Add column limit support, similar to exceljs#541

lib/xlsx/xform/sheet/row-xform.js

@@ -5,7 +5,8 @@ var BaseXform = require('../base-xform');
 
 var CellXform = require('./cell-xform');
 
-var RowXform = module.exports = function() {
+var RowXform = module.exports = function(options) {
+  this.maxItems = options && options.maxItems;
   this.map = {
     c: new CellXform()
   };
@@ -119,6 +120,9 @@ utils.inherits(RowXform, BaseXform, {
     if (this.parser) {
       if (!this.parser.parseClose(name)) {
         this.model.cells.push(this.parser.model);
+        if (this.maxItems && this.model.cells.length > this.maxItems) {
+          throw new Error('Max column count exceeded');
+        }
         this.parser = undefined;
       }
       return true;

lib/xlsx/xform/sheet/worksheet-xform.js

@@ -30,13 +30,14 @@ var RowBreaksXform = require('./row-breaks-xform');
 
 var WorkSheetXform = module.exports = function(options) {
   var maxRows = options && options.maxRows;
+  var maxCols = options && options.maxCols;
   this.map = {
     sheetPr: new SheetPropertiesXform(),
     dimension: new DimensionXform(),
     sheetViews: new ListXform({tag: 'sheetViews', count: false, childXform: new SheetViewXform()}),
     sheetFormatPr: new SheetFormatPropertiesXform(),
     cols: new ListXform({tag: 'cols', count: false, childXform: new ColXform()}),
-    sheetData: new ListXform({tag: 'sheetData', count: false, empty: true, childXform: new RowXform(), maxItems: maxRows}),
+    sheetData: new ListXform({tag: 'sheetData', count: false, empty: true, childXform: new RowXform({maxItems: maxCols}), maxItems: maxRows}),
     autoFilter: new AutoFilterXform(),
     mergeCells: new ListXform({tag: 'mergeCells', count: true, childXform: new MergeCellXform()}),
     rowBreaks: new RowBreaksXform(),

spec/integration/workbook-xlsx-reader.spec.js

@@ -53,6 +53,35 @@ describe('WorkbookReader', function() {
         return workbook.xlsx.readFile('./spec/integration/data/fibonacci.xlsx', {maxRows: 20});
       });
     });
+
+    describe('Column limit', function() {
+      it('should bail out if the file contains more cells than the limit', function() {
+        const workbook = new Excel.Workbook();
+        // The many-columns sheet has 20 columns in row 2
+        return workbook.xlsx.readFile('./spec/integration/data/many-columns.xlsx', {maxCols: 15})
+          .then(function() {
+            throw new Error('Promise unexpectedly fulfilled');
+          }, function(err) {
+            expect(err.message).to.equal('Max column count exceeded');
+          });
+      });
+
+      it('should fail fast on a huge file', function() {
+        this.timeout(20000);
+        const workbook = new Excel.Workbook();
+        return workbook.xlsx.readFile('./spec/integration/data/huge.xlsx', {maxCols: 10})
+          .then(function() {
+            throw new Error('Promise unexpectedly fulfilled');
+          }, function(err) {
+            expect(err.message).to.equal('Max column count exceeded');
+          });
+      });
+
+      it('should parse fine if the limit is not exceeded', function() {
+        const workbook = new Excel.Workbook();
+        return workbook.xlsx.readFile('./spec/integration/data/many-columns.xlsx', {maxCols: 40});
+      });
+    });
   });
 
   describe('#read', function() {