Ticket #1803: DPAgent.m

//
//  DPAgent.h
//  DarwinPorts
//
/*
 Copyright (c) 2003 Apple Computer, Inc.
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 3. Neither the name of Apple Computer, Inc. nor the names of its contributors
    may be used to endorse or promote products derived from this software
    without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
 */

#import "DPAgent.h"
#import "DPObject.h"

// package info
static NSString *DPPackageName = @"darwinports";
static NSString *DPPackageVersion = @"1.0";
static NSString *DPPackageInit = @"dportinit";

// commands
static NSString *DPSearchCommand = @"dportsearch";
static NSString *DPOpenCommand = @"dportopen";
static NSString *DPExecCommand = @"dportexec";
static NSString *DPCloseCommand = @"dportclose";

// arguments
static NSString *DPAnyPortArgument = @".+";

// results
static NSString *DPYesResult = @"1";
static NSString *DPNoResult = @"0";

// ui
static NSString *DPUIPuts = @"ui_puts";


@implementation DPAgent
/*
    Serves as a bridge between the GUI app and the tcl interpreter.   Uses distributed objects to communicate with a delegte (GUI front-end).  All values exposed by the APIs to this class are generic objective-c data-types and not TCL DPObjects... clients talking to this class should not know or care that there's a tcl interpreter hiding underneath.   This class should also be the place to encapsulate all knowledge about the internal structure/constants of the ports system so that clients do not need to know about those details.
    This class is multi-threaded but all port operations are currently serialized (see more comments on this below)\
    The agent does not cache any information but rather always calls the tcl engine to talk to the ports collection and get the most recent information.   Caching should (and is) performed in the application front-end.    
*/

/** Init and clean-up **/


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

        _interpLock = [[NSLock alloc] init];
        _ports = [[NSMutableDictionary alloc] init];
        
        // configure our tcl interpreter
        _interp = [[DPInterp alloc] init];
        [_interp loadPackage: DPPackageName version: DPPackageVersion usingCommand: DPPackageInit];
        [_interp redirectCommand: [DPObject objectWithString: DPUIPuts] toObject: self];

        // configure our d.o. connection
        _connection = [NSConnection defaultConnection];
        [_connection setRootObject: self];
        [_connection enableMultipleThreads];
                [_connection setDelegate: self];
        if ([_connection registerName: @"DPAgent"] == NO) 
        {
            NSLog(@"Couldn't register server on this host.");
            exit(0);
        }

        [[NSNotificationCenter defaultCenter] addObserver:self
            selector: @selector(connectionDidDie:)
            name: NSConnectionDidDieNotification
            object: _connection];
 
    }
    return self;

}


- (void) dealloc
{
    [_interp release];
    [_interpLock release];
    [super dealloc];
}


/** D.O. connection management **/


- (BOOL) connection: (NSConnection *)parentConnection shouldMakeNewConnection:(NSConnection *)newConnection
{
    /*
     * Ensure that connectionDidDie: is called if newConnection
     * dies without terminate being called
     */
    [[NSNotificationCenter defaultCenter] addObserver:self
        selector: @selector(connectionDidDie:)
        name: NSConnectionDidDieNotification
        object: newConnection];
    return YES;
}


- (void) connectionDidDie: (id)connection
{
    exit(0);
}


- (oneway void) terminate
{
    [self performSelector: @selector(connectionDidDie:) withObject: self afterDelay: 0.0];
}



/** Port operations **/


- (bycopy NSData *) portsData
/*
    Returns a serialized property list describing the ports collection
*/
{
    
    Tcl_Obj **objv;
    int count = 0, i=0;
    DPObject *result;
    NSString *error;
    NSData *portsData;
    
    [_interpLock lock];    
    
    [_ports removeAllObjects];
    result = [_interp evaluateCommand: [DPObject objectWithString: DPSearchCommand] 
        withObject: [DPObject objectWithString: DPAnyPortArgument]];
    Tcl_ListObjGetElements(NULL, [result tclObj], &count, &objv);

    while (++i < count) 
    {   

        NSMutableDictionary *portDict = [NSMutableDictionary dictionary];
        Tcl_Obj **innerobjs;
        int innercount = 0, j = 0;    
        Tcl_ListObjGetElements(NULL, objv[i++], &innercount, &innerobjs);

        while (j < innercount)
        {

            DPObject *keyObject = [DPObject objectWithTclObj: innerobjs[j++]];
            DPObject *valueObject = [DPObject objectWithTclObj: innerobjs[j++]];
            NSString *key = [keyObject stringValue];
            id value;
            
            if ([key isEqualToString: DPCategoriesKey] ||
                [key isEqualToString: DPMaintainersKey])
            {
                NSEnumerator *enm = [[[valueObject stringValue] componentsSeparatedByString: @" "] objectEnumerator];
                NSString *component;
                value = [NSMutableArray array];
                while (component = [enm nextObject])
                {
                    if (![value containsObject: component])
                    {
                        [value addObject: component];
                    }
                }
    
            }
            else if ([key rangeOfString: DPDependsKey].location != NSNotFound)
            {
                NSEnumerator *dependencyEnm = [[[valueObject stringValue] componentsSeparatedByString: @" "] objectEnumerator];
                NSString *component;
                value = [NSMutableArray array];
                while (component = [dependencyEnm nextObject])
                {
                    if ([component length] > 0)
                                        {
                                                NSString *dependencyName = [[component componentsSeparatedByString: @":"] objectAtIndex: 2];
                                                if (![value containsObject: dependencyName])
                                                {
                                                        [value addObject: dependencyName];
                                                }
                    }
                }
                key = DPDependsKey;
            }
            else
            {
                value = [valueObject stringValue];
            }
            [portDict setObject: value forKey: key];

        }
        [_ports setObject: portDict forKey: [portDict objectForKey: DPNameKey]];
    }
    [_interpLock unlock];    

    // we serialize the data before returning it so that we can pass a deep copy of
    // the entire dictionary back in a single D.O. exchange.   if we just pass
    // a copy of _ports back then the GUI app is still forced to query objects
    // stored in the dict via d.o. proxies - which is dirt slow when refreshing
    // the outline view in the GUI    
    portsData = [NSPropertyListSerialization dataFromPropertyList: _ports 
        format: NSPropertyListXMLFormat_v1_0 
        errorDescription: &error];

    return portsData;
    
}


- (oneway void) executeTarget: (NSString *)target forPortName: (NSString *)portName
/*
    Detaches a new thread to perform the specified target on the specified port... 
*/
{
    NSDictionary *op = [[NSMutableDictionary alloc] initWithObjectsAndKeys:
        portName, @"portName",
        [DPObject objectWithString: target], @"target",
        [DPObject objectWithString: [[_ports objectForKey: portName] objectForKey: DPPortURLKey]], @"url",
        nil];
    [NSThread detachNewThreadSelector: sel_getUid("_threadForOperation:") 
        toTarget: self 
        withObject: op];
}


/** Execution thread methods */

/*
    Everything beyond this point code executes in secondary threads.  I've made a conscious effort to not share any objects (except for the _interpLock) between the primary thread and the secondary threads to minimize the need to worry about thread-safe data sharing between threads.
    Even though we have a separate thread for each operation all operations are currently serialized using the _interpLock.   If we wish to allow multiple simultaneous operations in the future then each thread will have to instantiate it's own interpreter (and the gui will also have to be made more flexible to sort out messages coming back from multiple simultaneous operations).   
    If we allow multiple truly simultaneous operations we also need to think about situations such as what happens if you start installing Port A and Port B both of which have a dependency on C?  Does C get installed twice?  Or even worse what if you start installing port A which depends on port C and simultaneously start uninstalling C?  etc.   For now easier to sidestep the whole issue by serializing everything.
*/


- (void) _threadForOperation: (NSMutableDictionary *)op
{

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];    

    // establish a separate connection for communication from this thread
    // back to the PortsManager.app
    NSConnection *connection = [NSConnection connectionWithRegisteredName: @"PMApp" host: nil];
    id <DPDelegateProtocol> delegate = [connection rootProxy];
    [connection enableMultipleThreads];    
    [(NSDistantObject *)delegate setProtocolForProxy:@protocol(DPDelegateProtocol)];
    [[NSNotificationCenter defaultCenter] addObserver:self
        selector: @selector(connectionDidDie:)
        name: NSConnectionDidDieNotification
        object: connection];
    [[[NSThread currentThread] threadDictionary] setObject: delegate forKey: @"delegate"];
    
    if ([delegate shouldPerformTarget: [[op objectForKey: @"target"] stringValue] forPortName: [op objectForKey: @"portName"]])
    {
        DPObject *result = nil;
        [delegate willPerformTarget: [[op objectForKey: @"target"] stringValue] forPortName: [op objectForKey: @"portName"]];
        [_interpLock lock]; // this can block for a long time if another op is in progress
        _currentOp = op;
        DPObject *workName = [_interp evaluateCommand: [DPObject objectWithString: DPOpenCommand] 
            withObject: [op objectForKey: @"url"]];
        if ([_interp succeeded])
        {
            result = [_interp evaluateCommand: [DPObject objectWithString: DPExecCommand] 
                withObjects: workName : [op objectForKey: @"target"]];
            if ([_interp succeeded]) 
            {
                result = [_interp evaluateCommand: [DPObject objectWithString: DPCloseCommand] withObject: workName];            
            } 
        }
        _currentOp = nil;
        [_interpLock unlock];
        [delegate didPerformTarget: [[op objectForKey: @"target"] stringValue] forPortName: [op objectForKey: @"portName"] withResult: [result stringValue]];
    }

    // Be sure to unregister for NSConnectionDidDieNotification before
    // auto-releasing the connection object
    [[NSNotificationCenter defaultCenter] removeObserver:self
        name: NSConnectionDidDieNotification
        object: connection];

    [op release];
    [pool release];

}


- (DPObject *) ui_puts: (NSArray *)array 
{
    NSDictionary *message = [[array objectAtIndex: 1] dictionaryValue];
    if (message == nil)
        return [DPObject objectWithString: DPNoResult];

    NSString *data = [message objectForKey: @"data"];
    NSString *priority = [message objectForKey: @"priority"];
    if (data == nil || priority == nil)
        return [DPObject objectWithString: DPNoResult];

    id delegate = [[[NSThread currentThread] threadDictionary] objectForKey: @"delegate"];
    [delegate displayMessage: [NSString stringWithFormat: @"%@%@", data, @"\n"]
        withPriority: priority
        forPortName: [_currentOp objectForKey: @"portName"]];        
    return [DPObject objectWithString: DPYesResult];
}



@end