smartxml: Simple flat transactions for series of transformations

This change allows to indicate that transformations that follows must
be undoable in one step.

diff --git a/src/smartxml/smartxml.js b/src/smartxml/smartxml.js
index 2fd4e41..52236b6 100644 (file)
--- a/src/smartxml/smartxml.js
+++ b/src/smartxml/smartxml.js
@@ -249,6 +249,7 @@ var Document = function(xml) {
     this.loadXML(xml);
     this.undoStack = [];
     this.redoStack = [];
+    this._transactionStack = [];
     this._transformationLevel = 0;
     
     this._nodeMethods = {};
@@ -417,7 +418,11 @@ $.extend(Document.prototype, Backbone.Events, {
             this._transformationLevel++;
             toret = transformation.run({beUndoable:this._transformationLevel === 1});
             if(this._transformationLevel === 1 && !this._undoInProgress) {
-                this.undoStack.push(transformation);
+                if(this._transactionInProgress) {
+                    this._transactionStack.push(transformation);
+                } else {
+                    this.undoStack.push(transformation);
+                }
             }
             if(!this._undoInProgress && this._transformationLevel === 1) {
                 this.redoStack = [];
@@ -429,23 +434,73 @@ $.extend(Document.prototype, Backbone.Events, {
         }
     },
     undo: function() {
-        var transformation = this.undoStack.pop();
-        if(transformation) {
+        var transformationObject = this.undoStack.pop(),
+            doc = this,
+            transformations, stopAt;
+
+        if(transformationObject) {
             this._undoInProgress = true;
-            transformation.undo();
+
+            if(_.isArray(transformationObject)) {
+                // We will modify this array in a minute so make sure we work on a copy.
+                transformations = transformationObject.slice(0);
+            } else {
+                // Lets normalize single transformation to a transaction containing one transformation.
+                transformations = [transformationObject];
+            }
+
+            if(transformations.length > 1) {
+                // In case of real transactions we don't want to run undo on all of transformations if we don't have to.
+                stopAt = undefined;
+                transformations.some(function(t, idx) {
+                    if(!t.undo && t.getChangeRoot().sameNode(doc.root)) {
+                        stopAt = idx;
+                        return true; //break
+                    }
+                });
+                if(stopAt !== undefined) {
+                    // We will get away with undoing only this transformations as the one at stopAt reverses the whole document.
+                    transformations = transformations.slice(0, stopAt+1);
+                }
+            }
+
+            transformations.reverse();
+            transformations.forEach(function(t) {
+                t.undo();
+            });
+
             this._undoInProgress = false;
-            this.redoStack.push(transformation);
+            this.redoStack.push(transformationObject);
         }
     },
     redo: function() {
-        var transformation = this.redoStack.pop();
-        if(transformation) {
+        var transformationObject = this.redoStack.pop(),
+            transformations;
+        if(transformationObject) {
             this._transformationLevel++;
-            transformation.run({beUndoable: true});
+            transformations = _.isArray(transformationObject) ? transformationObject : [transformationObject];
+            transformations.forEach(function(t) {
+                t.run({beUndoable: true});
+            });
             this._transformationLevel--;
-            this.undoStack.push(transformation);
+            this.undoStack.push(transformationObject);
+        }
+    },
+
+    startTransaction: function() {
+        if(this._transactionInProgress) {
+            throw new Error('Nested transactions not supported!');
+        }
+        this._transactionInProgress = true;
+    },
 
+    endTransaction: function() {
+        if(!this._transactionInProgress) {
+            throw new Error('End of transaction requested, but there is no transaction in progress!');
         }
+        this._transactionInProgress = false;
+        this.undoStack.push(this._transactionStack);
+        this._transactionStack = [];
     },
 
     getNodeByPath: function(path) {

diff --git a/src/smartxml/smartxml.test.js b/src/smartxml/smartxml.test.js
index 4cda3bb..d82f823 100644 (file)
--- a/src/smartxml/smartxml.test.js
+++ b/src/smartxml/smartxml.test.js
@@ -1235,6 +1235,70 @@ describe('smartxml', function() {
             expect(doc.root.getAttr('outerAttr')).to.equal('test2');
 
         });
+
+        describe('Transactions', function() {
+            it('allows to undo/redo series of transformations at once', function() {
+                var doc = getDocumentFromXML('<div></div>');
+
+                doc.registerExtension({
+                    elementNode: {transformations: {
+                        test: function(v) {
+                            this.setAttr('test', v);
+                        }
+                    }}
+                });
+
+                doc.startTransaction();
+                doc.root.test('1');
+                doc.root.test('2');
+                doc.root.test('3');
+                doc.endTransaction();
+
+                doc.undo();
+                expect(doc.root.getAttr('test'), '1');
+                doc.redo();
+                expect(doc.root.getAttr('test'), '3');
+                doc.undo();
+                expect(doc.root.getAttr('test'), '1');
+                doc.redo();
+                expect(doc.root.getAttr('test'), '3');
+            });
+
+            it('doesn\'t break on optimizations', function() {
+                // This is a smoke test checking if optimizations made to transaction undoing
+                // doesnt't break anything.
+                var doc = getDocumentFromXML('<div smart="1" unaware="1"></div>');
+
+                doc.registerExtension({
+                    elementNode: {transformations: {
+                        unaware: function(v) {
+                            this.setAttr('unware', v);
+                        },
+                        smart: {
+                            impl: function(t, v) {
+                                t.oldVal = this.getAttr('smart');
+                                this.setAttr('smart', v);
+                            },
+                            undo: function(t) {
+                                this.setAttr('smart', t.oldVal);
+                            }
+                        }
+                    }}
+                });
+
+                doc.startTransaction();
+                doc.root.smart('2');
+                doc.root.unaware('2');
+                doc.root.smart('3');
+                doc.root.unaware('3');
+                doc.endTransaction();
+
+                doc.undo();
+
+                expect(doc.root.getAttr('smart')).to.equal('1');
+                expect(doc.root.getAttr('unaware')).to.equal('1');
+            });
+        });
     });
 
 });

diff --git a/src/smartxml/transformations.js b/src/smartxml/transformations.js
index 3f4b65f..053ed10 100644 (file)
--- a/src/smartxml/transformations.js
+++ b/src/smartxml/transformations.js
@@ -90,19 +90,15 @@ toret.createGenericTransformation = function(desc, name) {
         run: function(options) {
             var changeRoot;
             if(!desc.undo && options.beUndoable) {
-                if(desc.getChangeRoot) {
-                    changeRoot = desc.getChangeRoot.call(this);
-                    if(!changeRoot) {
-                        throw new Error(
-                            'Transformation {name} returned invalid change root value'
-                            .replace('{name}', name)
-                        );
-                    }
-                } else {
-                    changeRoot = this.document.root;
+                changeRoot = this.getChangeRoot();
+                if(!changeRoot) {
+                     throw new Error(
+                         'Transformation {name} returned invalid change root value'
+                         .replace('{name}', name)
+                     );
                 }
-                this.snapshot = changeRoot.clone();
                 this.changeRootPath = changeRoot.getPath();
+                this.snapshot = changeRoot.clone();
             }
             var argsToPass = desc.undo ? [this].concat(this.args) : this.args;
             var toret = desc.impl.apply(this.context, argsToPass);
@@ -116,6 +112,9 @@ toret.createGenericTransformation = function(desc, name) {
                 this.document.getNodeByPath(this.changeRootPath).replaceWith(this.snapshot);
             }
         },
+        getChangeRoot: desc.getChangeRoot || function() {
+            return this.document.root;
+        }
     });
 
     return GenericTransformation;