/*

     File: Element.m 

 Abstract: Root class for the scriptable objects in this sample. 

  Version: 1.2 

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 */

#import "Element.h"

#import "scriptLog.h"

#include <sys/types.h>

#include <unistd.h>

@implementation Element

    /* Instead of sythesizing our properties here, we implement them manually

       in order to perform logging for debugging purposes. */

    /* storage management

    The normal sequence of events when an object is created is as follows:

    1. an AppleScript 'make' command will allocate and initialize an instance

    of the class it has been asked to create.  For example, it may create a Trinket.

    2. then it will call the insertInXXXXX: insertInXXXXX:atIndex: method on the container

    object where the new object will be stored.  For example, if we were being asked

    to create a Trinket in a Bucket, then the make command would create an instance

    of Trinket and then it would call insertInTrinkets: on the Bucket object.

    3. Inside of the insertInXXXXX: or insertInXXXXX:atIndex: you must record the

    parent object and the parent's property key for the new object being created so

    you can create a objectSpecifier later.  In this class, we have defined the

    setContainer:andProperty: for that purpose.  For example, inside of our

    insertInTrinkets: method on our Bucket object, we the setContainer:andProperty:

    method on the trinket object like so:

       [trinket setContainer:self andProperty:@"trinkets"]

    to inform the trinket object who its container is and the name of the Cocoa key

    on that container object used for the list of trinkets.

    */

-(id) init {

    if ((self = [super init])) {

        static unsigned long gNameCounter = 1;

            /* calkl our unique id generator to make a new id */

        self.uniqueID = [Element calculateNewUniqueID];

            /* we use a global counter to generate unique names */

        self.name = [NSString stringWithFormat:@"Untitled %d", gNameCounter++];

    }

        /* I put the logging statement later after the initialization so we can see

        the uniqueID */

    SLOG(@"init element %@", self.uniqueID);

    return self;

}

    /* standard deallocation of our members followed by superclass.

    nothing out of the ordinary here. */

- (void) dealloc {

    SLOG(@"dealloc element %@", self.uniqueID);

    self.uniqueID = nil;

    [container release];

    [containerProperty release];

    self.name = nil;

    [super dealloc];

}

    /* calculateNewUniqueID returns a new unique id value that can be used

    to uniquely idenfity an scriptable object.  Our main concern here is that the

    id value be unique within our process AND that it is unique to the specific

    instance of our process (in case our application is re-launched for some reason

    while a script is running).

    To guarantee uniqueness within our process, we use a simple counting global

    variable, and to guarantee the values we return are unique to our process instance

    we mix in our process id number.

    For convenience and ease of idenfification, I put the application's initials at the

    beginning of the id string.  */

+ (NSString *)calculateNewUniqueID {

    static unsigned long gElementCounter; /* our element id generator */

    static pid_t gMyProcessID; /* unique id of our process */

    static BOOL gUniqueInited = NO; /* our element id generator */

    NSString* theID;

        /* set up code for our id generator */

    if ( ! gUniqueInited ) {

        gMyProcessID = getpid(); /* guaranteed unique for our process, see man getpid */

        gElementCounter = 1; /* guaranteed unique within our process */

        gUniqueInited = YES;

    }

        /* we'll return unique id values as strings composed of the process id followed

        by a unique count value.  see the man page for getpid for more info about process

        id values.  */

    theID = [NSString stringWithFormat:@"SSO-%d-%d", gMyProcessID, gElementCounter++];

    SLOG(@"new unique id ='%@'", theID);

    return theID;

}

    /* standard setter and getter methods for the container and

    containerProperty slots.  The only thing that's unusual here is that

    we have lumped the setter functions together because we will always

    call them together. */

- (id)container {

    SLOG(@" of %@ as %@", self.uniqueID, container);

    return [[container retain] autorelease];

}

- (NSString *)containerProperty {

    SLOG(@" return  %@ as '%@'", self.uniqueID, containerProperty);

    return [[containerProperty retain] autorelease];

}

- (void)setContainer:(id)value andProperty:(NSString *)property {

    SLOG(@" of %@ to %@ and '%@'", self.uniqueID, [value class], property);

    if (container != value) {

        [container release];

        container = [value retain];

    }

    if (containerProperty != property) {

        [containerProperty release];

        containerProperty = [property copy];

    }

}

    /* standard setter and getter methods for the 'uniqueID' property

    nothing out of the ordinary here. */

- (NSString *)uniqueID {

    return [[uniqueID retain] autorelease];

}

- (void)setUniqueID:(NSString *)value {

    SLOG(@" of %@ to '%@'", self.uniqueID, value);

    if (uniqueID != value) {

        [uniqueID release];

        uniqueID = [value copy];

    }

}

    /* standard setter and getter methods for the 'name' property

    nothing out of the ordinary here. */

- (NSString *)name {

    SLOG(@" of %@ as '%@'", self.uniqueID, name);

    return [[name retain] autorelease];

}

- (void)setName:(NSString *)value {

    SLOG(@" of %@ to '%@'", self.uniqueID, value);

    if (name != value) {

        [name release];

        name = [value copy];

    }

}

    /* calling objectSpecifier asks an object to return an object specifier

    record referring to itself.  You must call setContainer:andProperty: before

    you can call this method. */

- (NSScriptObjectSpecifier *)objectSpecifier {

    SLOG(@" of %@ ", self.uniqueID);

    return [[NSUniqueIDSpecifier allocWithZone:[self zone]]

        initWithContainerClassDescription:(NSScriptClassDescription*) [self.container classDescription]

            containerSpecifier:[self.container objectSpecifier]

            key:self.containerProperty uniqueID:self.uniqueID];

}

@end