YAJLParser.m

//
//  YAJLParser.m
//  YAJL
//
//  Created by Gabriel Handford on 6/14/09.
//  Copyright 2009. All rights reserved.
//
//  Permission is hereby granted, free of charge, to any person
//  obtaining a copy of this software and associated documentation
//  files (the "Software"), to deal in the Software without
//  restriction, including without limitation the rights to use,
//  copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the
//  Software is furnished to do so, subject to the following
//  conditions:
//
//  The above copyright notice and this permission notice shall be
//  included in all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//  OTHER DEALINGS IN THE SOFTWARE.
//


#import "YAJLParser.h"

NSString *const YAJLErrorDomain = @"YAJLErrorDomain";
NSString *const YAJLParserException = @"YAJLParserException";
NSString *const YAJLParsingUnsupportedException = @"YAJLParsingUnsupportedException";

NSString *const YAJLParserValueKey = @"YAJLParserValueKey";

@interface YAJLParser ()
@property (retain, nonatomic) NSError *parserError;
@end


@interface YAJLParser (Private)
- (void)_add:(id)value;
- (void)_mapKey:(NSString *)key;

- (void)_startDictionary;
- (void)_endDictionary;

- (void)_startArray;
- (void)_endArray;

- (NSError *)_errorForStatus:(NSInteger)code message:(NSString *)message value:(NSString *)value;
- (void)_cancelWithErrorForStatus:(NSInteger)code message:(NSString *)message value:(NSString *)value;
@end


@implementation YAJLParser

@synthesize parserError=parserError_, delegate=delegate_, parserOptions=parserOptions_;

- (id)init {
  return [self initWithParserOptions:0];
}

- (id)initWithParserOptions:(YAJLParserOptions)parserOptions {
  if ((self = [super init])) {
    parserOptions_ = parserOptions;   
  }
  return self;
}

- (void)dealloc {
  if (handle_ != NULL) {
    yajl_free(handle_);
    handle_ = NULL;
  } 
  
  [parserError_ release];
  [super dealloc];
}

#pragma mark Error Helpers

- (NSError *)_errorForStatus:(NSInteger)code message:(NSString *)message value:(NSString *)value {
  NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithObject:message forKey:NSLocalizedDescriptionKey];
  if (value) [userInfo setObject:value forKey:YAJLParserValueKey];
  return [NSError errorWithDomain:YAJLErrorDomain code:code userInfo:userInfo];
}

- (void)_cancelWithErrorForStatus:(NSInteger)code message:(NSString *)message value:(NSString *)value {
  self.parserError = [self _errorForStatus:code message:message value:value];
}

#pragma mark YAJL Callbacks

int yajl_null(void *ctx) {
  [(id)ctx _add:[NSNull null]];
  return 1;
}

int yajl_boolean(void *ctx, int boolVal) {
  NSNumber *number = [[NSNumber alloc] initWithBool:(BOOL)boolVal];
  [(id)ctx _add:number];
  [number release];
  return 1;
}

// Instead of using yajl_integer, and yajl_double we use yajl_number and parse
// as double (or long long); This is to be more compliant since Javascript numbers are represented
// as double precision floating point, though JSON spec doesn't define a max value 
// and is up to the parser?

//int yajl_integer(void *ctx, long integerVal) {
//  [(id)ctx _add:[NSNumber numberWithLong:integerVal]];
//  return 1;
//}
//
//int yajl_double(void *ctx, double doubleVal) {
//  [(id)ctx _add:[NSNumber numberWithDouble:doubleVal]];
//  return 1;
//}

int ParseDouble(void *ctx, const char *buf, const char *numberVal, unsigned int numberLen) {
  double d = strtod((char *)buf, NULL);
  if ((d == HUGE_VAL || d == -HUGE_VAL) && errno == ERANGE) {
    NSString *s = [[NSString alloc] initWithBytes:numberVal length:numberLen encoding:NSUTF8StringEncoding];
    [(id)ctx _cancelWithErrorForStatus:YAJLParserErrorCodeDoubleOverflow message:[NSString stringWithFormat:@"double overflow on '%@'", s] value:s];
    [s release];
    return 0;
  }
  NSNumber *number = [[NSNumber alloc] initWithDouble:d];
  [(id)ctx _add:number];
  [number release];
  return 1;
}

int yajl_number(void *ctx, const char *numberVal, unsigned int numberLen) {
  char buf[numberLen+1];
  memcpy(buf, numberVal, numberLen);
  buf[numberLen] = 0;
  
  if (memchr(numberVal, '.', numberLen) || memchr(numberVal, 'e', numberLen) || memchr(numberVal, 'E', numberLen)) {
    return ParseDouble(ctx, buf, numberVal, numberLen);
  } else {
    long long i = strtoll((const char *) buf, NULL, 10);
    if ((i == LLONG_MIN || i == LLONG_MAX) && errno == ERANGE) {
      if (([(id)ctx parserOptions] & YAJLParserOptionsStrictPrecision) == YAJLParserOptionsStrictPrecision) {
        NSString *s = [[NSString alloc] initWithBytes:numberVal length:numberLen encoding:NSUTF8StringEncoding];
        [(id)ctx _cancelWithErrorForStatus:YAJLParserErrorCodeIntegerOverflow message:[NSString stringWithFormat:@"integer overflow on '%@'", s] value:s];
        [s release];
        return 0;
      } else {
        // If we integer overflow lets try double precision for HUGE_VAL > double > LLONG_MAX 
        return ParseDouble(ctx, buf, numberVal, numberLen);
      }
    }
    NSNumber *number = [[NSNumber alloc] initWithLongLong:i];
    [(id)ctx _add:number];
    [number release];
  }
  
  return 1;
}

int yajl_string(void *ctx, const unsigned char *stringVal, unsigned int stringLen) {
  NSString *s = [[NSString alloc] initWithBytes:stringVal length:stringLen encoding:NSUTF8StringEncoding];
  [(id)ctx _add:s];
  [s release];
  return 1;
}

int yajl_map_key(void *ctx, const unsigned char *stringVal, unsigned int stringLen) {
  NSString *s = [[NSString alloc] initWithBytes:stringVal length:stringLen encoding:NSUTF8StringEncoding];
  [(id)ctx _mapKey:s];
  [s release];
  return 1;
}

int yajl_start_map(void *ctx) {
  [(id)ctx _startDictionary];
  return 1;
}

int yajl_end_map(void *ctx) {
  [(id)ctx _endDictionary];
  return 1;
}

int yajl_start_array(void *ctx) {
  [(id)ctx _startArray];
  return 1;
}

int yajl_end_array(void *ctx) {
  [(id)ctx _endArray];
  return 1;
}

static yajl_callbacks callbacks = {
yajl_null,
yajl_boolean,
NULL, // yajl_integer (using yajl_number)
NULL, // yajl_double (using yajl_number)
yajl_number,
yajl_string,
yajl_start_map,
yajl_map_key,
yajl_end_map,
yajl_start_array,
yajl_end_array
};

#pragma mark -

- (void)_add:(id)value {
  [delegate_ parser:self didAdd:value];
}

- (void)_mapKey:(NSString *)key {
  [delegate_ parser:self didMapKey:key];
}

- (void)_startDictionary {
  [delegate_ parserDidStartDictionary:self];
}

- (void)_endDictionary {
  [delegate_ parserDidEndDictionary:self];
}

- (void)_startArray { 
  [delegate_ parserDidStartArray:self];
}

- (void)_endArray {
  [delegate_ parserDidEndArray:self];
}

- (YAJLParserStatus)parse:(NSData *)data {
  if (!handle_) {
    yajl_parser_config cfg = {
      ((parserOptions_ & YAJLParserOptionsAllowComments) ? 1 : 0), // allowComments: if nonzero, javascript style comments will be allowed in the input (both /* */ and //)
      ((parserOptions_ & YAJLParserOptionsCheckUTF8) ? 1 : 0)  // checkUTF8: if nonzero, invalid UTF8 strings will cause a parse error
    };
    
    handle_ = yajl_alloc(&callbacks, &cfg, NULL, self);
    if (!handle_) { 
      self.parserError = [self _errorForStatus:YAJLParserErrorCodeAllocError message:@"Unable to allocate YAJL handle" value:nil];
      return YAJLParserStatusError;
    } 
  }
  
  yajl_status status = yajl_parse(handle_, [data bytes], [data length]);
  if (status == yajl_status_client_canceled) {
    // We cancelled because we encountered an error here in the client;
    // and parserError should be already set
    NSAssert(self.parserError, @"Client cancelled, but we have no parserError set");
    return YAJLParserStatusError;
  } else if (status == yajl_status_error) {
    unsigned char *errorMessage = yajl_get_error(handle_, 1, [data bytes], [data length]);
    NSString *errorString = [NSString stringWithUTF8String:(char *)errorMessage];
    self.parserError = [self _errorForStatus:status message:errorString value:nil];
    yajl_free_error(handle_, errorMessage);
    return YAJLParserStatusError;
  } else if (status == yajl_status_insufficient_data) {
    return YAJLParserStatusInsufficientData;
  } else if (status == yajl_status_ok) {
    return YAJLParserStatusOK;
  } else {
    self.parserError = [self _errorForStatus:status message:[NSString stringWithFormat:@"Unexpected status %d", status] value:nil];
    return YAJLParserStatusError;
  }
}

@end