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node_modules/parse5/lib/extensions/position_tracking/preprocessor_mixin.js

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+'use strict';
+
+var Mixin = require('../../utils/mixin'),
+    inherits = require('util').inherits,
+    UNICODE = require('../../common/unicode');
+
+//Aliases
+var $ = UNICODE.CODE_POINTS;
+
+var PositionTrackingPreprocessorMixin = module.exports = function (preprocessor) {
+    // NOTE: avoid installing tracker twice
+    if (!preprocessor.__locTracker) {
+        preprocessor.__locTracker = this;
+
+        Mixin.call(this, preprocessor);
+
+        this.preprocessor = preprocessor;
+        this.isEol = false;
+        this.lineStartPos = 0;
+        this.droppedBufferSize = 0;
+
+        this.col = -1;
+        this.line = 1;
+    }
+
+    return preprocessor.__locTracker;
+};
+
+inherits(PositionTrackingPreprocessorMixin, Mixin);
+
+Object.defineProperty(PositionTrackingPreprocessorMixin.prototype, 'offset', {
+    get: function () {
+        return this.droppedBufferSize + this.preprocessor.pos;
+    }
+});
+
+PositionTrackingPreprocessorMixin.prototype._getOverriddenMethods = function (mxn, orig) {
+    return {
+        advance: function () {
+            var cp = orig.advance.call(this);
+
+            //NOTE: LF should be in the last column of the line
+            if (mxn.isEol) {
+                mxn.isEol = false;
+                mxn.line++;
+                mxn.lineStartPos = mxn.offset;
+            }
+
+            if (cp === $.LINE_FEED)
+                mxn.isEol = true;
+
+            mxn.col = mxn.offset - mxn.lineStartPos + 1;
+
+            return cp;
+        },
+
+        retreat: function () {
+            orig.retreat.call(this);
+            mxn.isEol = false;
+
+            mxn.col = mxn.offset - mxn.lineStartPos + 1;
+        },
+
+        dropParsedChunk: function () {
+            var prevPos = this.pos;
+
+            orig.dropParsedChunk.call(this);
+
+            mxn.droppedBufferSize += prevPos - this.pos;
+        }
+    };
+};