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Changed: move functions declarations to `deltaTransform` object.

Szymon Cofalik 8 лет назад
Родитель
Сommit
31f3e95942

+ 224 - 230
packages/ckeditor5-engine/src/model/delta/transform.js

@@ -15,207 +15,255 @@ import arrayUtils from '@ckeditor/ckeditor5-utils/src/lib/lodash/array';
 const specialCases = new Map();
 
 const deltaTransform = {
-	transform,
-	defaultTransform,
-	addTransformationCase,
-	getTransformationCase,
-	transformDeltaSets
-};
+	/**
+	 * Transforms given {@link module:engine/model/delta/delta~Delta delta} by another {@link module:engine/model/delta/delta~Delta delta} and
+	 * returns the result of that transformation as an array containing one or more {@link module:engine/model/delta/delta~Delta delta}
+	 * instances.
+	 *
+	 * Delta transformations heavily base on {@link module:engine/model/operation/transform~transform operational transformations}. Since
+	 * delta is a list of operations most situations can be handled thanks to operational transformation. Unfortunately,
+	 * deltas are more complicated than operations and have they semantic meaning, as they represent user's editing intentions.
+	 *
+	 * Sometimes, simple operational transformation on deltas' operations might result in some unexpected results. Those
+	 * results would be fine from OT point of view, but would not reflect user's intentions. Because of such conflicts
+	 * we need to handle transformations in special cases in a custom way.
+	 *
+	 * The function itself looks whether two given delta types have a special case function registered. If so, the deltas are
+	 * transformed using that function. If not, {@link module:engine/model/delta/transform~defaultTransform default transformation algorithm}
+	 * is used.
+	 *
+	 * @param {module:engine/model/delta/delta~Delta} a Delta that will be transformed.
+	 * @param {module:engine/model/delta/delta~Delta} b Delta to transform by.
+	 * @param {Boolean} isAMoreImportantThanB Flag indicating whether the delta which will be transformed (`a`) should be treated
+	 * as more important when resolving conflicts. Note that this flag is used only if provided deltas have same
+	 * {@link module:engine/model/delta/delta~Delta._priority priority}. If deltas have different priorities, their importance is resolved
+	 * automatically and overwrites this flag.
+	 * @returns {Array.<module:engine/model/delta/delta~Delta>} Result of the transformation.
+	 */
+	transform: function( a, b, isAMoreImportantThanB ) {
+		const transformAlgorithm = deltaTransform.getTransformationCase( a, b ) || deltaTransform.defaultTransform;
+
+		const transformed = transformAlgorithm( a, b, isAMoreImportantThanB );
+		const baseVersion = arrayUtils.last( b.operations ).baseVersion;
+
+		return updateBaseVersion( baseVersion, transformed );
+	},
+
+	/**
+	 * The default delta transformation function. It is used for those deltas that are not in special case conflict.
+	 *
+	 * This algorithm is similar to a popular `dOPT` algorithm used in operational transformation, as we are in fact
+	 * transforming two sets of operations by each other.
+	 *
+	 * @param {module:engine/model/delta/delta~Delta} a Delta that will be transformed.
+	 * @param {module:engine/model/delta/delta~Delta} b Delta to transform by.
+	 * @param {Boolean} isAMoreImportantThanB Flag indicating whether the delta which will be transformed (`a`) should be treated
+	 * as more important when resolving conflicts. Note that this flag is used only if provided deltas have same
+	 * {@link module:engine/model/delta/delta~Delta._priority priority}. If deltas have different priorities, their importance is resolved
+	 * automatically and overwrites this flag.
+	 * @returns {Array.<module:engine/model/delta/delta~Delta>} Result of the transformation, that is an array with single delta instance.
+	 */
+	defaultTransform: function( a, b, isAMoreImportantThanB ) {
+		// First, resolve the flag real value.
+		isAMoreImportantThanB = getPriority( a.constructor, b.constructor, isAMoreImportantThanB );
+
+		// Create a new delta instance. Make sure that the new delta is of same type as transformed delta.
+		// We will transform operations in that delta but it doesn't mean the delta's "meaning" which is connected to
+		// the delta's type. Since the delta's type is heavily used in transformations and probably other parts
+		// of system it is important to keep proper delta type through all transformation process.
+		const transformed = new a.constructor();
+
+		// Array containing operations that we will transform by. At the beginning these are just operations from
+		let byOps = b.operations;
+
+		// This array is storing operations from `byOps` which got transformed by operation from delta `a`.
+		let newByOps = [];
+
+		// We take each operation from original set of operations to transform.
+		for ( let opA of a.operations ) {
+			// We wrap the operation in the array. This is important, because operation transformation algorithm returns
+			// an array of operations so we need to make sure that our algorithm is ready to handle arrays.
+			const ops = [ opA ];
+
+			// Now the real algorithm takes place.
+			for ( let opB of byOps ) {
+				// For each operation that we need transform by...
+				for ( let i = 0; i < ops.length; i++ ) {
+					// We take each operation to transform...
+					const op = ops[ i ];
+
+					// And transform both of them by themselves.
+
+					// The result of transforming operation from delta B by operation from delta A is saved in
+					// `newByOps` array. We will use that array for transformations in next loops. We need delta B
+					// operations after transformed by delta A operations to get correct results of transformations
+					// of next operations from delta A.
+					//
+					// It's like this because 2nd operation from delta A assumes that 1st operation from delta A
+					// is "already applied". When we transform 2nd operation from delta A by operations from delta B
+					// we have to be sure that operations from delta B are in a state that acknowledges 1st operation
+					// from delta A.
+					//
+					// This can be easier understood when operations sets to transform are represented by diamond diagrams:
+					// http://www.codecommit.com/blog/java/understanding-and-applying-operational-transformation
+
+					// Using push.apply because operationTransform function is returning an array with one or multiple results.
+					Array.prototype.push.apply( newByOps, operationTransform( opB, op, !isAMoreImportantThanB ) );
+
+					// Then, we transform operation from delta A by operation from delta B.
+					const results = operationTransform( op, opB, isAMoreImportantThanB );
+
+					// We replace currently processed operation from `ops` array by the results of transformation.
+					// Note, that we process single operation but the operationTransform result might be an array, so we
+					// might splice-in more operations. We will process them further in next iterations. Right now we
+					// just save them in `ops` array and move `i` pointer by proper offset.
+					Array.prototype.splice.apply( ops, [ i, 1 ].concat( results ) );
+
+					i += results.length - 1;
+				}
 
-export default deltaTransform;
+				// At this point a single operation from delta A got transformed by a single operation from delta B.
+				// The transformation result is in `ops` array and it may be one or more operations. This was just the first step.
+				// Operation from delta A has to be further transformed by the other operations from delta B.
+				// So in next iterator loop we will take another operation from delta B and use transformed delta A (`ops`)
+				// to transform it further.
+			}
 
-/**
- * Transforms given {@link module:engine/model/delta/delta~Delta delta} by another {@link module:engine/model/delta/delta~Delta delta} and
- * returns the result of that transformation as an array containing one or more {@link module:engine/model/delta/delta~Delta delta}
- * instances.
- *
- * Delta transformations heavily base on {@link module:engine/model/operation/transform~transform operational transformations}. Since
- * delta is a list of operations most situations can be handled thanks to operational transformation. Unfortunately,
- * deltas are more complicated than operations and have they semantic meaning, as they represent user's editing intentions.
- *
- * Sometimes, simple operational transformation on deltas' operations might result in some unexpected results. Those
- * results would be fine from OT point of view, but would not reflect user's intentions. Because of such conflicts
- * we need to handle transformations in special cases in a custom way.
- *
- * The function itself looks whether two given delta types have a special case function registered. If so, the deltas are
- * transformed using that function. If not, {@link module:engine/model/delta/transform~defaultTransform default transformation algorithm}
- * is used.
- *
- * @param {module:engine/model/delta/delta~Delta} a Delta that will be transformed.
- * @param {module:engine/model/delta/delta~Delta} b Delta to transform by.
- * @param {Boolean} isAMoreImportantThanB Flag indicating whether the delta which will be transformed (`a`) should be treated
- * as more important when resolving conflicts. Note that this flag is used only if provided deltas have same
- * {@link module:engine/model/delta/delta~Delta._priority priority}. If deltas have different priorities, their importance is resolved
- * automatically and overwrites this flag.
- * @returns {Array.<module:engine/model/delta/delta~Delta>} Result of the transformation.
- */
-function transform( a, b, isAMoreImportantThanB ) {
-	const transformAlgorithm = getTransformationCase( a, b ) || defaultTransform;
+			// We got through all delta B operations and have a final transformed state of an operation from delta A.
 
-	const transformed = transformAlgorithm( a, b, isAMoreImportantThanB );
-	const baseVersion = arrayUtils.last( b.operations ).baseVersion;
+			// As previously mentioned, we substitute operations from delta B by their transformed equivalents.
+			byOps = newByOps;
+			newByOps = [];
 
-	return updateBaseVersion( baseVersion, transformed );
-}
+			// We add transformed operation from delta A to newly created delta.
+			// Remember that transformed operation from delta A may consist of multiple operations.
+			for ( let op of ops ) {
+				transformed.addOperation( op );
+			}
 
-// Updates base versions of operations inside deltas (which are the results of delta transformation).
-function updateBaseVersion( baseVersion, deltas ) {
-	for ( let delta of deltas ) {
-		for ( let op of delta.operations ) {
-			op.baseVersion = ++baseVersion;
+			// In next loop, we will take another operation from delta A and transform it through (transformed) operations
+			// from delta B...
 		}
-	}
 
-	return deltas;
-}
+		return [ transformed ];
+	},
+
+	/**
+	 * Adds a special case callback for given delta classes.
+	 *
+	 * @external module:engine/model/delta/transform~transform
+	 * @function module:engine/model/delta/transform~transform.addTransformationCase
+	 * @param {Function} A Delta constructor which instance will get transformed.
+	 * @param {Function} B Delta constructor which instance will be transformed by.
+	 * @param {Function} resolver A callback that will handle custom special case transformation for instances of given delta classes.
+	 */
+	addTransformationCase: function( A, B, resolver ) {
+		let casesA = specialCases.get( A );
+
+		if ( !casesA ) {
+			casesA = new Map();
+			specialCases.set( A, casesA );
+		}
 
-/**
- * The default delta transformation function. It is used for those deltas that are not in special case conflict.
- *
- * This algorithm is similar to a popular `dOPT` algorithm used in operational transformation, as we are in fact
- * transforming two sets of operations by each other.
- *
- * @param {module:engine/model/delta/delta~Delta} a Delta that will be transformed.
- * @param {module:engine/model/delta/delta~Delta} b Delta to transform by.
- * @param {Boolean} isAMoreImportantThanB Flag indicating whether the delta which will be transformed (`a`) should be treated
- * as more important when resolving conflicts. Note that this flag is used only if provided deltas have same
- * {@link module:engine/model/delta/delta~Delta._priority priority}. If deltas have different priorities, their importance is resolved
- * automatically and overwrites this flag.
- * @returns {Array.<module:engine/model/delta/delta~Delta>} Result of the transformation, that is an array with single delta instance.
- */
-function defaultTransform( a, b, isAMoreImportantThanB ) {
-	// First, resolve the flag real value.
-	isAMoreImportantThanB = getPriority( a.constructor, b.constructor, isAMoreImportantThanB );
-
-	// Create a new delta instance. Make sure that the new delta is of same type as transformed delta.
-	// We will transform operations in that delta but it doesn't mean the delta's "meaning" which is connected to
-	// the delta's type. Since the delta's type is heavily used in transformations and probably other parts
-	// of system it is important to keep proper delta type through all transformation process.
-	const transformed = new a.constructor();
-
-	// Array containing operations that we will transform by. At the beginning these are just operations from
-	let byOps = b.operations;
-
-	// This array is storing operations from `byOps` which got transformed by operation from delta `a`.
-	let newByOps = [];
-
-	// We take each operation from original set of operations to transform.
-	for ( let opA of a.operations ) {
-		// We wrap the operation in the array. This is important, because operation transformation algorithm returns
-		// an array of operations so we need to make sure that our algorithm is ready to handle arrays.
-		const ops = [ opA ];
-
-		// Now the real algorithm takes place.
-		for ( let opB of byOps ) {
-			// For each operation that we need transform by...
-			for ( let i = 0; i < ops.length; i++ ) {
-				// We take each operation to transform...
-				const op = ops[ i ];
-
-				// And transform both of them by themselves.
-
-				// The result of transforming operation from delta B by operation from delta A is saved in
-				// `newByOps` array. We will use that array for transformations in next loops. We need delta B
-				// operations after transformed by delta A operations to get correct results of transformations
-				// of next operations from delta A.
-				//
-				// It's like this because 2nd operation from delta A assumes that 1st operation from delta A
-				// is "already applied". When we transform 2nd operation from delta A by operations from delta B
-				// we have to be sure that operations from delta B are in a state that acknowledges 1st operation
-				// from delta A.
-				//
-				// This can be easier understood when operations sets to transform are represented by diamond diagrams:
-				// http://www.codecommit.com/blog/java/understanding-and-applying-operational-transformation
-
-				// Using push.apply because operationTransform function is returning an array with one or multiple results.
-				Array.prototype.push.apply( newByOps, operationTransform( opB, op, !isAMoreImportantThanB ) );
-
-				// Then, we transform operation from delta A by operation from delta B.
-				const results = operationTransform( op, opB, isAMoreImportantThanB );
-
-				// We replace currently processed operation from `ops` array by the results of transformation.
-				// Note, that we process single operation but the operationTransform result might be an array, so we
-				// might splice-in more operations. We will process them further in next iterations. Right now we
-				// just save them in `ops` array and move `i` pointer by proper offset.
-				Array.prototype.splice.apply( ops, [ i, 1 ].concat( results ) );
-
-				i += results.length - 1;
-			}
+		casesA.set( B, resolver );
+	},
 
-			// At this point a single operation from delta A got transformed by a single operation from delta B.
-			// The transformation result is in `ops` array and it may be one or more operations. This was just the first step.
-			// Operation from delta A has to be further transformed by the other operations from delta B.
-			// So in next iterator loop we will take another operation from delta B and use transformed delta A (`ops`)
-			// to transform it further.
-		}
+	/**
+	 * Gets a special case callback which was previously {@link module:engine/model/delta/transform~transform.addTransformationCase added}.
+	 *
+	 * @param {module:engine/model/delta/delta~Delta} a Delta to transform.
+	 * @param {module:engine/model/delta/delta~Delta} b Delta to be transformed by.
+	 */
+	getTransformationCase: function( a, b ) {
+		let casesA = specialCases.get( a.constructor );
 
-		// We got through all delta B operations and have a final transformed state of an operation from delta A.
+		// If there are no special cases registered for class which `a` is instance of, we will
+		// check if there are special cases registered for any parent class.
+		if ( !casesA || !casesA.get( b.constructor ) ) {
+			const cases = specialCases.keys();
 
-		// As previously mentioned, we substitute operations from delta B by their transformed equivalents.
-		byOps = newByOps;
-		newByOps = [];
+			for ( let caseClass of cases ) {
+				if ( a instanceof caseClass && specialCases.get( caseClass ).get( b.constructor ) ) {
+					casesA = specialCases.get( caseClass );
 
-		// We add transformed operation from delta A to newly created delta.
-		// Remember that transformed operation from delta A may consist of multiple operations.
-		for ( let op of ops ) {
-			transformed.addOperation( op );
+					break;
+				}
+			}
 		}
 
-		// In next loop, we will take another operation from delta A and transform it through (transformed) operations
-		// from delta B...
-	}
+		if ( casesA ) {
+			return casesA.get( b.constructor );
+		}
 
-	return [ transformed ];
-}
+		return undefined;
+	},
+
+	/**
+	 * Transforms two sets of deltas by themselves. Returns both transformed sets. Does not modify passed parameters.
+	 *
+	 * @param {Array.<module:engine/model/delta/delta~Delta>} deltasA Array with first set of deltas to transform.
+	 * @param {Array.<module:engine/model/delta/delta~Delta>} deltasB Array with second set of deltas to transform.
+	 * @param {Boolean} isAMoreImportantThanB Flag indicating whether the deltas from `deltasA` set should be treated as more
+	 * important when resolving conflicts.
+	 * @returns {Object}
+	 * @returns {Array.<module:engine/model/delta/delta~Delta>} return.deltasA The first set of deltas transformed by the second set of deltas.
+	 * @returns {Array.<module:engine/model/delta/delta~Delta>} return.deltasB The second set of deltas transformed by the first set of deltas.
+	 */
+	transformDeltaSets: function( deltasA, deltasB, isAMoreImportantThanB ) {
+		let transformedDeltasA = Array.from( deltasA );
+		let transformedDeltasB = Array.from( deltasB );
+
+		for ( let i = 0; i < transformedDeltasA.length; i++ ) {
+			let deltaA = [ transformedDeltasA[ i ] ];
+
+			for ( let j = 0; j < transformedDeltasB.length; j++ ) {
+				let deltaB = [ transformedDeltasB[ j ] ];
+
+				for ( let k = 0; k < deltaA.length; k++ ) {
+					for ( let l = 0; l < deltaB.length; l++ ) {
+						let resultAB = deltaTransform.transform( deltaA[ k ], deltaB[ l ], isAMoreImportantThanB );
+						let resultBA = deltaTransform.transform( deltaB[ l ], deltaA[ k ], !isAMoreImportantThanB );
+
+						deltaA.splice( k, 1, ...resultAB );
+						k += resultAB.length - 1;
+
+						deltaB.splice( l, 1, ...resultBA );
+						l += resultBA.length - 1;
+					}
+				}
 
-/**
- * Adds a special case callback for given delta classes.
- *
- * @external module:engine/model/delta/transform~transform
- * @function module:engine/model/delta/transform~transform.addTransformationCase
- * @param {Function} A Delta constructor which instance will get transformed.
- * @param {Function} B Delta constructor which instance will be transformed by.
- * @param {Function} resolver A callback that will handle custom special case transformation for instances of given delta classes.
- */
-function addTransformationCase( A, B, resolver ) {
-	let casesA = specialCases.get( A );
+				transformedDeltasB.splice( j, 1, ...deltaB );
+				j += deltaB.length - 1;
+			}
 
-	if ( !casesA ) {
-		casesA = new Map();
-		specialCases.set( A, casesA );
-	}
+			transformedDeltasA.splice( i, 1, ...deltaA );
+			i += deltaA.length - 1;
+		}
 
-	casesA.set( B, resolver );
-}
+		const opsDiffA = getOpsCount( transformedDeltasA ) - getOpsCount( deltasA );
+		const opsDiffB = getOpsCount( transformedDeltasB ) - getOpsCount( deltasB );
 
-/**
- * Gets a special case callback which was previously {@link module:engine/model/delta/transform~transform.addTransformationCase added}.
- *
- * @param {module:engine/model/delta/delta~Delta} a Delta to transform.
- * @param {module:engine/model/delta/delta~Delta} b Delta to be transformed by.
- */
-function getTransformationCase( a, b ) {
-	let casesA = specialCases.get( a.constructor );
+		if ( opsDiffB < opsDiffA ) {
+			padWithNoOps( transformedDeltasB, opsDiffA - opsDiffB );
+		} else if ( opsDiffA < opsDiffB ) {
+			padWithNoOps( transformedDeltasA, opsDiffB - opsDiffA );
+		}
 
-	// If there are no special cases registered for class which `a` is instance of, we will
-	// check if there are special cases registered for any parent class.
-	if ( !casesA || !casesA.get( b.constructor ) ) {
-		const cases = specialCases.keys();
+		return { deltasA: transformedDeltasA, deltasB: transformedDeltasB };
+	}
+};
 
-		for ( let caseClass of cases ) {
-			if ( a instanceof caseClass && specialCases.get( caseClass ).get( b.constructor ) ) {
-				casesA = specialCases.get( caseClass );
+export default deltaTransform;
 
-				break;
-			}
+// Updates base versions of operations inside deltas (which are the results of delta transformation).
+function updateBaseVersion( baseVersion, deltas ) {
+	for ( let delta of deltas ) {
+		for ( let op of delta.operations ) {
+			op.baseVersion = ++baseVersion;
 		}
 	}
 
-	if ( casesA ) {
-		return casesA.get( b.constructor );
-	}
-
-	return undefined;
+	return deltas;
 }
 
 // Checks priorities of passed constructors and decides which one is more important.
@@ -230,60 +278,6 @@ function getPriority( A, B, isAMoreImportantThanB ) {
 	}
 }
 
-/**
- * Transforms two sets of deltas by themselves. Returns both transformed sets. Does not modify passed parameters.
- *
- * @param {Array.<module:engine/model/delta/delta~Delta>} deltasA Array with first set of deltas to transform.
- * @param {Array.<module:engine/model/delta/delta~Delta>} deltasB Array with second set of deltas to transform.
- * @param {Boolean} isAMoreImportantThanB Flag indicating whether the deltas from `deltasA` set should be treated as more
- * important when resolving conflicts.
- * @returns {Object}
- * @returns {Array.<module:engine/model/delta/delta~Delta>} return.deltasA The first set of deltas transformed by the second set of deltas.
- * @returns {Array.<module:engine/model/delta/delta~Delta>} return.deltasB The second set of deltas transformed by the first set of deltas.
- */
-function transformDeltaSets( deltasA, deltasB, isAMoreImportantThanB ) {
-	let transformedDeltasA = Array.from( deltasA );
-	let transformedDeltasB = Array.from( deltasB );
-
-	for ( let i = 0; i < transformedDeltasA.length; i++ ) {
-		let deltaA = [ transformedDeltasA[ i ] ];
-
-		for ( let j = 0; j < transformedDeltasB.length; j++ ) {
-			let deltaB = [ transformedDeltasB[ j ] ];
-
-			for ( let k = 0; k < deltaA.length; k++ ) {
-				for ( let l = 0; l < deltaB.length; l++ ) {
-					let resultAB = transform( deltaA[ k ], deltaB[ l ], isAMoreImportantThanB );
-					let resultBA = transform( deltaB[ l ], deltaA[ k ], !isAMoreImportantThanB );
-
-					deltaA.splice( k, 1, ...resultAB );
-					k += resultAB.length - 1;
-
-					deltaB.splice( l, 1, ...resultBA );
-					l += resultBA.length - 1;
-				}
-			}
-
-			transformedDeltasB.splice( j, 1, ...deltaB );
-			j += deltaB.length - 1;
-		}
-
-		transformedDeltasA.splice( i, 1, ...deltaA );
-		i += deltaA.length - 1;
-	}
-
-	const opsDiffA = getOpsCount( transformedDeltasA ) - getOpsCount( deltasA );
-	const opsDiffB = getOpsCount( transformedDeltasB ) - getOpsCount( deltasB );
-
-	if ( opsDiffB < opsDiffA ) {
-		padWithNoOps( transformedDeltasB, opsDiffA - opsDiffB );
-	} else if ( opsDiffA < opsDiffB ) {
-		padWithNoOps( transformedDeltasA, opsDiffB - opsDiffA );
-	}
-
-	return { deltasA: transformedDeltasA, deltasB: transformedDeltasB };
-}
-
 // Returns number of operations in given array of deltas.
 function getOpsCount( deltas ) {
 	return deltas.reduce( ( current, delta ) => {

+ 13 - 0
packages/ckeditor5-engine/tests/model/delta/transform/transform.js

@@ -45,6 +45,19 @@ describe( 'transform', () => {
 	} );
 
 	describe( 'transformDeltaSets', () => {
+		it( 'should use deltaTransform.transform', () => {
+			sinon.spy( deltaTransform, 'transform' );
+
+			const insertDelta = getInsertDelta( new Position( root, [ 0, 4 ] ), new Text( 'xxx' ), baseVersion );
+			const removeDelta = getRemoveDelta( new Position( root, [ 0, 0 ] ), 2, baseVersion );
+
+			transformDeltaSets( [ insertDelta ], [ removeDelta ] );
+
+			expect( deltaTransform.transform.called ).to.be.true;
+
+			deltaTransform.transform.restore();
+		} );
+
 		it( 'should transform two deltas', () => {
 			const insertDelta = getInsertDelta( new Position( root, [ 0, 4 ] ), new Text( 'xxx' ), baseVersion );
 			const removeDelta = getRemoveDelta( new Position( root, [ 0, 0 ] ), 2, baseVersion );