Re: [Hessianobjc-user] support for hessian-2 decoding

[Byron W. <by...@bl...>]

thanks Tore you rock! I'll patch and add some unit tests around this  
when I get a chance. I'll take a closer look but is this compatible  
with the 1.0 version (at first glance it mostly does look compatible)?  
I'll need to decide on whether to branch or allow support for the 1.0  
and 2.0 protocol.

thanks again,
Byron

On May 14, 2008, at 11:08 AM, Tore Halset wrote:

> Hello.
>
> I have implemented support for decoding of the new hessian-2  
> protocol. The patch is attached. It may not be complete for all  
> datatypes, but works fine so far in my application.
>
> Things to note:
> * It is tested against a hessian-3.1.6 server
> * hessian-3.1.6 has a bug in its enum encoding that this patch has a  
> simple workaround for. When/if the bug is fixed in the java  
> implementation, the workaround must be removed. See http://bugs.caucho.com/view.php?id=2662
> * ref-handling has been improved. The object is now alloc'ed before  
> adding to the refArray. Before this fix, getting a reffed object  
> would always result in a NSDictionary, not the real object.
>
> Things to do:
> * more data types. I think compact double/float/binary is missing.
> * fix byte order stuff for iPhone.
>
> Regards,
> - Tore.
> <hessianobjc.patch>
>
>
>
>
> Index: BBSHessianDecoder.h
> ===================================================================
> --- BBSHessianDecoder.h	(revision 92)
> +++ BBSHessianDecoder.h	(working copy)
> @@ -24,6 +24,10 @@
>     NSInputStream * dataInputStream;
>     NSMutableDictionary * classMapping;
>     NSMutableArray * refArray;
> +    NSMutableArray * classDef;
> +    NSMutableArray * typeMap;
> +    NSMutableArray * objectDefinitionMap;
> +    NSMutableDictionary * fieldsByTypeName;
> }
>
> /** Static method that decodes an object encoded in Hessian binary  
> protocol and returns the object value.
> Index: BBSHessianMapDecoder.m
> ===================================================================
> --- BBSHessianMapDecoder.m	(revision 92)
> +++ BBSHessianMapDecoder.m	(working copy)
> @@ -110,8 +110,10 @@
>     return YES;
> }
>
> +- (BOOL)containsValueForKey:(NSString *)key {
> +    return [[hessianMap allKeys] containsObject:key];
> +}
>
> -
> - (void) dealloc {
>     [hessianMap release];
>     hessianMap = nil;
> Index: BBSHessianDecoder.m
> ===================================================================
> --- BBSHessianDecoder.m	(revision 92)
> +++ BBSHessianDecoder.m	(working copy)
> @@ -27,18 +27,24 @@
> - (int) decodeStringLength;
> - (NSString *) decodeXml:(uint8_t) startCode;
> - (NSString *) decodeString:(uint8_t) startCode;
> -- (NSString *) decodeStringChunk;
> +- (NSString *) decodeStringChunk:(int) len;
> +- (NSString *) decodeCompactString;
> - (NSNumber *) decodeInt;
> +- (NSNumber *) decodeIntForCode:(uint8_t) startCode;
> +- (id) allocObjectWithType:(NSMutableDictionary *)dict andType: 
> (NSString *)type;
> /** Return an NSDictionary or a class instance if a mapping for this  
> "map" is available */
> - (id) decodeMap;
> -- (NSArray * ) decodeList;
> +- (NSArray * ) decodeList:(uint8_t) startCode;
> - (NSNumber *) decodeLong;
> - (NSNumber *) decodeDouble;
> - (NSDate *) decodeDate;
> - (NSData *) decodeByteChunks;
> - (NSData *) decodeBytes;
> - (NSError *) decodeFault;
> -- (id) decodeRef;
> +- (void) addToRefArray:(id) val;
> +- (id) decodeRef:(uint8_t) startCode;
> +- (void) decodeCompactObjectHeader;
> +- (id) decodeCompactObject;
>
> @end
>
> @@ -54,6 +60,10 @@
>     if((self = [super init]) != nil) {
>         classMapping = [[NSMutableDictionary dictionary] retain];
>         refArray = [[NSMutableArray array] retain];
> +        classDef = [[NSMutableArray array] retain];
> +        typeMap = [[NSMutableArray array] retain];
> +        objectDefinitionMap = [[NSMutableArray array] retain];
> +        fieldsByTypeName = [[NSMutableDictionary dictionary] retain];
>     }
>     return self;
> }
> @@ -107,6 +117,14 @@
>     dataInputStream = nil;
>     [refArray release];
>     refArray = nil;
> +    [classDef release];
> +    classDef = nil;
> +    [typeMap release];
> +    typeMap = nil;
> +    [objectDefinitionMap release];
> +    objectDefinitionMap = nil;
> +    [fieldsByTypeName release];
> +    fieldsByTypeName = nil;
>     [super dealloc];
> }
> @end
> @@ -121,7 +139,7 @@
>        return [self decodeObjectForCode:objectTag];
>     }
>     else {
> -        NSLog(@"no data available");
> +        NSLog(@"ERROR: no data available");
>     }
>     return obj;
> }
> @@ -137,17 +155,38 @@
>         case 'd': obj = [self decodeDate];break;
>         case 'D': obj = [self decodeDouble];break;
>         case 'f': obj = [self decodeFault] ; break;
> -        case 'I': obj = [self decodeInt]; break;
> -        case 'V': obj = [self decodeList]; break;
> +        case 'I': obj = [self decodeIntForCode:code]; break;
> +        case 'v': obj = [self decodeList:code]; break;
> +        case 'V': obj = [self decodeList:code]; break;
>         case 'L': obj = [self decodeLong] ;break;
>         case 'M': obj = [self decodeMap]; break;
>         case 'N': obj = nil ;break;
> -        case 'R': obj = [self decodeRef];break;
> -        case 's': obj = [self decodeString:'s'];break;
> -        case 'S': obj = [self decodeString:'S'];break;
> +        case 'o': obj = [self decodeCompactObject]; break;
> +        case 'O': [self decodeCompactObjectHeader] ; obj = [self  
> decodeObject]; break;
> +        case 'R': obj = [self decodeRef:code];break;
> +        case 0x4a: obj = [self decodeRef:code];break;
> +        case 0x4b: obj = [self decodeRef:code];break;
> +        case 's': obj = [self decodeString:code];break;
> +        case 'S': obj = [self decodeString:code];break;
>         case 'x': obj = [self decodeXml:'x'];break;
>         case 'X': obj = [self decodeXml:'X'];break;
>         default:  {
> +
> +            // TODO: fix. something fishy with the int type here
> +            if ((code >= 0x00)&&(code <= 0x1f)) {
> +                return [self decodeStringChunk:code];
> +            }
> +            if ((code >= 0x80)&&(code <= 0xbf)) {
> +                return [self decodeIntForCode:code];
> +            }
> +            if ((code >= 0xc0)&&(code <= 0xcf)) {
> +                return [self decodeIntForCode:code];
> +            }
> +            if ((code >= 0xd0)&&(code <= 0xd7)) {
> +                return [self decodeIntForCode:code];
> +            }
> +
> +
>             NSDictionary * userInfo = [NSDictionary  
> dictionaryWithObject:[NSString stringWithFormat:@"Unknown tag  
> returned %c",code]
>                                                                    
> forKey:NSLocalizedDescriptionKey];
>             obj = [NSError errorWithDomain:BBSHessianObjCError
> @@ -162,11 +201,11 @@
> - (NSString *) decodeXml:(uint8_t) startCode {
>     NSMutableString * xmlString = [NSMutableString string];
>     while(startCode == 'x') { //decode chunks
> -        [xmlString appendString:[self decodeStringChunk]];
> +        [xmlString appendString:[self decodeString:'S']];
>         [dataInputStream read:&startCode maxLength:1];
>     }
>     if(startCode == 'X') {
> -        [xmlString appendString:[self decodeStringChunk]];
> +        [xmlString appendString:[self decodeString:'S']];
>     }
>     else {
>         NSLog(@"expected 'X' for last xml chunk");
> @@ -174,8 +213,7 @@
>     return xmlString;
> }
>
> -- (NSString *) decodeStringChunk {
> -    int len = [self decodeStringLength];
> +- (NSString *) decodeStringChunk:(int) len {
>     if(len == 0) {
>         return @"";
>     }
> @@ -194,63 +232,157 @@
> }
>
> - (NSString *) decodeString:(uint8_t) startCode {
> +    int stringLength = 0;
>
> +    // Strings with length less than 32 may be encoded with a  
> single octet
> +    if (startCode < 32) {
> +        stringLength = startCode;
> +        return [self decodeStringChunk:stringLength];
> +    }
> +
>     NSMutableString * retString = [NSMutableString string];
>     while(startCode == 's') { //decode chunks
> -        [retString appendString:[self decodeStringChunk]];
> +        stringLength = [self decodeStringLength];
> +        if(stringLength == 0) {
> +            NSLog(@"ERROR: why have a string chunk of lenght 0?");
> +            break;
> +        }
> +        [retString appendString:[self  
> decodeStringChunk:stringLength]];
>         [dataInputStream read:&startCode maxLength:1];
>     }
>     if(startCode == 'S') {
> -        [retString appendString:[self decodeStringChunk]];
> +        stringLength = [self decodeStringLength];
> +        [retString appendString:[self  
> decodeStringChunk:stringLength]];
>     }
>     else {
> -        NSLog(@"expected 'S' for last string chunk");
> +        NSLog(@"ERROR: expected 'S' for last string chunk");
>     }
>     return retString;
> }
>
> +- (NSString *) decodeCompactString {
> +    uint8_t startCode = 'e';
> +    [dataInputStream read:&startCode maxLength:1];
> +
> +    // check if we should fall back to old
> +    if ((startCode == 's')||(startCode == 'S')) {
> +        return [self decodeString:startCode];
> +    }
> +
> +    int len  = 0;
> +    if (startCode < 32) {
> +        len = startCode;
> +    } else {
> +        len = [[self decodeIntForCode:startCode] intValue];
> +    }
> +    return [self decodeStringChunk:len];
> +}
> +
> - (NSNumber *) decodeInt {
> -    SInt32 val = 0;
> -    if([dataInputStream hasBytesAvailable]) {
> -       [dataInputStream read:(uint8_t *)&val maxLength:4];
> -       val = EndianS32_BtoN(val);
> -       return [NSNumber numberWithInt:val];
> +    return [self decodeIntForCode:'I'];
> +}
> +
> +- (NSNumber *) decodeIntForCode:(uint8_t) startCode {
> +
> +    if (startCode == 'I') {
> +        SInt32 val = 0;
> +        if([dataInputStream hasBytesAvailable]) {
> +           [dataInputStream read:(uint8_t *)&val maxLength:4];
> +           val = EndianS32_BtoN(val);
> +           return [NSNumber numberWithInt:val];
> +        }
> +        return nil;
>     }
> +
> +    NSNumber *val = nil;
> +    if ((startCode >= 0x80)&&(startCode <= 0xbf)) {
> +        // compact single octet integer
> +        val = [NSNumber numberWithInt:(startCode - 0x90)];
> +    } else if ((startCode >= 0xc0)&&(startCode <= 0xcf)) {
> +        // compact two octet integer
> +        uint8_t b0 = 0;
> +        [dataInputStream read:&b0 maxLength:1];
> +        val = [NSNumber numberWithInt:(((startCode - 0xc8) << 8) +  
> b0)];
> +    } else if ((startCode >= 0xd0)&&(startCode <= 0xd7)) {
> +        // compact three octet integer
> +        uint8_t b0 = 0;
> +        uint8_t b1 = 0;
> +        [dataInputStream read:&b0 maxLength:1];
> +        [dataInputStream read:&b1 maxLength:1];
> +        val = [NSNumber numberWithInt:(((startCode - 0xd4) << 16) +  
> (b1 << 8) + b0)];
> +    } else {
> +        NSLog(@"ERROR: unknown int start code %i", startCode);
> +    }
> +    return val;
> +}
> +
> +- (id) allocObjectWithType:(NSMutableDictionary *)dict andType: 
> (NSString *)type {
> +
> +    if((!type) || ([type length] == 0)) {
> +        return nil;
> +    }
> +
> +    Class mappedClass = nil;
> +    mappedClass  = [self classForClassName:type];
> +    if(!mappedClass) { //try the global mapping
> +        mappedClass = [BBSHessianDecoder classForClassName:type];
> +    }
> +    if(mappedClass) {
> +        [dict setObject:NSStringFromClass(mappedClass)  
> forKey:BBSHessianClassNameKey];
> +    }
> +    else {
> +        // not a mapped class. remember hessian class name
> +        [dict setObject:type forKey:BBSHessianClassNameKey];
> +    }
> +
> +    if(mappedClass) {
> +        // a mapped class, user map decoder to init object
> +        return [mappedClass alloc];
> +    }
>     return nil;
> }
>
> +
> - (id) decodeMap {
>     id dict = [NSMutableDictionary dictionary];
> -    //add the pointer to the ref array and not the actually value.
> -    [refArray addObject:[NSValue valueWithPointer:dict]];
> -    Class mappedClass = nil;
>     uint8_t objectTag = 'e';
> +    NSString *type = nil;
>     if([dataInputStream hasBytesAvailable]) {
>         [dataInputStream read:&objectTag maxLength:1];
>         if(objectTag == 't') {
>             //decode the type of map, maps with a type are objects  
> of a particular class
>             //if we have a class mapping for this then
> -            NSString * type = [self decodeString:'S'];
> -            if(type != nil && [type length] > 0) {
> -                mappedClass  = [self classForClassName:type];
> -                if(!mappedClass) { //try the global mapping
> -                    mappedClass = [BBSHessianDecoder  
> classForClassName:type];
> -                }
> -                if(mappedClass) {
> -                    [dict setObject:NSStringFromClass(mappedClass)  
> forKey:BBSHessianClassNameKey];
> -                }
> -                else {
> -                     // not a mapped class. remember hessian class  
> name
> -                    [dict setObject:type  
> forKey:BBSHessianClassNameKey];
> -                }
> -            }
> -        }
> +            type = [self decodeString:'S'];
> +            [typeMap addObject:type];
> +        } else if (objectTag == 0x75) {
> +            // type ref.
> +            [dataInputStream read:&objectTag maxLength:1];
> +            int typeRef = [[self decodeIntForCode:objectTag]  
> intValue];
> +            type = [typeMap objectAtIndex:typeRef];
> +        }
>
> +        id val = [self allocObjectWithType:dict andType:type];
> +        if(val) {
> +            [self addToRefArray:val];
> +        } else {
> +            [self addToRefArray:dict];
> +        }
> +
>         [dataInputStream read:&objectTag maxLength:1];
>          while(objectTag != 'z' && [dataInputStream  
> hasBytesAvailable]) {
>             //read the type
>             id key = [self decodeObjectForCode:objectTag];
>             [dataInputStream read:&objectTag maxLength:1];
> +            if(objectTag == 'z') {
> +                // java enum are serialized by hessian using a Map  
> with a single key, but no value
> +                [dict setObject:[NSNull null] forKey:key];
> +
> +                // special case for enum. looks like a bug in the  
> java implementation
> +                // http://bugs.caucho.com/view.php?id=2662
> +                NSLog(@"DEBUG: enum encoded as map should not be  
> added to refArray. remove");
> +                [refArray removeLastObject];
> +                break;
> +            }
>             id value = [self decodeObjectForCode:objectTag];
>             if(key != nil) {
>                 if(value == nil) {
> @@ -261,13 +393,14 @@
>             [dataInputStream read:&objectTag maxLength:1];
>         }
>
> -        if(mappedClass) {
> -            //a mapped class, user map decoder to init object
> +        if(val) {
>             BBSHessianMapDecoder * mapDecoder =  
> [[[BBSHessianMapDecoder alloc] initForReadingWithDictionary:dict]  
> autorelease];
> -            id obj = [[[mappedClass alloc]  
> initWithCoder:mapDecoder] autorelease];
> -            return obj;
> +            val = [[val initWithCoder:mapDecoder] autorelease];
> +            return val;
> +        } else {
> +            return dict;
>         }
> -        return dict;
> +
>     }
>     else {
>         NSLog(@"no data available");
> @@ -275,45 +408,78 @@
>     return nil;
> }
>
> -- (NSArray * ) decodeList {
> +- (NSArray * ) decodeList:(uint8_t) startCode {
> +
> +    NSString *type = nil;
> +    int length = -1;
> +
> +    if (startCode == 'v') {
> +        uint8_t st = 'e';
> +
> +        [dataInputStream read:&st maxLength:1];
> +        int typeRef = [[self decodeIntForCode:st] intValue];
> +        type = [typeMap objectAtIndex:typeRef];
> +
> +        [dataInputStream read:&st maxLength:1];
> +        length = [[self decodeIntForCode:st] intValue];
> +    }
> +
>     NSMutableArray * array = [NSMutableArray array];
> -    [refArray addObject:[NSValue valueWithPointer:array]];
> +    [self addToRefArray:array];
>     uint8_t objectTag = 'e';
> -    if([dataInputStream hasBytesAvailable]) {
> -        //type and length might be available, accord to the spec
> -        //type comes first then the length.
> -        [dataInputStream read:&objectTag maxLength:1];
> -        if(objectTag == 't') {
> -            //decode the type of list, we don't really care about  
> this
> -            //because we are using an NSArray
> -            NSString * type = [self decodeString:'S'];
> -            //if type exists then check for length also
> -            [dataInputStream read:&objectTag maxLength:1];
> -            #pragma unused (type)
> -        }
> +    uint8_t st = 'e';
> +
> +    // handle 'v' list with zero length as it does not end with a z
> +    if(length == 0) {
> +        return array;
> +    }
> +
> +    [dataInputStream read:&objectTag maxLength:1];
> +    while(objectTag != 'z' && [dataInputStream hasBytesAvailable]) {
> +
> +        switch(objectTag) {
> +            case 't':
> +                // type
> +                type = [self decodeString:'S'];
> +                [typeMap addObject:type];
> +                [dataInputStream read:&objectTag maxLength:1];
> +                continue;
> +            case 0x75:
> +                // type ref.
> +                st = 'e';
> +                [dataInputStream read:&st maxLength:1];
> +                int typeRef = [[self decodeIntForCode:st] intValue];
> +                type = [typeMap objectAtIndex:typeRef];
> +                continue;
> +            case 0x6e:
> +                st = 'e';
> +                [dataInputStream read:&st maxLength:1];
> +                length = [[self decodeIntForCode:st] intValue];
> +                [dataInputStream read:&objectTag maxLength:1];
> +                continue;
> +            case 'l':
> +                length = [[self decodeInt] intValue];
> +                [dataInputStream read:&objectTag maxLength:1];
> +                continue;
> +        }
> +
> +        id obj = [self decodeObjectForCode:objectTag];
> +        if(!obj) {
> +            obj = [NSNull null];
> +        }
> +        [array addObject:obj];
>
> -        if(objectTag == 'l') {
> -            //length of object in reply, gobble it up because we  
> don't really
> -            //care about this because we're creating an NSArray
> -            NSNumber * len = [self decodeInt];
> -            #pragma unused (len)
> -            //length exists, read in the next tag
> -            [dataInputStream read:&objectTag maxLength:1];
> +        // 'v' list does not end with a z
> +        if ((startCode == 'v') && (length == [array count])) {
> +            break;
>         }
> -
> -        while(objectTag != 'z' && [dataInputStream  
> hasBytesAvailable]) {
> -            id obj = [self decodeObjectForCode:objectTag];
> -            if(obj) {
> -                [array addObject:obj];
> -            }
> -            [dataInputStream read:&objectTag maxLength:1];
> -         }
> -         return array;
> -    }
> -    return nil;
> +
> +        [dataInputStream read:&objectTag maxLength:1];
> +     }
> +
> +     return array;
> }
>
> -
> - (NSNumber *) decodeLong {
>     SInt64 aLong = 0;
>     if([dataInputStream hasBytesAvailable]) {
> @@ -473,11 +639,93 @@
>
> }
>
> -- (id) decodeRef {   -    int ref = [[self decodeInt] intValue];
> -    return [[refArray objectAtIndex:ref] pointerValue];
> +- (void) addToRefArray:(id) val
> +{
> +    [refArray addObject:[NSValue valueWithPointer:val]];
> }
>
> +- (id) decodeRef:(uint8_t) startCode {
> +    int ref = 0;
> +    uint8_t helper = 'e';
> +    switch(startCode) {
> +        case 'R':
> +            ref = [[self decodeInt] intValue];
> +            break;
> +        case 0x4a:
> +            helper = 0;
> +            [dataInputStream read:&helper maxLength:1];
> +            ref = helper;
> +            break;
> +        case 0x4b:
> +            helper = 0;
> +            [dataInputStream read:&helper maxLength:1];
> +            ref = (helper << 8);
> +            helper = 0;
> +            [dataInputStream read:&helper maxLength:1];
> +            ref = ref + helper;
> +            break;
> +    }
> +    NSObject *val = [[refArray objectAtIndex:ref] pointerValue];
> +    return val;
> +}
> +
> +- (void) decodeCompactObjectHeader {
> +    NSString *type = [self decodeCompactString];
> +    [objectDefinitionMap addObject:type];
> +
> +    uint8_t aCode = 'e';
> +    [dataInputStream read:&aCode maxLength:1];
> +    int numOfFields = [[self decodeIntForCode:aCode] intValue];
> +
> +    NSMutableArray *fields = [NSMutableArray array];
> +    while(numOfFields-- > 0) {
> +        NSString *fieldName = [self decodeCompactString];
> +        [fields addObject:fieldName];
> +    }
> +    [fieldsByTypeName setObject:[NSArray arrayWithArray:fields]  
> forKey:type];
> +}
> +
> +- (id) decodeCompactObject {
> +
> +    uint8_t aCode = 'e';
> +    [dataInputStream read:&aCode maxLength:1];
> +    int typeIdx = [[self decodeIntForCode:aCode] intValue];
> +    NSString *type = [objectDefinitionMap objectAtIndex:typeIdx];
> +    NSArray *fields = [fieldsByTypeName objectForKey:type];
> +
> +    if(!fields) {
> +        NSLog(@"ERROR: could not find fields for type %@", type);
> +    }
> +
> +    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
> +
> +    id val = [self allocObjectWithType:dict andType:type];
> +    if(val) {
> +        [self addToRefArray:val];
> +    } else {
> +        [self addToRefArray:dict];
> +    }
> +
> +   unsigned int i = 0;
> +   for (i = 0; i < [fields count]; i++) {
> +    NSString *fieldName = [fields objectAtIndex:i];
> +
> +    id fieldValue = [self decodeObject];
> +    if (!fieldValue) {
> +        fieldValue = [NSNull null];
> +    }
> +    [dict setObject:fieldValue forKey:fieldName];
> +   }
> +
> +   if(val) {
> +        BBSHessianMapDecoder * mapDecoder = [[[BBSHessianMapDecoder  
> alloc] initForReadingWithDictionary:dict] autorelease];
> +        val = [[val initWithCoder:mapDecoder] autorelease];
> +        return val;
> +    } else {
> +        return dict;
> +    }
> +}
> +
> - (int) decodeStringLength {
>     UInt16 len = 0;
>     if([dataInputStream hasBytesAvailable]) {
> Index: BBSHessianCall.m
> ===================================================================
> --- BBSHessianCall.m	(revision 92)
> +++ BBSHessianCall.m	(working copy)
> @@ -83,7 +83,11 @@
>
> - (void) startCall {
>     char call = 'c';
> -    char char1 = 0x01;
> +    // 1.0
> +    //char char1 = 0x01;
> +    //char char0 = 0x00;
> +    // 2.0
> +    char char1 = 0x02;
>     char char0 = 0x00;
>     char m = 'm';
>     /*char H = 'H';
>
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