56       if (mapping.source != null) {
57         newMapping.source = mapping.source;
59           newMapping.source = util.relative(sourceRoot, newMapping.source);
106     var source = util.getArg(aArgs, 'source', null);
110       this._validateMapping(generated, original, source, name);
113     if (source != null) {
114       source = String(source);
115       if (!this._sources.has(source)) {
116         this._sources.add(source);
132       source: source,  property
142     var source = aSourceFile;
144       source = util.relative(this._sourceRoot, source);
153       this._sourcesContents[util.toSetString(source)] = aSourceContent;
157       delete this._sourcesContents[util.toSetString(source)];
205       if (mapping.source === sourceFile && mapping.originalLine != null) {
211         if (original.source != null) {
213           mapping.source = original.source;
215             mapping.source = util.join(aSourceMapPath, mapping.source)
218             mapping.source = util.relative(sourceRoot, mapping.source);
228       var source = mapping.source;
229       if (source != null && !newSources.has(source)) {
230         newSources.add(source);
300         source: aSource,  property
350       if (mapping.source != null) {
351         sourceIdx = this._sources.indexOf(mapping.source);
379     return aSources.map(function (source) {  argument
384         source = util.relative(aSourceRoot, source);
386       var key = util.toSetString(source);