mediawiki-extensions-Visual.../modules/ve/dm/ve.dm.TransactionProcessor.js
Trevor Parscal c40174b60c Changed to use MIT license per agreement with the VisualEditor team
This license change is aimed at maximizing the reusability of this code
in other projects. VisualEditor is more than just an awesome editor for
MediaWiki, it's the new editor for the entire internet.

Added license and author files, plus mentions of the license to all
VisualEditor PHP, JavaScript and CSS files. Parser files have not been
modified but are effectively re-licensed since there's no overriding
license information. 3rd party libraries are not changed, but are all
already MIT licensed.

Change-Id: I895b256325db7c8689756edab34523de4418b0f2
2012-07-19 13:25:45 -07:00

471 lines
15 KiB
JavaScript

/**
* VisualEditor data model TransactionProcessor class.
*
* @copyright 2011-2012 VisualEditor Team and others; see AUTHORS.txt
* @license The MIT License (MIT); see LICENSE.txt
*/
/**
* DataModel transaction processor.
*
* This class reads operations from a transaction and applies them one by one. It's not intended
* to be used directly; use the static functions ve.dm.TransactionProcessor.commit() and .rollback()
* instead.
*
* NOTE: Instances of this class are not recyclable: you can only call .process() on them once.
*
* @class
* @constructor
*/
ve.dm.TransactionProcessor = function( doc, transaction, reversed ) {
// Properties
this.document = doc;
this.operations = transaction.getOperations();
this.synchronizer = new ve.dm.DocumentSynchronizer( doc );
this.reversed = reversed;
// Linear model offset that we're currently at. Operations in the transaction are ordered, so
// the cursor only ever moves forward.
this.cursor = 0;
// Adjustment used to convert between linear model offsets in the original linear model and
// in the half-updated linear model.
this.adjustment = 0;
// Set and clear are lists of annotations which should be added or removed to content being
// inserted or retained. The format of these objects is { hash: annotationObjectReference }
// where hash is the result of ve.getHash( annotationObjectReference ).
this.set = {};
this.clear = {};
};
/* Static Members */
/**
* Processing methods.
*
* Each method is specific to a type of action. Methods are called in the context of a transaction
* processor, so they work similar to normal methods on the object.
*
* @static
* @member
*/
ve.dm.TransactionProcessor.processors = {};
/* Static methods */
/**
* Commit a transaction to a document.
*
* @static
* @method
* @param {ve.dm.Document} doc Document object to apply the transaction to
* @param {ve.dm.Transaction} transaction Transaction to apply
*/
ve.dm.TransactionProcessor.commit = function( doc, transaction ) {
new ve.dm.TransactionProcessor( doc, transaction, false ).process();
};
/**
* Roll back a transaction; this applies the transaction to the document in reverse.
*
* @static
* @method
* @param {ve.dm.Document} doc Document object to apply the transaction to
* @param {ve.dm.Transaction} transaction Transaction to apply
*/
ve.dm.TransactionProcessor.rollback = function( doc, transaction ) {
new ve.dm.TransactionProcessor( doc, transaction, true ).process();
};
/**
* Execute a retain operation.
*
* This method is called within the context of a document synchronizer instance.
*
* This moves the cursor by op.length and applies annotations to the characters that the cursor
* moved over.
*
* @static
* @method
* @param {Object} op Operation object:
* @param {Integer} op.length Number of elements to retain
*/
ve.dm.TransactionProcessor.processors.retain = function( op ) {
this.applyAnnotations( this.cursor + op.length );
this.cursor += op.length;
};
/**
* Execute an annotate operation.
*
* This method is called within the context of a document synchronizer instance.
*
* This will add an annotation to or remove an annotation from {this.set} or {this.clear}.
*
* @static
* @method
* @param {Object} op Operation object
* @param {String} op.method Annotation method, either 'set' to add or 'clear' to remove
* @param {String} op.bias Endpoint of marker, either 'start' to begin or 'stop' to end
* @param {String} op.annotation Annotation object to set or clear from content
* @throws 'Invalid annotation method'
*/
ve.dm.TransactionProcessor.processors.annotate = function( op ) {
var target, hash;
if ( op.method === 'set' ) {
target = this.reversed ? this.clear : this.set;
} else if ( op.method === 'clear' ) {
target = this.reversed ? this.set : this.clear;
} else {
throw 'Invalid annotation method ' + op.method;
}
hash = $.toJSON( op.annotation );
if ( op.bias === 'start' ) {
target[hash] = op.annotation;
} else {
delete target[hash];
}
// Tree sync is done by applyAnnotations()
};
/**
* Execute an attribute operation.
*
* This method is called within the context of a document synchronizer instance.
*
* This sets the attribute named op.key on the element at this.cursor to op.to , or unsets it if
* op.to === undefined . op.from is not checked against the old value, but is used instead of op.to
* in reverse mode. So if op.from is incorrect, the transaction will commit fine, but won't roll
* back correctly.
*
* @static
* @method
* @param {Object} op Operation object
* @param {String} op.key: Attribute name
* @param {Mixed} op.from: Old attribute value, or undefined if not previously set
* @param {Mixed} op.to: New attribute value, or undefined to unset
*/
ve.dm.TransactionProcessor.processors.attribute = function( op ) {
var element = this.document.data[this.cursor];
if ( element.type === undefined ) {
throw 'Invalid element error, can not set attributes on non-element data';
}
var to = this.reversed ? op.from : op.to;
var from = this.reversed ? op.to : op.from;
if ( to === undefined ) {
// Clear
if ( element.attributes ) {
delete element.attributes[op.key];
}
} else {
// Automatically initialize attributes object
if ( !element.attributes ) {
element.attributes = {};
}
// Set
element.attributes[op.key] = to;
}
this.synchronizer.pushAttributeChange(
this.document.getNodeFromOffset( this.cursor + 1 ),
op.key,
from, to
);
};
/**
* Execute a replace operation.
*
* This method is called within the context of a document synchronizer instance.
*
* This replaces a range of linear model data with another at this.cursor, figures out how the model
* tree needs to be synchronized, and queues this in the DocumentSynchronizer.
*
* op.remove isn't checked against the actual data (instead op.remove.length things are removed
* starting at this.cursor), but it's used instead of op.insert in reverse mode. So if
* op.remove is incorrect but of the right length, the transaction will commit fine, but won't roll
* back correctly.
*
* @static
* @method
* @param {Object} op Operation object
* @param {Array} op.remove Linear model data to remove
* @param {Array} op.insert Linear model data to insert
*/
ve.dm.TransactionProcessor.processors.replace = function( op ) {
var remove = this.reversed ? op.insert : op.remove,
insert = this.reversed ? op.remove : op.insert,
removeIsContent = ve.dm.Document.isContentData( remove ),
insertIsContent = ve.dm.Document.isContentData( insert ),
node, selection;
if ( removeIsContent && insertIsContent ) {
// Content replacement
// Update the linear model
ve.batchSplice( this.document.data, this.cursor, remove.length, insert );
this.applyAnnotations( this.cursor + insert.length );
// Get the node containing the replaced content
selection = this.document.selectNodes(
new ve.Range(
this.cursor - this.adjustment,
this.cursor - this.adjustment + remove.length
),
'leaves'
);
var removeHasStructure = ve.dm.Document.containsElementData( remove ),
insertHasStructure = ve.dm.Document.containsElementData( insert );
if ( removeHasStructure || insertHasStructure ) {
// Replacement is not exclusively text
// Rebuild all covered nodes
var range = new ve.Range( selection[0].nodeRange.start,
selection[selection.length - 1].nodeRange.end );
this.synchronizer.pushRebuild( range,
new ve.Range( range.start + this.adjustment,
range.end + this.adjustment + insert.length - remove.length )
);
} else {
// Text-only replacement
// Queue a resize for this node
node = selection[0].node;
this.synchronizer.pushResize( node, insert.length - remove.length );
}
// Advance the cursor
this.cursor += insert.length;
this.adjustment += insert.length - remove.length;
} else {
// Structural replacement
// It's possible that multiple replace operations are needed before the
// model is back in a consistent state. This loop applies the current
// replace operation to the linear model, then keeps applying subsequent
// operations until the model is consistent. We keep track of the changes
// and queue a single rebuild after the loop finishes.
var operation = op,
removeLevel = 0,
insertLevel = 0,
i,
type,
prevCursor,
affectedRanges = [],
scope,
minInsertLevel = 0,
coveringRange,
scopeStart,
scopeEnd,
opAdjustment = 0;
while ( true ) {
if ( operation.type === 'replace' ) {
var opRemove = this.reversed ? operation.insert : operation.remove,
opInsert = this.reversed ? operation.remove : operation.insert;
// Update the linear model for this insert
ve.batchSplice( this.document.data, this.cursor, opRemove.length, opInsert );
affectedRanges.push( new ve.Range(
this.cursor - this.adjustment,
this.cursor - this.adjustment + opRemove.length
) );
prevCursor = this.cursor;
this.cursor += opInsert.length;
// Paint the removed selection, figure out which nodes were
// covered, and add their ranges to the affected ranges list
if ( opRemove.length > 0 ) {
selection = this.document.selectNodes( new ve.Range(
prevCursor - this.adjustment,
prevCursor + opRemove.length - this.adjustment
), 'siblings' );
for ( i = 0; i < selection.length; i++ ) {
// .nodeRange is the inner range, we need the
// outer range (including opening and closing)
if ( selection[i].node.isWrapped() ) {
affectedRanges.push( new ve.Range(
selection[i].nodeRange.start - 1,
selection[i].nodeRange.end + 1
) );
} else {
affectedRanges.push( selection[i].nodeRange );
}
}
}
// Walk through the remove and insert data
// and keep track of the element depth change (level)
// for each of these two separately. The model is
// only consistent if both levels are zero.
for ( i = 0; i < opRemove.length; i++ ) {
type = opRemove[i].type;
if ( type !== undefined ) {
if ( type.charAt( 0 ) === '/' ) {
// Closing element
removeLevel--;
} else {
// Opening element
removeLevel++;
}
}
}
// Keep track of the scope of the insertion
// Normally this is the node we're inserting into, except if the
// insertion closes elements it doesn't open (i.e. splits elements),
// in which case it's the affected ancestor
for ( i = 0; i < opInsert.length; i++ ) {
type = opInsert[i].type;
if ( type !== undefined ) {
if ( type.charAt( 0 ) === '/' ) {
// Closing element
insertLevel--;
if ( insertLevel < minInsertLevel ) {
// Closing an unopened element at a higher
// (more negative) level than before
// Lazy-initialize scope
scope = scope || this.document.getNodeFromOffset( prevCursor );
// Push the full range of the old scope as an affected range
scopeStart = this.document.getDocumentNode().getOffsetFromNode( scope );
scopeEnd = scopeStart + scope.getOuterLength();
affectedRanges.push( new ve.Range( scopeStart, scopeEnd ) );
// Update scope
scope = scope.getParent() || scope;
}
} else {
// Opening element
insertLevel++;
}
}
}
// Update adjustment
this.adjustment += opInsert.length - opRemove.length;
opAdjustment += opInsert.length - opRemove.length;
} else {
// We know that other operations won't cause adjustments, so we
// don't have to update adjustment
this.executeOperation( operation );
}
if ( removeLevel === 0 && insertLevel === 0 ) {
// The model is back in a consistent state, so we're done
break;
}
// Get the next operation
operation = this.nextOperation();
if ( !operation ) {
throw 'Unbalanced set of replace operations found';
}
}
// From all the affected ranges we have gathered, compute a range that covers all
// of them, and rebuild that
coveringRange = ve.Range.newCoveringRange( affectedRanges );
this.synchronizer.pushRebuild(
coveringRange,
new ve.Range(
coveringRange.start + this.adjustment - opAdjustment,
coveringRange.end + this.adjustment
)
);
}
};
/* Methods */
/**
* Gets the next operation.
*
* @method
*/
ve.dm.TransactionProcessor.prototype.nextOperation = function() {
return this.operations[this.operationIndex++] || false;
};
/**
* Executes an operation.
*
* @method
* @param {Object} op Operation object to execute
* @throws 'Invalid operation error. Operation type is not supported'
*/
ve.dm.TransactionProcessor.prototype.executeOperation = function( op ) {
if ( op.type in ve.dm.TransactionProcessor.processors ) {
ve.dm.TransactionProcessor.processors[op.type].call( this, op );
} else {
throw 'Invalid operation error. Operation type is not supported: ' + op.type;
}
};
/**
* Processes all operations.
*
* When all operations are done being processed, the document will be synchronized.
*
* @method
*/
ve.dm.TransactionProcessor.prototype.process = function() {
var op;
// This loop is factored this way to allow operations to be skipped over or executed
// from within other operations
this.operationIndex = 0;
while ( ( op = this.nextOperation() ) ) {
this.executeOperation( op );
}
this.synchronizer.synchronize();
};
/**
* Apply the current annotation stacks. This will set all annotations in this.set and clear all
* annotations in this.clear on the data between the offsets this.cursor and this.cursor + to
*
* @method
* @param {Number} to Offset to stop annotating at. Annotating starts at this.cursor
* @throws 'Invalid transaction, can not annotate a branch element'
* @throws 'Invalid transaction, annotation to be set is already set'
* @throws 'Invalid transaction, annotation to be cleared is not set'
*/
ve.dm.TransactionProcessor.prototype.applyAnnotations = function( to ) {
if ( ve.isEmptyObject( this.set ) && ve.isEmptyObject( this.clear ) ) {
return;
}
var item,
element,
annotated,
annotations,
hash;
for ( var i = this.cursor; i < to; i++ ) {
item = this.document.data[i];
element = item.type !== undefined;
if ( element ) {
if ( item.type.charAt( 0 ) === '/' ) {
throw 'Invalid transaction, cannot annotate a branch closing element';
} else if ( ve.dm.nodeFactory.canNodeHaveChildren( item.type ) ) {
throw 'Invalid transaction, cannot annotate a branch opening element';
}
}
annotated = element ? 'annotations' in item : ve.isArray( item );
annotations = annotated ? ( element ? item.annotations : item[1] ) : {};
// Set and clear annotations
for ( hash in this.set ) {
if ( hash in annotations ) {
throw 'Invalid transaction, annotation to be set is already set';
}
annotations[hash] = this.set[hash];
}
for ( hash in this.clear ) {
if ( !( hash in annotations ) ) {
throw 'Invalid transaction, annotation to be cleared is not set';
}
delete annotations[hash];
}
// Auto initialize/cleanup
if ( !ve.isEmptyObject( annotations ) && !annotated ) {
if ( element ) {
// Initialize new element annotation
item.annotations = annotations;
} else {
// Initialize new character annotation
this.document.data[i] = [item, annotations];
}
} else if ( ve.isEmptyObject( annotations ) && annotated ) {
if ( element ) {
// Cleanup empty element annotation
delete item.annotations;
} else {
// Cleanup empty character annotation
this.document.data[i] = item[0];
}
}
}
this.synchronizer.pushAnnotation( new ve.Range( this.cursor, to ) );
};