(
+      entry => {
+        const { source, generatedColumn, originalLine, originalColumn, name } =
+          entry;
+        callback({
+          source,
+          generatedLine: generatedColumn,
+          generatedColumn: 0,
+          originalLine,
+          originalColumn,
+          name,
+        });
+      },
+      context,
+      order
+    );
+  }
+}
+
+exports.WasmRemap = WasmRemap;