Implementing preprocessing plugins

lib/less/parser/parser.js

@@ -92,14 +92,23 @@ var Parser = function Parser(context, imports, fileInfo) {
         // @param [additionalData] An optional map which can contains vars - a map (key, value) of variables to apply
         //
         parse: function (str, callback, additionalData) {
-            var root, error = null, globalVars, modifyVars, preText = "";
+            var root, error = null, globalVars, modifyVars, ignored, preText = "";
 
             globalVars = (additionalData && additionalData.globalVars) ? Parser.serializeVars(additionalData.globalVars) + '\n' : '';
             modifyVars = (additionalData && additionalData.modifyVars) ? '\n' + Parser.serializeVars(additionalData.modifyVars) : '';
 
+            if (context.pluginManager) {
+                var preProcessors = context.pluginManager.getPreProcessors();
+                for (var i = 0; i < preProcessors.length; i++) {
+                    str = preProcessors[i].process(str, { context: context, imports: imports, fileInfo: fileInfo });
+                }
+            }
+
             if (globalVars || (additionalData && additionalData.banner)) {
                 preText = ((additionalData && additionalData.banner) ? additionalData.banner : "") + globalVars;
-                imports.contentsIgnoredChars[fileInfo.filename] = preText.length;
+                ignored = imports.contentsIgnoredChars;
+                ignored[fileInfo.filename] = ignored[fileInfo.filename] || 0;
+                ignored[fileInfo.filename] += preText.length;
             }
 
             str = str.replace(/\r\n?/g, '\n');

lib/less/plugin-manager.js

@@ -4,6 +4,7 @@
 var PluginManager = function(less) {
     this.less = less;
     this.visitors = [];
+    this.preProcessors = [];
     this.postProcessors = [];
     this.installedPlugins = [];
     this.fileManagers = [];
@@ -35,6 +36,20 @@ PluginManager.prototype.addPlugin = function(plugin) {
 PluginManager.prototype.addVisitor = function(visitor) {
     this.visitors.push(visitor);
 };
+/**
+ * Adds a pre processor object
+ * @param {object} preProcessor
+ * @param {number} priority - guidelines 1 = before import, 1000 = import, 2000 = after import
+ */
+PluginManager.prototype.addPreProcessor = function(preProcessor, priority) {
+    var indexToInsertAt;
+    for (indexToInsertAt = 0; indexToInsertAt < this.preProcessors.length; indexToInsertAt++) {
+        if (this.preProcessors[indexToInsertAt].priority >= priority) {
+            break;
+        }
+    }
+    this.preProcessors.splice(indexToInsertAt, 0, {preProcessor: preProcessor, priority: priority});
+};
 /**
  * Adds a post processor object
  * @param {object} postProcessor
@@ -56,6 +71,18 @@ PluginManager.prototype.addPostProcessor = function(postProcessor, priority) {
 PluginManager.prototype.addFileManager = function(manager) {
     this.fileManagers.push(manager);
 };
+/**
+ *
+ * @returns {Array}
+ * @private
+ */
+PluginManager.prototype.getPreProcessors = function() {
+    var preProcessors = [];
+    for (var i = 0; i < this.preProcessors.length; i++) {
+        preProcessors.push(this.preProcessors[i].preProcessor);
+    }
+    return preProcessors;
+};
 /**
  *
  * @returns {Array}