split up babel core into multiple modules

packages/babel-generator/src/source-map.js

@@ -0,0 +1,66 @@
+import sourceMap from "source-map";
+import * as t from "babel-types";
+
+/**
+ * Build a sourcemap.
+ */
+
+export default class SourceMap {
+  constructor(position, opts, code) {
+    this.position = position;
+    this.opts     = opts;
+
+    if (opts.sourceMaps) {
+      this.map = new sourceMap.SourceMapGenerator({
+        file: opts.sourceMapTarget,
+        sourceRoot: opts.sourceRoot
+      });
+
+      this.map.setSourceContent(opts.sourceFileName, code);
+    } else {
+      this.map = null;
+    }
+  }
+
+  /**
+   * Get the sourcemap.
+   */
+
+  get() {
+    var map = this.map;
+    if (map) {
+      return map.toJSON();
+    } else {
+      return map;
+    }
+  }
+
+  /**
+   * Mark a node's generated position, and add it to the sourcemap.
+   */
+
+  mark(node, type) {
+    var loc = node.loc;
+    if (!loc) return; // no location info
+
+    var map = this.map;
+    if (!map) return; // no source map
+
+    if (t.isProgram(node) || t.isFile(node)) return; // illegal mapping nodes
+
+    var position = this.position;
+
+    var generated = {
+      line: position.line,
+      column: position.column
+    };
+
+    var original = loc[type];
+
+    map.addMapping({
+      source: this.opts.sourceFileName,
+      generated: generated,
+      original: original
+    });
+  }
+}