TiDataStream.m

/**
 * Appcelerator Titanium Mobile
 * Copyright (c) 2009-2011 by Appcelerator, Inc. All Rights Reserved.
 * Licensed under the terms of the Apache Public License
 * Please see the LICENSE included with this distribution for details.
 */

#import "TiDataStream.h"

@implementation TiDataStream
@synthesize data, mode;

#pragma mark Internals

-(id)init
{
    if (self = [super init]) {
        data = nil;
        mode = TI_READ;
        position = 0;
    }
    return self;
}

-(void)_destroy
{
    RELEASE_TO_NIL(data);
    [super _destroy];
}

#pragma mark I/O Stream implementation

-(int)readToBuffer:(TiBuffer *)toBuffer offset:(int)offset length:(int)length callback:(KrollCallback *)callback
{
    if (data == nil) {
        [self throwException:@"TiStreamException"
                   subreason:@"Attempt to read off of closed/nil data stream"
                    location:CODELOCATION];
    }
    
    // TODO: Codify in read() and write() when we have every method calling the wrappers... like it should.
    if ([[toBuffer data] length] == 0  && length != 0) {
        if (callback != nil) {
            NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",NUMINT(0),@"bytesProcessed", NUMINT(0),@"errorState",@"",@"errorDescription", nil];
            [self _fireEventToListener:@"read" withObject:event listener:callback thisObject:nil];
        }
        return 0;
    }
    
    // TODO: Throw exception, or no-op?  For now, assume NO-OP
    if (position >= [data length]) {
        if (callback != nil) {
            NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",NUMINT(-1),@"bytesProcessed",NUMINT(0),@"errorState",@"",@"errorDescription", nil];
            [self _fireEventToListener:@"read" withObject:event listener:callback thisObject:nil];
        }        
        return -1;
    }
    
    // TODO: This is a dumb convention. Go back and fix it.
    if (length == 0) {
        length = [data length];
        [toBuffer setLength:NUMINT(length)];
    }
    const void* bytes = [data bytes];
    void* toBytes = [[toBuffer data] mutableBytes];
   
    int bytesToWrite = MIN([data length] - position, length);
    memcpy(toBytes+offset, bytes+position, bytesToWrite);

    position += bytesToWrite;
    
    if (callback != nil) {
        NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",NUMINT(bytesToWrite),@"bytesProcessed",NUMINT(0),@"errorState",@"",@"errorDescription", nil];
        [self _fireEventToListener:@"read" withObject:event listener:callback thisObject:nil];
    }
    
    return bytesToWrite;
}

// TODO: Need to extend the data if we're writing past its current bounds
-(int)writeFromBuffer:(TiBuffer *)fromBuffer offset:(int)offset length:(int)length callback:(KrollCallback *)callback
{
    if (data == nil) {
        [self throwException:@"TiStreamException"
                   subreason:@"Attempt to write from closed/nil data stream"
                    location:CODELOCATION];
    }
    
    // Sanity check for mutable data (just in case...)
    if (![data isKindOfClass:[NSMutableData class]]) {
        NSString* errorStr = [NSString stringWithFormat:@"[ERROR] Attempt to write to unwritable stream"];
        DebugLog(errorStr);
        if (callback != nil) {
            NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",NUMINT(-1),@"bytesProcessed",errorStr,@"errorDescription",NUMINT(-1),@"errorState", nil];
            [self _fireEventToListener:@"write" withObject:event listener:callback thisObject:nil];
        }
        return -1;   
    }
    
    // TODO: Codify in read() and write() when we have every method calling the wrappers... like it should.
    if ([[fromBuffer data] length] == 0) {
        if (callback != nil) {
            NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",NUMINT(0),@"bytesProcessed",NUMINT(0),@"errorState",@"",@"errorDescription", nil];
            [self _fireEventToListener:@"write" withObject:event listener:callback thisObject:nil];
        }
        return 0;
    }
    
    // OK, even if we're working with NSData (and not NSMutableData) we have to cast away const here; we're going to assume that
    // even with immutable data (i.e. blob) if the user has specified WRITE or APPEND, they're OK with digging their own grave.
    NSMutableData* mutableData = (NSMutableData*)data;
    if (mode & TI_WRITE) {
        int overflow = length - ([data length] - position);
        if (overflow > 0) {
            [mutableData increaseLengthBy:overflow];
        }
        
        void* bytes = [mutableData mutableBytes];
        const void* fromBytes = [[fromBuffer data] bytes];
        
        memcpy(bytes+position, fromBytes+offset, length);
        position += length;        
    }
    else if (mode & TI_APPEND) {
        [mutableData appendData:[[fromBuffer data] subdataWithRange:NSMakeRange(offset,length)]];
        position = [data length];
    }

    
    if (callback != nil) {
        NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",NUMINT(length),@"bytesProcessed",NUMINT(0),@"errorState",@"",@"errorDescription",nil];
        [self _fireEventToListener:@"write" withObject:event listener:callback thisObject:nil];
    }
    
    return length;
}

-(int)writeToStream:(id<TiStreamInternal>)output chunkSize:(int)size callback:(KrollCallback *)callback
{
    if (data == nil) {
        [self throwException:@"TiStreamException"
                   subreason:@"Attempt to write from closed/nil data stream"
                    location:CODELOCATION];
    }
    
    int length = [data length];
    int totalBytes = 0;
    while (position < length) {
        TiBuffer* tempBuffer = [[[TiBuffer alloc] _initWithPageContext:[self executionContext]] autorelease];
        NSRange subdataRange = NSMakeRange(position,MIN(size,length-position));
        
        int bytesWritten = 0;
        @try {
			void* bytes = malloc(subdataRange.length);
			if (bytes == NULL) {
				[self throwException:TiExceptionMemoryFailure subreason:@"Failed to allocate for stream" location:CODELOCATION];
			}
			
			[data getBytes:bytes range:subdataRange];
			[tempBuffer setData:[NSMutableData dataWithBytesNoCopy:bytes length:subdataRange.length freeWhenDone:YES]];
			
            bytesWritten = [output writeFromBuffer:tempBuffer offset:0 length:subdataRange.length callback:nil];
        }
        @catch (NSException* e) {
            // TODO: We'll need some kind of information about:
            // 1. Error Code
            // 2. # bytes produced as part of the write
            // In the exception.
            if (callback != nil) {
                NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"fromStream",output,@"toStream",NUMINT(totalBytes),@"bytesWritten",[e reason],@"errorDescription", NUMINT(-1),@"errorState",nil];
                [self _fireEventToListener:@"writeToStream" withObject:event listener:callback thisObject:nil];
            }
            else {
                @throw e;
            }
        }
        if (bytesWritten == 0) {
            break;
        }
        
        totalBytes += bytesWritten;
        position += subdataRange.length;
    }
    
    if (callback != nil) {
        NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"fromStream",output,@"toStream",NUMINT(totalBytes),@"bytesProcessed",NUMINT(0),@"errorState",@"",@"errorDescription",nil];
        [self _fireEventToListener:@"writeToStream" withObject:event listener:callback thisObject:nil];
    }
    
    return totalBytes;
}

// We don't need the asynch hint
-(void)pumpToCallback:(KrollCallback *)callback chunkSize:(int)size asynch:(BOOL)asynch
{
    if (data == nil) {
        [self throwException:@"TiStreamException"
                   subreason:@"Attempt to write from closed/nil data stream"
                    location:CODELOCATION];
    }
    
    int totalBytes = 0;
    int bytesWritten = 0;
    int length = [data length];
    
    const void* source = [data bytes];
    while (position < length) {
        TiBuffer* tempBuffer = [[[TiBuffer alloc] _initWithPageContext:[self executionContext]] autorelease];

        int bytesToWrite = MIN(size, length-position);
        void* destination = malloc(bytesToWrite);
		if (destination == NULL) {
			NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",[NSNull null],@"buffer",NUMINT(-1),@"bytesProcessed",NUMINT(totalBytes),@"totalBytesProcessed", NUMINT(1),@"errorState",@"Memory allocation failure",@"errorDescription", nil];
			[self _fireEventToListener:@"pump" withObject:event listener:callback thisObject:nil];
			break;
		}
        memcpy(destination, source+position, bytesToWrite);
        [tempBuffer setData:[NSMutableData dataWithBytesNoCopy:destination length:bytesToWrite freeWhenDone:YES]];

        totalBytes += bytesToWrite;
        position += bytesToWrite;
        
        NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",tempBuffer,@"buffer",NUMINT(bytesToWrite),@"bytesProcessed",NUMINT(totalBytes),@"totalBytesProcessed", NUMINT(0),@"errorState",@"",@"errorDescription",nil];
        [self _fireEventToListener:@"pump" withObject:event listener:callback thisObject:nil];
    }
    
    // We've reached the end of the stream - so we need to pump the -1 EOF
    NSDictionary* event = [NSDictionary dictionaryWithObjectsAndKeys:self,@"source",[NSNull null],@"buffer",NUMINT(-1),@"bytesProcessed",NUMINT(totalBytes),@"totalBytesProcessed", NUMINT(0),@"errorState",@"",@"errorDescription", nil];
    [self _fireEventToListener:@"pump" withObject:event listener:callback thisObject:nil];
}

-(NSNumber*)isReadable:(id)_void
{
    return NUMBOOL(mode & TI_READ);
}

-(NSNumber*)isWritable:(id)_void
{
    return NUMBOOL(mode & (TI_WRITE | TI_APPEND));
}

-(void)close:(id)_void
{
    RELEASE_TO_NIL(data);
    position = 0;
}

@end