Make sourcemap generation a bit faster, roll #2

lib/less/source-map-output.js

@@ -1,10 +1,38 @@
 module.exports = function (environment) {
 
+    /**
+     * @param source The code
+     * @param ignoredCharsCount Number of characters at the start of the file to ignore.
+     * @constructor
+     */
+    var FileInfo = function (source, ignoredCharsCount) {
+        this.ignoredCharsCount = ignoredCharsCount;
+        this.source = source.slice(ignoredCharsCount);
+        this.sourceLines = this.source.split('\n');
+    };
+
+    /** Translate absolute source offset to line/column offset. */
+    FileInfo.prototype.getLocation = function (index) {
+        index = Math.max(0, index - this.ignoredCharsCount);
+        var line = 0;
+        for (; line < this.sourceLines.length && index >= this.sourceLines[line].length + 1; line++) {
+            index -= this.sourceLines[line].length + 1; // +1 for the '\n' character
+        }
+        return {line: line + 1, column: index};
+    };
+
     var SourceMapOutput = function (options) {
         this._css = [];
         this._rootNode = options.rootNode;
-        this._contentsMap = options.contentsMap;
-        this._contentsIgnoredCharsMap = options.contentsIgnoredCharsMap;
+
+        this._contentsInfoMap = {};
+        for (var key in options.contentsMap) {
+            if (options.contentsMap.hasOwnProperty(key)) {
+                this._contentsInfoMap[key] = new FileInfo(
+                    options.contentsMap[key], options.contentsIgnoredCharsMap[key] || 0);
+            }
+        }
+
         if (options.sourceMapFilename) {
             this._sourceMapFilename = options.sourceMapFilename.replace(/\\/g, '/');
         }
@@ -48,39 +76,22 @@ module.exports = function (environment) {
         }
 
         var lines,
-            sourceLines,
             columns,
-            sourceColumns,
             i;
 
-        if (fileInfo) {
-            var inputSource = this._contentsMap[fileInfo.filename];
-
-            // remove vars/banner added to the top of the file
-            if (this._contentsIgnoredCharsMap[fileInfo.filename]) {
-                // adjust the index
-                index -= this._contentsIgnoredCharsMap[fileInfo.filename];
-                if (index < 0) { index = 0; }
-                // adjust the source
-                inputSource = inputSource.slice(this._contentsIgnoredCharsMap[fileInfo.filename]);
-            }
-            inputSource = inputSource.substring(0, index);
-            sourceLines = inputSource.split("\n");
-            sourceColumns = sourceLines[sourceLines.length - 1];
-        }
-
         lines = chunk.split("\n");
         columns = lines[lines.length - 1];
 
         if (fileInfo) {
+            var location = this._contentsInfoMap[fileInfo.filename].getLocation(index);
             if (!mapLines) {
                 this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + 1, column: this._column},
-                    original: { line: sourceLines.length, column: sourceColumns.length},
+                    original: location,
                     source: this.normalizeFilename(fileInfo.filename)});
             } else {
                 for (i = 0; i < lines.length; i++) {
                     this._sourceMapGenerator.addMapping({ generated: { line: this._lineNumber + i + 1, column: i === 0 ? this._column : 0},
-                        original: { line: sourceLines.length + i, column: i === 0 ? sourceColumns.length : 0},
+                        original: { line: location.line + i, column: i === 0 ? location.column : 0},
                         source: this.normalizeFilename(fileInfo.filename)});
                 }
             }
@@ -104,12 +115,9 @@ module.exports = function (environment) {
         this._sourceMapGenerator = new this._sourceMapGeneratorConstructor({ file: this._outputFilename, sourceRoot: null });
 
         if (this._outputSourceFiles) {
-            for (var filename in this._contentsMap) {
-                if (this._contentsMap.hasOwnProperty(filename)) {
-                    var source = this._contentsMap[filename];
-                    if (this._contentsIgnoredCharsMap[filename]) {
-                        source = source.slice(this._contentsIgnoredCharsMap[filename]);
-                    }
+            for (var filename in this._contentsInfoMap) {
+                if (this._contentsInfoMap.hasOwnProperty(filename)) {
+                    var source = this._contentsInfoMap[filename].source;
                     this._sourceMapGenerator.setSourceContent(this.normalizeFilename(filename), source);
                 }
             }

test/index.js

@@ -40,6 +40,13 @@ lessTester.runTestSet({strictMath: true, strictUnits: true, sourceMap: true, glo
         }
         return path.join('test/sourcemaps', filename) + '.json';
     });
+lessTester.runTestSet({sourceMap: true, outputSourceFiles: true}, "sourcemaps-less-inline/",
+    lessTester.testSourcemap, null, lessTester.normalizeSourceMap,
+    function(filename, type, baseFolder) {
+        return path.join('test/sourcemaps-less-inline', filename) + '.json';
+    });
+lessTester.runTestSetNormalOnly({sourceMap: {sourceMapFileInline: true}}, "sourcemaps-map-inline/",
+    null, null, lessTester.normalizeSourceMap);
 lessTester.runTestSet({strictMath: true, strictUnits: true, sourceMap: {sourceMapFileInline: true}}, "sourcemaps-empty/", lessTester.testEmptySourcemap);
 lessTester.runTestSet({globalVars: true, banner: "/**\n  * Test\n  */\n"}, "globalVars/",
     null, null, null, function(name, type, baseFolder) { return path.join(baseFolder, name) + '.json'; });

test/less-test.js

@@ -255,9 +255,10 @@ module.exports = function() {
                     process.stdout.write("- " + path.join(baseFolder, css_name) + ": ");
 
                     css = css && doReplacements(css, path.join(baseFolder, foldername));
-                    if (result.css === css) { ok('OK'); }
+                    var actualCss = result.css && doReplacements(result.css, path.join(baseFolder, foldername));
+                    if (actualCss === css) { ok('OK'); }
                     else {
-                        difference("FAIL", css, result.css);
+                        difference("FAIL", css, actualCss);
                     }
                     release();
                 });
@@ -372,6 +373,16 @@ module.exports = function() {
         ok(stylize("OK\n", "green"));
     }
 
+    /**
+     * Source maps are different on different platforms (OS vs Unix). But we don't
+     * care about testing the source map library anyway, so replace inline
+     * source maps with "FakeMap".
+     */
+    function normalizeSourceMap(css) {
+        return css.replace(/sourceMappingURL=data:application\/json;base64,[a-zA-Z0-9=]* /,
+                           'sourceMappingURL=data:application/json;base64,FakeMap ')
+    }
+
     return {
         runTestSet: runTestSet,
         runTestSetNormalOnly: runTestSetNormalOnly,
@@ -381,6 +392,7 @@ module.exports = function() {
         testEmptySourcemap: testEmptySourcemap,
         testNoOptions: testNoOptions,
         prepBomTest: prepBomTest,
-        finished: finished
+        finished: finished,
+        normalizeSourceMap: normalizeSourceMap
     };
 };

test/less/sourcemaps-less-inline/main.less

@@ -0,0 +1,10 @@
+@var: black;
+
+.a() {
+  color: red;
+}
+
+.b {
+  .a();
+  background: @var;
+}

test/less/sourcemaps-map-inline/imported.less

@@ -0,0 +1,6 @@
+
+@my-black: black;
+
+.b {
+  color: green;
+}

test/less/sourcemaps-map-inline/main.less

@@ -0,0 +1,10 @@
+
+@import "imported";
+
+.a {
+  .b();
+}
+
+.c {
+  color: @my-black;
+}

test/sourcemaps-less-inline/main.json

@@ -0,0 +1 @@
+{"version":3,"sources":["testweb/sourcemaps-less-inline/main.less"],"names":[],"mappings":"AAMA;EAHE,UAAA;EAKA,iBAAA","file":"sourcemaps-less-inline/main.css","sourcesContent":["@var: black;\n\n.a() {\n  color: red;\n}\n\n.b {\n  .a();\n  background: @var;\n}\n"]}