jquery/src/deferred.js

173 lines
4.3 KiB
JavaScript

(function( jQuery ) {
var // Promise methods
promiseMethods = "then done fail isResolved isRejected promise".split( " " ),
// Static reference to slice
sliceDeferred = [].slice;
jQuery.extend({
// Create a simple deferred (one callbacks list)
_Deferred: function() {
var // callbacks list
callbacks = [],
// stored [ context , args ]
fired,
// to avoid firing when already doing so
firing,
// flag to know if the deferred has been cancelled
cancelled,
// the deferred itself
deferred = {
// done( f1, f2, ...)
done: function() {
if ( !cancelled ) {
var args = arguments,
i,
length,
elem,
type,
_fired;
if ( fired ) {
_fired = fired;
fired = 0;
}
for ( i = 0, length = args.length; i < length; i++ ) {
elem = args[ i ];
type = jQuery.type( elem );
if ( type === "array" ) {
deferred.done.apply( deferred, elem );
} else if ( type === "function" ) {
callbacks.push( elem );
}
}
if ( _fired ) {
deferred.resolveWith( _fired[ 0 ], _fired[ 1 ] );
}
}
return this;
},
// resolve with given context and args
resolveWith: function( context, args ) {
if ( !cancelled && !fired && !firing ) {
// make sure args are available (#8421)
args = args || [];
firing = 1;
try {
while( callbacks[ 0 ] ) {
callbacks.shift().apply( context, args );
}
}
finally {
fired = [ context, args ];
firing = 0;
}
}
return this;
},
// resolve with this as context and given arguments
resolve: function() {
deferred.resolveWith( this, arguments );
return this;
},
// Has this deferred been resolved?
isResolved: function() {
return !!( firing || fired );
},
// Cancel
cancel: function() {
cancelled = 1;
callbacks = [];
return this;
}
};
return deferred;
},
// Full fledged deferred (two callbacks list)
Deferred: function( func ) {
var deferred = jQuery._Deferred(),
failDeferred = jQuery._Deferred(),
promise;
// Add errorDeferred methods, then and promise
jQuery.extend( deferred, {
then: function( doneCallbacks, failCallbacks ) {
deferred.done( doneCallbacks ).fail( failCallbacks );
return this;
},
fail: failDeferred.done,
rejectWith: failDeferred.resolveWith,
reject: failDeferred.resolve,
isRejected: failDeferred.isResolved,
// Get a promise for this deferred
// If obj is provided, the promise aspect is added to the object
promise: function( obj ) {
if ( obj == null ) {
if ( promise ) {
return promise;
}
promise = obj = {};
}
var i = promiseMethods.length;
while( i-- ) {
obj[ promiseMethods[i] ] = deferred[ promiseMethods[i] ];
}
return obj;
}
} );
// Make sure only one callback list will be used
deferred.done( failDeferred.cancel ).fail( deferred.cancel );
// Unexpose cancel
delete deferred.cancel;
// Call given func if any
if ( func ) {
func.call( deferred, deferred );
}
return deferred;
},
// Deferred helper
when: function( firstParam ) {
var args = arguments,
i = 0,
length = args.length,
count = length,
deferred = length <= 1 && firstParam && jQuery.isFunction( firstParam.promise ) ?
firstParam :
jQuery.Deferred();
function resolveFunc( i ) {
return function( value ) {
args[ i ] = arguments.length > 1 ? sliceDeferred.call( arguments, 0 ) : value;
if ( !( --count ) ) {
// Strange bug in FF4:
// Values changed onto the arguments object sometimes end up as undefined values
// outside the $.when method. Cloning the object into a fresh array solves the issue
deferred.resolveWith( deferred, sliceDeferred.call( args, 0 ) );
}
};
}
if ( length > 1 ) {
for( ; i < length; i++ ) {
if ( args[ i ] && jQuery.isFunction( args[ i ].promise ) ) {
args[ i ].promise().then( resolveFunc(i), deferred.reject );
} else {
--count;
}
}
if ( !count ) {
deferred.resolveWith( deferred, args );
}
} else if ( deferred !== firstParam ) {
deferred.resolveWith( deferred, length ? [ firstParam ] : [] );
}
return deferred.promise();
}
});
})( jQuery );