SQLiteQueryPlugIn.m

/*
        File: SQLiteQueryPlugIn.m
    Abstract: SQLiteQueryPlugin class.
     Version: 1.0
    
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*/
 
/* It's highly recommended to use CGL macros instead of changing the current context for plug-ins that perform OpenGL rendering */
#import <OpenGL/CGLMacro.h>
 
#import "SQLiteQueryPlugIn.h"
 
#define kQCPlugIn_Name              @"SQLite Query"
#define kQCPlugIn_Description       @"Performs a query on a local SQLite database."
 
@implementation SQLiteQueryPlugIn
 
/* We need to declare the input / output properties as dynamic as Quartz Composer will handle their implementation */
@dynamic inputDataBasePath, inputQueryString, outputResultStructure;
 
+ (NSDictionary*) attributes
{
    /* Return the attributes of this plug-in */
    return [NSDictionary dictionaryWithObjectsAndKeys:kQCPlugIn_Name, QCPlugInAttributeNameKey, kQCPlugIn_Description, QCPlugInAttributeDescriptionKey, nil];
}
 
+ (NSDictionary*) attributesForPropertyPortWithKey:(NSString*)key
{
    /* Return the attributes for the plug-in property ports */
    if([key isEqualToString:@"inputDataBasePath"])
    return [NSDictionary dictionaryWithObjectsAndKeys:@"Database Path", QCPortAttributeNameKey, @"myDatabase.db", QCPortAttributeDefaultValueKey, nil];
    if([key isEqualToString:@"inputQueryString"])
    return [NSDictionary dictionaryWithObjectsAndKeys:@"Query String", QCPortAttributeNameKey, @"select * from myTable;", QCPortAttributeDefaultValueKey, nil];
    if([key isEqualToString:@"outputResultStructure"])
    return [NSDictionary dictionaryWithObject:@"Result Structure" forKey:QCPortAttributeNameKey];
    
    return nil;
}
 
+ (QCPlugInExecutionMode) executionMode
{
    /* This plug-in is a processor (it runs a command line tool) */
    return kQCPlugInExecutionModeProcessor;
}
 
+ (QCPlugInTimeMode) timeMode
{
    /* This plug-in does not depend on the time (time parameter is completely ignored in the -execute:atTime:withArguments: method) */
    return kQCPlugInTimeModeNone;
}
 
@end
 
@implementation NSMutableData (SQLiteQueryPlugIn)
 
/* Extend the NSMutableData class to add a method called by NSFileHandleDataAvailableNotification to automatically append the new data */
- (void) _SQLiteQueryPlugInFileHandleDataAvailable:(NSNotification*)notification
{
    NSFileHandle*           fileHandle = [notification object];
    
    [self appendData:[fileHandle availableData]];
    
    [fileHandle waitForDataInBackgroundAndNotify];
}
 
@end
 
@implementation SQLiteQueryPlugIn (Execution)
 
- (int) _runTask:(NSTask*)task inData:(NSData*)inData outData:(NSData**)outData errorData:(NSData**)errorData
{
    NSPipe*             inPipe = nil;
    NSPipe*             outPipe = nil;
    NSPipe*             errorPipe = nil;
    NSFileHandle*       fileHandle;
    
    /* Reset output variables */
    if(outData)
    *outData = nil;
    if(errorData)
    *errorData = nil;
    
    /* Safe check */
    if(task == nil)
    return -1;
    
    /* Create standard input pipe */
    if([inData length]) {
        if(inPipe = [NSPipe new]) {
            [task setStandardInput:inPipe];
            [inPipe release];
        }
        else {
            task = nil;
            goto Exit;
        }
    }
    
    /* Create standard output pipe */
    if(outData) {
        if(outPipe = [NSPipe new]) {
            [task setStandardOutput:outPipe];
            [outPipe release];
        }
        else {
            task = nil;
            goto Exit;
        }
    }
    
    /* Create standard error pipe */
    if(errorData) {
        if(errorPipe = [NSPipe new]) {
            [task setStandardError:errorPipe];
            [errorPipe release];
        }
        else {
            task = nil;
            goto Exit;
        }
    }
    
    /* Launch task */
NS_DURING
    [task launch];
NS_HANDLER
    task = nil;
NS_ENDHANDLER
    if(task == nil)
    goto Exit;
    
    /* Write data to standard input pipe */
    if(fileHandle = [inPipe fileHandleForWriting]) {
NS_DURING
        [fileHandle writeData:inData];
        [fileHandle closeFile];
NS_HANDLER
        [task terminate];
        [task interrupt];
        task = nil;
NS_ENDHANDLER
    }
    if(task == nil)
    goto Exit;
    
    /* Read data from standard output and standard error pipes in background */
    if(fileHandle = [outPipe fileHandleForReading]) {
        *outData = [NSMutableData data];
        [[NSNotificationCenter defaultCenter] addObserver:*outData selector:@selector(_SQLiteQueryPlugInFileHandleDataAvailable:) name:NSFileHandleDataAvailableNotification object:fileHandle];
        [fileHandle waitForDataInBackgroundAndNotify];
    }
    if(fileHandle = [errorPipe fileHandleForReading]) {
        *errorData = [NSMutableData data];
        [[NSNotificationCenter defaultCenter] addObserver:*errorData selector:@selector(_SQLiteQueryPlugInFileHandleDataAvailable:) name:NSFileHandleDataAvailableNotification object:fileHandle];
        [fileHandle waitForDataInBackgroundAndNotify];
    }
    
    /* We cannot use -[NSTask waitUntilExit] as it runs the runloop in default mode which might make Quartz Composer re-enter its execution e.g. from a QCView, so we run in a private mode */
    while([task isRunning])
    [[NSRunLoop currentRunLoop] runMode:@"SQLiteQueryPlugInMode" beforeDate:[NSDate dateWithTimeIntervalSinceNow:1.0]];
    
    /* Finish reading data */
    if(fileHandle = [errorPipe fileHandleForReading]) {
        [[NSNotificationCenter defaultCenter] removeObserver:*errorData name:NSFileHandleDataAvailableNotification object:fileHandle];
        [(NSMutableData*)*errorData appendData:[fileHandle readDataToEndOfFile]];
    }
    if(fileHandle = [outPipe fileHandleForReading]) {
        [[NSNotificationCenter defaultCenter] removeObserver:*outData name:NSFileHandleDataAvailableNotification object:fileHandle];
        [(NSMutableData*)*outData appendData:[fileHandle readDataToEndOfFile]];
    }
    
Exit:
    [[inPipe fileHandleForReading] closeFile];
    [[inPipe fileHandleForWriting] closeFile];
    [[outPipe fileHandleForReading] closeFile];
    [[outPipe fileHandleForWriting] closeFile];
    [[errorPipe fileHandleForReading] closeFile];
    [[errorPipe fileHandleForWriting] closeFile];
    
    return (task ? [task terminationStatus] : -1);
}
 
+ (NSURL*) urlFromString:(NSString*)string withCompositionURL:(NSURL*)compositionURL
{
    NSURL*                  url = nil;
    CFURLRef                urlRef;
    CFStringRef             stringRef;
    
    if([string length]) {
        /* Do we have a patch relative to the user directory? */
        if([string characterAtIndex:0] == '~')
        url = [NSURL fileURLWithPath:[string stringByExpandingTildeInPath]];
        /* Do we have an absolute path? */
        else if([string characterAtIndex:0] == '/')
        url = [NSURL fileURLWithPath:string];
        else {
            url = [NSURL URLWithString:string];
            /* Do we have a relative URL? */
            if([url scheme] == nil) {
                url = nil;
                if(compositionURL && (urlRef = CFURLCreateCopyDeletingLastPathComponent(kCFAllocatorDefault, (CFURLRef)compositionURL))) {
                    if(stringRef = CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (CFStringRef)string, NULL, NULL, kCFStringEncodingUTF8)) {
                        url = [(id)CFMakeCollectable(CFURLCreateWithString(kCFAllocatorDefault, stringRef, urlRef)) autorelease];
                        CFRelease(stringRef);
                    }
                    CFRelease(urlRef);
                }
            }
        }
    }
    
    return url;
}
 
+ (NSArray*) arrayFromSQLiteResult:(NSString*)result
{
    NSMutableArray*         array = [NSMutableArray array];
    NSScanner*              scanner;
    NSString*               line;
    NSMutableDictionary*    dictionary;
    NSRange                 range;
    
    /* Scan the result string in "line" mode and convert it to an array of dictionaries */
    scanner = [[NSScanner alloc] initWithString:result];
    [scanner setCharactersToBeSkipped:nil];
    while(![scanner isAtEnd]) {
        dictionary = [NSMutableDictionary new];
        while(1) {
            [scanner scanCharactersFromSet:[NSCharacterSet whitespaceCharacterSet] intoString:NULL];
            if(![scanner scanUpToString:@"\n" intoString:&line])
            break;
            
            range = [line rangeOfString:@" = "];
            if(range.location != NSNotFound)
            [dictionary setObject:[line substringWithRange:NSMakeRange(range.location + range.length, [line length] - range.location - range.length)] forKey:[line substringWithRange:NSMakeRange(0, range.location)]];
            
            if(![scanner isAtEnd])
            [scanner setScanLocation:([scanner scanLocation] + 1)];
        }
        if([dictionary count])
        [array addObject:dictionary];
        [dictionary release];
        
        if(![scanner scanString:@"\n" intoString:NULL])
        break;
    }
    [scanner release];
    
    return array;
}
 
- (BOOL) execute:(id<QCPlugInContext>)context atTime:(NSTimeInterval)time withArguments:(NSDictionary*)arguments
{
    NSURL*                  databaseURL = [SQLiteQueryPlugIn urlFromString:self.inputDataBasePath withCompositionURL:[context compositionURL]];
    NSTask*                 task;
    NSMutableArray*         args;
    NSUInteger              i;
    NSData*                 outData;
    int                     status;
    NSString*               string;
    
    /* Make sure we have a valid database URL and a valid query */
    if(![databaseURL isFileURL] || ![self.inputQueryString length]) {
        self.outputResultStructure = nil;
        return YES;
    }
    
    /* Create task */
    task = [NSTask new];
    [task setLaunchPath:@"/usr/bin/sqlite3"];
    [task setArguments:[NSArray arrayWithObject:[databaseURL path]]];
    
    /* Execute task */
    if([self _runTask:task inData:[[@".mode line\n" stringByAppendingString:self.inputQueryString] dataUsingEncoding:NSUTF8StringEncoding] outData:&outData errorData:NULL] == 0) {
        if([outData length]) {
            string = [[NSString alloc] initWithBytes:[outData bytes] length:([outData length] - 1) encoding:NSUTF8StringEncoding];
            self.outputResultStructure = [SQLiteQueryPlugIn arrayFromSQLiteResult:string];
            [string release];
        }
        else
        self.outputResultStructure = [NSArray array];
    }
    else {
        [context logMessage:@"SQLite Error: %@", ([outData length] ? [[[NSString alloc] initWithBytes:[outData bytes] length:([outData length] - 1) encoding:NSUTF8StringEncoding] autorelease] : nil)];
        self.outputResultStructure = nil;
    }
    
    /* Destroy task */
    [task release];
    
    return YES;
}
 
@end


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