cappuccino/Foundation/CPKeyValueCoding.j

/*
 * CPKeyValueCoding.j
 * Foundation
 *
 * Created by Francisco Tolmasky.
 * Copyright 2008, 280 North, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

@import "CPArray.j"
@import "CPDictionary.j"
@import "CPNull.j"
@import "CPObject.j"


CPUndefinedKeyException     = @"CPUndefinedKeyException";
CPTargetObjectUserInfoKey   = @"CPTargetObjectUserInfoKey";
CPUnknownUserInfoKey        = @"CPUnknownUserInfoKey";

var CPObjectAccessorsForClassKey            = @"$CPObjectAccessorsForClassKey",
    CPObjectModifiersForClassKey            = @"$CPObjectModifiersForClassKey",
    CPObjectInstanceVariablesForClassKey    = @"$CPObjectInstanceVariablesForClassKey";

var _accessorForKey = function(theClass, aKey)
{
    var selector = nil,
        accessors = theClass[CPObjectAccessorsForClassKey];

    if (!accessors)
        accessors = theClass[CPObjectAccessorsForClassKey] = { };

    else if (accessors.hasOwnProperty(aKey))
        return accessors[aKey];

    var capitalizedKey = aKey.charAt(0).toUpperCase() + aKey.substr(1);

    [theClass instancesRespondToSelector:selector = CPSelectorFromString("get" + capitalizedKey)] ||
    [theClass instancesRespondToSelector:selector = CPSelectorFromString(aKey)] ||
    [theClass instancesRespondToSelector:selector = CPSelectorFromString("is" + capitalizedKey)] ||
    //FIXME: is deprecated in Cocoa 10.3
    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_get" + capitalizedKey)] ||
    //FIXME: is deprecated in Cocoa 10.3
    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_" + aKey)] ||
    //FIXME: was NEVER supported by Cocoa
    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_is" + capitalizedKey)] ||
    (selector = nil);

    accessors[aKey] = selector;

    return selector;
}

var _modifierForKey = function(theClass, aKey)
{
    var selector = nil,
        modifiers = theClass[CPObjectModifiersForClassKey];

    if (!modifiers)
        modifiers = theClass[CPObjectModifiersForClassKey] = { };

    else if (modifiers.hasOwnProperty(aKey))
        return modifiers[aKey];

    var capitalizedKey = aKey.charAt(0).toUpperCase() + aKey.substr(1) + ':';

    [theClass instancesRespondToSelector:selector = CPSelectorFromString("set" + capitalizedKey)] ||
    //FIXME: deprecated in Cocoa 10.3
    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_set" + capitalizedKey)] ||
    (selector = nil);

    modifiers[aKey] = selector;

    return selector;
}

var _ivarForKey = function(theClass, aKey)
{
    var variables = theClass[CPObjectInstanceVariablesForClassKey];

    if (!variables)
        variables = theClass[CPObjectInstanceVariablesForClassKey] = { };

    else if (variables.hasOwnProperty(aKey))
        return variables[aKey];

    var name = '_' + aKey;

    if (!class_getInstanceVariable(theClass, name))
    {
        var isKey = "is" + aKey.charAt(0).toUpperCase() + aKey.substr(1);

        class_getInstanceVariable(theClass, name = '_' + isKey) ||
        class_getInstanceVariable(theClass, name = aKey) ||
        class_getInstanceVariable(theClass, name = isKey) ||
        (name = nil);
    }

    variables[aKey] = name;

    return name;
}

@implementation CPObject (CPKeyValueCoding)

+ (BOOL)accessInstanceVariablesDirectly
{
    return YES;
}

- (id)valueForKey:(CPString)aKey
{
    var theClass = [self class],
        selector = _accessorForKey(theClass, aKey);

    if (selector)
        return objj_msgSend(self, selector);

    //FIXME: at this point search for array access methods: "countOf<Key>", "objectIn<Key>AtIndex:", "<key>AtIndexes:"
    // or set access methods: "countOf<Key>", "enumeratorOf<Key>", "memberOf<Key>:"
    //and return (immutable) array/set proxy! (see NSKeyValueCoding.h)

    if ([theClass accessInstanceVariablesDirectly])
    {
        var ivar = _ivarForKey(theClass, aKey);

        if (ivar)
            return self[ivar];
    }

    return [self valueForUndefinedKey:aKey];
}

- (id)valueForKeyPath:(CPString)aKeyPath
{
    var firstDotIndex = aKeyPath.indexOf(".");

    if (firstDotIndex === CPNotFound)
        return [self valueForKey:aKeyPath];

    var firstKeyComponent = aKeyPath.substring(0, firstDotIndex),
        remainingKeyPath = aKeyPath.substring(firstDotIndex + 1),
        value = [self valueForKey:firstKeyComponent];

    return [value valueForKeyPath:remainingKeyPath];
}

- (CPDictionary)dictionaryWithValuesForKeys:(CPArray)keys
{
    var index = 0,
        count = keys.length,
        dictionary = [CPDictionary dictionary];

    for (; index < count; ++index)
    {
        var key = keys[index],
            value = [self valueForKey:key];

        if (value === nil)
            [dictionary setObject:[CPNull null] forKey:key];

        else
            [dictionary setObject:value forKey:key];
    }

    return dictionary;
}

- (id)valueForUndefinedKey:(CPString)aKey
{
    [[CPException exceptionWithName:CPUndefinedKeyException
                            reason:[self description] + " is not key value coding-compliant for the key " + aKey
                          userInfo:[CPDictionary dictionaryWithObjects:[self, aKey] forKeys:[CPTargetObjectUserInfoKey, CPUnknownUserInfoKey]]] raise];
}

- (void)setValue:(id)aValue forKeyPath:(CPString)aKeyPath
{
    if (!aKeyPath)
        aKeyPath = @"self";

    var firstDotIndex = aKeyPath.indexOf(".");

    if (firstDotIndex === CPNotFound)
        return [self setValue:aValue forKey:aKeyPath];

    var firstKeyComponent = aKeyPath.substring(0, firstDotIndex),
        remainingKeyPath = aKeyPath.substring(firstDotIndex + 1),
        value = [self valueForKey:firstKeyComponent];

    return [value setValue:aValue forKeyPath:remainingKeyPath];
}

- (void)setValue:(id)aValue forKey:(CPString)aKey
{
    var theClass = [self class],
        selector = _modifierForKey(theClass, aKey);

    if (selector)
        return objj_msgSend(self, selector, aValue);

    if ([theClass accessInstanceVariablesDirectly])
    {
        var ivar = _ivarForKey(theClass, aKey);

        if (ivar)
        {
            [self willChangeValueForKey:aKey];

            self[ivar] = aValue;

            [self didChangeValueForKey:aKey];

            return;
        }
    }

    [self setValue:aValue forUndefinedKey:aKey];
}

- (void)setValuesForKeysWithDictionary:(CPDictionary)keyedValues
{
    var value,
        key,
        keyEnumerator = [keyedValues keyEnumerator];

    while (key = [keyEnumerator nextObject])
    {
        value = [keyedValues objectForKey: key];

        if (value === [CPNull null])
            [self setValue: nil forKey: key];

        else
            [self setValue: value forKey: key];
    }
}

- (void)setValue:(id)aValue forUndefinedKey:(CPString)aKey
{
    [[CPException exceptionWithName:CPUndefinedKeyException
                            reason:[self description] + " is not key value coding-compliant for the key " + aKey
                          userInfo:[CPDictionary dictionaryWithObjects:[self, aKey] forKeys:[CPTargetObjectUserInfoKey, CPUnknownUserInfoKey]]] raise];
}

@end

@implementation CPDictionary (CPKeyValueCoding)

- (id)valueForKey:(CPString)aKey
{
    if ([aKey hasPrefix:@"@"])
        return [super valueForKey:aKey.substr(1)];

    return [self objectForKey:aKey];
}

- (void)setValue:(id)aValue forKey:(CPString)aKey
{
    if (aValue !== nil)
        [self setObject:aValue forKey:aKey];

    else
        [self removeObjectForKey:aKey];
}

@end

@implementation CPNull (CPKeyValueCoding)

- (id)valueForKey:(CPString)aKey
{
    return self;
}

@end

@import "CPKeyValueObserving.j"