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Diffstat (limited to 'vendor/oojs/oojs-ui/src/Process.js')
-rw-r--r-- | vendor/oojs/oojs-ui/src/Process.js | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/vendor/oojs/oojs-ui/src/Process.js b/vendor/oojs/oojs-ui/src/Process.js new file mode 100644 index 00000000..649ffb99 --- /dev/null +++ b/vendor/oojs/oojs-ui/src/Process.js @@ -0,0 +1,166 @@ +/** + * A Process is a list of steps that are called in sequence. The step can be a number, a jQuery promise, + * or a function: + * + * - **number**: the process will wait for the specified number of milliseconds before proceeding. + * - **promise**: the process will continue to the next step when the promise is successfully resolved + * or stop if the promise is rejected. + * - **function**: the process will execute the function. The process will stop if the function returns + * either a boolean `false` or a promise that is rejected; if the function returns a number, the process + * will wait for that number of milliseconds before proceeding. + * + * If the process fails, an {@link OO.ui.Error error} is generated. Depending on how the error is + * configured, users can dismiss the error and try the process again, or not. If a process is stopped, + * its remaining steps will not be performed. + * + * @class + * + * @constructor + * @param {number|jQuery.Promise|Function} step Number of miliseconds to wait before proceeding, promise + * that must be resolved before proceeding, or a function to execute. See #createStep for more information. see #createStep for more information + * @param {Object} [context=null] Execution context of the function. The context is ignored if the step is + * a number or promise. + * @return {Object} Step object, with `callback` and `context` properties + */ +OO.ui.Process = function ( step, context ) { + // Properties + this.steps = []; + + // Initialization + if ( step !== undefined ) { + this.next( step, context ); + } +}; + +/* Setup */ + +OO.initClass( OO.ui.Process ); + +/* Methods */ + +/** + * Start the process. + * + * @return {jQuery.Promise} Promise that is resolved when all steps have successfully completed. + * If any of the steps return a promise that is rejected or a boolean false, this promise is rejected + * and any remaining steps are not performed. + */ +OO.ui.Process.prototype.execute = function () { + var i, len, promise; + + /** + * Continue execution. + * + * @ignore + * @param {Array} step A function and the context it should be called in + * @return {Function} Function that continues the process + */ + function proceed( step ) { + return function () { + // Execute step in the correct context + var deferred, + result = step.callback.call( step.context ); + + if ( result === false ) { + // Use rejected promise for boolean false results + return $.Deferred().reject( [] ).promise(); + } + if ( typeof result === 'number' ) { + if ( result < 0 ) { + throw new Error( 'Cannot go back in time: flux capacitor is out of service' ); + } + // Use a delayed promise for numbers, expecting them to be in milliseconds + deferred = $.Deferred(); + setTimeout( deferred.resolve, result ); + return deferred.promise(); + } + if ( result instanceof OO.ui.Error ) { + // Use rejected promise for error + return $.Deferred().reject( [ result ] ).promise(); + } + if ( Array.isArray( result ) && result.length && result[ 0 ] instanceof OO.ui.Error ) { + // Use rejected promise for list of errors + return $.Deferred().reject( result ).promise(); + } + // Duck-type the object to see if it can produce a promise + if ( result && $.isFunction( result.promise ) ) { + // Use a promise generated from the result + return result.promise(); + } + // Use resolved promise for other results + return $.Deferred().resolve().promise(); + }; + } + + if ( this.steps.length ) { + // Generate a chain reaction of promises + promise = proceed( this.steps[ 0 ] )(); + for ( i = 1, len = this.steps.length; i < len; i++ ) { + promise = promise.then( proceed( this.steps[ i ] ) ); + } + } else { + promise = $.Deferred().resolve().promise(); + } + + return promise; +}; + +/** + * Create a process step. + * + * @private + * @param {number|jQuery.Promise|Function} step + * + * - Number of milliseconds to wait before proceeding + * - Promise that must be resolved before proceeding + * - Function to execute + * - If the function returns a boolean false the process will stop + * - If the function returns a promise, the process will continue to the next + * step when the promise is resolved or stop if the promise is rejected + * - If the function returns a number, the process will wait for that number of + * milliseconds before proceeding + * @param {Object} [context=null] Execution context of the function. The context is + * ignored if the step is a number or promise. + * @return {Object} Step object, with `callback` and `context` properties + */ +OO.ui.Process.prototype.createStep = function ( step, context ) { + if ( typeof step === 'number' || $.isFunction( step.promise ) ) { + return { + callback: function () { + return step; + }, + context: null + }; + } + if ( $.isFunction( step ) ) { + return { + callback: step, + context: context + }; + } + throw new Error( 'Cannot create process step: number, promise or function expected' ); +}; + +/** + * Add step to the beginning of the process. + * + * @inheritdoc #createStep + * @return {OO.ui.Process} this + * @chainable + */ +OO.ui.Process.prototype.first = function ( step, context ) { + this.steps.unshift( this.createStep( step, context ) ); + return this; +}; + +/** + * Add step to the end of the process. + * + * @inheritdoc #createStep + * @return {OO.ui.Process} this + * @chainable + */ +OO.ui.Process.prototype.next = function ( step, context ) { + this.steps.push( this.createStep( step, context ) ); + return this; +}; |