mediawiki-extensions-Visual.../modules/ve2/dm/ve.dm.TransactionProcessor.js

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/**
* 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 ) {
this.document = doc;
this.operations = transaction.getOperations();
// TODO add DocumentSynchronizer
//this.synchronizer = new ve.dm.DocumentSynchronizer( this.model );
this.reversed = reversed;
// Linear model offset that we're currently at
// The operations in the transaction are ordered, so the cursor only ever moves forward
this.cursor = 0;
// Annotation stacks used by the annotate operation. Any data that passes through an
// operation will have these annotation changes applied to them.
// The format is { hash: annotationObjectReference }
this.set = {}; // Annotations to add to data passing through
this.clear = {}; // Annotations to remove from data passing through
};
/* Static methods */
/**
* Commit a transaction to a document.
*
* @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.
*
* @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();
};
/* Methods */
ve.dm.TransactionProcessor.prototype.nextOperation = function() {
return this.operations[this.operationIndex++] || false;
};
ve.dm.TransactionProcessor.prototype.executeOperation = function( op ) {
if ( op.type in this ) {
this[op.type]( op );
} else {
throw 'Invalid operation error. Operation type is not supported: ' + operation.type;
}
};
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 );
}
// TODO add DocumentSynchronizer
//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
*
* @param {Number} to Offset to stop annotating at. Annotating starts at this.cursor
*/
ve.dm.TransactionProcessor.prototype.applyAnnotations = function( to ) {
var i, hash, ann;
for ( i = this.cursor; i < to; i++ ) {
character = this.document.data[i];
if ( character.type !== undefined ) {
// Not a character but an element, skip
continue;
}
ann = ve.isArray( character ) ? character[1] : null;
for ( hash in this.set ) {
if ( ann === null ) {
// Create annotations object
ann = {};
this.document.data[i] = [ character, ann ];
}
ann[hash] = this.set[hash];
}
if ( ann !== null ) {
for ( hash in this.clear ) {
delete ann[hash];
}
if ( $.isEmptyObject( ann ) ) {
// Clean up empty annotations object
this.document.data[i] = character[0];
}
}
}
};
/**
* Execute a retain operation.
*
* This moves the cursor by op.length and applies annotations to the characters that the cursor
* moved over.
*
* @param {Object} op Operation object:
* length: Number of elements to retain
*/
ve.dm.TransactionProcessor.prototype.retain = function( op ) {
this.applyAnnotations( this.cursor + op.length );
this.cursor += op.length;
};
/**
* Execute an annotate operation.
*
* This adds or removes an annotation to this.set or this.clear
*
* @param {Object} op Operation object
* method: 'set' to set an annotation, 'clear' to clear it
* bias: 'start' to start setting or clearing, 'stop' to stop setting or clearing
* annotation: annotation object
*/
ve.dm.TransactionProcessor.prototype.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];
}
// TODO sync model tree
};
/**
* Execute an attribute operation.
*
* 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.
*
* @param {Object} op Operation object
* key: attribute name
* from: old attribute value, or undefined if not previously set
* to: new attribute value, or undefined to unset
*/
ve.dm.TransactionProcessor.prototype.attribute = function( op ) {
var element = this.model.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;
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;
}
// TODO sync model tree
};
/**
* Execute a replace operation.
*
* This replaces one fragment 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.replacement 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.
*
*
* @param {Object} op Operation object
* remove: Linear model data fragment to remove
* replacement: Linear model data fragment to insert
*/
ve.dm.TransactionProcessor.prototype.replace = function( op ) {
// TODO
};